WO2014188945A1

WO2014188945A1 - Manufacturing method for wiring board

Info

Publication number: WO2014188945A1
Application number: PCT/JP2014/062928
Authority: WO
Inventors: 豊田　裕二; 寛彦後閑; 川合　宣行; 中川　邦弘
Original assignee: 三菱製紙株式会社
Priority date: 2013-05-22
Filing date: 2014-05-15
Publication date: 2014-11-27
Also published as: JP2017183744A; JP2018139318A; CN107969077B; KR20160013007A; TWI625996B; CN107969076A; CN107969077A; CN107969076B; TW201509256A; CN107979919A; JP6514807B2; JP2015216332A; CN107979919B; CN105210460B; CN105210460A; KR102076479B1; JP6416323B2; JP6224520B2

Abstract

The present invention is a manufacturing method for a wiring board, which is characterized in including steps for: (A) forming solder mask layers of different thickness on both surfaces of a circuit board; (C1) for a solder mask layer of a first surface which is of thinner thickness than a solder mask layer of a second surface, exposing portions other than areas to be thinned in step (B), which is a later step; (C2) for the solder mask layer of the second surface, exposing portions other than areas to be developed in step (D), which is a later step; (B) by way of a thin-film processing solution, thinning the solder mask layer of the first surface of the non-exposed portions until reaching thicknesses that are less than or equal to connection pads; (C3) for the solder mask layer of the first surface, exposing the area-portions that have been thinned in step (B); and (D) removing, by way of a developer solution, the solder mask layers of the non-exposed portions of the second surface.

Description

Wiring board manufacturing method

The present invention relates to a method for manufacturing a wiring board, and more particularly to a method for manufacturing a wiring board having a plurality of connection pads for connecting electronic components such as a semiconductor chip and other printed wiring boards.

A wiring board inside various electric devices has a circuit board having an insulating layer and a conductor wiring formed on the surface of the insulating layer on one or both surfaces thereof. Also, a solder resist layer is formed on the entire surface of the circuit board of the wiring board so that the solder does not adhere to the conductor wiring that does not require soldering. The solder resist layer plays a role of preventing the conductor wiring from being oxidized, electrically insulating, and protecting from the external environment.

When mounting electronic components such as semiconductor chips on a wiring board, a large number of connection pads are formed on the surface of the wiring board for connecting to electronic components such as semiconductor chips and other printed wiring boards. . The connection pad is produced by exposing the whole or part of the conductor wiring on the surface of the circuit board from the solder resist layer. In recent years, the density of the connection pads has been increased, and the pitch between the connection pads to be arranged is narrow, for example, there is a narrow pitch of 50 μm or less.

As a method of mounting electronic components on connection pads arranged at high density, there is a method by flip chip connection. In flip chip connection, a part of the connection pad for connecting an electronic component provided on the wiring board is exposed corresponding to the arrangement of the electrode terminals of the electronic component, and the exposed part of the connection pad for connecting the electronic component and the electronic component are connected. It means that the electrode terminals are opposed to each other and electrically connected via solder bumps.

For the connection pad, the solder resist layer is partially removed to expose the whole or part of the connection pad surface, and the solder mask layer is partially removed to remove the connection pad. There is an NSMD (Non Solder Mask Defined) structure that is completely exposed.

FIG. 1A is a schematic cross-sectional view showing an example of a wiring board having an SMD structure. A solder resist layer 2 is formed on the surface of the circuit board 1 provided with the conductor wiring 7 and the connection pads 3 which are part of the conductor wiring on the surface of the insulating layer 8. The periphery of the connection pad 3 is covered with the solder resist layer 2. Therefore, there is an advantage that peeling of the connection pad 3 due to mechanical impact and disconnection of the neck portion in the lead-out wiring from the connection pad 3 are unlikely to occur. On the other hand, in order to securely fix the electrical connection between the electrode terminal of the electronic component and the corresponding connection pad 3, it is necessary to secure the amount of solder necessary for the joint formed on the exposed surface of the connection pad 3. Since the size of the connection pad 3 is increased, it is difficult to meet the demand for higher density of the connection pad 3 due to the downsizing and higher performance of electronic components.

FIG. 1B is a schematic cross-sectional view showing an example of a wiring board having an NSMD structure. A solder resist layer 2 is formed on the surface of the circuit board 1 provided with the conductor wiring 7 and the connection pads 3 which are part of the conductor wiring on the surface of the insulating layer 8. A plurality of connection pads 3 are arranged in the same opening of the solder resist layer 2, and these connection pads 3 are exposed from the solder resist layer 2. In the NSMD structure, the solder resist layer 2 in the vicinity of the connection pad 3 is completely removed, and the side surface of the connection pad 3 is completely exposed. Therefore, the bonding strength between the connection pad 3 and the solder can be ensured even with a small connection pad 3 as compared with the SMD structure. On the other hand, when the side surface of the connection pad 3 is completely exposed, the adhesive strength between the connection pad 3 and the insulating layer 8 may be reduced. In addition, in the connection pads 3 arranged at a narrow pitch, if a short circuit occurs between the connection pads 3 due to electroless nickel / gold plating in a later process, or if solder bumps are arranged on the connection pads 3, melting occurs. In some cases, the solder that has flowed out flows to the adjacent connection pads 3 and short-circuits between the connection pads 3.

In order to solve the problem of the adhesive strength between the connection pad and the insulating layer, an opening having a depth of about 0 to 15 μm is formed in a part of the solder resist layer provided on the circuit board surface by laser light irradiation. A method of manufacturing a printed wiring board having a structure in which a part of the side surface of the connection pad is exposed from the solder resist layer has been proposed (for example, see Patent Document 1). By using the printed wiring board obtained by the method described in Patent Document 1, the connection pad and the insulating layer are compared with the printed wiring board in which the connection pad existing under the solder resist layer is completely exposed. It becomes possible to improve the adhesive strength between.

In order to solve the problem of short circuit in the connection pads 3 arranged at a narrow pitch, a method of manufacturing a wiring board in which the solder resist layer 2 is filled between adjacent connection pads 3 has been proposed (for example, a patent). Reference 2). According to the method of Patent Document 2, as shown in FIG. 2, the solder resist layer 2 is filled between the connection pads 3, and the thickness of the filled solder resist layer 2 is equal to or less than the thickness of the connection pad 3. An NSMD structure can be formed. Specifically, a solder resist layer 2 is formed on the circuit board 1, and after exposing portions other than the region to be thinned until the thickness of the solder resist layer 2 is equal to or less than the thickness of the connection pad 3, an alkaline aqueous solution is obtained. The solder resist layer 2 in the non-exposed portion is thinned with the thinning treatment liquid until the thickness of the connection pad 3 or less. As a result, a solder resist layer 2 having a multi-stage structure including a portion less than the thickness of the connection pad 3 and a portion exceeding the thickness of the connection pad 3 is formed, and a part of the conductor wiring that becomes the connection pad 3 is exposed. A wiring board can be manufactured.

Usually, in a wiring board on which electronic parts are mounted, a large number of external connection pads are formed on the back surface at high density. The connection pad for external connection is also produced by exposing a part of the conductor wiring on the back surface of the circuit board from the solder resist layer. The exposed portion of the connection pad for external connection and a conductor wiring of an external electric substrate such as a mother board are opposed to each other and electrically connected via solder bumps.

When the solder resist layer is formed on both sides of the circuit board, the thickness of the solder resist layer on the connection pad varies depending on the density of the surrounding conductor wiring including the connection pad. For example, when the density of the conductor wiring is small, the amount of the solder resist layer filled in the gap between the conductor wirings increases, and the thickness of the solder resist layer on the connection pad tends to be thin. On the other hand, when the density of the conductor wiring is large, the amount of the solder resist layer filled in the gap between the conductor wirings is reduced, and the thickness of the solder resist layer on the connection pad tends to be thick.

In the case of a wiring board on which electronic components are mounted by flip chip connection, the density of the surrounding conductor wiring including the connection pads for external connection on the back surface is higher than the density of the surrounding conductor wiring including the connection pads for connecting electronic components on the front surface. May be large. Therefore, the thickness of the solder resist layer on the connection pad for external connection on the back surface may be thicker than the thickness of the solder resist layer on the connection pad for electronic component connection on the front surface. In the method of thinning the solder resist layer with the thinning solution and exposing the connection pads, the following problems may occur when attempting to thin the both surfaces simultaneously.

First, when it is based on thinning the solder resist layer 2 on the front surface until the thickness of the connection pad 3 for connecting electronic components is less than the thickness, the solder resist layer 2 on the back surface is also thinned by the same amount as the surface at the same time. However, since the solder resist layer 2 on the back surface is thicker than the solder resist layer 2 on the front surface, the solder resist layer 2 remains as a residue on the connection pad 4 for external connection on the back surface, and this residue causes poor electrical insulation. There was a case where a problem arises (FIG. 3).

On the contrary, when it is assumed that the solder resist layer 2 on the back surface is thinned to the thickness of the connection pad 4 for external connection or less, the solder resist layer 2 on the front surface is also thinned by the same amount as the back surface at the same time. However, since the solder resist layer 2 on the back surface is thicker than the solder resist layer 2 on the front surface, the thickness of the solder resist layer 2 filling the space between the connection pads 3 for connecting the electronic components on the front surface is larger than the desired thickness. In some cases, the thickness becomes thinner, causing a short circuit between adjacent connection pads 3 for connecting electronic components.

By the way, in a printed wiring board in which electronic components are flip-chip connected to a circuit board, the gap between the electronic components and the circuit board is underfilled (sealing resin) in order to ensure the connection reliability between the electronic component and the circuit board. Fill with reinforced. In order to ensure the reinforcing effect, a sufficient amount of underfill must be filled in the gap between the electronic component and the circuit board. However, when the flip-chip connection is performed using the printed wiring board obtained by Patent Document 1, when the underfill is filled with sufficient underfill to ensure the reinforcing effect, the underfill may be a gap between the electronic component and the circuit board. In some cases, it overflowed to the surroundings and adversely affected the electrical operation. Therefore, a printed wiring board having a dam structure has been proposed in order to prevent the underfill from overflowing to the surroundings (see, for example, Patent Documents 3 to 5).

In Patent Document 3, a solder resist layer is formed on a circuit board having a conductor circuit, and then a partial exposure is performed. Thereafter, an unexposed portion is developed to partially expose the upper portion of the connection pad from the solder resist layer. A method of forming a dam shape by forming an opening to be formed, performing a second partial exposure, and then thinning an unexposed portion of the second partial exposure by a desmear process is disclosed. Since the opening of the solder resist layer by this method has an SMD structure, it is difficult to securely fix the electrical connection between the electrode terminal of the electronic component and the corresponding connection pad. In some cases, the electrical connection was insufficient. Moreover, since the dam structure is formed by the desmear process by this method, the strength of the solder resist layer is lowered by roughening the solder resist layer, and the reliability of the printed wiring board is sufficient. In some cases, it could not be secured.

Patent Document 4 discloses an opening that completely exposes a connection pad from a solder resist layer by forming a solder resist layer on a circuit board having a conductor circuit, performing partial exposure, and then developing the unexposed portion. Forming a second portion, then forming a second solder resist, then performing a second partial exposure in which an unexposed portion that is one size larger than the first partial exposure region is generated, and then developing the unexposed portion Discloses a method for forming a dam shape. The opening of the solder resist layer by this method has an NSMD structure, and the connection pad is completely removed from the periphery of the solder resist layer, and the side surface of the connection pad is completely exposed. There is a risk that the adhesive strength between the two will decrease.

In Patent Document 5, a solder resist layer is formed on a circuit board having a conductor circuit, and then a partial exposure process is performed, and then an unexposed portion of the solder resist layer is thinned so that openings and dams are formed in the solder resist layer. A method of forming a shape is disclosed. The opening of the solder resist layer by this method has an SMD structure, and the connection pad is covered with the solder resist layer in the vicinity of the periphery, so that the electrical connection between the electrode terminal of the electronic component and the corresponding connection pad is made. It is difficult to securely fix the connection, and the electrical connection between the connection pad and the solder ball may be insufficient.

Japanese Patent No. 3346263 International Publication No. 2012/043201 Pamphlet JP 2012-238668 A JP 05-226505 A JP 2011-77191 A

An object of the present invention is to have a circuit board having an insulating layer and a connection pad formed on the surface of the insulating layer on both surfaces, and having a solder resist layer on both surfaces of the circuit board, and connecting from the solder resist layer In the method of manufacturing a wiring board in which a part of the pad is exposed, there is no electrical short circuit between the connection pads exposed from the solder resist layer on both surfaces of the wiring board, and on the exposed connection pads. An object of the present invention is to provide a method for manufacturing a wiring board in which no residue of a solder resist layer remains. Another object of the present invention is to obtain a printed wiring board having high adhesion strength between a connection pad and an insulating layer and between the connection pad and solder, no electrical malfunction due to underfill outflow, and high solder resist layer strength. It is providing the manufacturing method of the printed wiring board which can be performed.

As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by the following invention.

(1) It has a circuit board which has an insulating layer and a connection pad formed on the surface of the insulating layer on both surfaces, and has a solder resist layer on both surfaces of the circuit board. In the method of manufacturing a wiring board in which a part is exposed,
(A) a step in which solder resist layers having different thicknesses are formed on both surfaces of a circuit board having an insulating layer and a connection pad formed on the surface of the insulating layer on both surfaces;
(C1) A step in which a portion other than the region to be thinned in the step (B) which is a subsequent step is exposed to the solder resist layer on the first surface which is thinner than the solder resist layer on the second surface,
(C2) A step of exposing a portion other than the region to be developed in step (D), which is a subsequent step, to the solder resist layer on the second surface,
(B) On the first surface, the solder resist layer of the non-exposed part is thinned until the thickness of the connection pad becomes equal to or less than the thickness of the connection pad by the thinning treatment solution, and a part of the connection pad is exposed.
(C3) The step of exposing the area portion thinned in step (B) to the solder resist layer on the first surface,
(D) the step of removing the solder resist layer of the non-exposed portion of the second surface with a developer;
A method for manufacturing a wiring board, comprising:

(2) It has a circuit board which has an insulating layer and a connection pad formed on the surface of the insulating layer on both surfaces, has a solder resist layer on both surfaces of the circuit board, and one of the connection pads from the solder resist layer. In the manufacturing method of the wiring board in which the part is exposed,
(A) a step in which solder resist layers having different thicknesses are formed on both surfaces of a circuit board having an insulating layer and a connection pad formed on the surface of the insulating layer on both surfaces;
(C1) A step of exposing a portion other than the region to be thinned in the step (B1), which is a subsequent step, to the solder resist layer on the first surface that is thinner than the solder resist layer on the second surface,
(C2) A step of exposing a portion other than the region to be developed in step (D), which is a subsequent step, to the solder resist layer on the second surface,
(B1) In the first surface, the step in which the solder resist layer of the non-exposed part is thinned by the thinning treatment liquid in a range where the connection pad is not exposed,
(C4) A step of exposing a portion other than the region to be thinned in the step (B2), which is a subsequent step, to the solder resist layer on the first surface,
(B2) On the first surface, the solder resist layer of the non-exposed portion is thinned until the thickness of the connection pad becomes equal to or less than the thickness of the connection pad by the thinning treatment solution, and a part of the connection pad is exposed.
(C5) The step of exposing the thinned region in step (B2) to the solder resist layer on the first surface,
(D) the step of removing the solder resist layer of the non-exposed portion of the second surface with a developer;
A method for manufacturing a wiring board, comprising:

(3) It has a circuit board which has an insulating layer and a connection pad formed on the surface of the insulating layer on both surfaces, a solder resist layer on both surfaces of the circuit board, and one of the connection pads from the solder resist layer. In the method of manufacturing a wiring board in which a part is exposed,
(A1) a step in which first solder resist layers having different thicknesses are formed on both surfaces of a circuit board having an insulating layer and connection pads formed on the surfaces of the insulating layer on both surfaces;
(C1) The first solder resist layer on the first surface, which is thinner than the first solder resist layer on the second surface, is exposed to a portion other than the region to be thinned in the subsequent step (B). Process
(C2) A step of exposing a portion other than the region to be developed in step (D1), which is a subsequent step, to the first solder resist layer on the second surface,
(B) On the first surface, the first solder resist layer of the non-exposed part is thinned until the thickness of the connection pad is equal to or less than the thickness of the connection pad by the thinning treatment liquid, and a part of the connection pad is exposed;
(C3) The step of exposing the region portion thinned in step (B) to the first solder resist layer on the first surface,
(A2) A step of forming a second solder resist layer on the first solder resist layer on the first surface of the circuit board completed up to the step (C3),
(C6) A step in which a portion other than a region to be developed in the step (D1) which is a subsequent step is exposed to the second solder resist layer on the first surface;
(D1) a step of removing the second solder resist layer of the non-exposed portion of the first surface and the first solder resist layer of the non-exposed portion of the second surface with a developer;
A method for manufacturing a wiring board, comprising:

(4) It has a circuit board which has an insulating layer and a connection pad formed on the surface of the insulating layer on both surfaces, has a solder resist layer on both surfaces of the circuit board, and one of the connection pads from the solder resist layer. In the method of manufacturing a wiring board in which a part is exposed,
(A1) a step in which first solder resist layers having different thicknesses are formed on both surfaces of a circuit board having an insulating layer and connection pads formed on the surfaces of the insulating layer on both surfaces;
(C1) The first solder resist layer on the first surface, which is thinner than the first solder resist layer on the second surface, is exposed to a portion other than the region to be thinned in the subsequent step (B). Process
(C2) A step of exposing a portion other than a region to be developed in step (D), which is a subsequent step, to the first solder resist layer on the second surface;
(B) On the first surface, the first solder resist layer of the non-exposed part is thinned until the thickness of the connection pad is equal to or less than the thickness of the connection pad by the thinning treatment liquid, and a part of the connection pad is exposed;
(C3) The step of exposing the region portion thinned in step (B) to the first solder resist layer on the first surface,
(D) the step of removing the first solder resist layer of the non-exposed portion of the second surface with a developer;
(A2) A step in which a second solder resist layer is formed on the first solder resist layer on the first surface of the circuit board completed up to step (D),
(C6) A step in which a portion other than the region to be developed in the step (D2) which is a subsequent step is exposed to the second solder resist layer on the first surface,
(D2) a step of removing the second solder resist layer of the non-exposed portion of the first surface with a developer;
A method for manufacturing a wiring board, comprising:

(5) a circuit board having an insulating layer and a connection pad formed on the surface of the insulating layer on both surfaces; a solder resist layer on both surfaces of the circuit board; In the method of manufacturing a wiring board in which a part is exposed,
(A1) a step in which first solder resist layers having different thicknesses are formed on both surfaces of a circuit board having an insulating layer and connection pads formed on the surfaces of the insulating layer on both surfaces;
(C2) A step of exposing a portion other than the region to be developed in step (D1), which is a subsequent step, to the first solder resist layer on the second surface,
(B) On the first surface, the first solder resist layer of the non-exposed part is thinned until the thickness of the connection pad is equal to or less than the thickness of the connection pad by the thinning treatment liquid, and a part of the connection pad is exposed;
(C3) The step of exposing the region portion thinned in step (B) to the first solder resist layer on the first surface,
(A2) A step of forming a second solder resist layer on the first solder resist layer on the first surface of the circuit board completed up to the step (C3),
(C6) A step of exposing a portion other than the region to be thinned in the subsequent step (B3) to the second solder resist layer on the first surface;
(B3) On the first surface, the second solder resist layer of the non-exposed part is thinned by the thinning treatment liquid in a range where the connection pad is not exposed,
(C7) A step in which a portion other than the region to be developed in the step (D1) which is a subsequent step is exposed to the second solder resist layer on the first surface;
(D1) a step of removing the second solder resist layer of the non-exposed portion of the first surface and the first solder resist layer of the non-exposed portion of the second surface with a developer;
A method for manufacturing a wiring board, comprising:

(6) The method for manufacturing a wiring board according to any one of (1) to (4), wherein the step (C2) is performed before the step (C1).
(7) The method for manufacturing a wiring board according to any one of (1) to (4), wherein the step (C1) and the step (C2) are performed simultaneously.

(8) The method for manufacturing a wiring board according to any one of (1), (3), and (4), wherein the exposure in the step (C3) is performed by a non-contact exposure method in an oxygen atmosphere.
(9) The method for manufacturing a wiring board according to (5), wherein the exposure in the step (C3) and the step (C7) is performed by a non-contact exposure method in an oxygen atmosphere.
(10) The method for manufacturing a wiring board according to (2), wherein the exposure in the step (C4) and the step (C5) is performed by a non-contact exposure method in an oxygen atmosphere.

(11) The exposure amount in the step (C3) is any one of the above (1), (3), (4), and (8), which is 1 to 5 times the exposure amount in the step (C1). A method for manufacturing a wiring board.
(12) The method for producing a wiring board according to (5) or (9), wherein the exposure amount in the step (C3) and the step (C7) is 1 to 5 times the exposure amount in the step (C6).
(13) The method for producing a wiring board according to (2) or (10), wherein the exposure amount in the step (C4) and the step (C5) is 1 to 5 times the exposure amount in the step (C1).

(14) Any of (1), (3), (4), (8), and (11) above, wherein the thinning process of the solder resist layer in the step (B) is performed with the thinning process surface facing up. The manufacturing method of the wiring board as described in 2 ..
(15) The solder resist layer thinning process in the step (B) and the step (B3) is performed with the thinning processing surface facing up, according to any one of the above (5), (9), and (12) A method for manufacturing a wiring board.
(16) The solder resist layer thinning process in the step (B1) and the step (B2) is performed with the thinning processing surface facing up, according to any one of the above (2), (10), and (13) A method for manufacturing a wiring board.

According to the present invention, the circuit board having the insulating layer and the connection pad formed on the surface of the insulating layer is provided on both surfaces, the solder resist layer is provided on both surfaces of the circuit board, and the connection is made from the solder resist layer. In the method of manufacturing a wiring board in which a part of the pad is exposed, there is no electrical short circuit between the connection pads exposed from the solder resist layer on both surfaces of the wiring board, and the exposed connection pads It is possible to provide a method of manufacturing a wiring board in which no residue of the solder resist layer remains. In addition, according to the present invention, it is possible to obtain a printed wiring board having a high bonding strength between the connection pad and the insulating layer and the connection pad and the solder, no electrical malfunction due to an underfill outflow, and a high strength of the solder resist layer. The manufacturing method of the printed wiring board which can be provided can be provided.

It is a schematic sectional drawing which shows an example of a wiring board. It is a schematic sectional drawing which shows an example of a wiring board. It is a schematic sectional drawing which shows an example of a wiring board. It is sectional process drawing which shows an example of the manufacturing method of the wiring board of this invention. It is sectional process drawing which shows an example of the manufacturing method of the wiring board of this invention. It is sectional process drawing which shows an example of the manufacturing method of the wiring board of this invention. It is sectional process drawing which shows an example of the manufacturing method of the wiring board of this invention. It is sectional process drawing which shows an example of the manufacturing method of the wiring board of this invention. It is a schematic sectional drawing which shows an example of the wiring board which can be manufactured by this invention. It is a schematic sectional drawing which shows an example of the wiring board which can be manufactured by this invention. It is a schematic sectional drawing which shows an example of the wiring board which can be manufactured by this invention. It is a schematic sectional drawing which shows an example of the wiring board which can be manufactured by this invention. It is a schematic sectional drawing which shows an example of a multilayer circuit board.

Hereinafter, the manufacturing method of the wiring board of the present invention will be described in detail.

FIGS. 4A and 4B are cross-sectional process diagrams illustrating an example of the manufacturing method (1) of the wiring board. A circuit board having the insulating layer 8 and the conductor wiring 7 formed on the surface of the insulating layer 8 on both surfaces is prepared. Part of the conductor wiring 7 is the

connection pads

3 and 4. In the step (A), a solder resist layer 2 is formed on both surfaces of the circuit board 1 so as to cover the entire surface. The formation of the solder resist layer 2 on the first surface and the second surface may be performed simultaneously on both surfaces or on each side, but depending on the thickness of the solder resist layer to be formed, heating conditions are set so as not to overheat. There is a need to. The thicknesses of the solder resist layers 2 on both surfaces are different. The thinner one is the “first surface”, and the thicker one is the “second surface”. When the solder resist layer 2 is formed under the same conditions on both surfaces, the thickness of the solder resist layer 2 varies depending on the density of the conductor wiring 7 including the

connection pads

3 and 4 on each surface. In FIG. 4-1, the density of the conductor wiring 7 is higher on the lower second surface than on the upper first surface, and the thickness of the solder resist layer 2 on the second surface conductor wiring 7 is It becomes thicker than the thickness of the solder resist layer 2 on the conductor wiring 7 on the first surface. In the case of a wiring board on which electronic components are mounted, the peripheral conductor wiring 7 including the external connection connection pads 4 on the back surface is compared with the density of the surrounding conductor wiring 7 including the electronic component connection connection pads 3 on the front surface. May have a large density, the front surface being the first surface and the back surface being the second surface.

In step (C1), the solder resist layer 2 on the first surface is exposed to a portion other than the region to be thinned in the subsequent step (B). At a process (C2), parts other than the area | region developed in the process (D) which is a post process are exposed with respect to the soldering resist layer 2 of a 2nd surface. In the exposed portion of the solder resist layer 2, the solder resist is photopolymerized and has resistance to the thinning process and the developing process.

In the step (B), on the first surface, the solder resist layer 2 in the non-exposed part is thinned by the thinning treatment solution until the thickness of the connection pad 3 becomes equal to or less, and a part of the connection pad 3 is exposed. . In the case of a wiring board on which electronic components are mounted, the connection pads 3 exposed in this step (B) are used as the connection pads 3 for connecting electronic components. In the step (B), the solder resist layer 2 of the non-exposed portion on the second surface is also thinned simultaneously, but on the connection pad 4 on the second surface rather than the solder resist layer 2 on the connection pad 3 on the first surface. Since the solder resist layer 2 is thicker, a residue of the solder resist layer 2 remains on the connection pad 4.

In step (C3), the solder resist layer 2 on the first surface is exposed to the region thinned in step (B). In the exposed portion of the solder resist layer 2, the solder resist is photopolymerized and has resistance to the development process.

In step (D), on the second surface, the solder resist layer 2 in the non-exposed portion is removed with a developer, and a part of the connection pad 4 is exposed. By the step (D), the residue of the solder resist layer 2 remaining on the connection pad 4 is removed. In the case of a wiring board on which electronic components are mounted, the connection pads 4 exposed in this step (D) are used as connection pads 4 for external connection. In the solder resist layer 2 on the first surface, the region thinned in the step (B) is exposed in the step (C3) performed before the step (D) and has resistance to the development step. , Not removed by developer.

In the manufacturing method (1) of the wiring board, the exposure area in the step (C1) can be changed to an arbitrary shape. By changing the exposure area, for example, a wiring board having a cross-sectional shape shown in FIG. It is possible. In a of FIG. 9, the convex part of the soldering resist layer 2 is formed between the connection pads 3 of the 1st surface. In FIG. 9 b, the connection pads 3 exposed from the solder resist layer 2 and the conductor wirings 7 covered with the solder resist layer 2 are alternately arranged on the first surface.

5-1, FIG. 5-2, and FIG. 5-3 are cross-sectional process diagrams illustrating an example of a method (2) for manufacturing a wiring board. The difference from the manufacturing method (1) of the wiring board is that the exposure process and the thinning process of the solder resist layer 2 are added once each on the first surface. When electronic components are mounted on a wiring board by flip chip connection, due to the difference in thermal expansion coefficient between the electronic components and the wiring board, when a thermal shock is applied, stress concentrates on the connecting portion, causing deformation or destruction of the connecting portion. Sometimes. In order to prevent stress from concentrating on the connection portion and improve connection reliability, it is common to seal between the electronic component and the wiring board with a resin composition called underfill. By the wiring board manufacturing method (2), it is possible to form a two-stage solder resist layer having a dam structure for blocking an underfill filling between the electronic component and the wiring board.

In step (A), a solder resist layer 2 is formed on both surfaces of the circuit board 1 so as to cover the entire surface. At a process (C1), parts other than the area | region thinned in the process (B1) which is a post process are exposed with respect to the soldering resist layer 2 of a 1st surface. At a process (C2), parts other than the area | region developed in the process (D) which is a post process are exposed with respect to the soldering resist layer 2 of a 2nd surface.

In step (B1), the solder resist layer 2 in the non-exposed part is thinned on the first surface with the thinning treatment solution in a range where the connection pads 3 are not exposed. In the step (B1), the solder resist layer 2 of the non-exposed portion on the second surface is also thinned at the same time.

In step (C4), the solder resist layer 2 on the first surface is exposed to a portion other than the region to be thinned in the subsequent step (B2).

In the step (B2), on the first surface, the solder resist layer 2 in the non-exposed part is thinned by the thinning treatment liquid until the thickness of the connection pad 3 becomes equal to or less, and a part of the connection pad 3 is exposed. . In the case of a wiring board on which electronic components are mounted, the connection pads 3 exposed in this step (B2) are used as the connection pads 3 for connecting electronic components. In the step (B2), the solder resist layer 2 of the non-exposed portion on the second surface is also thinned simultaneously, but on the connection pad 4 on the second surface rather than the solder resist layer 2 on the connection pad 3 on the first surface. Since the solder resist layer 2 is thicker, a residue of the solder resist layer 2 remains on the connection pad 4.

In step (C5), the solder resist layer 2 on the first surface is exposed to the region thinned in step (B2).

In step (D), on the second surface, the solder resist layer 2 in the non-exposed portion is removed with a developer, and a part of the connection pad 4 is exposed. By the step (D), the residue of the solder resist layer 2 remaining on the connection pad 4 is removed. In the case of a wiring board on which electronic components are mounted, the connection pads 4 exposed in this step (D) are used as connection pads 4 for external connection.

In the manufacturing method (2) of the wiring board, the exposure area in the step (C4) can be changed to an arbitrary shape. By changing the exposure area, for example, a wiring board having a cross-sectional shape shown in FIG. It is possible. In FIG. 10 c, the convex portion of the solder resist layer 2 is formed between the connection pads 3 on the first surface. In FIG. 10 d, the connection pads 3 exposed from the solder resist layer 2 and the conductor wirings 7 covered with the solder resist layer 2 are alternately arranged on the first surface.

FIGS. 6A, 6B, and 6C are cross-sectional process diagrams illustrating an example of a method (3) of manufacturing a wiring board. The difference from the manufacturing method (2) of the wiring board is that the solder resist layer on the first surface is composed of the first solder resist layer 2-1 and the second solder resist layer 2-2. In the manufacturing method (3) of the wiring board, after the thickness of the first solder resist layer 2-1 in the non-exposed portion of the first surface is reduced to be equal to or less than the thickness of the connection pad 3, the first solder resist layer After the second solder resist layer 2-2 is formed on the surface of 2-1 and exposed, the second solder resist layer 2-2 in the non-exposed portion is developed. Thus, as in the case of using the wiring board manufacturing method (2), a two-stage solder resist layer having a dam structure for blocking an underfill filling between the electronic component and the wiring board is formed. Can do.

In step (A1), first solder resist layers 2-1 having different thicknesses are formed on the first surface and the second surface of the circuit board 1. The first solder resist layer 2-1 on the first surface and the second surface may be formed on both surfaces at the same time or one surface at a time. However, depending on the thickness of the solder resist layer to be formed, it does not excessively heat cure. It is necessary to set the heating conditions.

In step (C1), the first solder resist layer 2-1 on the first surface, which is thinner than the first solder resist layer 2-1 on the second surface, is thinned in the subsequent step (B). A portion other than the region to be converted is exposed. In the step (C2), the first solder resist layer 2-1 on the second surface is exposed to a portion other than the region to be developed in the subsequent step (D1).

In the step (B), on the first surface, the first solder resist layer 2-1 in the non-exposed part is thinned with a thinning treatment solution until the thickness of the connection pad 3 is less than or equal to the thickness of the connection pad 3. Expose the part. In the step (B), the first solder resist layer 2-1 in the non-exposed portion on the second surface is also thinned at the same time. However, the first solder resist layer 2-1 on the connection pad 4 on the second surface is thicker than the first solder resist layer 2-1 on the connection pad 3 on the first surface. A residue of one solder resist layer 2-1 remains.

In step (C3), the first solder resist layer 2-1 on the first surface is exposed to the area portion thinned in step (B).

In step (A2), a second solder resist layer 2-2 is formed on the first solder resist layer 2-1 on the first surface of the circuit board completed up to step (C3). At this time, the heating condition applied to the second solder resist layer 2-2 on the first surface is adjusted so that the non-exposed portion of the first solder resist layer 2-1 on the second surface is not excessively cured.

In step (C6), the second solder resist layer 2-2 on the first surface is exposed to a portion other than the region to be developed in the subsequent step (D1).

In the step (D1), the second solder resist layer 2-2 in the non-exposed portion on the first surface and the first solder resist layer 2-1 in the non-exposed portion on the second surface are removed with a developer, and the connection pad 3 And a portion of 4 are exposed. By the step (D1), the residue of the first solder resist layer 2-1 remaining on the connection pad 4 is removed. In the case of a wiring board on which electronic components are mounted, the connection pads 3 exposed in this step (D1) are used as the connection pads 3 for electronic component connection, and the connection pads 4 are used as the connection pads 4 for external connection.

FIGS. 7A, 7B, and 7C are cross-sectional process diagrams illustrating an example of a method (4) of manufacturing a wiring board. The difference from the manufacturing method (3) of the wiring board is that the first solder resist layer 2-1 on the second surface is removed with a developer before the second solder resist layer 2-2 on the first surface is formed. It is. First, when the second solder resist layer 2-2 of the first surface is formed by removing the first solder resist layer 2-1 of the non-exposed portion of the second surface with a developing solution, It is not necessary to adjust the heating conditions so that the first solder resist layer 2-1 in the exposed area is simultaneously heated and is not excessively cured. The wiring board manufacturing method (4) has a dam structure for damming the underfill filling between the electronic component and the wiring board as in the case of using the wiring board manufacturing methods (2) and (3). A two-stage solder resist layer can be formed.

In step (A1), first solder resist layers 2-1 having different thicknesses are formed on the first surface and the second surface of the circuit board 1. In step (C1), the first solder resist layer 2-1 on the first surface, which is thinner than the first solder resist layer 2-1 on the second surface, is thinned in the subsequent step (B). A portion other than the region to be converted is exposed. In the step (C2), the first solder resist layer 2-1 on the second surface is exposed to a portion other than the region to be developed in the subsequent step (D).

In step (D), the first solder resist layer 2-1 in the non-exposed portion on the second surface is removed with a developer, and a part of the connection pad 4 is exposed. By the step (D), the residue of the first solder resist layer 2-1 remaining on the connection pad 4 is removed. In the case of a wiring board on which electronic components are mounted, the connection pads 4 exposed in this step (D) are used as connection pads 4 for external connection.

In step (A2), a second solder resist layer 2-2 is formed on the first solder resist layer 2-1 on the first surface of the circuit board completed up to step (D).

In step (C6), the second solder resist layer 2-2 on the first surface is exposed to a portion other than the region to be developed in the subsequent step (D2).

In step (D2), the second solder resist layer 2-2 in the non-exposed portion on the first surface is removed with a developer, and a part of the connection pad 3 is exposed. In the case of a wiring board on which electronic components are mounted, the connection pads 3 exposed in this step (D2) are used as the connection pads 3 for connecting electronic components.

In the wiring board manufacturing methods (3) and (4), the exposure area in the step (C1) can be changed to an arbitrary shape. By changing the exposure area, for example, the wiring having the cross-sectional shape shown in FIG. It is possible to produce a substrate. In e of FIG. 11, the convex part of the 1st soldering resist layer 2-1 is formed between the connection pads 3 of the 1st surface. In FIG. 11f, the connection pads 3 exposed from the first solder resist layer 2-1 and the conductor wirings 7 covered with the first solder resist layer 2-1 are alternately arranged.

8-1, FIG. 8-2, and FIG. 8-3 are cross-sectional process diagrams showing an example of a method (5) of manufacturing a wiring board. In the wiring board manufacturing method (5), on the first surface, the thickness of the first solder resist layer 2-1 becomes equal to or less than the thickness of the connection pad 3 before the first solder resist layer 2-1 is exposed. Thin film processing. Thereafter, a second solder resist layer 2-2 is formed on the surface of the first solder resist layer 2-1, and after exposure, the second solder resist layer 2-2 in the non-exposed part is thinned, Exposure is performed again, and the remaining second solder resist layer 2-2 in the unexposed area is developed. The wiring board manufacturing method (5) has a dam structure for damming the underfill filling between the electronic component and the wiring board, as in the case of using the wiring board manufacturing methods (2) to (4). A two-stage solder resist layer can be formed.

In step (A1), first solder resist layers 2-1 having different thicknesses are formed on the first surface and the second surface of the circuit board 1. In the step (C2), the first solder resist layer 2-1 on the second surface is exposed to a portion other than the region to be developed in the subsequent step (D1).

In the step (B), on the first surface, the first solder resist layer 2-1 in the non-exposed portion is thinned with the thinning treatment solution until the thickness of the connection pad 3 is less than or equal to all the connection pads 3 To expose a part of In the step (B), the first solder resist layer 2-1 in the non-exposed portion on the second surface is also thinned at the same time. However, the first solder resist layer 2-1 on the connection pad 4 on the second surface is thicker than the first solder resist layer 2-1 on the connection pad 3 on the first surface. A residue of one solder resist layer 2-1 remains.

In step (A2), a second solder resist layer 2-2 is formed on the first solder resist layer 2-1 on the first surface of the circuit board completed up to step (C3).

In step (C6), the second solder resist layer 2-2 on the first surface is exposed to a portion other than the region to be thinned in the subsequent step (B3).

In step (B3), on the first surface, the second solder resist layer 2-2 in the non-exposed portion is thinned by the thinning treatment solution in a range where the connection pad 3 is not exposed. In the step (B3), the first solder resist layer 2-1 in the non-exposed portion on the second surface is also thinned at the same time. However, a residue of the first solder resist layer 2-1 may remain on the connection pad 4.

In step (C7), the second solder resist layer 2-2 on the first surface is exposed to a portion other than the region to be developed in the subsequent step (D1).

In the step (D1), the second solder resist layer 2-2 in the non-exposed portion on the first surface and the first solder resist layer 2-1 in the non-exposed portion on the second surface are removed with a developer, and the connection pad 3 A part of the connection pad 4 is exposed again, and at the same time, a part of the connection pad 4 is exposed. By the step (D1), the residue of the first solder resist layer 2-1 remaining on the connection pad 4 is removed. In the case of a wiring board on which electronic components are mounted, the connection pads 3 exposed in this step (D1) are used as the connection pads 3 for electronic component connection, and the connection pads 4 are used as the connection pads 4 for external connection.

In the manufacturing method (5) of the wiring board, the exposure area in the step (C7) can be changed to an arbitrary shape. By changing the exposure area, for example, a wiring board having a cross-sectional shape shown in FIG. It is possible. In FIG. 12g, a convex portion of the second solder resist layer 2-2 is formed between the connection pads 3 on the first surface. In h of FIG. 12, the connection pads 3 exposed from the first solder resist layer 2-1 and the conductor wirings 7 covered with the first solder resist layer 2-1 and the second solder resist layer 2-2 are alternately arranged. It is out.

The circuit board 1 according to the present invention includes an insulating layer 8 and

connection pads

3 and 4 formed on the surface of the insulating layer 8. Conductor wiring 7 is formed on the surface of the insulating layer 8, and the

connection pads

3 and 4 are part of the conductor wiring 7. The wiring board according to the present invention has solder resist layers 2 on both surfaces of the circuit board 1, and part of the

connection pads

3 and 4 are exposed from the solder resist layer 2. In the case of a wiring board on which electronic components are mounted, the connection pads 3 for connecting electronic components are provided on the front surface, and the connection pads 4 for external connection are provided on the back surface. The electronic component connecting connection pad 3 on the front surface and the electronic component are bonded, and the external connecting connection pad 4 on the back surface and the conductor wiring of the external electric substrate are bonded.

The circuit board according to the present invention is produced, for example, by alternately laminating build-up insulating layers and conductor wiring on an insulating substrate on which conductor wiring is disposed. 13A and 13B are schematic cross-sectional views showing an example of a circuit board produced by alternately laminating build-up insulating layers and conductor wirings on an insulating board on which conductor wirings are arranged. 4 to 8 are sectional process diagrams showing an example of a method for manufacturing a wiring board of the present invention, and FIGS. 9 to 12 are schematic sectional views showing examples of a wiring board that can be manufactured according to the present invention. Although the circuit board 1 having the conductor wiring 7 formed on both surfaces of the insulating layer 8 is described, the circuit board 1 used in the method for manufacturing a wiring board according to the present invention is shown in FIG. As shown in B, the insulating layer 8 and the conductor wiring 7 formed on the surface of the insulating layer 8 are produced by alternately laminating build-up insulating layers and conductor wiring on the insulating substrate on which the conductor wiring is disposed. The circuit board 1 having both of the surfaces is included. Examples of the insulating substrate include a resin substrate made of an electrically insulating material in which a glass cloth is impregnated with a thermosetting resin such as a bismaleimide triazine resin or an epoxy resin. As an insulating layer for buildup, for example, an electrical insulating material in which a glass cloth is impregnated with a thermosetting resin, as in the case of an insulating substrate, an inorganic filler such as silicon oxide is dispersed in a thermosetting resin such as an epoxy resin. Examples include electrical insulating materials. The conductor wiring is formed by, for example, a subtractive method, a semi-additive method, an additive method, or the like. In the subtractive method, for example, after forming a copper layer on an insulating layer, an etching resist layer is formed, and exposure, development, etching, and resist stripping are performed to form a conductor wiring. In the semi-additive method, a base metal layer for electrolytic copper plating is provided on the surface of the insulating layer by electroless copper plating. Next, a plating resist layer having an opening corresponding to the conductor wiring is formed, and an electrolytic copper plating layer is formed on the surface of the base metal layer exposed by electrolytic copper plating. Thereafter, the plating resist layer is peeled off, and the exposed base metal layer is removed by flash etching to form a conductor wiring.

In the case of a wiring board on which an electronic component is mounted, the connection pad on the surface of the wiring board is a connection pad for connecting to the electronic component. The electronic component is flip-chip mounted on the wiring board by being electrically connected to the connection pad via the solder bump. In order to improve the adhesion with the solder resist layer, the surface of the connection pad can be roughened or can be treated with a coupling agent. The connection pad on the back surface of the wiring board is a connection pad for external connection. Flip chip mounting is performed on the mother board by electrically connecting the connection pads and conductor wiring of an external electric board such as the mother board through solder bumps.

As the solder resist according to the present invention, an alkali developing type solder resist can be used. Further, it may be either a one-component or two-component liquid resist, or a dry film resist. The solder resist contains, for example, an alkali-soluble resin, a monofunctional acrylic monomer, a polyfunctional acrylic monomer, a photopolymerization initiator, an epoxy resin, an inorganic filler, and the like.

Examples of the alkali-soluble resin include alkali-soluble resins having both photo-curing properties and thermosetting properties. For example, a secondary hydroxyl group of a resin obtained by adding acrylic acid to a novolak-type epoxy resin to form an epoxy acrylate. A resin to which an acid anhydride has been added may be mentioned. Examples of the polyfunctional acrylic monomer include trimethylolpropane triacrylate (Trimethylol Propane Triacrylate), dipentaerythritol hexaacrylate (Di-pentaerythritol Polyacrylate), and pentaerythritol triacrylate (Pentaerythritol Triacrylate). As a photopolymerization initiator, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (2-Methyl-1- (4-Methylthiophenyl) -2-Morpholinopropan-1-one) Etc. Epoxy resin is used as a curing agent. It is cross-linked by reacting with carboxylic acid of alkali-soluble resin to improve heat resistance and chemical resistance, but carboxylic acid and epoxy react at room temperature, so the storage stability is poor and alkaline In general, the development type solder resist often takes a two-component form to be mixed before use. Examples of the inorganic filler include talc, silica, barium sulfate, titanium oxide, and zinc oxide.

The solder resist layer is formed so as to cover the entire surface on both surfaces of the circuit board. For forming the solder resist layer, for example, if it is a liquid resist, screen printing method, roll coating method, spray method, dipping method, curtain coating method, bar coating method, air knife method, hot melt method, gravure coating method, brush A coating method or an offset printing method can be used. In the case of a film-like resist, a laminating method or a vacuum laminating method is used.

Solder resist layer 2 formed in step (A) in wiring board manufacturing methods (1) and (2), and first formed in steps (A1) in wiring board manufacturing methods (3) to (5). The solder resist layer 2-1 has different thicknesses on both surfaces of the circuit board. The thinner one is the “first surface” and the thicker one is the “second surface”. When forming solder resist layers on both surfaces of a circuit board, the same conditions are generally set on both surfaces. This is because the solder resist has thermosetting properties. In the case of a liquid resist, it is necessary to heat and dry to remove the solvent after coating. Therefore, if the coating amount is different on each surface, the drying conditions must be changed on each surface. Such a condition must be set. In the case of dry film resists, heating is required during lamination, so if dry film resists with different thicknesses are used on each surface, the heating conditions during lamination must be changed on each surface. The conditions must be set so as not to overheat. Instead of changing the thickness of the solder resist layer on each surface, heat drying conditions, etc. in this way, it is better to make the type, thickness, heat drying conditions, etc. of the solder resist layer on both surfaces the same conditions. This is preferable because it can be simplified.

When the solder resist layer is formed on both surfaces of the circuit board under the same conditions, the thickness of the solder resist layer varies depending on the density of the surrounding conductor wiring including the connection pads on each surface. For example, in a wiring board on which electronic components are mounted, when the external connection connection pads on the back surface are arranged in an area array type, the back surface is compared with the density of the surrounding conductor wiring including the connection pads for electronic component connection on the front surface. The density of the surrounding conductor wiring including the external connection pad is increased. As a result, the thickness of the solder resist layer on the external connection connection pad on the back surface is larger than the thickness of the solder resist layer on the electronic component connection connection pad on the front surface. In this case, the front surface is the first surface and the back surface is the second surface.

The process in which the solder resist layer according to the present invention is thinned is a micellization process (thinning process) in which the solder resist layer components in the non-exposed area are micellized with a thinning solution, and then the micelles are removed with a micelle removal solution. It is a process including the micelle removal process to remove. Further, it may include a washing process for washing away the micelles that could not be removed, the remaining thinning treatment liquid and the micelle removal liquid by washing with water, and a drying process for removing the washing water.

The thinning treatment (micellar treatment) is a treatment in which the solder resist layer components in the non-exposed part are micelleed with a thinning treatment solution and the micelles are insolubilized in the thinning treatment solution.

An alkaline aqueous solution can be used for the thinning solution according to the present invention. Alkaline aqueous solutions that can be used as the thinning solution include alkali metal silicate (Alkali Metal Silicate), alkali metal hydroxide (Alkali Metal Hydroxide), alkali metal phosphate (Alkali Metal Phosphate), alkali metal carbonate ( Alkali Metal Carbonate), aqueous solutions of inorganic alkaline compounds such as ammonium phosphate and ammonium carbonate; monoethanolamine, diethanolamine, triethanolamine, methylamine, dimethylamine, ethylamine, diethylamine, triethylamine, cyclohexylamine, tetramethylammonium hydroxy (Tetramethylammonium Hydroxide, T AH), tetraethylammonium hydroxide, trimethyl-2-hydroxyethyl ammonium hydroxide (choline, include aqueous solutions of organic alkaline compounds such as Choline). Examples of the alkali metal include lithium, sodium, and potassium. The inorganic alkaline compound and organic alkaline compound may be used alone or in combination. Inorganic alkaline compounds and organic alkaline compounds may be used in combination.

Also, in order to make the surface of the solder resist layer more uniform, sulfates and sulfites can be added to the thinning solution. Examples of the sulfate or sulfite include alkali metal sulfates or sulfites such as lithium, sodium or potassium, and alkaline earth metal sulfates or sulfites such as magnesium and calcium.

Among these, as the thinning treatment liquid, among these, an inorganic alkaline compound selected from alkali metal carbonates, alkali metal phosphates, alkali metal hydroxides, alkali metal silicates, and TMAH (tetramethylammonium hydroxide) ), A thinning solution containing at least one of the organic alkaline compounds selected from choline and containing 3 to 25% by mass of the inorganic alkaline compound and the organic alkaline compound has a more uniform surface. Can be preferably used. If it is less than 3% by mass, unevenness may easily occur in the thinning process. Moreover, when it exceeds 25 mass%, precipitation of an inorganic alkaline compound will occur easily and it may be inferior to the temporal stability of a liquid, and workability | operativity. The content of the alkaline compound is more preferably 5 to 20% by mass, and further preferably 7 to 15% by mass. The pH of the thinning treatment solution is preferably 10 or more. Further, a surfactant, an antifoaming agent, a solvent and the like can be added as appropriate.

In the thinning of the solder resist layer, the presence of inorganic fillers that are insoluble in the thinning solution contained in the solder resist layer cannot be ignored. The size of the inorganic filler depends on its type, but it has a certain particle size distribution from submicron order called nanofiller to several tens of microns, and it is 30-70% by mass in the layer. Present in content. Thinning proceeds after the alkaline compound penetrates into the solder resist layer and then proceeds through the process of micelle formation and micelle removal of the solder resist layer components, but the presence of insoluble inorganic filler suppresses the penetration of the alkaline compound, resulting in thinning. The speed may be slow.

The pH of the thinning solution is preferably 12.5 or more, and more preferably 13.0 or more, with respect to the inhibition of the penetration of the alkaline compound by such an inorganic filler. The higher the pH of the thinning solution, the greater the swelling of the solder resist layer when the alkaline compound penetrates, and the less the influence of the penetration inhibition by the inorganic filler.

In the present invention, when a part of the connection pad on the first surface is exposed by thinning, the exposed connection pad can be used as a connection pad for connecting an electronic component. Usually, the surface of the connection pad is roughened, and the anchor effect improves the adhesion between the connection pad and the solder resist layer, and high insulation reliability is maintained for a long time. In conventional solder resist pattern formation, when removing the solder resist layer and exposing the connection pad surface, it is common to use a low-concentration sodium carbonate aqueous solution with excellent dispersion ability as the developer. Almost no residue of the solder resist layer is generated. However, if the solder resist layer is thinned using a low-concentration sodium carbonate aqueous solution, it cannot be uniformly thinned in the surface, and in-plane unevenness occurs.

The temperature of the thinning treatment liquid is preferably 15 to 35 ° C, more preferably 20 to 30 ° C. If the temperature is too low, the penetration rate of the alkaline compound into the solder resist layer may be slow, and it takes a long time to reduce the desired thickness. On the other hand, if the temperature is too high, the micelle removal process proceeds simultaneously with the micelle formation of the solder resist layer components, which may cause uneven film thickness in the surface, which is not preferable.

In the thinning treatment using the thinning treatment liquid, methods such as immersion treatment, paddle treatment, spray treatment, brushing, and scraping can be used, but immersion treatment is preferred. In the treatment methods other than the immersion treatment, bubbles are likely to be generated in the thinning treatment liquid, and the generated bubbles may adhere to the surface of the solder resist layer during the thinning, resulting in uneven film thickness. When spraying or the like is used, it is preferable to make the spray pressure as small as possible so that bubbles are not generated.

After the thinning treatment with the thinning solution, the micelles are dissolved all at once by spraying the micelle removal solution in the micelle removal treatment that removes the micelles of the solder resist layer components insolubilized in the thinning solution. Remove.

As the micelle removal liquid, tap water, industrial water, pure water or the like can be used. Further, by using an aqueous solution having a pH of 5 to 10 containing at least one of inorganic alkaline compounds selected from alkali metal carbonates, alkali metal phosphates, and alkali metal silicates as a micelle removal solution, a thinning treatment is performed. The solder resist layer component insolubilized with the liquid is easily redispersed. When the pH of the micelle removal solution is less than 5, the solder resist layer components aggregate and become insoluble sludge, which may adhere to the surface of the solder resist layer that has been thinned. On the other hand, when the pH of the micelle removal solution exceeds 10, micelle formation of the solder resist layer component and the micelle removal process are promoted at the same time, and uneven film thickness tends to occur in the surface. In addition, the pH of the micelle removal solution can be adjusted using sulfuric acid, phosphoric acid, hydrochloric acid, or the like.

The spray conditions in the micelle removal process will be described. The spray conditions (temperature, time, spray pressure) are appropriately adjusted according to the dissolution rate of the solder resist layer to be thinned. Specifically, the treatment temperature is preferably 10 to 50 ° C., more preferably 22 to 50 ° C. If the temperature of the aqueous solution is less than 10 ° C., poor dissolution of the solder resist layer components may occur, and the solder resist layer residue may easily remain on the roughened connection pad surface. On the other hand, when the temperature exceeds 50 ° C., problems such as evaporation of the aqueous solution, temperature management in continuous operation, and restrictions on the device design may occur, which is not preferable. The spray pressure is preferably 0.01 to 0.5 MPa, more preferably 0.1 to 0.3 MPa. The supply flow rate of the micelle removal liquid is preferably 0.030 to 1.0 L / min, more preferably 0.050 to 1.0 L / min, and further 0.10 to 1.0 L / min per 1 cm ^{2 of} the solder resist layer. preferable. When the supply flow rate is within this range, the micelles can be removed substantially uniformly in the surface without leaving insoluble components on the surface of the solder resist layer after thinning. When the supply flow rate per 1 cm ² of the solder resist layer is less than 0.030 L / min, insoluble components of the solder resist layer may remain. On the other hand, when the supply flow rate exceeds 1.0 L / min, parts such as a pump necessary for supply become enormous and a large-scale device may be required. Furthermore, when the supply amount exceeds 1.0 L / min, the effect of dissolving and removing the solder resist layer components may not change.

Solder resist formed on the first surface in step (A) in wiring board manufacturing methods (1) and (2) and in steps (A1) and (A2) in wiring board manufacturing methods (3) to (5) Layer 2, first solder resist layer 2-1, second solder resist layer 2-2 thickness, wiring board manufacturing method (1), steps (B) in (3) to (5), wiring board manufacturing In the steps (B1) and (B2) in the method (2) and the step (B3) in the manufacturing method (5) of the wiring board, the solder resist layer 2 and the first solder resist layer 2-1 in the non-exposed portion of the first surface Depending on the thickness of the second solder resist layer 2-2, the thickness of the solder resist layer 2 around the connection pad 3 exposed on the first surface, the thickness of the first solder resist layer 2-1, and underfill damming Part of the dam and That the solder resist layer 2, the first solder resist layer 2-1, the thickness of the second solder resist layer 2-2 is determined. In the present invention, the amount of thin film can be adjusted as appropriate within a range of 0.01 to 500 μm. The height from the surface of the solder resist layer 2 or the first solder resist layer 2-1 that has been thinned until the thickness of the connection pad becomes equal to or less than the thickness of the connection pad 3 exposed as appropriate depends on the amount of solder required later. adjust. Also, the thickness of the solder resist layer 2, the first solder resist layer 2-1, and the second solder resist layer 2-2, which are part of the dam for underfill damming, determines the size of the electronic component and the connection of the electronic component. It is adjusted as appropriate according to the size of the terminal and the amount of underfill filled between the electronic component and the wiring board.

In the wiring board manufacturing method (6), the process (C2) is performed before the process (C1) in the wiring board manufacturing methods (1) to (4). Also, in the wiring board manufacturing method (7), the steps (C1) and (C2) are simultaneously performed in the wiring board manufacturing methods (1) to (4). As described above, in the wiring board manufacturing methods (1) to (4), the order of the step (C1) and the step (C2) can be interchanged, or the step (C1) and the step (C2) can be performed simultaneously. it can.

In step (C1) in the manufacturing method (1) of the wiring substrate, the solder resist layer 2 on the first surface is selectively exposed to a portion other than the region to be thinned in the subsequent step (B). The In step (C1) in the manufacturing method (2) of the wiring board, the solder resist layer 2 on the first surface is selectively exposed to a portion other than the region to be thinned in the subsequent step (B1). The In the step (C1) in the manufacturing methods (3) and (4) of the wiring board, the first solder resist layer 2-1 on the first surface is other than the region to be thinned in the subsequent step (B). Are selectively exposed. In step (C4) in the manufacturing method (2) of the wiring board, the solder resist layer 2 on the first surface is selectively exposed to a portion other than the region to be thinned in the subsequent step (B2). The In the step (C6) in the method (3) for manufacturing the wiring board and the step (C7) in the method (5) for manufacturing the wiring substrate, a step that is a subsequent step with respect to the second solder resist layer 2-2 on the first surface. In (D1), a portion other than the region to be developed is selectively exposed. In step (C6) in the method (4) of manufacturing the wiring board, a portion other than the region developed in the subsequent step (D2) is selectively selected with respect to the second solder resist layer 2-2 on the first surface. To expose. In step (C6) in the method (5) of manufacturing the wiring substrate, the second solder resist layer 2-2 on the first surface is exposed to a portion other than the region to be thinned in the subsequent step (B3). To do. The exposed solder resist is photopolymerized, and the solder resist layer 2, the first solder resist layer 2-1, and the second solder resist layer 2-2 are cured. In FIGS. 4A to 8C, the actinic ray 6 is exposed through the photomask 5, but it may be performed by a direct drawing method. As the exposure method, for example, a xenon lamp, a high-pressure mercury lamp, a low-pressure mercury lamp, an ultra-high pressure mercury lamp, a reflected image exposure method using a UV fluorescent lamp as a light source, a contact exposure method using a photomask, a proximity method, a projection method, or a laser scanning Examples include an exposure method. The “region to be thinned” on the first surface is, for example, a region around the connection pad including on the connection pad and between the connection pads. More specifically, a mounting area for mounting an electronic component and its surroundings.

In the process (C2) in the manufacturing methods (1) and (2) of the wiring board, the portion other than the region developed in the process (D) which is a subsequent process is selective to the solder resist layer 2 on the second surface. To be exposed. In step (C2) in the manufacturing method (4) of the wiring board, the portion other than the region developed in step (D), which is a subsequent step, is selective to the first solder resist layer 2-1 on the second surface. To be exposed. In the step (C2) in the manufacturing methods (3) and (5) of the wiring board, the region other than the region developed in the subsequent step (D1) with respect to the first solder resist layer 2-1 on the second surface. A portion is selectively exposed. The exposed solder resist is photopolymerized, and the solder resist layer 2 and the first solder resist layer 2-1 are cured. As the exposure method, a method similar to the step (C1) in the wiring substrate manufacturing method (1) described above can be used. The “region to be developed” on the second surface is, for example, a region around the connection pad including on the connection pad and between the connection pads. More specifically, it is a circular opening region that exposes a part of connection pads arranged in an area array type for mounting with conductor wiring of an external electric substrate.

In the step (C3) of the wiring board manufacturing method (1), the solder resist layer 2 on the first surface is exposed to the region thinned in the step (B). In step (C3) in the manufacturing methods (3) to (5) of the wiring board, the first solder resist layer 2-1 on the first surface is exposed to the area portion thinned in step (B). . In step (C5) in the manufacturing method (2) of the wiring board, the area portion thinned in step (B2) is exposed to the solder resist layer 2 on the first surface. As the exposure method, a method similar to the step (C1) in the wiring substrate manufacturing method (1) described above can be used. After the step (C3) in the manufacturing method (1), (3) to (5) of the wiring substrate and the step (C5) in the manufacturing method (2) of the wiring substrate, the solder resist layer 2 of the non-exposed portion, the first The process of developing and removing the solder resist layer 2-1 and the second solder resist layer 2-2 (process (D) in the manufacturing method (1), (2) and (4) of the wiring board, the manufacturing method of the wiring board ( 3) and (5), there is a step (D1) and a step (D2)) in the manufacturing method (4) of the wiring board, so that the region where the solder resist layer is finally formed is exposed to photopolymerize the solder resist. There is a need. The part exposed in step (C3) in the method (1), (3), (4) of manufacturing the wiring board includes at least the region thinned in step (B), and the part exposed in step (C1) It is preferable to include a boundary with the region thinned in the step (B). Further, the portion exposed in step (C5) in the manufacturing method (2) of the wiring board includes at least the region thinned in step (B2), the portion exposed in step (C4) and the thin film in step (B2). It is preferable to include a boundary portion with the normalized region.

Step (C1) in wiring board manufacturing method (1) to (4), wiring board manufacturing method (1), step (C3) in (3) to (5), wiring board manufacturing method (1) to ( Step (C2) in Step 5), Steps (C4) and (C5) in Method (2) for Manufacturing the Wiring Board, Step (C6) in Methods (3) to (5) for Manufacturing the Wiring Board, The exposure amount in step (C7) in 5) is appropriately determined according to the photosensitivity of the solder resist. More specifically, the wiring board manufacturing method (1), the steps (B) in (3) to (5), the steps (B1) and (B2) in the wiring board manufacturing method (2), the wiring board manufacturing method ( The thinning solution used in the step (B3) in 5) or the manufacturing method (1), (2), (4) of the wiring substrate, the manufacturing method (3) and (3) of the wiring substrate in (4) The solder resist is photopolymerized and cured to the extent that the solder resist does not dissolve or swell with respect to the developer used in the step (D1) in 5) and the step (D2) in the manufacturing method (4) of the wiring board. Usually, it is 100 to 600 mJ / cm ² .

Step (C3) in wiring board manufacturing method (1), (3), (4), steps (C4) and (C5) in wiring board manufacturing method (2), and wiring board manufacturing method (5) The exposure in (C3) and step (C7) is preferably performed by a non-contact exposure method in an oxygen atmosphere. Examples of the non-contact exposure method include a proximity method, a projection method, and a direct drawing method that does not use a photo mask, in which a gap is provided between the photo mask and the wiring board to perform non-contact exposure. By performing non-contact exposure in an oxygen atmosphere in the absence of a support layer film on the solder resist layer 2, the first solder resist layer 2-1, and the second solder resist layer 2-2, the surface layer of each solder resist layer Photopolymerization in the vicinity (depth from the solder resist layer surface of about 0 to 0.5 μm) is inhibited by the influence of oxygen to become an uncured portion, and only the portion away from the surface layer is cured. Therefore, step (D) in the manufacturing method (1) of the wiring substrate, steps (B2) and (D) in the manufacturing method (2) of the wiring substrate, the step (D1) in the manufacturing method (3) of the wiring substrate, the wiring substrate The steps (D) and (D2) in the manufacturing method (4) of step (D1) in the manufacturing method (5) of the wiring board remove the uncured portion near the surface layer, and the solder resist layer 2 and the first solder resist The surfaces of the layer 2-1 and the second solder resist layer 2-2 are roughened. When the surface of the solder resist layer around the connection pads for connecting electronic components on the surface of the wiring board is roughened, the adhesiveness with the underfill becomes stronger when the surface is roughened. It is possible to prevent stress from being concentrated on the connection part between the electronic component and the wiring board due to the impact, and the connection reliability is further improved. Adhesion with the underfill is improved by roughening the surfaces of the solder resist layer 2, the first solder resist layer 2-1, and the second solder resist layer 2-2 by non-contact exposure in an oxygen atmosphere. In addition, high connection reliability can be obtained. The surface roughness Ra of the solder resist layer preferable for improving the adhesion with the underfill is 0.30 μm or more and 0.50 μm or less. When the surface roughness Ra exceeds 0.50 μm, the strength of the solder resist is lowered and insulation reliability may not be obtained. The surface roughness Ra is an arithmetic average surface roughness.

The exposure amount in the step (C3) in the method (1), (3), (4) for manufacturing the wiring substrate and the steps (C4) and (C5) in the method (2) for manufacturing the wiring substrate are the exposure amounts in the step (C1). The amount is preferably 1 to 5 times, more preferably 1.5 to 3 times the amount. Similarly, the exposure amount in the step (C3) and the step (C7) in the manufacturing method (5) of the wiring board is preferably 1 to 5 times the exposure amount in the step (C6), more preferably It is 1.5 times or more and 3 times or less. In non-contact exposure in an oxygen atmosphere, the amount of exposure required to cure the solder resist to such an extent that the solder resist does not dissolve or swell is given to prevent polymerization by oxygen on the surface of the solder resist layer. Can be minimized. The larger the exposure amount, the more effective the suppression of polymerization inhibition is. On the other hand, too much exposure amount is not preferable because not only the resolution of the solder resist deteriorates but also the exposure time becomes too long. .

In the step (B) in the manufacturing method (1), (3) to (5) of the wiring substrate and the step (B2) in the manufacturing method (2) of the wiring substrate, the connection pad is formed on the first surface with the thinning treatment liquid. The solder resist layer 2 and the first solder resist layer 2-1 in the non-exposed part are thinned until the thickness becomes 3 or less, and a part of the connection pad 3 is exposed. In the step (B1) in the manufacturing method (2) of the wiring substrate and the step (B3) in the manufacturing method (5) of the wiring substrate, the first surface is not exposed to the extent that the connection pad 3 is not exposed by the thinning solution. The solder resist layer 2 and the second solder resist layer 2-2 in the exposed portion are thinned. When a film-like resist is used and a support layer film is provided, the support layer film is peeled off before thinning.

In the step (B) in the wiring board manufacturing method (1), (3) to (5) and in the step (B2) in the wiring board manufacturing method (2), the solder resist layer 2 and the first solder resist after thinning Thinning is performed until the thickness of the layer 2-1 is equal to or less than the thickness of the connection pad 3 exposed on the first surface. If the thickness of the solder resist layer 2 and the first solder resist layer 2-1 after thinning is too thin, the electrical insulation between the exposed connection pads 3 becomes insufficient, and an electroless nickel / gold plating short circuit occurs. Or a short circuit may occur between the connection pads 3 due to solder. Therefore, the thickness of the solder resist layer 2 and the first solder resist layer 2-1 after thinning is preferably at least one third of the thickness of the connection pad 3, more preferably at least two thirds. It is good to be.

In the step (B) in the manufacturing method (1) of the wiring substrate and the steps (B1) and (B2) in the manufacturing method (2) of the wiring substrate, when the solder resist layer 2 of the non-exposed portion on the first surface is thinned, The solder resist layer 2 on the non-exposed portion on the second surface is also thinned at the same time. In the step (B) in the manufacturing methods (3) to (5) of the wiring board, when the first solder resist layer 2-1 in the non-exposed portion on the first surface is thinned, the first in the non-exposed portion on the second surface is obtained. The solder resist layer 2-1 is also thinned at the same time. In the step (B3) in the method (5) of manufacturing the wiring board, when the second solder resist layer 2-2 in the non-exposed portion on the first surface is thinned, the first solder resist layer 2 in the non-exposed portion on the second surface is formed. -1 is also thinned at the same time. The amount of thinning of the second surface varies depending on the heat-cured state of the solder resist layer 2 and the first solder resist layer 2-1 in the non-exposed portion on the second surface, but the solder resist layer 2 under the same heating conditions on both surfaces, When the first solder resist layer 2-1 is formed, the solder resist layer 2 and the first solder resist layer 2-1 in the non-exposed portion of the first surface and the second surface are usually thinned in the same amount at the same time. .

Step (B) in wiring board manufacturing method (1), (3) to (5), step (B1) and (B2) in wiring board manufacturing method (2), step in wiring board manufacturing method (5) In (B3), the thinning treatment is preferably performed with the first surface facing up. As a processing method for the thinning treatment, dipping treatment is effective because bubbles are not easily generated in the thinning treatment solution. In the unlikely event that bubbles are generated in the thinning solution, the bubbles will rise in the thinning solution and adhere to the solder resist layer 2 on the lower surface (second surface) and the surface of the first solder resist layer 2-1. To do. Due to the adhesion of the bubbles, the film thickness after thinning on the second surface may become non-uniform. However, the manufacturing method (1), (2), and (4) of the wiring board, which is a subsequent process, the process (D1) in the manufacturing methods (3) and (5) of the wiring board, and the manufacturing of the wiring board In the step (D2) in the method (4), the solder resist layer 2 and the first solder resist layer 2-1 in the non-exposed portion on the second surface are developed and removed, and therefore, unevenness of the film thickness eventually becomes a problem. There is no.

In the step (D) in the manufacturing method (1) and (2) of the wiring board, the solder resist layer 2 in the non-exposed part on the second surface is removed by development. In the step (D) in the manufacturing method (4) of the wiring board, the first solder resist layer 2-1 in the non-exposed portion on the second surface is removed by development. In the step (D1) in the manufacturing methods (3) and (5) of the wiring substrate, the second solder resist layer 2-2 in the non-exposed portion on the first surface and the first solder in the non-exposed portion on the second surface are developed by development. The resist layer 2-1 is removed. In step (D2) in the method (4) for manufacturing the wiring board, the second solder resist layer 2-2 in the non-exposed portion on the first surface is removed by development. As a developing method, a developer corresponding to the solder resist to be used is used, spray is sprayed on both surfaces of the circuit board, and unnecessary portions of each solder resist layer are removed. A dilute alkaline aqueous solution is used as the developer, and generally a 0.3 to 3 mass% sodium carbonate aqueous solution or potassium carbonate aqueous solution is used.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Examples 1 to 6 are examples relating to the manufacturing method (1) of the wiring board shown in FIGS. 4-1 and 4-2.

(Example 1)
<Process (A)>
Using a semi-additive method, a circuit board 1 (area 170 mm × 200 mm, conductor thickness 15 μm, board thickness 0.4 mm) having conductor wirings 7 formed on both surfaces was produced. On the front surface (first surface) side, there is a conductor wiring having a line width of 25 μm and an interval of 50 μm used as the connection pad 3 for connecting electronic components. A circular conductor wiring having a diameter of 600 μm used as the external connection pad 4 is formed on the back surface (second surface) side. Next, using a vacuum laminator, a 25 μm thick solder resist film (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded to both surfaces of the circuit board 1 (lamination temperature). 75 ° C., suction time 30 seconds, pressurization time 10 seconds). Thereby, the soldering resist layer 2 was formed. In the solder resist layer 2 on the first surface, the thickness from the surface of the insulating layer 8 was 30 μm, and the thickness on the connection pad 3 for connecting electronic components was 15 μm. In the solder resist layer 2 on the second surface, the thickness from the surface of the insulating layer 8 was 38 μm, and the thickness on the connection pad 4 for external connection was 23 μm. On the first surface where the density of the conductor wiring is smaller, the thickness of the solder resist layer 2 is 8 μm thinner than on the second surface where the density of the conductor wiring is larger.

<Process (C1)>
A photomask 5 having a pattern in which actinic rays 6 are irradiated to a region outside the outer periphery 200 μm away from the end portions of the plurality of connection pads 3 for connecting electronic components to the solder resist layer 2 on the first surface. The contact exposure was performed at an exposure amount of 200 mJ / cm ² .

<Process (C2)>
A photomask having a pattern in which actinic rays 6 are irradiated in areas other than the circular opening area in order to provide a circular opening area having a diameter of 500 μm on the external connection pad 4 for the solder resist layer 2 on the second surface. 5 was used for contact exposure at an exposure amount of 200 mJ / cm ² .

<Process (B)>
After peeling off the support layer film on the solder resist layer 2 on the first surface and the second surface, 10% by mass of sodium metasilicate aqueous solution (liquid temperature 25 ° C.) is used as the thinning treatment solution, Then, the circuit board 1 was immersed in the thinning treatment solution for 50 seconds to perform micellization treatment (thinning treatment). Thereafter, the micelle removal treatment by spraying the micelle removal liquid (liquid temperature 25 ° C.), the water washing treatment (liquid temperature 25 ° C.) and the drying treatment are performed, and the thickness of the solder resist layer 2 of the non-exposed portion on the first surface is the electronic component. The solder resist layer 2 having an average of 20 μm was thinned to 5.0 μm below the surface of the connection pad 3 for connection. When observed with an optical microscope, the surface of the solder resist layer 2 on the first surface was free from uneven processing, and good in-plane uniformity was obtained. On the other hand, the solder resist layer 2 having an average thickness of 20 μm was also thinned on the second surface, but bubbles in the thinning treatment liquid adhered to the solder resist layer 2 in the non-exposed area on the second surface, and the film thickness was not improved. There was a uniform spot. Further, a residue of about 3 μm of the solder resist layer 2 remained on the connection pad 4 for external connection.

<Process (C3)>
The actinic ray 6 is irradiated to the solder resist layer 2 on the first surface to the region portion thinned in the step (B) and the region from the boundary portion of the thinned region to the outside of 200 μm. Using a photomask 5 having a pattern, exposure was performed at an exposure amount of 400 mJ / cm ² by non-contact exposure in an oxygen atmosphere.

<Process (D)>
Development was performed for 30 seconds using a 1% by mass aqueous sodium carbonate solution (liquid temperature 30 ° C., spray pressure 0.15 MPa), and the solder resist layer 2 in the non-exposed area on the second surface was removed. As a result of observation with an optical microscope, no residue of the solder resist layer 2 was found on the connection pad 3 for connecting electronic parts and the connection pad 4 for external connection on both the first surface and the second surface. On the first surface, the solder resist layer 2 was filled between the connection pads 3 for electronic component connection up to 5.5 μm below the surface of the connection pads 3 for electronic component connection. The non-contact exposure in the oxygen atmosphere in the step (C3) suppresses the photopolymerization of the surface of the solder resist layer 2 between the connection pads 3 for connecting electronic components, and as a result, the thickness of the solder resist layer 2 is 0.5 μm. It was decreasing.

Next, in order to cure the solder resist layer 2 on the first surface and the second surface, the entire surface is exposed with an exposure amount of 1000 mJ / cm ² , and then a thermosetting process is performed at 150 ° C. for 60 minutes to obtain a wiring board. It was. As a result of observation with an optical microscope, on the first surface, the conductor wiring 7 having a thickness of 15 μm is covered with the solder resist layer 2 having a thickness of 30 μm, and the connection pad 3 for connecting an electronic component having a thickness of 15 μm is exposed. The solder resist layer 2 having a thickness of 9.5 μm was filled between the connection pads 3 for connecting electronic components. On the second surface, a circular opening of the solder resist layer 2 having a thickness of 38 μm and a diameter of 500 μm is formed on a part of the connection pad 4 for external connection having a thickness of 15 μm. A part of was exposed.

Next, the surface roughness of the solder resist layer 2 between adjacent connection pads 3 for connecting electronic components was measured. When the surface roughness was measured using an ultra-deep shape measuring microscope (manufactured by Keyence Corporation, product number “VK-8500”), the surface roughness Ra was 0.40 μm.

The arithmetic average surface roughness Ra by an ultra-deep shape measuring microscope (manufactured by Keyence Corporation, product number “VK-8500”) uses a calculation formula according to JIS B0601-1994 surface roughness-definition. The measurement area was 900 μm ² and the reference length was 40 μm.

(Example 2)
The steps (A) to (D) were performed in the same manner as in Example 1 except that the order of the steps (C1) and (C2) was changed. As a result of observation with an optical microscope, no residue of the solder resist layer 2 was found on the connection pads 3 for connecting electronic components and the connection pads 4 for external connection on both the first surface and the second surface. Further, on the first surface, the solder resist layer 2 was filled between the connection pads 3 for connecting electronic components up to 5.5 μm below the surface of the connection pads 3 for connecting electronic components. The non-contact exposure in the oxygen atmosphere in the step (C3) suppresses photopolymerization of the surface of the solder resist layer 2 between the connection pads 3 for connecting electronic components, and as a result, the thickness of the solder resist layer 2 is reduced by 0.5 μm. Was.

Next, in order to cure the solder resist layer 2 on the first surface and the second surface, the entire surface is exposed with an exposure amount of 1000 mJ / cm ² , and then a thermosetting process is performed at 150 ° C. for 60 minutes to obtain a wiring board. It was. As a result of observation with an optical microscope, on the first surface, the conductor wiring 7 having a thickness of 15 μm is covered with the solder resist layer 2 having a thickness of 30 μm, and the connection pad 3 for connecting an electronic component having a thickness of 15 μm is exposed. The solder resist layer 2 having a thickness of 9.5 μm was filled between the connection pads 3 for connecting electronic components. On the second surface, a circular opening of a solder resist layer having a thickness of 38 μm and a diameter of 500 μm is formed on a part of the connection pad 4 for external connection having a thickness of 15 μm. Some were exposed.

Next, when the surface roughness of the solder resist layer 2 between the adjacent connection pads 3 for connecting electronic components was measured, the surface roughness Ra was 0.40 μm.

(Example 3)
Steps (A) to (D) were performed in the same manner as in Example 1 except that the exposure amount in step (C3) was 200 mJ / cm ² . As a result of observation with an optical microscope, no residue of the solder resist layer 2 was found on the connection pads 3 for connecting electronic components and the connection pads 4 for external connection on both the first surface and the second surface. On the first surface, the solder resist layer 2 was filled between the connection pads 3 for electronic component connection up to 6.0 μm below the surface of the connection pads 3 for electronic component connection. By the non-contact exposure in the oxygen atmosphere in the step (C3), photopolymerization of the surface of the solder resist layer 2 between the connection pads 3 for connecting electronic components is suppressed, and as a result, the thickness of the solder resist layer 2 is reduced by 1.0 μm. Was.

Next, in order to cure the solder resist layer 2 on the first surface and the second surface, the entire surface is exposed with an exposure amount of 1000 mJ / cm ² , and then a thermosetting process is performed at 150 ° C. for 60 minutes to obtain a wiring board. It was. As a result of observation with an optical microscope, on the first surface, the conductor wiring 7 having a thickness of 15 μm is covered with the solder resist layer 2 having a thickness of 30 μm, and the connection pad 3 for connecting an electronic component having a thickness of 15 μm is exposed. The solder resist layer 2 having a thickness of 9.0 μm was filled between the connection pads 3 for connecting the electronic components. On the second surface, a circular opening of the solder resist layer 2 having a thickness of 38 μm and a diameter of 500 μm is formed on a part of the connection pad 4 for external connection having a thickness of 15 μm. A part of was exposed.

Next, when the surface roughness of the solder resist layer 2 between the adjacent connection pads 3 for connecting electronic components was measured, the surface roughness Ra was 0.50 μm.

Example 4
Steps (A) to (D) were performed in the same manner as in Example 1 except that the exposure amount in step (C3) was 1000 mJ / cm ² . As a result of observation with an optical microscope, no residue of the solder resist layer 2 was found on the connection pads 3 for connecting electronic components and the connection pads 4 for external connection on both the first surface and the second surface. On the first surface, the solder resist layer 2 was filled between the connection pads 3 for electronic component connection up to 5.0 μm below the surface of the connection pads 3 for electronic component connection. No film loss of the solder resist layer 2 on the first surface due to inhibition of oxygen polymerization in the step (C3) was confirmed.

Next, in order to cure the solder resist layer 2 on the first surface and the second surface, the entire surface is exposed with an exposure amount of 1000 mJ / cm ² , and then a thermosetting process is performed at 150 ° C. for 60 minutes to obtain a wiring board. It was. As a result of observation with an optical microscope, on the first surface, the conductor wiring 7 having a thickness of 15 μm is covered with the solder resist layer 2 having a thickness of 30 μm, and the connection pads 3 for connecting an electronic component having a thickness of 15 μm are exposed. The solder resist layer 2 having a thickness of 10.0 μm was filled between the connection pads 3 for connecting electronic components. On the second surface, a circular opening of the solder resist layer 2 having a thickness of 38 μm and a diameter of 500 μm is formed on a part of the connection pad 4 for external connection having a thickness of 15 μm. A part of was exposed.

Next, when the surface roughness of the solder resist layer 2 between the adjacent connection pads 3 for connecting electronic components was measured, the surface roughness Ra was 0.30 μm.

(Example 5)
The same method as in Example 1 except that the exposure in the step (C3) was performed at an exposure amount of 400 mJ / cm ² using a direct drawing apparatus (trade name: LI-8500, manufactured by Dainippon Screen Mfg. Co., Ltd.) in an oxygen atmosphere. Then, steps (A) to (D) were carried out. As a result of observation with an optical microscope, no residue of the solder resist layer 2 was found on the connection pads 3 for connecting electronic components and the connection pads 4 for external connection on both the first surface and the second surface. On the first surface, the solder resist layer 2 was filled between the connection pads 3 for electronic component connection up to 5.5 μm below the surface of the connection pads 3 for electronic component connection. The non-contact exposure in the oxygen atmosphere in the step (C3) suppresses photopolymerization of the surface of the solder resist layer 2 between the connection pads 3 for connecting electronic components, and as a result, the thickness of the solder resist layer 2 is reduced by 0.5 μm. Was.

(Example 6)
Steps (A) to (D) were carried out in the same manner as in Example 1 except that in the step (C3), the exposure was performed by the contact exposure method. As a result of observation with an optical microscope, no residue of the solder resist layer 2 was found on the connection pads 3 for connecting electronic components and the connection pads 4 for external connection on both the first surface and the second surface. On the first surface, the solder resist layer 2 was filled between the connection pads 3 for electronic component connection up to 5.0 μm below the surface of the connection pads 3 for electronic component connection. In the step (C3), the surface of the solder resist layer 2 is not roughened because the exposure is performed in a non-oxygen atmosphere by sufficiently releasing the air during the contact exposure, and as a result, the thickness of the solder resist layer 2 is increased. Did not decrease.

Next, in order to cure the solder resist layer 2 on the first surface and the second surface, the entire surface is exposed with an exposure amount of 1000 mJ / cm ² , and then a thermosetting process is performed at 150 ° C. for 60 minutes to obtain a wiring board. It was. As a result of observation with an optical microscope, on the first surface, the conductor wiring 7 having a thickness of 15 μm is covered with the solder resist layer 2 having a thickness of 30 μm, and the connection pad 3 for connecting an electronic component having a thickness of 15 μm is exposed. The solder resist layer 2 having a thickness of 10 μm was filled between the connection pads 3 for connecting electronic components. On the second surface, a circular opening of the solder resist layer 2 having a thickness of 38 μm and a diameter of 500 μm is formed in a part on the external connection pad 4 having a thickness of 15 μm so that the conductor pad 4 is exposed. It was.

Next, when the surface roughness of the solder resist layer 2 between the adjacent connection pads 3 for connecting electronic components was measured, the surface roughness Ra was 0.10 μm.

In Examples 1 to 6, since there is a solder resist layer 2 having a sufficient thickness between adjacent connection pads 3 for connecting electronic components, it is ensured that an electrical short circuit due to solder occurs when electronic components are mounted. I was able to prevent it. In addition, since there is no residue of the solder resist layer 2 on the connection pads 4 for external connection, a highly reliable wiring board that does not cause poor electrical insulation even when mounted on an external electric board could be produced. . Comparing Examples 1 to 6, the wiring manufactured in Examples 1 to 5 is more preferable than the wiring board manufactured in Example 6 in which the surface of the solder resist layer 2 between the connection pads 3 for connecting electronic components is smooth. The board had higher adhesion to the underfill and better connection reliability.

(Comparative Example 1)
<Process (A)>
Using a semi-additive method, a circuit board 1 (area 170 mm × 200 mm, conductor thickness 15 μm, board thickness 0.4 mm) having conductor wirings 7 formed on both surfaces was produced. On the surface (first surface), there is a conductor wiring having a line width of 25 μm and an interval of 50 μm used as the connection pad 3 for connecting electronic components. A circular conductor wiring having a diameter of 600 μm used as the external connection pad 4 is formed on the back surface (second surface). Next, using a vacuum laminator, a 25 μm thick solder resist film (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded to both surfaces of the circuit board 1 (lamination temperature). 75 ° C., suction time 30 seconds, pressurization time 10 seconds). Thereby, the soldering resist layer 2 was formed. In the solder resist layer 2 on the first surface, the thickness from the surface of the insulating layer 8 was 30 μm, and the thickness on the connection pad 3 for connecting electronic components was 15 μm. In the solder resist layer 2 on the second surface, the thickness from the surface of the insulating layer 8 was 38 μm, and the thickness on the connection pad 4 for external connection was 23 μm. On the first surface where the density of the conductor wiring is smaller, the thickness of the solder resist layer 2 is 8 μm thinner than on the second surface where the density of the conductor wiring is larger.

<Process (B)>
After peeling off the support layer film on the solder resist layer 2 on the first surface and the second surface, 10% by mass of sodium metasilicate aqueous solution (liquid temperature 25 ° C.) is used as the thinning treatment solution, Then, the circuit board 1 was immersed in the thinning treatment solution for 50 seconds to perform micellization treatment (thinning treatment). Thereafter, the micelle removal treatment by spraying the micelle removal liquid (liquid temperature 25 ° C.), the water washing treatment (liquid temperature 25 ° C.) and the drying treatment are performed, and the thickness of the solder resist layer 2 of the non-exposed portion on the first surface is the electronic component. The solder resist layer 2 having an average of 20 μm was thinned to 5.0 μm below the surface of the connection pad 3 for connection. When observed with an optical microscope, the surface of the solder resist layer 2 on the first surface was free from uneven processing, and good in-plane uniformity was obtained. On the other hand, the solder resist layer 2 on the second surface was also thinned by an average of 20 μm, but bubbles in the thinning treatment liquid adhered to the solder resist layer 2 on the non-exposed portion of the second surface, resulting in non-uniform film thickness. There was a place. Further, the residue of the solder resist layer 2 of about 3 μm remained on the connection pad 4 for external connection.

Next, in order to cure the solder resist layer 2 on the first surface and the second surface, the entire surface is exposed with an exposure amount of 1000 mJ / cm ² , and then a thermosetting process is performed at 150 ° C. for 60 minutes to obtain a wiring board. It was. As a result of observation with an optical microscope, on the first surface, the conductor wiring 7 having a thickness of 15 μm is covered with the solder resist layer 2 having a thickness of 30 μm, and the connection pads 3 for connecting an electronic component having a thickness of 15 μm are exposed. The solder resist layer 2 having a thickness of 10.0 μm was filled between the connection pads 3 for connecting electronic components. Further, the second surface was formed with a circular opening of the solder resist layer 2 having a thickness of 38 μm and a diameter of 500 μm on a part of the connection pad 4 for external connection having a thickness of 15 μm. Residue of the solder resist layer 2 having a thickness of 3 μm remained on the top.

When mounting an electronic component, there was a solder resist layer 2 of sufficient thickness between adjacent connection pads 3 for connecting an electronic component, and an electrical short circuit due to solder could be reliably prevented. When mounting, due to the residue of the solder resist layer 2 remaining on the connection pad 4 for external connection, an electrical insulation failure occurred in the solder bump connection.

When the surface roughness of the solder resist layer 2 between the adjacent connection pads 3 for connecting electronic components was measured, the surface roughness Ra was 0.03 μm. The wiring board manufactured in Examples 1 to 5 has better adhesion to the underfill than the wiring board manufactured in Comparative Example 1 in which the solder resist surface between the connection pads 3 for connecting electronic components is smooth. High connection reliability.

Examples 7 to 11 are examples relating to the method (2) for manufacturing the wiring board shown in FIGS. 5-1, 5-2, and 5-3.

(Example 7)
<Process (A)>
Using a semi-additive method, a circuit board 1 (area 170 mm × 200 mm, conductor thickness 15 μm, board thickness 0.4 mm) having conductor wirings 7 formed on both surfaces was produced. On the surface (first surface), there is a conductor wiring having a line width of 25 μm and an interval of 50 μm used as the connection pad 3 for connecting electronic components. A circular conductor wiring having a diameter of 600 μm used as the external connection pad 4 is formed on the back surface (second surface). Next, using a vacuum laminator, a 25 μm thick solder resist film (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded to both surfaces of the circuit board 1 (lamination temperature). 75 ° C., suction time 30 seconds, pressurization time 10 seconds). Thereby, the soldering resist layer 2 was formed. In the solder resist layer 2 on the first surface, the thickness from the surface of the insulating layer 8 was 30 μm, and the thickness on the connection pad 3 for connecting electronic components was 15 μm. In the solder resist layer 2 on the second surface, the thickness from the surface of the insulating layer 8 was 38 μm, and the thickness on the connection pad 4 for external connection was 23 μm. On the first surface where the density of the conductor wiring is smaller, the thickness of the solder resist layer 2 is 8 μm thinner than on the second surface where the density of the conductor wiring is larger.

<Process (C1)>
A photomask 5 having a pattern in which actinic rays 6 are irradiated to a region outside the outer periphery 400 μm away from the end portions of the plurality of connection pads 3 for connecting electronic components to the solder resist layer 2 on the first surface. The contact exposure was performed at an exposure amount of 200 mJ / cm ² .

<Process (B1)>
After peeling off the support layer film on the solder resist layer 2 on the first side and the second side, the first side is turned up using a 10% by mass sodium metasilicate aqueous solution (liquid temperature 25 ° C.) as a thinning solution. Then, the circuit board 1 was immersed in the thinning treatment solution for 25 seconds to perform micellization treatment (thinning treatment). Then, the micelle removal process by spraying the micelle removal liquid (liquid temperature 25 ° C.), the water washing process (liquid temperature 25 ° C.) and the drying process are performed, and the thickness of the solder resist layer 2 in the non-exposed portion on the first surface is the electronic component. The solder resist layer 2 having an average of 10 μm was thinned to 5.0 μm on the surface of the connection pad 3 for connection. When observed with an optical microscope, the surface of the solder resist layer 2 on the first surface was free from uneven processing, and good in-plane uniformity was obtained. On the other hand, the solder resist layer 2 on the second surface was also thinned by an average of 10 μm, but bubbles in the thinning treatment liquid adhered to the solder resist layer 2 on the non-exposed portion of the second surface, resulting in non-uniform film thickness. There was a place. Further, the residue of the solder resist layer 2 of about 13 μm remained on the connection pad 4 for external connection.

<Process (C4)>
A photomask 5 having a pattern in which actinic rays 6 are irradiated to a region outside the outer periphery that is 200 μm away from the end portions of the plurality of connection pads 3 for connecting electronic components to the solder resist layer 2 on the first surface. Was exposed at an exposure amount of 400 mJ / cm ² by non-contact exposure in an oxygen atmosphere.

<Process (B2)>
Using 10% by mass of sodium metasilicate aqueous solution (liquid temperature: 25 ° C.) as the thinning treatment solution, the circuit board 1 is immersed in the thinning treatment solution for 25 seconds with the first side facing up, and the micelle treatment (thinning) Treatment). Thereafter, the micelle removal treatment by spraying the micelle removal liquid (liquid temperature 25 ° C.), the water washing treatment (liquid temperature 25 ° C.) and the drying treatment are performed, and the thickness of the solder resist layer 2 of the non-exposed portion on the first surface is the electronic component. The solder resist layer 2 having an average of 10 μm was thinned to 5.0 μm below the surface of the connection pad 3 for connection. When observed with an optical microscope, the surface of the solder resist layer 2 on the first surface was free from uneven processing, and good in-plane uniformity was obtained. Solder resist layer 2 in the region from the outer periphery 200 μm away to the outer periphery 400 μm away from the end of the connection pad 3 for connecting electronic components arranged on the first surface by non-contact exposure in an oxygen atmosphere in step (C4) Surface photopolymerization was suppressed, and as a result, the thickness of the solder resist layer 2 was reduced by 0.5 μm. On the other hand, the solder resist layer 2 on the second surface was also thinned by an average of 10 μm, but bubbles in the thinning treatment liquid adhered to the solder resist layer 2 on the non-exposed portion of the second surface, resulting in non-uniform film thickness. There was a place. Further, the residue of the solder resist layer 2 of about 3 μm remained on the connection pad 4 for external connection.

<Process (C5)>
The actinic ray 6 is irradiated to the solder resist layer 2 on the first surface to the region part thinned in the step (B2) and the region from the boundary part of the thinned region to the outside of 200 μm. Using a photomask 5 having a pattern, exposure was performed at an exposure amount of 400 mJ / cm ² by non-contact exposure in an oxygen atmosphere.

<Process (D)>
Development was performed for 30 seconds using a 1% by mass aqueous sodium carbonate solution (liquid temperature 30 ° C., spray pressure 0.15 MPa), and the solder resist layer 2 in the non-exposed area on the second surface was removed. As a result of observation with an optical microscope, no residue of the solder resist layer 2 was found on the connection pad 3 for connecting electronic parts and the connection pad 4 for external connection on both the first surface and the second surface. On the first surface, the solder resist layer 2 was filled between the connection pads 3 for electronic component connection up to 5.5 μm below the surface of the connection pads 3 for electronic component connection. Photopolymerization of the surface of the solder resist layer 2 other than the region irradiated with the actinic ray 6 in the contact exposure in the step (C1) on the first surface by the non-contact exposure in the oxygen atmosphere in the steps (C4) and (C5). As a result, the thickness of the solder resist layer 2 was reduced by 0.5 μm.

Next, in order to cure the solder resist layer 2 on the first surface and the second surface, the entire surface is exposed with an exposure amount of 1000 mJ / cm ² , and then a thermosetting process is performed at 150 ° C. for 60 minutes to obtain a wiring board. It was. As a result of observation with an optical microscope, on the first surface, a conductor wiring 7 with a thickness of 15 μm is covered with a solder resist layer 2 with a thickness of 30 μm and 19.5 μm, and an underfill weir with a thickness of 10.5 μm corresponding to the step. A stop dam was formed. In addition, the electronic component connecting connection pads 3 having a thickness of 15 μm were exposed, and the solder resist layer 2 having a thickness of 9.5 μm was filled between the adjacent electronic component connecting connection pads 3. On the second surface, a circular opening of the solder resist layer 2 having a thickness of 38 μm and a diameter of 500 μm is formed on a part of the connection pad 4 for external connection having a thickness of 15 μm. A part of was exposed.

Next, a solder having a thickness of 19.5 μm in a region between the outer periphery 200 μm away from the ends of the plurality of connection pads 3 for connecting electronic components arranged on the first surface and the outer periphery 400 μm away from the ends When the surface roughness of the resist layer 2 was measured, the surface roughness Ra was 0.40 μm. Moreover, when the surface roughness of the soldering resist layer 2 between the adjacent connection pads 3 for electronic component connection was measured, the surface roughness Ra was 0.40 μm.

(Example 8)
Steps (A) to (D) were performed in the same manner as in Example 7 except that the order of the steps (C1) and (C2) was changed. As a result of observation with an optical microscope, no residue of the solder resist layer 2 was found on the connection pads 3 for connecting electronic components and the connection pads 4 for external connection on both the first surface and the second surface. Further, the solder resist layer 2 was filled up to 5.5 μm below the surface of the connection pad 3 for connecting electronic components arranged on the first surface. Photopolymerization of the surface of the solder resist layer 2 other than the region irradiated with the actinic ray 6 in the contact exposure in the step (C1) on the first surface by the non-contact exposure in the oxygen atmosphere in the steps (C4) and (C5). As a result, the thickness of the solder resist layer 2 was reduced by 0.5 μm.

Example 9
Steps (A) to (D) were carried out in the same manner as in Example 7 except that the exposure dose in steps (C4) and (C5) was 200 mJ / cm ² . As a result of observation with an optical microscope, no residue of the solder resist layer 2 was found on the connection pads 3 for connecting electronic components and the connection pads 4 for external connection on both the first surface and the second surface. Further, the solder resist layer 2 was filled up to 6.0 μm below the surface of the connection pad 3 for connecting electronic components arranged on the first surface. Photopolymerization of the surface of the solder resist layer 2 other than the region irradiated with the actinic ray 6 in the contact exposure in the step (C1) on the first surface by the non-contact exposure in the oxygen atmosphere in the steps (C4) and (C5). As a result, the thickness of the solder resist layer 2 was reduced by 1.0 μm.

Next, in order to cure the solder resist layer 2 on the first surface and the second surface, the entire surface is exposed with an exposure amount of 1000 mJ / cm ² , and then a thermosetting process is performed at 150 ° C. for 60 minutes to obtain a wiring board. It was. As a result of observation with an optical microscope, on the first surface, a conductor wiring 7 with a thickness of 15 μm is covered with a solder resist layer 2 with a thickness of 30 μm and a thickness of 19 μm. Was formed. Further, the connection pad 3 for connecting an electronic component having a thickness of 15 μm was exposed, and the solder resist layer 2 having a thickness of 9.0 μm was filled between adjacent connection pads 3 for connecting an electronic component. On the second surface, a circular opening of the solder resist layer 2 having a thickness of 38 μm and a diameter of 500 μm is formed on a part of the connection pad 4 for external connection having a thickness of 15 μm. A part of was exposed.

Next, a 19 μm thick solder resist layer in a region between the outer periphery 200 μm away from the ends of the plurality of connection pads 3 for connecting electronic components disposed on the first surface and the outer periphery 400 μm away from the ends When the surface roughness 2 was measured, the surface roughness Ra was 0.50 μm. Further, when the surface roughness of the solder resist layer 2 between the adjacent connection pads 3 for connecting electronic components was measured, the surface roughness Ra was 0.50 μm.

(Example 10)
Steps (A) to (D) were performed in the same manner as in Example 6 except that the exposure dose in steps (C4) and (C5) was 1000 mJ / cm ² . As a result of observation with an optical microscope, no residue of the solder resist layer 2 was found on the connection pads 3 for connecting electronic components and the connection pads 4 for external connection on both the first surface and the second surface. Further, the solder resist layer 2 is filled up to 5.0 μm below the surface of the connection pad 3 for connecting electronic components arranged on the first surface, and the first surface due to the inhibition of oxygen polymerization in the steps (C4) and (C5) The film loss of the solder resist layer 2 was not confirmed.

Next, in order to cure the solder resist layer 2 on the first surface and the second surface, the entire surface is exposed with an exposure amount of 1000 mJ / cm ² , and then a thermosetting process is performed at 150 ° C. for 60 minutes to obtain a wiring board. It was. As a result of observation with an optical microscope, on the first surface, a conductor wiring 7 with a thickness of 15 μm is covered with a solder resist layer 2 with a thickness of 30 μm and a thickness of 20 μm. Was formed. Further, the connection pad 3 for connecting an electronic component having a thickness of 15 μm was exposed, and the solder resist layer 2 having a thickness of 10.0 μm was filled between adjacent connection pads 3 for connecting an electronic component. On the second surface, a circular opening of the solder resist layer 2 having a thickness of 38 μm and a diameter of 500 μm is formed on a part of the connection pad 4 for external connection having a thickness of 15 μm. A part of was exposed.

Next, a solder resist layer having a thickness of 20 μm in a region between the outer periphery 200 μm away from the ends of the plurality of connection pads 3 for connecting electronic components arranged on the first surface and the outer periphery 400 μm away from the ends When the surface roughness 2 was measured, the surface roughness Ra was 0.30 μm. Further, when the surface roughness of the solder resist layer 2 between the adjacent connection pads 3 for connecting electronic components was measured, the surface roughness Ra was 0.30 μm.

(Example 11)
In the steps (C4) and (C5), the steps (A) to (D) were carried out in the same manner as in Example 7 except that the exposure was performed by the contact exposure method. As a result of observation with an optical microscope, no residue of the solder resist layer 2 was found on the connection pads 3 for connecting electronic components and the connection pads 4 for external connection on both the first surface and the second surface. On the first surface, the solder resist layer 2 was filled between the connection pads 3 for electronic component connection up to 5.0 μm below the surface of the connection pads 3 for electronic component connection. In the steps (C4) and (C5), the surface of the solder resist layer 2 was not roughened because exposure was performed in a non-oxygen atmosphere by sufficiently releasing air during contact exposure. As a result, the solder resist layer was not roughened. The thickness of 2 did not decrease.

Next, a solder resist layer having a thickness of 20 μm in a region between the outer periphery 200 μm away from the ends of the plurality of connection pads 3 for connecting electronic components arranged on the first surface and the outer periphery 400 μm away from the ends When the surface roughness 2 was measured, the surface roughness Ra was 0.10 μm. Further, when the surface roughness of the solder resist layer 2 between the adjacent connection pads 3 for connecting electronic components was measured, the surface roughness Ra was 0.10 μm.

In Examples 7 to 11, since there is a solder resist layer 2 having a sufficient thickness between adjacent connection pads 3 for connecting electronic components, it is ensured that an electrical short circuit due to solder occurs when the electronic components are mounted. I was able to prevent it. Since there is no residue of the solder resist layer 2 on the connection pad 4 for external connection, a highly reliable wiring board that does not cause an electrical insulation failure when mounted on the external electric board can be produced. Comparing Examples 7 to 11, it is manufactured in Examples 7 to 10 rather than the wiring board manufactured in Example 11 in which the surface of the solder resist layer 2 between and around the connection pads 3 for connecting electronic components is smooth. The printed wiring board had higher adhesion to the underfill and better connection reliability.

(Comparative Example 2)
<Process (A)>
Using a semi-additive method, a circuit board 1 (area 170 mm × 200 mm, conductor thickness 15 μm, board thickness 0.4 mm) having conductor wirings 7 formed on both surfaces was produced. On the surface (first surface), there is a conductor wiring having a line width of 25 μm and an interval of 50 μm used as the connection pad 3 for connecting electronic components. A circular conductor wiring having a diameter of 600 μm used as the external connection pad 4 is formed on the back surface (second surface). Next, using a vacuum laminator, a 25 μm thick solder resist film (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded to both surfaces of the circuit board 1 (lamination temperature). 75 ° C., suction time 30 seconds, pressurization time 10 seconds). Thereby, the soldering resist layer 2 was formed. In the solder resist layer 2 on the first surface, the thickness from the surface of the insulating layer 8 was 30 μm, and the thickness on the connection pad 3 for connecting electronic components was 15 μm. In the solder resist layer 2 on the second surface, the thickness from the surface of the insulating layer 8 was 38 μm, and the thickness on the connection pad 4 for external connection was 23 μm. On the first surface where the density of the conductor wiring is smaller, the thickness of the solder resist layer 2 is 8 μm thinner than on the second surface where the density of the conductor wiring is larger.

<Process (C4)>
The actinic ray 6 irradiates the area between the outer periphery 200 μm away from the ends of the plurality of connection pads 3 for connecting electronic components and the outer periphery 400 μm away from the ends of the solder resist layer 2 on the first surface. Using the photomask 5 having such a pattern, exposure was performed at a dose of 400 mJ / cm ² by non-contact exposure in an oxygen atmosphere.

Next, in order to cure the solder resist layer 2 on the first surface and the second surface, the entire surface is exposed with an exposure amount of 1000 mJ / cm ² , and then a thermosetting process is performed at 150 ° C. for 60 minutes to obtain a wiring board. It was. As a result of observation with an optical microscope, on the first surface, a conductor wiring 7 with a thickness of 15 μm is covered with a solder resist layer 2 with a thickness of 30 μm and 19.5 μm, and an underfill weir with a thickness of 10.5 μm corresponding to the step. A stop dam was formed. In addition, the electronic component connecting connection pads 3 having a thickness of 15 μm were exposed, and the solder resist layer 2 having a thickness of 9.5 μm was filled between the adjacent electronic component connecting connection pads 3. Further, the second surface has a circular opening of the solder resist layer 2 having a thickness of 38 μm and a diameter of 500 μm formed on a part of the connection pad 4 for external connection having a thickness of 15 μm. Residue of 3 μm solder resist layer 2 remained on the top.

When mounting electronic components, there is a solder resist layer 2 of sufficient thickness between adjacent connection pads 3 for connecting electronic components, which can prevent electrical short circuit due to soldering, but can be mounted on an external electric board. At this time, due to the residue of the solder resist layer 2 remaining on the connection pads 4 for external connection, an electrical insulation failure occurred in the solder bump connection.

When the surface roughness of the solder resist layer 2 between the adjacent connection pads 3 for connecting electronic components was measured, the surface roughness Ra was 0.03 μm. The wiring board manufactured in Examples 7 to 11 has better adhesion to the underfill than the wiring board manufactured in Comparative Example 2 in which the solder resist surface between the connection pads 3 for connecting electronic components is smooth. High connection reliability.

Examples 12 to 16 are examples relating to the manufacturing method (3) of the wiring board shown in FIGS. 6-1, 6-2, and 6-3.

Example 12
<Process (A1)>
Using a semi-additive method, a circuit board 1 (area 170 mm × 200 mm, conductor thickness 15 μm, board thickness 0.4 mm) having conductor wirings 7 formed on both surfaces was produced. On the surface (first surface), there is a conductor wiring having a line width of 25 μm and an interval of 50 μm used as the connection pad 3 for connecting electronic components. A circular conductor wiring having a diameter of 600 μm used as the external connection pad 4 is formed on the back surface (second surface). Next, using a vacuum laminator, a 15 μm thick solder resist film (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) is applied to the surface of the circuit board 1 and a 25 μm thick solder resist film ( Taiyo Ink Mfg. Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded to the back surface of the circuit board 1 (lamination temperature 75 ° C., suction time 30 seconds, pressurization time 10 seconds). Thereby, the first solder resist layer 2-1 was formed. In the first solder resist layer 2-1 on the first surface, the thickness from the surface of the insulating layer 8 was 20 μm, and the thickness on the connection pad 3 for connecting electronic components was 5 μm. In the first solder resist layer 2-1 on the second surface, the thickness from the surface of the insulating layer 8 was 38 μm, and the thickness on the connection pad 4 for external connection was 23 μm.

<Process (C1)>
The first solder resist layer 2-1 on the first surface has a pattern in which actinic rays 6 are irradiated to a region outside the outer periphery that is 200 μm away from the ends of the plurality of connection pads 3 for connecting electronic components. Using the photomask 5, contact exposure was performed with an exposure amount of 200 mJ / cm ² .

<Process (C2)>
In order to provide a circular opening area having a diameter of 500 μm on the external connection pad 4 with respect to the first solder resist layer 2-1 on the second surface, the actinic ray 6 is irradiated in a region other than the circular opening area. Using the photomask 5 having a pattern, contact exposure was performed at an exposure amount of 200 mJ / cm ² .

<Process (B)>
After peeling off the support layer film on the first solder resist layer 2-1 on the first surface and the second surface, a 10% by mass sodium metasilicate aqueous solution (liquid temperature 25 ° C.) was used as the thinning treatment solution. The circuit board 1 was immersed for 25 seconds in a thinning solution with one side facing up to perform micellization (thinning). Thereafter, the micelle removal treatment by spraying the micelle removal liquid (liquid temperature 25 ° C.), the water washing treatment (liquid temperature 25 ° C.) and the drying treatment are performed, and the thickness of the first solder resist layer 2-1 in the non-exposed portion of the first surface The first solder resist layer 2-1 having an average of 10 μm was thinned until the thickness became 5.0 μm below the surface of the connection pad 3 for connecting electronic parts. When observed with an optical microscope, the surface of the first solder resist layer 2-1 on the first surface was not uneven and good in-plane uniformity was obtained. On the other hand, the first solder resist layer 2-1 on the second surface was also thinned by an average of 10 μm, but bubbles in the thinning treatment liquid adhered to the first solder resist layer 2-1 on the non-exposed portion of the second surface. However, there was a portion where the film thickness was non-uniform. Further, the residue of the first solder resist layer 2-1 of about 13 μm remained on the connection pad 4 for external connection.

<Process (C3)>
Using a photomask 5 having a pattern in which actinic rays 6 are irradiated onto the thinned region in step (B) with respect to the first solder resist layer 2-1 on the first surface, in an oxygen atmosphere. In this non-contact exposure, exposure was performed at an exposure amount of 400 mJ / cm ² .

<Process (A2)>
The first solder on the first surface of the circuit board 1 which has completed the solder resist film (trade name: PFR-800 AUS410, manufactured by Taiyo Ink Manufacturing Co., Ltd.) having a thickness of 15 μm up to the step (C3) using a vacuum laminator. A vacuum thermocompression bonding was performed on the resist layer 2-1 (lamination temperature 75 ° C., suction time 30 seconds, pressurization time 10 seconds). As a result, the second solder resist layer 2-2 on the first surface was formed. In the second solder resist layer 2-2 on the first surface, the thickness from the surface of the insulating layer 8 was 30 μm.

<Process (C6)>
A photo of a pattern in which the active light beam 6 is irradiated to a region outside the outer periphery 400 μm away from the end of the connection pad 3 for connecting the electronic component to the second solder resist layer 2-2 on the first surface. Using mask 5, contact exposure was performed at an exposure amount of 200 mJ / cm ² .

<Process (D1)>
Development is performed for 30 seconds using a 1% by mass aqueous sodium carbonate solution (liquid temperature 30 ° C., spray pressure 0.15 MPa), and the second solder resist layer 2-2 in the non-exposed area on the first surface and the non-exposed surface on the second surface The first solder resist layer 2-1 in the exposed area was removed. As a result, an underfill dam is formed, and the electronic component connecting connection pad 3 exposed from the first solder resist layer 2-1 covered with the second solder resist layer 2-2 and its surroundings are formed. The first solder resist layer 2-1 was exposed again. As a result of observation with an optical microscope, residues of the first solder resist layer 2-1 and the second solder resist layer 2-2 on the connection pads 3 for electronic component connection and the connection pads 4 for external connection on both the first surface and the second surface Was not seen. Further, the first solder resist layer 2-1 was filled up to 5.5 μm below the surface of the connection pad 3 for connecting electronic parts arranged on the first surface. By non-contact exposure in an oxygen atmosphere in the step (C3), photopolymerization of the surface of the first solder resist layer 2-1 between the connection pads 3 for connecting electronic components arranged on the first surface is suppressed, and as a result, The thickness of the first solder resist layer 2-1 on the first surface was reduced by 0.5 μm.

Next, in order to cure the first solder resist layer 2-1 and the second solder resist layer 2-2 on the first surface and the first solder resist layer 2-1 on the second surface, the entire surface is exposed at an exposure amount of 1000 mJ / cm ² . The substrate was exposed and subsequently subjected to thermosetting at 150 ° C. for 60 minutes to obtain a wiring board. As a result of observation with an optical microscope, on the first surface, the conductor wiring 7 with a thickness of 15 μm is covered with the first solder resist layer 2-1 and the second solder resist layer 2-2 with a thickness of 30 μm and 20 μm, and the step is A corresponding underfill dam with a thickness of 10 μm was formed. Further, the electronic component connecting connection pads 3 having a thickness of 15 μm were exposed, and the first solder resist layer 2-1 having a thickness of 9.5 μm was filled between the adjacent electronic component connecting connection pads 3. On the second surface, a circular opening of the first solder resist layer 2-1 having a thickness of 38 μm and a diameter of 500 μm is formed on a part of the connection pad 4 for external connection having a thickness of 15 μm. A part of the connection pad 4 was exposed.

Next, a first solder having a thickness of 20 μm in a region between the outer periphery 200 μm away from the end of the plurality of connection pads 3 for connecting electronic components arranged on the first surface and the outer periphery 400 μm away from the end When the surface roughness of the resist layer 2-1 was measured, the surface roughness Ra was 0.05 μm. Further, when the surface roughness of the first solder resist layer 2-1 in the region between adjacent electronic component connection pads 3 was measured, the surface roughness Ra was 0.40 μm.

(Example 13)
The steps (A1) to (D1) were carried out in the same manner as in Example 12 except that the order of the steps (C1) and (C2) was changed. As a result of observation with an optical microscope, residues of the first solder resist layer 2-1 and the second solder resist layer 2-2 on the connection pads 3 for electronic component connection and the connection pads 4 for external connection on both the first surface and the second surface Was not seen. Further, the first solder resist layer 2-1 was filled up to 5.5 μm below the surface of the connection pad 3 for connecting electronic parts arranged on the first surface. By non-contact exposure in an oxygen atmosphere in the step (C3), the photopolymerization of the surface of the first solder resist layer 2-1 between the connection pads 3 for connecting electronic components arranged on the first surface is suppressed, and as a result, The thickness of the first solder resist layer 2-1 was reduced by 0.5 μm.

(Example 14)
Steps (A1) to (D1) were performed in the same manner as in Example 12 except that the exposure dose in step (C3) was 200 mJ / cm ² . As a result of observation with an optical microscope, residues of the first solder resist layer 2-1 and the second solder resist layer 2-2 on the connection pads 3 for electronic component connection and the connection pads 4 for external connection on both the first surface and the second surface Was not seen. Further, the first solder resist layer 2-1 was filled up to 6.0 μm below the surface of the connection pad 3 for connecting electronic components arranged on the first surface. By non-contact exposure in an oxygen atmosphere in the step (C3), the photopolymerization of the surface of the first solder resist layer 2-1 between the connection pads 3 for connecting electronic components arranged on the first surface is suppressed, and as a result, The thickness of the first solder resist layer 2-1 was reduced by 1.0 μm.

Next, in order to cure the first solder resist layer 2-1 and the second solder resist layer 2-2 on the first surface and the first solder resist layer 2-1 on the second surface, the entire surface is exposed at an exposure amount of 1000 mJ / cm ² . The substrate was exposed and subsequently subjected to thermosetting at 150 ° C. for 60 minutes to obtain a wiring board. As a result of observation with an optical microscope, on the first surface, the conductor wiring 7 with a thickness of 15 μm is covered with the first solder resist layer 2-1 and the second solder resist layer 2-2 with a thickness of 30 μm and 20 μm, and the step is A corresponding underfill dam with a thickness of 10 μm was formed. Further, the connection pad 3 for connecting an electronic component having a thickness of 15 μm was exposed, and the first solder resist layer 2-1 having a thickness of 9.0 μm was filled between adjacent connection pads 3 for connecting an electronic component. On the second surface, a circular opening of the first solder resist layer 2-1 having a thickness of 38 μm and a diameter of 500 μm is formed on a part of the connection pad 4 for external connection having a thickness of 15 μm. A part of the connection pad 4 was exposed.

Next, a first solder having a thickness of 20 μm in a region between the outer periphery 200 μm away from the end of the plurality of connection pads 3 for connecting electronic components arranged on the first surface and the outer periphery 400 μm away from the end When the surface roughness of the resist layer 2-1 was measured, the surface roughness Ra was 0.05 μm. Further, when the surface roughness of the first solder resist layer 2-1 in the region between adjacent electronic component connection pads 3 was measured, the surface roughness Ra was 0.50 μm.

(Example 15)
Steps (A1) to (D1) were performed in the same manner as in Example 12 except that the exposure dose in step (C3) was 1000 mJ / cm ² . As a result of observation with an optical microscope, residues of the first solder resist layer 2-1 and the second solder resist layer 2-2 on the connection pads 3 for electronic component connection and the connection pads 4 for external connection on both the first surface and the second surface Was not seen. Also, the first solder resist layer 2-1 is filled up to 5.0 μm below the surface of the connection pad 3 for connecting electronic components arranged on the first surface, and the first surface due to inhibition of oxygen polymerization in the step (C3) No film loss of the first solder resist layer 2-1 was confirmed.

Next, in order to cure the first solder resist layer 2-1 and the second solder resist layer 2-2 on the first surface and the first solder resist layer 2-1 on the second surface, the entire surface is exposed at an exposure amount of 1000 mJ / cm ² . The exposure was followed by a thermosetting treatment at 150 ° C. for 60 minutes. As a result of observation with an optical microscope, on the first surface, the conductor wiring 7 with a thickness of 15 μm is covered with the first solder resist layer 2-1 and the second solder resist layer 2-2 with a thickness of 30 μm and 20 μm, and the step is A corresponding underfill dam with a thickness of 10 μm was formed. Further, the connection pad 3 for connecting an electronic component having a thickness of 15 μm was exposed, and the first solder resist layer 2-1 having a thickness of 10.0 μm was filled between adjacent connection pads 3 for connecting an electronic component. On the second surface, a circular opening of the first solder resist layer 2-1 having a thickness of 38 μm and a diameter of 500 μm is formed on a part of the connection pad 4 for external connection having a thickness of 15 μm. A part of the connection pad 4 was exposed.

Next, a first solder having a thickness of 20 μm in a region between the outer periphery 200 μm away from the end of the plurality of connection pads 3 for connecting electronic components arranged on the first surface and the outer periphery 400 μm away from the end When the surface roughness of the resist layer 2-1 was measured, the surface roughness Ra was 0.05 μm. Further, when the surface roughness of the first solder resist layer 2-1 in the region between the adjacent electronic component connection pads 3 was measured, the surface roughness Ra was 0.30 μm.

(Example 16)
Step (A1) to Step (D1) were carried out in the same manner as in Example 12 except that the exposure in the contact exposure method was performed in Step (C3). As a result of observation with an optical microscope, residues of the first solder resist layer 2-1 and the second solder resist layer 2-2 on the connection pads 3 for electronic component connection and the connection pads 4 for external connection on both the first surface and the second surface Was not seen. Further, the first solder resist layer 2-1 was filled up to 5.0 μm below the surface of the connection pad 3 for connecting electronic parts arranged on the first surface. In step (C3), the surface of the first solder resist layer 2-1 was not roughened because the exposure was performed in a non-oxygen atmosphere by sufficiently releasing the air during contact exposure. As a result, the first solder resist layer 2-1 was not roughened. The thickness of the resist layer 2-1 did not decrease.

Next, a first solder having a thickness of 20 μm in a region between the outer periphery 200 μm away from the end of the plurality of connection pads 3 for connecting electronic components arranged on the first surface and the outer periphery 400 μm away from the end When the surface roughness of the resist layer 2-1 was measured, the surface roughness Ra was 0.05 μm. Further, when the surface roughness of the first solder resist layer 2-1 between the adjacent connection pads 3 for connecting electronic components was measured, the surface roughness Ra was 0.10 μm.

In Examples 12 to 16, since the first solder resist layer 2-1 having a sufficient thickness is provided between the adjacent connection pads 3 for connecting electronic components, an electrical short circuit due to solder occurs when the electronic components are mounted. It was possible to prevent this reliably. Since there is no residue of the first solder resist layer 2-1 on the connection pad 4 for external connection, it is possible to manufacture a highly reliable wiring board that does not cause an electrical insulation failure even when mounted on the external electric board. did it. Comparing the examples 12 to 16, the examples 12 to 15 are more suitable than the wiring board manufactured in the example 16 in which the surface of the first solder resist layer 2-1 between the connection pads 3 for connecting the electronic parts is smooth. The manufactured wiring board had higher adhesion to the underfill and better connection reliability.

Examples 17 to 21 are examples relating to the method (4) of manufacturing the wiring board shown in FIGS. 7-1, 7-2 and 7-3.

(Example 17)
<Process (A1)>
Using a semi-additive method, a circuit board 1 (area 170 mm × 200 mm, conductor thickness 15 μm, board thickness 0.4 mm) having conductor wirings 7 formed on both surfaces was produced. On the surface (first surface), there is a conductor wiring having a line width of 25 μm and an interval of 50 μm used as the connection pad 3 for connecting electronic components. A circular conductor wiring having a diameter of 600 μm used as the external connection pad 4 is formed on the back surface (second surface). Next, using a vacuum laminator, a 15 μm thick solder resist film (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) is applied to the surface of the circuit board 1 and a 25 μm thick solder resist film ( Taiyo Ink Mfg. Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded to the back surface of the circuit board 1 (lamination temperature 75 ° C., suction time 30 seconds, pressurization time 10 seconds). Thereby, the first solder resist layer 2-1 was formed. In the first solder resist layer 2-1 on the first surface, the thickness from the surface of the insulating layer 8 was 20 μm, and the thickness on the connection pad 3 for connecting electronic components was 5 μm. In the first solder resist layer 2-1 on the second surface, the thickness from the surface of the insulating layer 8 was 38 μm, and the thickness on the connection pad 4 for external connection was 23 μm.

<Process (D)>
Development was performed for 30 seconds using a 1% by mass aqueous sodium carbonate solution (liquid temperature 30 ° C., spray pressure 0.15 MPa) to remove the first solder resist layer 2-1 in the non-exposed area on the second surface.

<Process (A2)>
The first solder on the first surface of the circuit board 1 that has been processed up to the step (D) by using a vacuum laminator to complete a solder resist film having a thickness of 15 μm (trade name: PFR-800 AUS410, manufactured by Taiyo Ink Manufacturing Co., Ltd.) A vacuum thermocompression bonding was performed on the resist layer 2-1 (lamination temperature 75 ° C., suction time 30 seconds, pressurization time 10 seconds). As a result, the second solder resist layer 2-2 on the first surface was formed. In the second solder resist layer 2-2 on the first surface, the thickness from the surface of the insulating layer 8 was 30 μm.

<Process (D2)>
Development was performed for 30 seconds using a 1% by mass aqueous sodium carbonate solution (liquid temperature 30 ° C., spray pressure 0.15 MPa) to remove the second solder resist layer 2-2 in the non-exposed area on the first surface. As a result, an underfill dam is formed, and the electronic component connecting connection pad 3 exposed from the first solder resist layer 2-1 covered with the second solder resist layer 2-2 and its surroundings are formed. The first solder resist layer 2-1 was exposed again. As a result of observation with an optical microscope, residues of the first solder resist layer 2-1 and the second solder resist layer 2-2 on the connection pads 3 for electronic component connection and the connection pads 4 for external connection on both the first surface and the second surface Was not seen. Further, the first solder resist layer 2-1 was filled up to 5.5 μm below the surface of the connection pad 3 for connecting electronic parts arranged on the first surface. By non-contact exposure in an oxygen atmosphere in the step (C3), photopolymerization of the surface of the first solder resist layer 2-1 between the connection pads 3 for connecting electronic components arranged on the first surface is suppressed, and as a result, The thickness of the first solder resist layer 2-1 on the first surface was reduced by 0.5 μm.

(Example 18)
The steps (A1) to (D2) were performed in the same manner as in Example 17 except that the order of the steps (C1) and (C2) was changed. As a result of observation with an optical microscope, residues of the first solder resist layer 2-1 and the second solder resist layer 2-2 on the connection pads 3 for electronic component connection and the connection pads 4 for external connection on both the first surface and the second surface Was not seen. Further, the first solder resist layer 2-1 was filled up to 5.5 μm below the surface of the connection pad 3 for connecting electronic parts arranged on the first surface. By non-contact exposure in an oxygen atmosphere in the step (C3), photopolymerization of the surface of the first solder resist layer 2-1 between the connection pads 3 for connecting electronic components arranged on the first surface is suppressed, and as a result, The thickness of the first solder resist layer 2-1 on the first surface was reduced by 0.5 μm.

(Example 19)
Steps (A1) to (D2) were carried out in the same manner as in Example 17 except that the exposure amount in step (C3) was 200 mJ / cm ² . As a result of observation with an optical microscope, residues of the first solder resist layer 2-1 and the second solder resist layer 2-2 on the connection pads 3 for electronic component connection and the connection pads 4 for external connection on both the first surface and the second surface Was not seen. Further, the first solder resist layer 2-1 was filled up to 6.0 μm below the surface of the connection pad 3 for connecting electronic components arranged on the first surface. By non-contact exposure in an oxygen atmosphere in the step (C3), the photopolymerization of the surface of the first solder resist layer 2-1 between the connection pads 3 for connecting electronic components arranged on the first surface is suppressed, and as a result, The thickness of the first solder resist layer 2-1 on the first surface was reduced by 1.0 μm.

(Example 20)
Steps (A1) to (D2) were carried out in the same manner as in Example 17 except that the exposure dose in step (C3) was 1000 mJ / cm ² . As a result of observation with an optical microscope, residues of the first solder resist layer 2-1 and the second solder resist layer 2-2 on the connection pads 3 for electronic component connection and the connection pads 4 for external connection on both the first surface and the second surface Was not seen. Also, the first solder resist layer 2-1 is filled up to 5.0 μm below the surface of the connection pad 3 for connecting electronic components arranged on the first surface, and the first surface due to inhibition of oxygen polymerization in the step (C3) No film loss of the first solder resist layer 2-1 was confirmed.

Next, in order to cure the first solder resist layer 2-1 and the second solder resist layer 2-2 on the first surface and the first solder resist layer 2-1 on the second surface, the entire surface is exposed at an exposure amount of 1000 mJ / cm ² . The substrate was exposed and subsequently subjected to thermosetting at 150 ° C. for 60 minutes to obtain a wiring board. As a result of observation with an optical microscope, on the first surface, the conductor wiring 7 with a thickness of 15 μm is covered with the first solder resist layer 2-1 and the second solder resist layer 2-2 with a thickness of 30 μm and 20 μm, and the step is A corresponding underfill dam with a thickness of 10 μm was formed. Further, the connection pad 3 for connecting an electronic component having a thickness of 15 μm was exposed, and the first solder resist layer 2-1 having a thickness of 10.0 μm was filled between adjacent connection pads 3 for connecting an electronic component. On the second surface, a circular opening of the first solder resist layer 2-1 having a thickness of 38 μm and a diameter of 500 μm is formed on a part of the connection pad 4 for external connection having a thickness of 15 μm. A part of the connection pad 4 was exposed.

(Example 21)
Step (A1) to Step (D2) were carried out in the same manner as in Example 17 except that the exposure in the contact exposure method was performed in Step (C3). As a result of observation with an optical microscope, residues of the first solder resist layer 2-1 and the second solder resist layer 2-2 on the connection pads 3 for electronic component connection and the connection pads 4 for external connection on both the first surface and the second surface Was not seen. Further, the first solder resist layer 2-1 was filled up to 5.0 μm below the surface of the connection pad 3 for connecting electronic parts arranged on the first surface. In step (C3), the surface of the first solder resist layer 2-1 was not roughened because the exposure was performed in a non-oxygen atmosphere by sufficiently releasing the air during contact exposure. As a result, the first solder resist layer 2-1 was not roughened. The thickness of the resist layer 2-1 did not decrease.

Next, a first solder having a thickness of 20 μm in a region between the outer periphery 200 μm away from the end of the plurality of connection pads 3 for connecting electronic components arranged on the first surface and the outer periphery 400 μm away from the end When the surface roughness of the resist layer 2-1 was measured, the surface roughness Ra was 0.05 μm. Further, when the surface roughness of the first solder resist layer 2-2 between the adjacent connection pads 3 for connecting electronic components was measured, the surface roughness Ra was 0.10 μm.

In Examples 17 to 21, since the first solder resist layer 2-1 having a sufficient thickness is provided between adjacent connection pads 3 for connecting electronic components, an electrical short circuit due to solder occurs when the electronic components are mounted. It was possible to prevent this reliably. Since there is no residue of the first solder resist layer 2-1 on the connection pad 4 for external connection, it is possible to manufacture a highly reliable wiring board that does not cause an electrical insulation failure even when mounted on the external electric board. did it. Comparing Examples 17 to 21, in Examples 17 to 20, the surface of the first solder resist layer 2-1 between the connection pads 3 for connecting electronic components is smoother than the wiring board manufactured in Example 21. The manufactured wiring board had higher adhesion to the underfill and better connection reliability.

Examples 22 to 25 are examples relating to the manufacturing method (5) of the wiring board shown in FIGS. 8-1, FIG. 8-2, and FIG. 8-3.

(Example 22)
<Process (A1)>
Using a semi-additive method, a circuit board 1 (area 170 mm × 200 mm, conductor thickness 15 μm, board thickness 0.4 mm) having conductor wirings 7 formed on both surfaces was produced. On the surface (first surface), there is a conductor wiring having a line width of 25 μm and an interval of 50 μm used as the connection pad 3 for connecting electronic components. A circular conductor wiring having a diameter of 600 μm used as the external connection pad 4 is formed on the back surface (second surface). Next, using a vacuum laminator, a 15 μm thick solder resist film (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) is applied to the surface of the circuit board 1 and a 25 μm thick solder resist film ( Taiyo Ink Mfg. Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded to the back surface of the circuit board 1 (lamination temperature 75 ° C., suction time 30 seconds, pressurization time 10 seconds). Thereby, the first solder resist layer 2-1 was formed. In the first solder resist layer 2-1 on the first surface, the thickness from the surface of the insulating layer 8 was 20 μm, and the thickness on the connection pad 3 for connecting electronic components was 5 μm. In the first solder resist layer 2-1 on the second surface, the thickness from the surface of the insulating layer 8 was 38 μm, and the thickness on the connection pad 4 for external connection was 23 μm.

<Process (A2)>
The first solder on the first surface of the circuit board 1 that has completed the process up to step (C) using a vacuum laminator to complete a 20 μm thick solder resist film (manufactured by Taiyo Ink Manufacturing Co., Ltd., product name: PFR-800 AUS410). A vacuum thermocompression bonding was performed on the resist layer 2-1 (lamination temperature 75 ° C., suction time 30 seconds, pressurization time 10 seconds). As a result, the second solder resist layer 2-2 on the first surface was formed. In the second solder resist layer 2-2 on the first surface, the thickness from the surface of the insulating layer 8 was 30 μm.

<Process (B3)>
After peeling off the support layer film on the second solder resist layer 2-2 on the first surface, 10% by mass sodium metasilicate aqueous solution (liquid temperature 25 ° C.) was used as the thinning treatment solution, and the first surface was Then, the circuit board 1 was immersed in the thinning treatment solution for 25 seconds to perform micellization treatment (thinning treatment). Thereafter, the micelle removal treatment by spraying the micelle removal solution (liquid temperature 25 ° C.), the water washing treatment (liquid temperature 25 ° C.) and the drying treatment are performed, and the thickness of the second solder resist layer 2-2 in the non-exposed portion of the first surface The second solder resist layer 2-2 having an average thickness of 10 μm was thinned until the thickness became 5.0 μm on the surface of the connection pad 3 for connecting electronic components. When observed with an optical microscope, the surface of the second solder resist layer 2-2 on the first surface was not uneven and good in-plane uniformity was obtained. On the other hand, the first solder resist layer 2-1 on the second surface was also thinned by an average of 10 μm, but bubbles in the thinning treatment liquid adhered to the first solder resist layer 2-1 on the non-exposed portion of the second surface. However, there was a portion where the film thickness was non-uniform. Further, the residue of the first solder resist layer 2-1 of about 3 μm remained on the connection pad 4 for external connection.

<Process (C7)>
A photo of a pattern in which the active light beam 6 is irradiated to a region outside the outer periphery 200 μm away from the end of the connection pad 3 for connecting the electronic component to the second solder resist layer 2-2 on the first surface The mask 5 was used for exposure at an exposure amount of 400 mJ / cm ² by non-contact exposure in an oxygen atmosphere.

<Process (D1)>
Development is performed for 30 seconds using a 1% by mass aqueous sodium carbonate solution (liquid temperature 30 ° C., spray pressure 0.15 MPa), and the second solder resist layer 2-2 in the non-exposed area on the first surface and the non-exposed surface on the second surface The first solder resist layer 2-1 in the exposed area was removed. As a result, an underfill dam is formed, and the electronic component connecting connection pad 3 exposed from the first solder resist layer 2-1 covered with the second solder resist layer 2-2 and its surroundings are formed. The first solder resist layer 2-1 was exposed again. As a result of observation with an optical microscope, residues of the first solder resist layer 2-1 and the second solder resist layer 2-2 on the connection pads 3 for electronic component connection and the connection pads 4 for external connection on both the first surface and the second surface Was not seen. Further, the first solder resist layer 2-1 was filled up to 5.5 μm below the surface of the connection pad 3 for connecting electronic parts arranged on the first surface. By non-contact exposure in an oxygen atmosphere in the step (C3), photopolymerization of the surface of the first solder resist layer 2-1 between the connection pads 3 for connecting electronic components arranged on the first surface is suppressed, and as a result, The thickness of the first solder resist layer 2-1 on the first surface was reduced by 0.5 μm. Further, by non-contact exposure in an oxygen atmosphere in the step (C7), the outer periphery separated from the ends of the plurality of connection pads 3 for connecting electronic components arranged on the first surface by 200 μm and the outer periphery separated from the ends by 400 μm The photopolymerization of the surface of the second solder resist layer 2-2 having a thickness of 20 μm in the region between the second solder resist layer 2-2 is suppressed, and as a result, the thickness of the surface of the second solder resist layer 2-2 having a thickness of 20 μm is reduced to 0. It was reduced by 5 μm.

Next, in order to cure the first solder resist layer 2-1 and the second solder resist layer 2-2 on the first surface and the first solder resist layer 2-1 on the second surface, the entire surface is exposed at an exposure amount of 1000 mJ / cm ² . The substrate was exposed and subsequently subjected to thermosetting at 150 ° C. for 60 minutes to obtain a wiring board. As a result of observation with an optical microscope, on the first surface, the conductor wiring 7 having a thickness of 15 μm is covered with the second solder resist layer 2-2 having a thickness of 30 μm and 19.5 μm, and the thickness corresponding to the step is 10.5 μm. An underfill weir dam was formed. Further, the electronic component connecting connection pads 3 having a thickness of 15 μm were exposed, and the first solder resist layer 2-1 having a thickness of 9.5 μm was filled between the adjacent electronic component connecting connection pads 3. On the second surface, a circular opening of the first solder resist layer 2-1 having a thickness of 38 μm and a diameter of 500 μm is formed on a part of the connection pad 4 for external connection having a thickness of 15 μm. A part of the connection pad 4 was exposed.

Next, a 19.5 μm-thick first electrode in a region between the outer periphery 200 μm away from the ends of the plurality of connection pads 3 for connecting electronic components arranged on the first surface and the outer periphery 400 μm away from the ends. When the surface roughness of the two solder resist layer 2-2 was measured, the surface roughness Ra was 0.40 μm. Further, when the surface roughness of the first solder resist layer 2-1 in the region between adjacent electronic component connection pads 3 was measured, the surface roughness Ra was 0.40 μm.

(Example 23)
Steps (A1) to (D1) were performed in the same manner as in Example 22 except that the exposure dose in steps (C3) and (C7) was 200 mJ / cm ² . As a result of observation with an optical microscope, residues of the first solder resist layer 2-1 and the second solder resist layer 2-2 on the connection pads 3 for electronic component connection and the connection pads 4 for external connection on both the first surface and the second surface Was not seen. Further, the first solder resist layer 2-1 was filled up to 6.0 μm below the surface of the connection pad 3 for connecting electronic components arranged on the first surface. By non-contact exposure in an oxygen atmosphere in the step (C3), the photopolymerization of the surface of the first solder resist layer 2-1 between the connection pads 3 for connecting electronic components arranged on the first surface is suppressed, and as a result, The thickness of the first solder resist layer 2-1 on the first surface was reduced by 1.0 μm. Further, by non-contact exposure in an oxygen atmosphere in the step (C7), the outer periphery separated from the ends of the plurality of connection pads 3 for connecting electronic components arranged on the first surface by 200 μm and the outer periphery separated from the ends by 400 μm The photopolymerization of the surface of the second solder resist layer 2-2 having a thickness of 20 μm in the region between the first and second layers is suppressed. As a result, the thickness of the surface of the second solder resist layer 2-2 having a thickness of 20 μm is reduced to 1. It was reduced by 0.0 μm.

Next, in order to cure the solder resist layers 2-1 and 2-2 on the first surface and the first solder resist layer 2-1 on the second surface, the entire surface is exposed with an exposure amount of 1000 mJ / cm ² , and subsequently 150 A wiring board was obtained by performing a thermosetting treatment at 60 ° C. for 60 minutes. As a result of observation with an optical microscope, on the first surface, the conductor wiring 7 having a thickness of 15 μm is covered with the first solder resist layer 2-1 and the second solder resist layer 2-2 having a thickness of 30 μm and 19 μm, and the step is A corresponding underfill weir dam with a thickness of 11 μm was formed. Further, the connection pad 3 for connecting an electronic component having a thickness of 15 μm was exposed, and the first solder resist layer 2-1 having a thickness of 9.0 μm was filled between adjacent connection pads 3 for connecting an electronic component. On the second surface, a circular opening of the first solder resist layer 2-1 having a thickness of 38 μm and a diameter of 500 μm is formed on a part of the connection pad 4 for external connection having a thickness of 15 μm. A part of the connection pad 4 was exposed.

Next, a second solder having a thickness of 19 μm in a region between the outer periphery 200 μm away from the ends of the plurality of connection pads 3 for connecting electronic components arranged on the first surface and the outer periphery 400 μm away from the ends When the surface roughness of the resist layer 2-2 was measured, the surface roughness Ra was 0.50 μm. Further, when the surface roughness of the first solder resist layer 2-1 in the region between adjacent electronic component connection pads 3 was measured, the surface roughness Ra was 0.50 μm.

(Example 24)
Steps (A1) to (D1) were performed in the same manner as in Example 22 except that the exposure dose in steps (C3) and (C7) was 1000 mJ / cm ² . As a result of observation with an optical microscope, residues of the first solder resist layer 2-1 and the second solder resist layer 2-2 on the connection pads 3 for electronic component connection and the connection pads 4 for external connection on both the first surface and the second surface Was not seen. Further, the first solder resist layer 2-1 is filled up to 5.0 μm below the surface of the connection pad 3 for connecting the electronic parts arranged on the first surface, and oxygen polymerization inhibition in the steps (C3) and (C7) No film loss of the first solder resist layer 2-1 on the first surface and the second solder resist layer 2-2 on the first surface due to was confirmed.

Next, a second solder having a thickness of 20 μm in a region between the outer periphery 200 μm away from the end of the plurality of connection pads 3 for connecting electronic components arranged on the first surface and the outer periphery 400 μm away from the end When the surface roughness of the resist layer 2-2 was measured, the surface roughness Ra was 0.30 μm. Further, when the surface roughness of the first solder resist layer 2-1 in the region between the adjacent electronic component connection pads 3 was measured, the surface roughness Ra was 0.30 μm.

(Example 25)
In steps (C3) and (C7), steps (A1) to (D1) were performed in the same manner as in Example 22 except that the exposure was performed by the contact exposure method. As a result of observation with an optical microscope, residues of the first solder resist layer 2-1 and the second solder resist layer 2-2 on the connection pads 3 for electronic component connection and the connection pads 4 for external connection on both the first surface and the second surface Was not seen. Further, the first solder resist layer 2-1 was filled up to 5.0 μm below the surface of the connection pad 3 for connecting electronic parts arranged on the first surface. In the steps (C3) and (C7), the surface of the solder resist layer 2 was not roughened because the exposure was performed in a non-oxygen atmosphere by sufficiently releasing the air during contact exposure. The thicknesses of the first solder resist layer 2-1 and the second solder resist layer 2-2 on the first surface did not decrease.

Next, in order to cure the first solder resist layer 2-1 and the second solder resist layer 2-2 on the first surface and the first solder resist layer 2-1 on the second surface, the entire surface is exposed at an exposure amount of 1000 mJ / cm ² . The exposure was followed by a thermosetting treatment at 150 ° C. for 60 minutes. As a result of observation with an optical microscope, on the first surface, the conductor wiring 7 with a thickness of 15 μm is covered with the first solder resist layer 2-1 and the second solder resist layer 2-2 with a thickness of 30 μm and 20 μm, and the step is A corresponding underfill dam with a thickness of 10 μm was formed. Further, the connection pad 3 for connecting an electronic component having a thickness of 15 μm was exposed, and the first solder resist layer 2-1 having a thickness of 10 μm was filled between the connection pads 3 for connecting an electronic component adjacent to each other. On the second surface, a circular opening of the first solder resist layer 2-1 having a thickness of 38 μm and a diameter of 500 μm is formed on a part of the connection pad 4 for external connection having a thickness of 15 μm. A part of the connection pad 4 was exposed.

Next, a second solder having a thickness of 20 μm in a region between the outer periphery 200 μm away from the end of the plurality of connection pads 3 for connecting electronic components arranged on the first surface and the outer periphery 400 μm away from the end When the surface roughness of the resist layer 2-2 was measured, the surface roughness Ra was 0.10 μm. Further, when the surface roughness of the first solder resist layer 2-1 between the adjacent connection pads 3 for connecting electronic components was measured, the surface roughness Ra was 0.10 μm.

In Examples 22 to 25, since the first solder resist layer 2-1 having a sufficient thickness is provided between the adjacent connection pads 3 for connecting electronic components, an electrical short circuit due to solder occurs when the electronic components are mounted. It was possible to prevent this reliably. Since there is no residue of the first solder resist layer 2-1 on the connection pad 4 for external connection, it is possible to manufacture a highly reliable wiring board that does not cause an electrical insulation failure even when mounted on the external electric board. did it. Comparing Examples 22 to 25, the surfaces of the first solder resist layer 2-1 between the electronic component connecting connection pads 3 and the second solder resist layer 2-2 around the electronic component connecting connection pads 3 are smooth. Compared to the wiring board manufactured in Example 25, the wiring boards manufactured in Examples 22 to 24 had higher adhesion to the underfill and better connection reliability.

As described above, in the wiring boards manufactured according to Examples 1 to 6, a part of the connection pads 3 for connecting electronic components on the first surface is exposed from the solder resist layer 2. When flip-chip connection is performed using this wiring board, even in a wiring board in which the electronic component connecting connection pads 3 are arranged at a high density, a sufficient thickness is provided between the adjacent electronic component connecting connection pads 3. Since the solder resist layer 2 is provided, it is possible to reliably prevent an electrical short circuit due to solder when the electronic component is mounted. Further, the adhesive strength between the insulating layer 8 and the connection pad 3 for connecting electronic parts and the adhesive strength between the connection pad 3 for connecting electronic parts and solder are increased, and high connection reliability is obtained. Furthermore, when the exposure in the step (C3) is performed by a non-contact exposure method in an oxygen atmosphere, the surface of the solder resist layer 2 around the connection pad 3 for connecting electronic parts is sufficiently roughened, so Good adhesion to the fill and high connection reliability. Moreover, since there is no residue of the solder resist layer 2 on the surface of the external connection pad 4 on the second surface, there is no electrical insulation failure in solder connection when mounting on an external substrate, and high connection reliability is achieved. can get.

As described above, in the wiring boards manufactured according to Examples 7 to 26, part of the connection pads 3 for connecting electronic components is exposed from the solder resist layer 2 (first solder resist layer 2-1). And an underfill dam for preventing underfill formed by the two-stage solder resist layer 2 (the first solder resist layer 2-1 and the second solder resist layer 2-2). When flip-chip connection is performed using this wiring board, it is possible to prevent an underfill filling between the electronic component and the wiring board from overflowing around and adversely affecting electrical connection reliability. . Further, even in a wiring board in which the connection pads 3 for connecting electronic components are arranged at high density, a solder resist layer 2 (first solder resist layer 2-1) having a sufficient thickness between the adjacent connection pads 3 for connecting electronic components. Therefore, it is possible to reliably prevent an electrical short circuit due to solder when mounting an electronic component. The adhesive strength between the insulating layer 8 and the connection pad 3 for connecting electronic parts and the adhesive strength between the connection pad 3 for connecting electronic parts and solder are increased, and high connection reliability is obtained. Further, the steps (C4) and (C5) of the method (2) for manufacturing the wiring substrate, the methods (3), (4), (5) for manufacturing the wiring substrate (C3), and the method (5) for manufacturing the wiring substrate. When the exposure in the step (C7) is performed by a non-contact exposure method in an oxygen atmosphere, the solder resist layer 2 (first solder resist layer 2-1) between or around the connection pads 3 for connecting electronic components is used. Second solder resist layer 2-2) Since the surface is sufficiently roughened, adhesion to the underfill is good and high connection reliability is obtained. Further, since there is no residue of the first solder resist layer 2-1 on the surface of the external connection pad 4 on the second surface, there is no occurrence of electrical insulation failure in solder connection when mounted on the external substrate. Connection reliability can be obtained.

The method for manufacturing a wiring board according to the present invention can be applied, for example, to an application for manufacturing a wiring board having a plurality of connection pads for connecting electronic components such as semiconductor chips and other printed wiring boards.

1 Circuit Board 2 Solder Resist Layer 2-1 First Solder Resist Layer 2-2 Second Solder Resist Layer 3 Electronic Component Connection Pad, First Side Connection Pad 4 External Connection Connection Pad, Second Side Connection Pad 5 Photomask 6 Actinic ray 7 Conductor wiring 8 Insulating layer

Claims

A circuit board having an insulating layer and a connection pad formed on the surface of the insulating layer on both surfaces, a solder resist layer on both surfaces of the circuit board, and a part of the connection pad exposed from the solder resist layer In the manufacturing method of the wiring board which is doing,
(A) a step in which solder resist layers having different thicknesses are formed on both surfaces of a circuit board having an insulating layer and a connection pad formed on the surface of the insulating layer on both surfaces;
(C1) A step in which a portion other than the region to be thinned in the step (B) which is a subsequent step is exposed to the solder resist layer on the first surface which is thinner than the solder resist layer on the second surface,
(C2) A step of exposing a portion other than the region to be developed in step (D), which is a subsequent step, to the solder resist layer on the second surface,
(B) On the first surface, the solder resist layer of the non-exposed part is thinned until the thickness of the connection pad becomes equal to or less than the thickness of the connection pad by the thinning treatment solution, and a part of the connection pad is exposed.
(C3) The step of exposing the area portion thinned in step (B) to the solder resist layer on the first surface,
(D) the step of removing the solder resist layer of the non-exposed portion of the second surface with a developer;
A method for manufacturing a wiring board, comprising:
A circuit board having an insulating layer and a connection pad formed on the surface of the insulating layer on both surfaces, a solder resist layer on both surfaces of the circuit board, and a part of the connection pad exposed from the solder resist layer In the manufacturing method of the wiring board which is doing,
(A) a step in which solder resist layers having different thicknesses are formed on both surfaces of a circuit board having an insulating layer and a connection pad formed on the surface of the insulating layer on both surfaces;
(C1) A step of exposing a portion other than the region to be thinned in the step (B1), which is a subsequent step, to the solder resist layer on the first surface that is thinner than the solder resist layer on the second surface,
(C2) A step of exposing a portion other than the region to be developed in step (D), which is a subsequent step, to the solder resist layer on the second surface,
(B1) In the first surface, the step in which the solder resist layer of the non-exposed part is thinned by the thinning treatment liquid in a range where the connection pad is not exposed,
(C4) A step of exposing a portion other than the region to be thinned in the step (B2), which is a subsequent step, to the solder resist layer on the first surface,
(B2) On the first surface, the solder resist layer of the non-exposed portion is thinned until the thickness of the connection pad becomes equal to or less than the thickness of the connection pad by the thinning treatment solution, and a part of the connection pad is exposed.
(C5) The step of exposing the thinned region in step (B2) to the solder resist layer on the first surface,
(D) the step of removing the solder resist layer of the non-exposed portion of the second surface with a developer;
A method for manufacturing a wiring board, comprising:
A circuit board having an insulating layer and a connection pad formed on the surface of the insulating layer on both surfaces, a solder resist layer on both surfaces of the circuit board, and a part of the connection pad exposed from the solder resist layer In the manufacturing method of the wiring board which is doing,
(A1) a step in which first solder resist layers having different thicknesses are formed on both surfaces of a circuit board having an insulating layer and connection pads formed on the surfaces of the insulating layer on both surfaces;
(C1) The first solder resist layer on the first surface, which is thinner than the first solder resist layer on the second surface, is exposed to a portion other than the region to be thinned in the subsequent step (B). Process
(C2) A step of exposing a portion other than the region to be developed in step (D1), which is a subsequent step, to the first solder resist layer on the second surface,
(B) On the first surface, the first solder resist layer of the non-exposed part is thinned until the thickness of the connection pad is equal to or less than the thickness of the connection pad by the thinning treatment liquid, and a part of the connection pad is exposed;
(C3) The step of exposing the region portion thinned in step (B) to the first solder resist layer on the first surface,
(A2) A step of forming a second solder resist layer on the first solder resist layer on the first surface of the circuit board completed up to the step (C3),
(C6) A step in which a portion other than a region to be developed in the step (D1) which is a subsequent step is exposed to the second solder resist layer on the first surface;
(D1) a step of removing the second solder resist layer of the non-exposed portion of the first surface and the first solder resist layer of the non-exposed portion of the second surface with a developer;
A method for manufacturing a wiring board, comprising:
A circuit board having an insulating layer and a connection pad formed on the surface of the insulating layer on both surfaces, a solder resist layer on both surfaces of the circuit board, and a part of the connection pad exposed from the solder resist layer In the manufacturing method of the wiring board which is doing,
(A1) a step in which first solder resist layers having different thicknesses are formed on both surfaces of a circuit board having an insulating layer and connection pads formed on the surfaces of the insulating layer on both surfaces;
(C1) The first solder resist layer on the first surface, which is thinner than the first solder resist layer on the second surface, is exposed to a portion other than the region to be thinned in the subsequent step (B). Process
(C2) A step of exposing a portion other than a region to be developed in step (D), which is a subsequent step, to the first solder resist layer on the second surface;
(B) On the first surface, the first solder resist layer of the non-exposed part is thinned until the thickness of the connection pad is equal to or less than the thickness of the connection pad by the thinning treatment liquid, and a part of the connection pad is exposed;
(C3) The step of exposing the region portion thinned in step (B) to the first solder resist layer on the first surface,
(D) the step of removing the first solder resist layer of the non-exposed portion of the second surface with a developer;
(A2) A step in which a second solder resist layer is formed on the first solder resist layer on the first surface of the circuit board completed up to step (D),
(C6) A step in which a portion other than the region to be developed in the step (D2) which is a subsequent step is exposed to the second solder resist layer on the first surface,
(D2) a step of removing the second solder resist layer of the non-exposed portion of the first surface with a developer;
A method for manufacturing a wiring board, comprising:
A circuit board having an insulating layer and a connection pad formed on the surface of the insulating layer on both surfaces, a solder resist layer on both surfaces of the circuit board, and a part of the connection pad exposed from the solder resist layer In the manufacturing method of the wiring board which is doing,
(A1) a step in which first solder resist layers having different thicknesses are formed on both surfaces of a circuit board having an insulating layer and connection pads formed on the surfaces of the insulating layer on both surfaces;
(C2) A step of exposing a portion other than the region to be developed in step (D1), which is a subsequent step, to the first solder resist layer on the second surface,
(B) On the first surface, the first solder resist layer of the non-exposed part is thinned until the thickness of the connection pad is equal to or less than the thickness of the connection pad by the thinning treatment liquid, and a part of the connection pad is exposed;
(C3) The step of exposing the region portion thinned in step (B) to the first solder resist layer on the first surface,
(A2) A step of forming a second solder resist layer on the first solder resist layer on the first surface of the circuit board completed up to the step (C3),
(C6) A step of exposing a portion other than the region to be thinned in the subsequent step (B3) to the second solder resist layer on the first surface;
(B3) On the first surface, the second solder resist layer of the non-exposed part is thinned by the thinning treatment liquid in a range where the connection pad is not exposed,
(C7) A step in which a portion other than the region to be developed in the step (D1) which is a subsequent step is exposed to the second solder resist layer on the first surface;
(D1) a step of removing the second solder resist layer of the non-exposed portion of the first surface and the first solder resist layer of the non-exposed portion of the second surface with a developer;
A method for manufacturing a wiring board, comprising:
The method for manufacturing a wiring board according to any one of claims 1 to 4, wherein the step (C2) is performed before the step (C1).
The method for manufacturing a wiring board according to claim 1, wherein the step (C1) and the step (C2) are performed simultaneously.
5. The method of manufacturing a wiring board according to claim 1, wherein the exposure in the step (C3) is performed by a non-contact exposure method in an oxygen atmosphere.
The method for manufacturing a wiring board according to claim 5, wherein the exposure in the step (C3) and the step (C7) is performed by a non-contact exposure method in an oxygen atmosphere.
The method for manufacturing a wiring board according to claim 2, wherein the exposure in the step (C4) and the step (C5) is performed by a non-contact exposure method in an oxygen atmosphere.
The method for manufacturing a wiring board according to any one of claims 1, 3, 4, and 8, wherein an exposure amount in the step (C3) is 1 to 5 times the exposure amount in the step (C1).
The method for manufacturing a wiring board according to claim 5 or 9, wherein the exposure amount in the step (C3) and the step (C7) is 1 to 5 times the exposure amount in the step (C6).
The method for manufacturing a wiring board according to claim 2 or 10, wherein the exposure amount in the step (C4) and the step (C5) is 1 to 5 times the exposure amount in the step (C1).
The method for manufacturing a wiring board according to any one of claims 1, 3, 4, 8, and 11, wherein the thinning process of the solder resist layer in the step (B) is performed with the thinning process surface facing up.
The method for manufacturing a wiring board according to any one of claims 5, 9, and 12, wherein the thinning process of the solder resist layer in the step (B) and the step (B3) is performed with the thinning process surface facing upward.
14. The method for manufacturing a wiring board according to claim 2, wherein the thinning process of the solder resist layer in the step (B1) and the step (B2) is performed with the thinning process surface facing up.