JP3209290U - Printed wiring board - Google Patents

Abstract

[PROBLEMS] To provide a high bonding strength between a connecting portion and an insulating substrate and between a connecting portion and solder, hardly causing an electrical malfunction due to an underfill outflow, a high strength of a solder resist layer, and an adhesive strength between a solder resist layer and an underfill. Provided is a printed wiring board that is strong and has smear removed reliably. A circuit board having a connection part 2 for connecting an electronic component is formed on an insulating substrate 1, and a solder resist layer 3 having an opening 4 is provided on the surface of the circuit board. 2 is a printed wiring board partially exposed from the solder resist layer 3, and the opening width 5 at the top of the opening 4 in the solder resist layer 3 is equal to or less than the opening width 6 at the bottom 10 of the opening It is a printed wiring board characterized by having. [Selection] Figure 1

Description

  The present invention relates to a printed wiring board provided with a connecting portion for connecting electronic components.

  2. Description of the Related Art Conventionally, there is known a printed wiring board having a circuit board having a connection portion formed on an insulating substrate and having a surface insulating layer made of a solder resist layer provided on the surface of the circuit board.

  In general, connecting portions such as bumps or ball pads are provided on the surface of the printed wiring board, and electronic components such as semiconductor elements and other printed wiring boards are generally connected via solder balls disposed on the connecting portions. Has been done. In addition, in this connection part 2, the SMD (Solder Mask Defined) structure (FIG. 13) produced by removing the soldering resist layer 3 partially and exposing the whole or part of the connection part 2 surface, There is an NSMD (Non Solder Mask Defined) structure (FIG. 14) produced by partially removing the solder resist layer 3 and completely exposing the connection part 2.

  In the SMD structure, the periphery of the connection portion 2 is covered with the solder resist layer 3. Therefore, there is an advantage that peeling of the connection portion 2 due to mechanical impact and disconnection of the neck portion in the lead-out wiring from the connection portion 2 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 portion, it is necessary to secure a necessary amount of solder at the joint portion formed on the exposed surface of the connection portion 2. is there. Therefore, since the connection part 2 becomes large, there exists a fault that it is difficult to respond to the request | requirement of the high density of a connection part accompanying the miniaturization and performance enhancement of an electronic component.

  In the NSMD structure, the solder resist layer 3 in the vicinity of the connection portion 2 is completely removed, and the side surface of the connection portion 2 is completely exposed. Therefore, compared with the SMD structure, there is an advantage that even the small connection portion 2 can ensure the bonding strength between the connection portion 2 and the solder.

  However, there are drawbacks in that the adhesive strength between the connection portion 2 and the insulating substrate 1 is reduced, and that the neck portion in the lead-out wiring from the connection portion 2 is likely to break. As a printed wiring board in which this defect is improved, as shown in FIG. 15, a structure is disclosed in which the entire surface and a part of the side surface of the connection portion 2 are exposed from the solder resist layer 3 (for example, Patent Documents). 1 and 2). The NSMD structure shown in FIG. 14 is suitable and the structure shown in FIG. 15 is more suitable in order to meet the demand for high density connection.

  The NSMD structure shown in FIG. 14 is manufactured by exposing a portion of the solder resist layer 3 other than the region of the opening 4 with actinic rays and removing the unexposed portion of the solder resist layer 3 by development processing. ing. The structure of FIG. 15 is manufactured by forming the opening 4 in the solder resist layer 3 by laser beam irradiation. The case where the opening 4 is formed in the solder resist layer 3 by exposure / development processing and the case where the opening 4 is formed in the solder resist layer 3 by laser light irradiation have a common point in the cross-sectional shape of the opening 4. FIG. 2 is a diagram for explaining this common point, and is a cross-sectional view of a printed wiring board in which an opening 4 is formed in the solder resist layer 3. In the printed wiring board of FIG. 2, the printed circuit board includes a circuit board in which the connection portion 2 is formed on the insulating substrate 1 and a solder resist layer 3 provided on the surface of the circuit board, and the opening 4 provided in the solder resist layer 3 A part of the surface of the connection part 2 and a part of the side surface are exposed from the solder resist layer 3. The opening 4 of the solder resist layer 3 formed by removing a part of the solder resist layer 3 by exposure / development processing or laser light irradiation has a shape in which the opening width becomes smaller as the depth increases. That is, in FIG. 14 and FIG. 15, for convenience, in the opening 4 of the solder resist layer 3, the opening width 5 at the top of the opening and the opening width 6 at the bottom of the opening are drawn equally. When the opening 4 is formed by processing or laser light irradiation, the opening width 5 at the top of the opening is larger than the opening width 6 at the bottom of the opening as shown in FIG. In the shape of the opening 4 of the solder resist layer 3, the bonding strength between the connecting portion 2 and the solder is insufficient, and there may be a problem in connection reliability between the printed wiring board and the electronic component. The magnitude relationship between the opening width 5 at the top of the opening and the opening width 6 at the bottom of the opening is due to processing characteristics of exposure / development processing and laser light irradiation. Therefore, for example, it is difficult to form a shape in which the opening width 5 at the top of the opening is smaller than the opening width 6 at the bottom of the opening by exposure / development processing or laser light irradiation.

  Furthermore, in the formation of the opening 4 in the solder resist layer 3 by laser light irradiation, there is a phenomenon that the components (smear) of the solder resist layer 3 are not decomposed and removed and remain on the periphery of the opening 4, the bottom, and the connection portion 2. Arise. If such a smear remains, the bonding strength between the connecting portion 2 and the solder becomes insufficient, and a problem occurs in the connection reliability between the printed wiring board and the electronic component. In order to avoid such problems, a process of removing this smear (desmear process) is usually required. In such a desmear process, a wet method is generally used in which smear is swollen with a concentrated alkaline solution and then smear is decomposed and removed with a permanganate solution.

  However, if the desmear is surely performed by such a method, the surface of the solder resist layer 3 in contact with these chemicals is roughened, so that the strength of the solder resist layer 3 is reduced, and the print is printed. In some cases, sufficient reliability of the wiring board could not be ensured. On the other hand, if this roughening phenomenon is to be suppressed, there is a problem that smear cannot be reliably removed.

  By the way, in a printed wiring board on which electronic components are mounted by flip-chip connection, in order to ensure the connection reliability and insulation reliability between the electronic component and the printed wiring board, the gap between the electronic component and the printed wiring board is underfilled ( Fill with sealing resin. In order to ensure the effects of connection reliability and insulation reliability, a sufficient amount of underfill must be injected into the gap between the electronic component and the printed wiring board. When this underfill is injected, the underfill may overflow from the gap between the electronic component and the printed wiring board to the surroundings, and adversely affect the electrical operation. Therefore, a printed wiring board having a dam structure is disclosed in order to prevent the underfill from overflowing to the surroundings (see, for example, Patent Documents 3 to 4).

  Patent Document 3 describes a printed wiring board having an SMD structure. As shown in FIG. 16, this printed wiring board has a circuit board in which a connection portion 2 is formed on an insulating substrate 1, and has a solder resist layer 3 on the surface of the circuit board. In this printed wiring board, the first opening portion 11 is formed by opening the electronic component mounting portion and the surrounding solder resist layer 3. Moreover, the surface of the connection part 2 is partially exposed from the solder resist layer 3 by opening a part of the solder resist layer 3 at the bottom 12 of the first opening. In the printed wiring board disclosed in Patent Document 3, since the solder resist layer 3 has a multi-stage structure and the dam structure 20 is formed, when the underfill is filled, the underfill and the electronic component are printed. It is possible to prevent overflowing from the gap with the wiring board.

  In the printed wiring board having the SMD structure and the dam structure of Patent Document 3, after forming the solder resist layer 3 on the circuit board having the connection part 2, the region of the dam structure 20 is exposed with actinic rays, and then the non-exposed part. The solder resist layer 3 is thinned to form the first opening 11, and then a region other than a part of the surface of the connection portion 2 is exposed with actinic rays, and the unexposed portion of the solder resist layer 3 is developed by a development process. And the second opening 14 is formed. However, as described above, the printed wiring board of Patent Document 3 has an SMD structure, and the periphery of the connection portion 2 is covered with the solder resist layer 3. For this reason, it is difficult to meet the demand for high density connection. In addition, it is difficult to reliably fix the electrical connection between the electrode terminal of the electronic component and the corresponding connecting portion 2 by the solder resist layer 3 on the surface of the connecting portion 2, and the connection between the connecting portion 2 and the solder In some cases, the electrical connection was insufficient.

  Patent Document 4 describes a printed wiring board having an NSMD structure suitable for increasing the density of connecting portions. As shown in FIG. 17, this printed wiring board has a circuit board in which a connection portion 2 is formed on an insulating substrate 1, and has a solder resist layer 3 on the surface of the circuit board. In this printed wiring board, the first opening portion 11 is formed by opening the electronic component mounting portion and the surrounding solder resist layer 3. Moreover, the whole connection part 2 is exposed from the soldering resist layer 3 by opening a part of the soldering resist layer 3 of the bottom part 12 of a 1st opening part. In the printed wiring board disclosed in Patent Document 4, since the solder resist layer 3 has a multistage structure and the dam structure 20 is formed, when the underfill is filled, the underfill and the electronic component are printed. It is possible to prevent overflowing from the gap with the wiring board.

  In the printed wiring board having the NSMD structure and the dam structure of Patent Document 4, after forming the first solder resist layer on the circuit board having the connection part 2, the part other than the area of the opening part 4 is exposed with actinic rays, By developing, the first solder resist layer in the unexposed area is removed, the second opening 14 is formed, and the second solder resist layer is formed again thereon, and then the region of the dam structure 20 is activated with actinic rays. The second solder resist layer in the unexposed part is removed by exposure and development processing, and the first opening 11 is formed.

  As described above, the opening portion of the solder resist layer formed by removing a part of the solder resist layer 3 by the exposure / development process has a shape with a smaller opening width as it is deeper (FIG. 2). In the printed wiring board of patent document 4, both the 1st opening part 11 and the 2nd opening part 14 become a shape with a small opening width, so that it is a deep part. For this reason, the bonding strength between the connecting portion 2 and the solder is insufficient, which may cause a problem in the connection reliability between the printed wiring board and the electronic component, and the bonding strength between the underfill and the solder resist layer 3. In some cases, the insulation reliability of the printed wiring board is problematic.

  The printed wiring board having the structure shown in FIG. 15 disclosed in Patent Documents 1 and 2 can also meet the demand for higher density of the connecting portion. In the printed wiring board having the structure shown in FIG. 15, when the dam structure 20 is provided, for example, as shown in FIG. 11, the circuit board has the circuit board in which the connection portion 2 is formed on the insulating substrate 1. A solder resist layer 3 is provided on the surface. In this printed wiring board, the first opening portion 11 is formed by opening the electronic component mounting portion and the surrounding solder resist layer 3. Further, by opening a part of the solder resist layer 3 at the bottom 12 of the first opening, the surface of the connecting part 2 and a part of the side surface are exposed from the solder resist layer 3. In the printed wiring board having the structure shown in FIG. 15, the solder resist layer 3 has a multistage structure and the dam structure 20 is formed. It is possible to prevent overflowing from the gap with the plate.

  In the manufacture of the printed wiring board having the structure shown in FIG. 15, the dam structure 20 can be formed by irradiating the solder resist layer 3 with laser light. However, in the formation of the opening in the solder resist layer 3 by laser light irradiation, as described above, the strength of the solder resist layer 3 is reduced, and the reliability of the printed wiring board may not be sufficiently ensured.

  Further, as described above, the opening 4 of the solder resist layer 3 formed by removing a part of the solder resist layer 3 by laser light irradiation has a shape with a smaller opening width at a deeper portion. In some cases, the adhesive strength of the solder resist layer 3 is insufficient and a problem occurs in the insulation reliability of the printed wiring board.

JP 11-54896 A JP 2009-33084 A JP 2011-77191 A JP 2006-351559 A

  Adhesive strength between the connecting part and insulating substrate and between the connecting part and solder is high, electrical operation failure due to underfill outflow hardly occurs, the strength of the solder resist layer is high, and the adhesive between the solder resist layer and the underfill It is an object of the present invention to provide a printed wiring board having high strength and having smear removed reliably.

  The inventors have found that the above-described problems can be solved by the following means.

(1) A circuit board having a connection part for connecting an electronic component is formed on an insulating substrate, and has a solder resist layer having an opening on the surface of the circuit board, and the connection part is part of the solder resist layer in the opening. An exposed printed wiring board having a structure in which the opening width at the top of the opening in the opening of the solder resist layer is equal to or smaller than the opening width at the bottom of the opening.
(2) The printed wiring board according to the above (1), wherein the surface roughness Ra of the solder resist layer surface and the bottom of the solder resist layer opening is 0.50 μm or less.
(3) A circuit board having a connection part for connecting an electronic component is formed on an insulating substrate, a solder resist layer is provided on the surface of the circuit board, and the electronic component mounting part and the surrounding solder resist layer are opened. A second opening formed by opening a part of the solder resist layer at the bottom of the first opening, and the connecting portion is exposed from the solder resist layer in the second opening. And a structure A in which the opening width at the top of the opening in the first opening is equal to or less than the opening width at the bottom of the opening, and the opening width at the top of the opening in the second opening is the opening at the bottom of the opening A printed wiring board having at least one structure selected from the group consisting of a structure B having a width equal to or less than the width.
(4) The printed wiring according to the above (3), wherein the surface roughness Ra of at least one surface selected from the group consisting of the surface of the solder resist layer, the bottom of the first opening, and the bottom of the second opening is 0.50 μm or less. Board.
(5) The printed wiring board according to (3) or (4), wherein in the second opening, the entire surface of the connecting portion and a part of the side surface are exposed from the solder resist layer.

  With the printed wiring board of the present invention, the adhesive strength between the connecting portion and the insulating substrate and the adhesive strength between the connecting portion and the solder are high, electrical operation failure due to underfill outflow hardly occurs, the strength of the solder resist layer is high, It is possible to provide a printed wiring board in which the solder resist layer and the underfill have a high adhesive strength and smear is reliably removed.

It is explanatory drawing which shows the cross-section of the printed wiring board of this invention. It is explanatory drawing which shows the cross-section of the conventional printed wiring board. It is explanatory drawing which shows an example of the method of manufacturing the printed wiring board of this invention. It is explanatory drawing which shows the cross-section of the printed wiring board of this invention. It is explanatory drawing which shows the cross-section of the printed wiring board of this invention. It is explanatory drawing which shows the cross-section of the printed wiring board of this invention. It is explanatory drawing which shows an example of the method of manufacturing the printed wiring board of this invention. It is explanatory drawing which shows an example of the method of manufacturing the printed wiring board of this invention. It is explanatory drawing which shows an example of the method of manufacturing the printed wiring board of this invention. It is explanatory drawing which shows an example of the method of manufacturing the printed wiring board of this invention. It is explanatory drawing which shows the cross-section of the printed wiring board of this invention. It is explanatory drawing which shows an example of the method of manufacturing the printed wiring board of this invention. It is explanatory drawing which shows the cross-section of a printed wiring board (SMD structure). It is explanatory drawing which shows the cross-section of a printed wiring board (NSMD structure). It is explanatory drawing which shows the cross-section of a printed wiring board. It is explanatory drawing which shows the cross-section of the printed wiring board (SMD structure) which has a dam structure. It is explanatory drawing which shows the cross-section of the printed wiring board (NSMD structure) which has a dam structure.

  A printed wiring board of the present invention will be described with reference to the drawings. First, the shape of the printed wiring board (1) of this invention is demonstrated using FIG. The printed wiring board (1) of the present invention has a circuit board in which a connecting portion 2 is formed on an insulating substrate 1, and has a solder resist layer 3 having an opening 4 on the surface of the circuit board. The connection part 2 is a printed wiring board partially exposed from the solder resist layer 3, and the opening width 5 at the upper part of the opening part 4 of the solder resist layer 3 is less than the opening width 6 at the bottom part of the opening part. It is a printed wiring board characterized by being. The “connecting portion” 2 is a part of the conductor circuit, and is used for connecting electronic components such as semiconductor elements and other printed wiring boards. In the printed wiring board (1) of the present invention, the state that “the connecting portion 2 is partially exposed from the solder resist layer 3 in the opening 4” means that the connecting portion 2 is in a state as shown in FIG. The entire surface is completely exposed from the solder resist layer 3, and a part of the side surface of the connection portion 2 is exposed from the solder resist layer 3.

  The shape of the printed wiring board (2) of the present invention is such that the surface roughness Ra of the solder resist layer surface 9 and the solder resist layer opening bottom 10 is 0.50 μm or less in the printed wiring board (1) of the present invention. A printed wiring board.

  Next, the shape of the printed wiring board (3) of this invention is demonstrated using FIG. 5 and FIG. The printed wiring board (3) of the present invention has a circuit board on which a connecting portion 2 for connecting electronic components is formed on an insulating substrate 1, has a solder resist layer 3 on the surface of the circuit board, and has an electronic component mounting portion. And a first opening 11 formed by opening the solder resist layer 3 around the first opening 11 and a second opening 14 formed by opening a part of the solder resist layer 3 at the bottom 12 of the first opening. In the second opening 14, the connection portion 2 is exposed from the solder resist layer 3, and the opening width 15 at the top of the opening in the first opening 11 is equal to or less than the opening width 16 at the bottom of the opening. A print having at least one structure selected from the group consisting of a certain structure A and a structure B in which the opening width 17 at the top of the opening in the second opening 14 is equal to or less than the opening width 18 at the bottom of the opening It is a wiring board. The “connecting portion” 2 is a part of the conductor circuit, and is used for connecting electronic components such as semiconductor elements and other printed wiring boards. The “electronic component mounting portion” is an area occupied by an electronic component on the circuit board when an electronic component such as a semiconductor element or other printed wiring board is mounted on the surface of the circuit board on which the solder resist layer 3 is formed. Point to. “Ambient” in “Electronic component mounting portion and its surroundings” refers to a range of 0 mm to 2 mm from the end of the electronic component. In the present invention, the state where the “connection portion is exposed from the solder resist layer” means that the entire surface of the connection portion 2 is completely exposed from the solder resist layer 3 as shown in FIGS. State. And the printed wiring board (5) from which the one part side surface of the connection part 2 is exposed from the soldering resist layer 3 is a more preferable state like FIG.

  The shape of the printed wiring board (4) of the present invention consists of the solder resist layer surface 9, the bottom 12 of the first opening, and the bottom 13 of the second opening in the printed wiring board (3) of the present invention. It is a printed wiring board in which the surface roughness Ra of at least one surface selected from the group is 0.50 μm or less.

  The connection part 2 in the printed wiring boards (1) to (5) of the present invention can be used as a so-called bump or ball pad. That is, a solder ball or the like is disposed on the exposed connection portion 2, and an electronic component such as a semiconductor element or other printed wiring board is connected through the solder ball while ensuring conduction to the connection portion 2. can do.

  As the electronic component, flip-chip, BGA (ball grid array), chip scale package, chip size package, or pad of electronic component such as TCP (tape carrier package), leadless chip carrier, or the like is mounted. A printed wiring board is mentioned.

  The effects of the printed wiring boards (1) to (2) of the present invention will be described. In the printed wiring board (1) of the present invention, the connection part 2 is exposed from the opening part 4 of the solder resist layer 3, and the opening width 5 above the opening part in the opening part 4 of the solder resist layer 3. The length is equal to or less than the length of the opening width 6 at the bottom of the opening.

  In the opening 4 of the solder resist layer 3, the opening width 5 at the top of the opening is equal to or less than the opening width 6 at the bottom of the opening, so that the solder resist layer 3 bites into the solder and is connected to the solder by the anchor effect. Since the adhesive strength with the part 2 improves, when connecting an electronic component via the solder ball arrange | positioned at the connection part 2, high connection reliability can be acquired between both. Further, in the printed wiring board (1) of the present invention, the side surface of the connection portion 2 is partially covered with the solder resist layer 3, and the effect of improving the adhesive strength between the connection portion 2 and the insulating substrate 1, An effect of increasing the contact area between the connecting portion 2 and the solder is obtained.

  In the printed wiring board (2) of the present invention, the surface roughness Ra of the solder resist layer surface 9 and the solder resist layer opening bottom 10 is 0.50 μm or less in the printed wiring board (1) of the present invention. As a result, the printed wiring board (2) of the present invention has the strength of the solder resist layer 3 in addition to the operational effects of the printed wiring board (1) of the present invention, and can improve the reliability of the printed wiring board. it can.

  The effect of the printed wiring board (3) of this invention is demonstrated. The printed wiring board (3) of the present invention has a first opening portion 11 in which an electronic component mounting portion corresponding to the upper portion of the connection portion 2 and a solder resist layer 3 around the electronic component mounting portion are opened. Further, the connection portion 2 is exposed from the solder resist layer 3 by the second opening portion 14 in which a part of the solder resist layer 3 at the bottom portion 12 of the first opening portion is opened. The opening width 15 at the top of the opening in the first opening 11 of the solder resist layer 3 is equal to or less than the opening width 16 at the bottom of the opening, and the opening width 17 at the top of the opening in the second opening 14 is open. It has at least one structure selected from the group consisting of structure B having an opening width 18 or less at the bottom.

  Accordingly, the printed wiring board (3) of the present invention has a dam structure that prevents the underfill from overflowing from the gap between the electronic component and the circuit board when the gap between the electronic component and the circuit board is filled with the underfill. 20. Therefore, an effect of preventing an adverse effect on the electrical operation due to the underfill overflowing from the gap between the electronic component and the circuit board to the periphery can be obtained. Further, in the printed wiring board (5) of the present invention, the side surface of the connection portion 2 is partially covered by the solder resist layer 3, and the effect of improving the adhesive strength between the connection portion 2 and the insulating substrate 1, An effect of increasing the contact area between the connecting portion 2 and the solder is obtained. In addition, the structure A in which the opening width 15 at the top of the opening in the first opening 11 of the solder resist layer 3 is equal to or less than the opening width 16 at the bottom of the opening, and the opening width 17 at the top of the opening in the second opening 14 is open. By having at least one structure selected from the group consisting of the structure B having an opening width 18 or less at the bottom of the bottom portion, the solder resist layer 3 bites into the underfill, and the anchor effect causes the solder resist layer 3 and the underfill to Since the adhesive strength is improved, the insulation reliability of the printed wiring board can be improved. In addition, when the solder resist layer 3 bites into the solder and the adhesive strength between the solder and the connection portion 2 is improved by the anchor effect, when connecting an electronic component via the solder ball arranged in the connection portion 2, High connection reliability can be obtained between the two.

  The effect of the printed wiring board (4) of this invention is demonstrated. The printed wiring board (4) of the present invention is selected from the group consisting of the solder resist layer surface 9, the bottom 12 of the first opening, and the bottom 13 of the second opening in the printed wiring board (3) of the present invention. The surface roughness Ra of at least one surface is 0.50 μm or less. Thereby, the printed wiring board (4) of the present invention has high strength of the solder resist layer 3 in addition to the operational effects of the printed wiring board (3) of the present invention, and can improve the reliability of the printed wiring board. it can.

  An example of a method for producing the printed wiring boards (1) and (2) of the present invention will be described with reference to FIG. In this method, the opening 4 is formed by thinning the solder resist layer 3 around the connection portion 2, and the connection portion 2 is partially exposed from the solder resist layer 3. First, a circuit board having a connection portion 2 formed on an insulating substrate 1 is prepared (FIG. 3a). A conductor circuit 19 other than the connection portion 2 may be formed on the circuit board. The connection part 2 can be formed using a subtractive method, a semi-additive method, an additive method, or the like. Next, an alkali developing type solder resist layer 3 is formed so as to cover the entire surface of the circuit board (FIG. 3b). Next, a portion of the solder resist layer 3 other than the region where the opening 4 is formed is exposed with the actinic ray 7 (FIG. 3c). In FIG. 3c, the photomask 8 is used, but a direct drawing method may be used. Subsequently, by forming the opening 4 by thinning the solder resist layer 3 in the non-exposed part, a printed wiring board in which the connection part 2 is partially exposed from the solder resist layer 3 is formed as shown in FIG. it can.

  According to this method, the relationship between the opening width 5 at the top of the opening and the opening width 6 at the bottom of the opening can be easily controlled by changing the processing conditions. Since the solder resist contains a large amount of filler, the closer to the insulating substrate 1 of the solder resist layer 3, the actinic rays at the time of exposure are difficult to reach and the photocuring is weakened. Thus, when the opening 4 is formed by thinning the solder resist layer 3, the opening width 5 at the top of the opening tends to be less than or equal to the opening width 6 at the bottom of the opening, and the solder resist layer 3 is formed. The cross-sectional shape of the opening 4 is likely to be the shape shown in FIGS. Moreover, the opening width 5 at the top of the opening can be made smaller than the opening width 6 at the bottom of the opening by making the exposure amount smaller than the recommended exposure conditions of various solder resists. When the opening width 5 at the top of the opening is smaller than the opening width 6 at the bottom of the opening, compared with the case where the opening width 5 at the top of the opening and the opening width 6 at the bottom of the opening are equal, This is preferable because the adhesive strength is further improved.

  Furthermore, in the printed wiring board manufactured by this method, the surface roughness Ra of the solder resist layer surface 9 and the solder resist layer opening bottom 10 becomes 0.50 μm or less. More specifically, the surface roughness Ra of the solder resist layer surface 9 is 0.10 μm or less, and the surface roughness Ra of the solder resist layer opening bottom 10 is 0.50 μm or less. Further, since the solder resist layer 3 at the bottom 10 of the solder resist layer opening is not subjected to photocuring by actinic rays, it is in a flexible state and can be easily changed in surface roughness and smoothed. is there. For example, as a smoothing treatment, the surface roughness Ra of the solder resist layer opening bottom 10 can be reduced to 0.15 μm or less by exposing it to an environment of 80 ° C. for 15 seconds. Moreover, the surface roughness Ra of the solder resist layer opening bottom 10 can be reduced to 0.10 μm or less by exposing it to an environment of 80 ° C. for 30 seconds. The lower the surface roughness Ra of the solder resist layer surface 9 and the solder resist layer opening bottom 10 is, the better the strength of the solder resist layer is. The preferable temperature of the smoothing treatment is 25 to 120 ° C., and the preferable time is 5 to 1800 seconds. When the smoothing treatment temperature is lower than 25 ° C., the time required for the smoothing treatment becomes too long. Therefore, in consideration of productivity, the temperature is preferably 25 ° C. or more. Further, when the smoothing treatment temperature is higher than 120 ° C., the solder resist layer may start to be thermally cured. Therefore, the smoothing treatment is preferably performed at 120 ° C. or less.

  An example of a method for manufacturing the printed wiring boards (3) to (5) of the present invention will be described with reference to FIG. In this method, the first opening 11 is formed by thinning the electronic component mounting portion and the surrounding solder resist layer 3, and then a part of the solder resist layer 3 at the bottom 12 of the first opening is thinned. Thus, the connection portion 2 is partially exposed from the solder resist layer 3.

  First, a circuit board having a connection portion 2 formed on an insulating substrate 1 is prepared (FIG. 7a). A conductor circuit 19 other than the connection portion 2 may be formed on the circuit board. The connection part 2 can be formed using a subtractive method, a semi-additive method, an additive method, or the like. Next, an alkali developing type solder resist layer 3 is formed so as to cover the entire surface of the circuit board (FIG. 7A). Next, a portion of the solder resist layer 3 other than the region where the first opening 11 is formed is exposed with the actinic ray 7 (FIG. 7 (C1)). Although exposure is performed through the photomask 8 in FIG. 7C1, exposure may be performed by a direct drawing method. Subsequently, after the carrier film on the solder resist layer 3 is peeled off, the solder resist layer 3 in the non-exposed part is thinned to form the first opening 11 (FIG. 7 (B1)).

  Next, of the solder resist layer 3 at the bottom 12 of the first opening, a portion other than the region for forming the opening for partially exposing the connection portion 2 from the solder resist layer 3 is exposed with the active light 7 ( FIG. 7 (C2)). Although exposure is performed through the photomask 8 in FIG. 7C2, exposure may be performed by a direct drawing method. In addition, there is no carrier film on the solder resist layer 3 after being thinned in the step (B1). When exposed in the step (C2) without the carrier film, polymerization inhibition may occur in the surface layer of the solder resist layer 3 due to the influence of oxygen in the air. The portion where the polymerization inhibition has occurred is thinned in the subsequent step (B2), and the solder resist layer 3 is reduced in thickness. Subsequently, the solder resist layer 3 in the non-exposed part is thinned, and an opening for partially exposing the connection part 2 from the solder resist layer 3 is formed in the solder resist layer 3 in the bottom 12 of the first opening. By doing so, as shown in FIG. 7 (B2), the first opening 11 is formed in the solder resist layer 3 on the surface of the circuit board, and by opening the solder resist layer 3 at the bottom 12 of the first opening, A printed wiring board in which the second opening 14 is formed and the connection part 2 is partially exposed from the solder resist layer 3 can be formed.

  According to this method, by changing the processing conditions, the relationship between the opening width 15 at the top of the first opening and the opening width 16 at the bottom of the first opening, and the opening width 17 and the second opening at the top of the second opening. The relationship of the bottom opening width 18 can be easily controlled. Since the solder resist contains a large amount of filler, the closer to the insulating substrate 1 of the solder resist layer 3, the actinic rays at the time of exposure are difficult to reach and the photocuring is weakened. Thus, when the first opening 11 and the second opening 14 are formed by thinning the solder resist layer 3, the opening width 15 at the top of the first opening is equal to or less than the opening width 16 at the bottom of the first opening. The opening width 17 at the top of the second opening is likely to be equal to or less than the opening width 18 at the bottom of the second opening. Moreover, the opening width 15 at the top of the first opening can be made smaller than the opening width 16 at the bottom of the first opening by making the exposure amount smaller than the recommended exposure conditions of various solder resists. When the opening width 15 at the top of the first opening is smaller than the opening width 16 at the bottom of the first opening, the opening width 15 at the top of the first opening is equal to the opening width 16 at the bottom of the first opening. In addition, the adhesive strength between the solder resist layer 3 and the underfill is improved, which is preferable. Similarly, the opening width 17 at the top of the second opening can be made smaller than the opening width 18 at the bottom of the second opening. When the opening width 17 at the top of the second opening is smaller than the opening width 18 at the bottom of the second opening, the opening width 17 at the top of the second opening is equal to the opening width 18 at the bottom of the second opening. Therefore, it is preferable because the adhesive strength between the solder and the connecting portion 2 is further improved.

  Moreover, in the manufacturing method of the printed wiring boards (3) to (5) of the present invention according to the procedure of FIG. 7, it is possible to change the exposure areas of the step (C1) and the step (C2) to an arbitrary shape. By changing the exposure region, for example, a circuit board having a cross-sectional shape shown in FIG. 11 can be manufactured. In FIG. 11 a, the thickness of the solder resist layer 3 between the connection portions 2 is thinner than that of the connection portions 2. In FIG. 11 b, there is a conductor circuit 19 covered with the exposed connection portion 2 and the solder resist layer 3.

  In the printed wiring board manufactured by this method, the surface roughness Ra of the solder resist layer surface 9, the bottom 12 of the first opening, and the bottom 13 of the second opening tends to be 0.50 μm or less. More specifically, the surface roughness Ra of the solder resist layer surface 9 is 0.10 μm or less, and the surface roughness Ra of the bottom 12 of the first opening and the bottom 13 of the second opening is 0.50 μm or less. Preferably there is.

  Further, after the formation of the first opening 11 (FIG. 7B1), in order to partially expose the connection portion 2 from the solder resist layer 3 in the solder resist layer 3 at the bottom 12 of the first opening. The solder resist layer 3 at the bottom 12 of the first opening in a state prior to exposing the portion other than the region for forming the opening with the active light 7 (FIG. 7C2) has undergone photocuring with the active light. Therefore, it is in a flexible state, and the surface roughness can be easily changed and smoothed. Similarly, since the solder resist layer 3 at the bottom 13 of the second opening is not subjected to photocuring by actinic rays, it is in a flexible state and can be easily changed in surface roughness and smoothed. is there.

  For example, the surface roughness Ra of the bottom 12 of the first opening and the bottom 13 of the second opening can be reduced to 0.15 μm or less by subjecting to an environment of 80 ° C. for 15 seconds as a smoothing process. . Further, the surface roughness Ra of the bottom 12 of the first opening and the bottom 13 of the second opening can be reduced to 0.10 μm or less by exposing to an environment of 80 ° C. for 30 seconds. The lower the surface roughness Ra of the solder resist layer surface 9 and the bottom 12 of the first opening and the bottom 13 of the second opening, the better the strength of the solder resist layer. The preferable temperature of the smoothing treatment is 25 to 120 ° C., and the preferable time is 5 to 1800 seconds. When the smoothing treatment temperature is lower than 25 ° C., the time required for the smoothing treatment becomes too long. Therefore, in consideration of productivity, the temperature is preferably 25 ° C. or more. Further, when the smoothing treatment temperature is higher than 120 ° C., the solder resist layer may start to be thermally cured. Therefore, the smoothing treatment is preferably performed at 120 ° C. or less.

  Another example of the method for producing printed wiring boards (3) to (5) of the present invention will be described with reference to FIG. In this method, first of all, the first solder resist layer 3-1 around the connection portion 2 is thinned out of the first solder resist layer 3-1 formed on the surface of the circuit board. It is partially exposed from the solder resist layer 3-1. Next, by forming the second solder resist layer 3-2 on the surface of the first solder resist layer 3-1, and developing the electronic component mounting portion and the surrounding second solder resist layer 3-2, A first opening 11 is formed.

  First, a circuit board having a connection portion 2 formed on an insulating substrate 1 is prepared (FIG. 8a). A conductor circuit 19 other than the connection portion 2 may be formed on the circuit board. The connection part 2 can be formed using a subtractive method, a semi-additive method, an additive method, or the like. Next, in step (A1), an alkali development type first solder resist layer 3-1 is formed so as to cover the entire surface of the circuit board (FIG. 8A1). Next, in the step (C1), in the first solder resist layer 3-1, a portion other than a region where an opening for partially exposing the connection portion 2 from the first solder resist layer 3-1 is activated. Exposure is performed with light 7 (FIG. 8C1). Although exposure is performed through the photomask 8 in FIG. 8C1, exposure may be performed by a direct drawing method. Next, after peeling off the carrier film on the first solder resist layer 3-1, in the step (B), the first solder resist layer 3-1 of the non-exposed part is thinned to partially connect the connection part 2. An opening to be exposed from one solder resist layer 3-1 is formed (FIG. 8B). Subsequently, in step (C2), the region thinned in step (B) is exposed with actinic rays 7 (FIG. 8 (C2)). Although exposure is performed through the photomask 8 in FIG. 8C2, direct exposure may be used. Moreover, after thinning at the process (B), there is no carrier film on the 1st soldering resist layer 3-1. When exposed in the step (C2) without this carrier film, polymerization inhibition may occur in the surface layer of the first solder resist layer 3-1 due to the influence of oxygen in the air. The portion where the polymerization inhibition has occurred is developed in the subsequent step (D), and the film loss of the first solder resist layer 3-1 occurs.

  Next, in step (A2), an alkali development type second solder resist layer 3-2 is formed on the entire first solder resist layer 3-1 that has completed the steps up to step (C2) (FIG. 8 ( A2)). Next, in the step (C3), portions of the second solder resist layer 3-2 other than the region of the first opening 11 are exposed with the actinic ray 7 (FIG. 8 (C3)). Although exposure is performed through the photomask 8 in FIG. 8C3, exposure may be performed by a direct drawing method. Subsequently, in the step (D), the second solder resist layer 3-2 in the unexposed portion is removed by development processing, whereby the first solder resist layer 3 is formed on the surface of the circuit board as shown in FIG. 8D. -1 and the second solder resist layer 3-2 are formed, the first opening 11 is formed in the solder resist layer 3, and the solder resist layer 3 at the bottom 12 of the first opening. The printed wiring board in which the connection part 2 is partially exposed from the solder resist layer 3 can be formed by the second opening 14 formed in the above.

  According to this method, the relationship between the opening width 17 at the top of the second opening and the opening width 18 at the bottom of the second opening can be easily controlled by changing the processing conditions. Since the solder resist contains a large amount of filler, the closer to the insulating substrate 1 of the solder resist layer 3, the actinic rays at the time of exposure are difficult to reach and the photocuring is weakened. Accordingly, when the solder resist layer 3 is thinned to form the second opening 14, the opening width 17 at the top of the second opening tends to be equal to or smaller than the opening width 18 at the bottom of the second opening. Moreover, the opening width 17 at the top of the second opening can be made smaller than the opening width 18 at the bottom of the second opening by making the exposure amount smaller than the recommended exposure conditions for various solder resists. When the opening width 17 at the top of the second opening is smaller than the opening width 18 at the bottom of the second opening, the opening width 17 at the top of the second opening is equal to the opening width 18 at the bottom of the second opening. Therefore, it is preferable because the adhesive strength between the solder and the connecting portion 2 is further improved.

  Moreover, in the manufacturing method of the printed wiring boards (3) to (5) of the present invention according to the procedure of FIG. 8, it is possible to change the exposure areas of the step (C1) and the step (C3) to an arbitrary shape. By changing the exposure region, for example, a circuit board having a cross-sectional shape shown in FIG. 11 can be manufactured. In FIG. 11 a, the thickness of the solder resist layer 3 between the connection portions 2 is thinner than that of the connection portions 2. In FIG. 11 b, there is a conductor circuit 19 covered with the exposed connection portion 2 and the solder resist layer 3.

  In the printed wiring board manufactured by this method, the surface roughness Ra of the solder resist layer surface 9, the bottom 12 of the first opening, and the bottom 13 of the second opening tends to be 0.50 μm or less. In the present invention, the surface roughness Ra of the solder resist layer surface 9 and the bottom 12 of the first opening is preferably 0.10 μm or less, and the surface roughness Ra of the bottom 13 of the second opening is 0.1. It is preferable that it is 50 micrometers or less. The surface roughness Ra is an arithmetic average surface roughness.

  Moreover, since the 1st soldering resist layer 3-1 of the bottom part 13 of the 2nd opening part of a state before a process (C2) after a process (B) is not receiving the photocuring by actinic light, it is flexible. In this state, it is possible to easily change the surface roughness and smooth the surface.

  Another example of the method for producing the printed wiring boards (3) to (5) of the present invention will be described with reference to FIG. In this method, first, the connection portion 2 is partially exposed from the first solder resist layer 3-1 by thinning the entire surface of the first solder resist layer 3-1 formed on the surface of the circuit board. Next, the 2nd soldering resist layer 3-2 is formed on the surface of the 1st soldering resist layer 3-1, and the connection part 2 does not expose the electronic component mounting part and the surrounding 2nd soldering resist layer 3-2. The first opening is formed by reducing the film thickness within the range. Next, the connection part 2 is partially exposed from the solder resist layer 3 by developing a part of the second solder resist layer 3-2 at the bottom of the first opening.

  First, a circuit board having a connection portion 2 formed on an insulating substrate 1 is prepared (FIG. 9a). A conductor circuit 19 other than the connection portion 2 may be formed on the circuit board. The connection part 2 can be formed using a subtractive method, a semi-additive method, an additive method, or the like. Next, in step (A1), an alkali development type first solder resist layer 3-1 is formed so as to cover the entire surface of the circuit board (FIG. 9A1). Next, after peeling off the carrier film on the first solder resist layer 3-1, in the step (B1), the entire surface of the first solder resist layer 3-1 is thinned, whereby the first solder resist layer 3-1. Then, the connection part 2 is partially exposed (FIG. 9 (B1)). Next, in the step (C1), the entire surface of the first solder resist layer 3-1 is exposed (FIG. 9 (C1)). In addition, there is no carrier film on the first solder resist layer 3-1 after being thinned in the step (B1). When exposed in the step (C1) without this carrier film, polymerization inhibition may occur in the surface layer of the first solder resist layer 3-1 due to the influence of oxygen in the air. The portion where the polymerization inhibition has occurred is developed in the subsequent step (D), and the film loss of the first solder resist layer 3-1 occurs.

  Next, in step (A2), an alkali-developable second solder resist layer 3-2 is formed on the entire first solder resist layer 3-1 that has completed the steps up to step (C1) (FIG. 9 ( A2)). Next, in the step (C2), portions of the second solder resist layer 3-2 other than the region of the first opening 11 are exposed with the active light 7 (FIG. 9 (C2)). Although exposure is performed through the photomask 8 in FIG. 9C2, exposure may be performed by a direct drawing method. Subsequently, after peeling off the carrier film on the second solder resist layer 3-2, in the step (B2), the second solder resist layer 3-2 of the unexposed portion is thinned, thereby forming the first opening 11. It forms (FIG. 9 (B2)).

  Next, in the step (C3), in the second solder resist layer 3-2 at the bottom 12 of the first opening, other than the region for forming the opening for partially exposing the connection portion 2 from the solder resist layer 3 Is exposed with actinic light 7 (FIG. 9 (C3)). Although exposure is performed through the photomask 8 in FIG. 9C3, exposure may be performed by a direct drawing method. In addition, there is no carrier film on the second solder resist layer 3-2 after being thinned in the step (B2). When exposed in step (C3) in the absence of this carrier film, polymerization inhibition may occur in the surface layer of the second solder resist layer 3-2 due to the influence of oxygen in the air. The portion where the polymerization inhibition has occurred is developed in the subsequent step (D), and the film loss of the second solder resist layer 3-2 occurs. Subsequently, in the step (D), the second solder resist layer 3-2 in the unexposed portion is removed by development processing, whereby the first solder resist layer 3 is formed on the surface of the circuit board as shown in FIG. 9D. -1 and the second solder resist layer 3-2 are formed, the first opening 11 is formed in the solder resist layer 3, and the solder resist layer 3 at the bottom 12 of the first opening. The printed wiring board in which the connection part 2 is partially exposed from the solder resist layer 3 can be formed by the second opening 14 formed in the above.

  According to this method, the relationship between the opening width 15 at the top of the first opening and the opening width 16 at the bottom of the first opening can be easily controlled by changing the processing conditions. Since the solder resist contains a large amount of filler, the closer to the insulating substrate 1 of the solder resist layer 3, the actinic rays at the time of exposure are difficult to reach and the photocuring is weakened. Thus, when the solder resist layer 3 is thinned to form the first opening 11, the opening width 15 at the top of the first opening tends to be equal to or less than the opening width 16 at the bottom of the first opening. Moreover, the opening width 15 at the top of the first opening can be made smaller than the opening width 16 at the bottom of the first opening by making the exposure amount smaller than the recommended exposure conditions of various solder resists. When the opening width 15 at the top of the first opening is smaller than the opening width 16 at the bottom of the first opening, the opening width 15 at the top of the first opening is equal to the opening width 16 at the bottom of the first opening. In addition, the adhesive strength between the solder resist layer 3 and the underfill is improved, which is preferable.

  Moreover, in the manufacturing method of the printed wiring boards (3) to (5) of the present invention according to the procedure of FIG. 9, it is possible to change the exposure area of the step (C2) and the step (C3) into an arbitrary shape, By changing the exposure region, for example, a circuit board having a cross-sectional shape shown in FIG. 11 can be manufactured. In FIG. 11 a, the thickness of the solder resist layer 3 between the connection portions 2 is thinner than that of the connection portions 2. In FIG. 11 b, there is a conductor circuit 19 covered with the exposed connection portion 2 and the solder resist layer 3.

  In the printed wiring board manufactured by this method, the surface roughness Ra of the solder resist layer surface 9, the bottom 12 of the first opening, and the bottom 13 of the second opening tends to be 0.50 μm or less. In the present invention, the surface roughness Ra of the solder resist layer surface 9 is preferably 0.10 μm or less, and the surface roughness Ra of the bottom 13 of the second opening and the bottom 12 of the first opening is 0. It is preferable that it is 50 micrometers or less. The surface roughness Ra is an arithmetic average surface roughness.

  Also, after the step (B1), the first solder resist layer 3-1 at the bottom 13 of the second opening in the state before the step (C1), and after the step (B2) and before the step (C3) Since the second solder resist layer 3-2 at the bottom 12 of the first opening in the state is not subjected to photocuring by actinic rays, it is in a flexible state and easily changes and smoothes the surface roughness. It is possible.

  Another example of the method for producing the printed wiring boards (3) to (5) of the present invention will be described with reference to FIG. In this method, first, the connection portion 2 is partially exposed from the first solder resist layer 3-1 by thinning the entire surface of the first solder resist layer 3-1 formed on the surface of the circuit board. Next, the second solder resist layer 3-2 is formed on the surface of the first solder resist layer 3-1, the second solder resist layer 3-2 around the connection portion 2 is removed by development, and the solder resist layer 3 is removed. Then, the connecting portion 2 is exposed again. Next, a third solder resist layer 3-3 is formed on the surface of the second solder resist layer 3-2, and a component mounting portion such as a semiconductor and the surrounding third solder resist layer 3-3 are removed by development. The first opening 11 is formed, and the connecting portion 2 is exposed from the solder resist layer 3 again.

  First, a circuit board having a connection portion 2 formed on an insulating substrate 1 is prepared (FIG. 10a). A conductor circuit 19 other than the connection portion 2 may be formed on the circuit board. The connection part 2 can be formed using a subtractive method, a semi-additive method, an additive method, or the like. Next, in step (A1), an alkali development type first solder resist layer 3-1 is formed so as to cover the entire surface of the circuit board (FIG. 10A1). Next, after peeling off the carrier film on the first solder resist layer 3-1, in the step (B1), the entire surface of the first solder resist layer 3-1 is thinned, whereby the first solder resist layer 3-1. Then, the connection part 2 is partially exposed (FIG. 10B1). Next, in the step (C1), the entire surface of the first solder resist layer 3-1 is exposed (FIG. 10 (C1)). In addition, there is no carrier film on the first solder resist layer 3-1 after being thinned in the step (B1). When exposed in the step (C1) without this carrier film, polymerization inhibition may occur in the surface layer of the first solder resist layer 3-1 due to the influence of oxygen in the air. The portion where the polymerization inhibition has occurred is developed in the subsequent step (D1), and the film loss of the first solder resist layer 3-1 occurs.

  Next, in step (A2), an alkali-developable second solder resist layer 3-2 is formed on the entire first solder resist layer 3-1 that has completed the steps up to step (C1) (FIG. 10 ( A2)). Next, in the step (C2), a portion of the second solder resist layer 3-2 other than the region for forming the opening for partially exposing the connection portion 2 from the solder resist layer 3 is exposed with the actinic ray 7. (FIG. 10 (C2)). Although exposure is performed through the photomask 8 in FIG. 10C2, exposure may be performed by a direct drawing method. Next, in the step (D1), the connection portion 2 is partially exposed from the first solder resist layer 3-1 by developing the unexposed portion of the second solder resist layer (FIG. 10 (D1)).

  Next, in the step (A3), the alkali developing type third solder resist layer 3 is entirely formed on the first solder resist layer 3-1 and the second solder resist layer 3-2 after the steps up to the step (D1) are completed. -3 is formed (FIG. 10A3). Next, in the step (C3), portions of the third solder resist layer 3-3 other than the region where the first opening is formed are exposed with the active light 7 (FIG. 10 (C3)). In FIG. 10C3, exposure is performed through the photomask 8, but exposure may be performed by a direct drawing method. Subsequently, in the step (D2), the third solder resist layer 3-3 in the unexposed portion is removed by development processing, whereby the first solder resist layer 3 is formed on the surface of the circuit board as shown in FIG. 10 (D2). -1, the second solder resist layer 3-2 and the third solder resist layer 3-3 are formed, the first opening 11 is formed in the solder resist layer 3, and the first opening A printed wiring board in which the connection portion 2 is partially exposed from the solder resist layer 3 can be formed by the second opening portion 14 formed in the solder resist layer 3 at the bottom portion 12.

  Further, in the method of manufacturing a printed wiring board according to the present invention according to the procedure of FIG. 10, the exposure areas in the steps (C2) and (C3) can be changed to arbitrary shapes. It is possible to manufacture a circuit board having a cross-sectional shape shown in FIG. In FIG. 11 a, the thickness of the solder resist layer 3 between the connection portions 2 is thinner than that of the connection portions 2. In FIG. 11 b, there is a conductor circuit 19 covered with the exposed connection portion 2 and the solder resist layer 3.

  In the printed wiring board manufactured by this method, the surface roughness Ra of the solder resist layer surface 9, the bottom 12 of the first opening, and the bottom 13 of the second opening tends to be 0.50 μm or less. In the present invention, the surface roughness Ra of the solder resist layer surface 9 and the bottom 12 of the first opening is preferably 0.10 μm or less, and the surface roughness Ra of the bottom 13 of the second opening is 0.1. It is preferable that it is 50 micrometers or less. The surface roughness Ra is an arithmetic average surface roughness.

  In addition, the first solder resist layer 3-1 at the bottom 13 of the second opening in the state before the step (C1) after the step (B1) is not subjected to photocuring by actinic rays, so that it is flexible. In this state, it is possible to easily change the surface roughness and smooth the surface.

  Another example of the method for producing the printed wiring boards (3) to (5) of the present invention will be described with reference to FIG. In this method, the first opening 11 is formed by thinning the electronic component mounting portion and the surrounding solder resist layer 3, and then a part of the solder resist layer 3 at the bottom 12 of the first opening is developed. By doing so, the connecting portion 2 is exposed from the solder resist layer 3.

  First, a circuit board having a connection portion 2 formed on an insulating substrate 1 is prepared (FIG. 12a). A conductor circuit 19 other than the connection portion 2 may be formed on the circuit board. The connection part 2 can be formed using a subtractive method, a semi-additive method, an additive method, or the like. Next, an alkali developing type solder resist layer 3 is formed so as to cover the entire surface of the circuit board (FIG. 12A). Next, a portion of the solder resist layer 3 other than the region where the first opening 11 is formed is exposed with the actinic ray 7 (FIG. 12 (C1)). Although exposure is performed through the photomask 8 in FIG. 12C1, exposure may be performed by a direct drawing method. Subsequently, after the carrier film on the solder resist layer 3 is peeled off, the solder resist layer 3 in the non-exposed portion is thinned to form the first opening 11 (FIG. 12B).

  Next, of the solder resist layer 3 at the bottom 12 of the first opening, a portion other than the region for forming the opening for partially exposing the connection portion 2 from the solder resist layer 3 is exposed with the active light 7 ( FIG. 12 (C2)). In FIG. 12C2, the exposure is performed through the photomask 8, but the exposure may be performed by a direct drawing method. Further, there is no carrier film on the solder resist layer 3 after being thinned in the step (B). When exposed in the step (C2) without the carrier film, polymerization inhibition may occur in the surface layer of the solder resist layer 3 due to the influence of oxygen in the air. The portion where the polymerization inhibition has occurred is developed in the subsequent step (D), and the solder resist layer 3 is reduced. Subsequently, the solder resist layer 3 in the non-exposed part is removed by development processing, and an opening for exposing the connection part 2 from the solder resist layer 3 is formed in the solder resist layer 3 in the bottom 12 of the first opening. By doing so, as shown in FIG. 12 (D), the first opening 11 is formed in the solder resist layer 3 on the surface of the circuit board, and the solder resist layer 3 at the bottom 12 of the first opening is opened, A printed wiring board in which the second opening 14 is formed and the connecting portion 2 is exposed from the solder resist layer 3 can be formed.

  According to this method, the relationship between the opening width 15 at the top of the first opening and the opening width 16 at the bottom of the first opening can be easily controlled by changing the processing conditions. Since the solder resist contains a large amount of filler, the closer to the insulating substrate 1 of the solder resist layer 3, the actinic rays at the time of exposure are difficult to reach and the photocuring is weakened. Thus, when the solder resist layer 3 is thinned to form the first opening 11, the opening width 15 at the top of the first opening tends to be equal to or less than the opening width 16 at the bottom of the first opening. Moreover, the opening width 15 at the top of the first opening can be made smaller than the opening width 16 at the bottom of the first opening by making the exposure amount smaller than the recommended exposure conditions of various solder resists. When the opening width 15 at the top of the first opening is smaller than the opening width 16 at the bottom of the first opening, the opening width 15 at the top of the first opening is equal to the opening width 16 at the bottom of the first opening. In addition, the adhesive strength between the solder resist layer 3 and the underfill is improved, which is preferable.

  Moreover, in the manufacturing method of the printed wiring boards (3) to (5) of the present invention according to the procedure of FIG. 12, it is possible to change the exposure areas of the step (C1) and the step (C2) to an arbitrary shape. By changing the exposure region, for example, a circuit board having a cross-sectional shape shown in FIG. 17 can be manufactured. In FIG. 17a, the solder resist layer 3 between the connection parts 2 is removed, and the side surfaces of the connection parts 2 are completely exposed. In FIG. 17 b, there is a conductor circuit 19 covered with the exposed connection portion 2 and the solder resist layer 3.

  In the printed wiring board manufactured by this method, the surface roughness Ra of the solder resist layer surface 9 and the bottom 12 of the first opening tends to be 0.50 μm or less. More specifically, the surface roughness Ra of the solder resist layer surface 9 is preferably 0.10 μm or less, and the surface roughness Ra of the bottom 12 of the first opening is preferably 0.50 μm or less.

  Further, after the formation of the first opening 11 (FIG. 12B), the opening for exposing the connecting portion 2 from the solder resist layer 3 in the solder resist layer 3 at the bottom 12 of the first opening. Because the solder resist layer 3 at the bottom 12 of the first opening in the state before the exposure of the portion other than the region that forms the region with the active light 7 (FIG. 12 (C2)) has not been photocured by the active light It is in a flexible state, and it is possible to easily change the surface roughness and smooth the surface.

  For example, the surface roughness Ra of the bottom 12 of the first opening can be reduced to 0.15 μm or less by subjecting to an environment of 80 ° C. for 15 seconds as a smoothing treatment. Further, the surface roughness Ra of the bottom 12 of the first opening can be reduced to 0.10 μm or less by exposing it to an environment of 80 ° C. for 30 seconds. The lower the surface roughness Ra of the solder resist layer surface 9 and the bottom 12 of the first opening, the better the strength of the solder resist layer. The preferable temperature of the smoothing treatment is 25 to 120 ° C., and the preferable time is 5 to 1800 seconds. When the smoothing treatment temperature is lower than 25 ° C., the time required for the smoothing treatment becomes too long. Therefore, in consideration of productivity, the temperature is preferably 25 ° C. or more. Further, when the smoothing treatment temperature is higher than 120 ° C., the solder resist layer may start to be thermally cured. Therefore, the smoothing treatment is preferably performed at 120 ° C. or less.

  As the insulating substrate 1 in the present invention, for example, a substrate made of a synthetic resin, a composite resin substrate made of a synthetic resin and an inorganic filler, a composite resin substrate made of a synthetic resin and an inorganic fabric, or the like can be used. The insulating substrate can be provided with a connection portion, a through hole, or the like on the surface or inside thereof. The insulating substrate can be provided with bumps or ball pads for mounting electronic components.

  The circuit board in the present invention is a board in which a connecting portion 2 made of a metal such as copper is formed on an insulating board 1. Bumps or ball pads for connecting electronic components such as semiconductor chips may be formed. Examples of the method for producing the circuit board include a subtractive method, a semi-additive method, and an additive method. In the subtractive method, for example, an etching resist is formed on a copper clad laminate in which a copper foil is bonded to a glass base epoxy resin, and a circuit board is manufactured by performing exposure, development, etching, and resist peeling.

  As the solder resist according to the present invention, an alkali developing type can be used. Further, it may be either a one-component or two-component liquid resist, may be a dry film resist, and any one that can be developed with an aqueous alkaline solution can be used. The composition of the alkali development type solder resist includes, for example, an alkali-soluble resin, 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 an acrylic acid to a novolac-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, dipentaerythritol hexaacrylate, pentaerythritol triacrylate, and the like. Examples of the photopolymerization initiator include 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one. 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 barium sulfate and silica.

  Any method may be used to form the solder resist layer 3 on the surface of the circuit board. For example, a screen printing method, a roll coating method, a spray method, a dipping method, a curtain coating method, a bar coating method, an air knife method, a hot melt method, and the like. Method, gravure coating method, brush coating method, and offset printing method. In the case of a dry film-shaped solder resist, a laminating method may be mentioned.

  The exposure to the solder resist layer 3 is performed by irradiating with actinic rays, reflection image exposure using a xenon lamp, high pressure mercury lamp, low pressure mercury lamp, ultra high pressure mercury lamp, UV fluorescent lamp as a light source, single-sided, double-sided contact exposure using a photomask. Alternatively, a proximity method, a projection method, laser scanning exposure, or the like can be used. When performing scanning exposure, a laser light source such as a UV laser, a He—Ne laser, a He—Cd laser, an argon laser, a krypton ion laser, a ruby laser, a YAG laser, a nitrogen laser, a dye laser, or an excimer laser is used as an emission wavelength. Accordingly, the exposure can be performed by scanning exposure using SHG wavelength conversion or scanning exposure using a liquid crystal shutter or a micromirror array shutter.

  A method for forming the opening by thinning the solder resist layer 3 will be described. The step of thinning the solder resist layer 3 is a micellization treatment (thinning treatment) in which the photocrosslinkable resin component in the unexposed part solder resist layer 3 is micellized with a thinning treatment solution, and then with a micelle removal solution. It is a process including a micelle removal process for removing micelles. Furthermore, the surface of the solder resist layer that could not be removed, the remaining thinning treatment liquid and the micelle removal liquid may be washed with water, and may include drying treatment for removing the washing water.

  The thinning process (micellar process) is a process in which the resin component of the solder resist layer is made into micelles with a thinning process liquid, and the micelles are insolubilized in the thinning process liquid. The thinning treatment liquid is a highly concentrated alkaline aqueous solution. Examples of the alkaline aqueous solution used as the thinning treatment liquid include alkali metal silicates such as lithium, sodium and potassium, alkali metal hydroxides, alkali metal phosphates, alkali metal carbonates, ammonium phosphates, An aqueous solution of an inorganic alkaline compound such as ammonium carbonate; monoethanolamine, diethanolamine, triethanolamine, methylamine, dimethylamine, ethylamine, diethylamine, triethylamine, cyclohexylamine, tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, An aqueous solution of an organic alkaline compound such as trimethyl-2-hydroxyethylammonium hydroxide (choline) can be used. The inorganic alkaline compound and organic alkaline compound can also be used as a mixture.

  The content of the alkaline compound can be 0.1% by mass or more and 50% by mass or less. In addition, sulfate and sulfite can be added to the thinning treatment solution in order to make the resist layer surface more uniform. 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.

  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 organics selected from TMAH and choline A thinning solution containing at least one of the alkaline compounds and having an inorganic alkaline compound content and an organic alkaline compound content of 5 to 25% by mass can be more suitably used because the surface can be made more uniform. it can. If it is less than 5% by mass, unevenness may easily occur in the process of thinning. 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. As for content of an alkaline compound, 7-17 mass% is more preferable, and 8-13 mass% is further more preferable. 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.

  As the thinning treatment, methods such as immersion treatment, paddle treatment, spray treatment, brushing, and scraping can be used, and immersion treatment is preferable. In a treatment method 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 treatment, resulting in a non-uniform film thickness.

  The depth of the solder resist layer opening is determined by the thickness after the solder resist layer is formed and the amount by which the solder resist layer is thinned. Moreover, the thinning amount of the resist layer can be freely adjusted in the range of 0.01 to 500 μm.

  In the micelle removal treatment for removing the micelles of the resin component of the solder resist layer insolubilized in the thinning treatment solution, the micelles are dissolved and removed at once by spraying the micelle removal solution.

  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 any one of inorganic alkaline compounds selected from alkali metal carbonates, alkali metal phosphates, and alkali metal silicates as a micelle removal solution, thinning treatment is performed. The photocrosslinkable resin component insolubilized with the liquid is easily redispersed. When the pH of the micelle removal solution is less than 5, the photocrosslinkable resin component aggregates and becomes 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, the solder resist layer may be excessively dissolved and diffused, and film thickness unevenness may easily 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 15 to 35 ° C. 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 per 1 cm ^{2 of} the solder resist layer, more preferably 0.050 to 1.0 L / min, and further 0.10 to 1.0 L / min. 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, the resin component of the insolubilized resist layer may be poorly dissolved. 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 on the dissolution and diffusion of the resin component of the solder resist layer may not change.

  After the micelle removal treatment, the solder resist layer that could not be removed, and the thinning treatment solution remaining on the surface of the solder resist layer and the micelle removal solution can be washed away by a water washing treatment. As a method of washing with water, a spray method is preferable from the viewpoint of diffusion rate and liquid supply uniformity. As flush water, tap water, industrial water, pure water or the like can be used. Of these, it is preferable to use pure water. Pure water that is generally used for industrial purposes can be used.

  In the drying process, either hot air drying or room temperature ventilation drying can be used. Preferably, high-pressure air is supplied from an air gun or a blower, and a large amount of air is supplied from the blower to remove water remaining on the surface of the solder resist layer with an air knife. A drying method that blows away is good.

  In order to further reduce the surface roughness inside the opening formed by the thinning process, a smoothing process can be performed. As a method of the smoothing treatment, heating is performed at 25 to 120 ° C. for 5 seconds to 30 minutes using hot air drying, room temperature blowing drying or the like. In addition, the printed wiring board that has undergone the opening forming process by the thinning process and the subsequent smoothing process process has no residual smear that occurs in the formation of the opening in the solder resist layer using a conventional technique using a laser. Since there is no desmear process, the solder resist layer is not roughened.

  As a developing method, a developer corresponding to the solder resist layer to be used is used, spray is sprayed onto the surface of the circuit board, and unnecessary portions of the 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.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to this Example.

  Examples 1-6 manufacture the printed wiring board with the manufacturing method of FIG.

Example 1
A circuit board having a circular connection portion 2 having a diameter of 50 μm was produced by a subtractive method using an etching resist on a copper-clad laminate (area 170 mm × 200 mm, copper foil thickness 18 μm, base material thickness 0.4 mm). Next, a solder resist film (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded onto the circuit board (lamination temperature 75 ° C., suction time 30 seconds, pressurization time 10 seconds). . Thus, the solder resist layer 3 having a dry film thickness of 38.0 μm from the surface of the insulating substrate 1 to the surface of the solder resist layer 3 was formed.

Next, using a photomask 8 having a pattern in which actinic rays are irradiated outside the region from the center of the connection portion 2 to the outside to the outside of 80 μm, with a contact exposure machine at an energy of 300 mJ / cm ² . The solder resist layer 3 was exposed.

  Next, after peeling off the carrier film, the solder resist layer 3 in the unexposed area was thinned by being immersed in 10% by mass of sodium metasilicate (liquid temperature: 25 ° C.) for 28 seconds. Thereafter, after the micelle removal process, the water washing process, and the drying process, each part of the opening 4 of the solder resist layer 3 was measured. The depth of the opening 4 was 26.0 μm, and the opening width at the upper part of the opening 5 was 160 μm, and the opening width 6 at the bottom of the opening was 160 μm. Further, when the surface roughness was measured using an ultra-deep shape measuring microscope (manufactured by KEYENCE, product number “VK-8500”), the surface roughness Ra of the solder resist layer surface 9 was 0.03 μm. The surface roughness Ra of the bottom 10 of the solder resist layer opening was 0.40 μm. Furthermore, when the periphery of the opening 4 of the solder resist layer 3 and the bottom 10 of the solder resist layer opening were observed with a microscope, no residual smear could be confirmed.

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)
When each part of the printed wiring board produced by the same method as in Example 1 was measured except that the smoothing process (80 ° C., 15 seconds) was performed after the drying process after the thinning process, an opening was obtained. The depth of 4 was 26.0 μm, the opening width 5 at the top of the opening was 160 μm, and the opening width 6 at the bottom of the opening was 160 μm. Similarly, when the surface roughness was measured, the surface roughness Ra of the solder resist layer surface 9 was 0.03 μm, and the surface roughness Ra of the solder resist layer opening bottom 10 was 0.14 μm.

Example 3
When each part of the printed wiring board produced by the same method as in Example 1 was measured except that the smoothing process (80 ° C., 30 seconds) was performed after the drying process after the thinning process, an opening was obtained. The depth of 4 was 26.0 μm, the opening width 5 at the top of the opening was 160 μm, and the opening width 6 at the bottom of the opening was 160 μm. Similarly, when the surface roughness was measured, the surface roughness Ra of the solder resist layer surface 9 was 0.03 μm, and the surface roughness Ra of the solder resist layer opening bottom 10 was 0.08 μm.

Example 4
Measurement of each part of the printed wiring board produced by the same method as in Example 1 except that the exposure amount was 200 mJ / cm ² revealed that the depth of the opening 4 was 26.0 μm, and the upper part of the opening The opening width 5 was 160 μm, and the opening width 6 at the bottom of the opening was 180 μm. Similarly, when the surface roughness was measured, the surface roughness Ra of the solder resist layer surface 9 was 0.03 μm, and the surface roughness Ra of the solder resist layer opening bottom 10 was 0.40 μm.

(Example 5)
The printed wiring board produced by the same method as Example 1 except performing exposure amount at 200 mJ / cm < ² > and performing the smoothing process (80 degreeC, 15 second) after performing the drying process after thin film formation process. When each part was measured, the depth of the opening 4 was 26.0 μm, the opening width 5 at the top of the opening was 160 μm, and the opening width 6 at the bottom of the opening was 180 μm. Similarly, when the surface roughness was measured, the surface roughness Ra of the solder resist layer surface 9 was 0.03 μm, and the surface roughness Ra of the solder resist layer opening bottom 10 was 0.14 μm.

(Example 6)
The printed wiring board produced by the method similar to Example 1 except performing exposure amount at 200 mJ / cm < ² > and performing the smoothing process (80 degreeC, 30 second) after performing the drying process after thin film formation process. When each part was measured, the depth of the opening 4 was 26.0 μm, the opening width 5 at the top of the opening was 160 μm, and the opening width 6 at the bottom of the opening was 180 μm. Similarly, when the surface roughness was measured, the surface roughness Ra of the solder resist layer surface 9 was 0.03 μm, and the surface roughness Ra of the solder resist layer opening bottom 10 was 0.08 μm.

(Comparative Example 1)
A circuit board having a circular connection portion 2 having a diameter of 50 μm was produced by a subtractive method using an etching resist on a copper-clad laminate (area 170 mm × 200 mm, copper foil thickness 18 μm, base material thickness 0.4 mm). Next, a solder resist film (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded onto the circuit board (lamination temperature 75 ° C., suction time 30 seconds, pressurization time 10 seconds). . Thus, the solder resist layer 3 having a dry film thickness of 38.0 μm from the surface of the insulating substrate 1 to the surface of the solder resist layer 3 was formed. Thereafter, the entire surface of the solder resist layer 3 was exposed with an energy of 1000 mJ / cm ² using a contact exposure machine, and further heated at 150 ° C. for 30 minutes using a hot air dryer.

  Next, an excimer laser beam (wavelength: 248 nm, output: 50 W) was irradiated to a region from the center of the connection portion 2 to the outside by 80 μm to form an opening 4 in the solder resist layer 3.

  When the solder resist layer surface 9 irradiated with the laser beam was observed with a microscope, the solder resist layer surface 9, the upper portion of the connection portion 2, the upper portion of the opening portion 4, and the opening portion 4 were formed by the laser beam irradiation when the opening portion 4 was formed and the connection portion 2 was exposed. Smear occurred at the bottom.

  Next, a solution containing sodium hydroxide as a main component (manufactured by Meltex Co., Ltd., trade name: ENPLATE (registered trademark) MLB-496A) and a solution containing 1-methoxy-2-propanol (Meltex) Made by Tex Co., Ltd., trade name: ENPLATE (registered trademark) MLB-496B) and a mixed solution of distilled water, the solder resist layer 3 in which smear is generated is immersed at 60 ° C. for 15 minutes to swell the smear It was. Next, a solution containing sodium permanganate as a main component (Meltex Co., Ltd., trade name: ENPLATE (registered trademark) MLB-497A) and a solution containing sodium hydroxide as a main component (Meltex Co., Ltd.) The product was soaked in a mixed solution of ENPLATE (registered trademark) MLB-497B) and distilled water at 80 ° C. for 10 minutes to decompose and remove the swollen smear.

  When each part of the printed wiring board was measured, the depth of the opening 4 was 26.0 μm, the opening width 5 at the top of the opening was 160 μm, and the opening width 6 at the bottom of the opening was 150 μm. Similarly, when the surface roughness was measured, the surface roughness Ra of the solder resist layer surface 9 was 0.80 μm, and the surface roughness Ra of the solder resist layer opening bottom 10 was 0.90 μm. Further, when the solder resist layer surface 9 around the solder resist layer opening 4, the opening 4, and the solder resist layer opening bottom 10 around the connecting portion 2 were observed with a microscope, the entire surface of the solder resist layer 3 was roughened. It was.

(Comparative Example 2)
A circuit board having a circular connection portion 2 having a diameter of 50 μm was produced by a subtractive method using an etching resist on a copper-clad laminate (area 170 mm × 200 mm, copper foil thickness 18 μm, base material thickness 0.4 mm). Next, a solder resist film (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded onto the circuit board (lamination temperature 75 ° C., suction time 30 seconds, pressurization time 10 seconds). . Thus, the solder resist layer 3 having a dry film thickness of 38.0 μm from the surface of the insulating substrate 1 to the surface of the solder resist layer 3 was formed. Thereafter, the entire surface of the solder resist layer 3 was exposed with an energy of 1000 mJ / cm ² using a contact exposure machine, and further heated at 150 ° C. for 30 minutes using a hot air dryer.

Next, a resist film for blasting (trade name: MS7100, manufactured by Mitsubishi Paper Industries Co., Ltd.) was thermocompression bonded. Next, using a photomask 8 having a pattern in which actinic rays are irradiated to a region other than the region extending from the center of the connection portion 2 to the outside by 80 μm, energy of 100 mJ / cm ² is obtained using a contact exposure machine. Then, the blast resist film was exposed to light, and then developed, and the unexposed blast resist film was removed.

  Next, sand blasting (abrasive: SiC # 800, blast pressure 0.15 MPa) was performed on the blast resist film to form an opening 4 in the solder resist layer 3, and then the blast resist film was peeled off. When the depth from the solder resist layer surface 9 to the bottom 10 of the solder resist layer opening was measured, the depth was 26.0 μm, the opening width 5 at the top of the opening was 160 μm, and the opening width 6 at the bottom of the opening was 140 μm. Met. Further, the surface roughness Ra of the solder resist layer surface 9 was 0.03 μm, and the surface roughness Ra of the solder resist layer opening bottom 10 was 1.20 μm. Furthermore, when the solder resist layer 3 at the bottom 10 of the solder resist layer opening was observed with a microscope, the entire surface was roughened.

  Since the printed wiring boards manufactured in Examples 1 to 6 and Comparative Examples 1 and 2 are in a state where the connection portion 2 is partially exposed from the solder resist layer 3 by the opening 4, this printed wiring board is used. Thus, when connecting the electronic parts by solder balls or the like using the connection portions 2 exposed in the openings 4 as bumps or ball pads, the connection portions 2 are insulated from the connection portions 2 even in a printed wiring board in which the connection portions 2 are arranged at high density. The bonding strength between the substrate 1 and the bonding strength between the connecting portion 2 and the solder increases, and high connection reliability is obtained.

  Furthermore, the printed wiring board produced and manufactured by Examples 1-6 is compared with the printed wiring board of the comparative example 3 and the comparative example 4 which formed the opening part 4 in the soldering resist layer by laser processing, a desmear process, and sandblasting. The strength of the solder resist layer 3 is high, and high connection reliability is obtained.

  In Examples 1 to 6, a printed wiring board in which the opening width 5 at the top of the opening in the opening 4 of the solder resist layer 3 was equal to or less than the opening width 6 at the bottom of the opening was obtained. In these printed wiring boards, when the electronic parts are connected by solder balls or the like using the connection portions 2 exposed in the openings 4 as bumps or ball pads, the opening width 5 at the top of the opening is the opening width 6 at the bottom of the opening. Compared to a larger conventional printed wiring board, the adhesive strength between the solder and the connecting portion 2 is increased, and high connection reliability is obtained. Further, when Examples 1 to 3 and Examples 4 to 6 are compared, the printed wiring boards of Examples 4 to 6 in which the opening width 5 at the top of the opening is smaller than the opening width 6 at the bottom of the opening are higher at the top of the opening. Higher connection reliability than the printed wiring boards of Examples 1 to 3 having the same opening width 5 and opening width 6 at the bottom of the opening. Further, the printed wiring boards of Examples 2, 3, 5 and 6 in which the surface roughness Ra of the bottom part 4 of the opening is reduced by the smoothing treatment are more solder solder layer 3 than the printed wiring boards of Examples 1 and 4. The strength of the printed circuit board is high, and the reliability of the printed wiring board can be improved.

  Examples 7-22 manufacture the printed wiring board with the manufacturing method of FIG.

(Example 7)
<Process (A)>
Set an area assuming a part of a copper-clad laminate (area 170 mm x 200 mm, copper foil thickness 18 μm, substrate thickness 0.4 mm) as an electronic component mounting part of 600 μm x 600 μm, and use an etching resist in that area A circuit board having a circular connection portion 2 having a diameter of 100 μm was produced by the subtractive method. Next, a dry film shape solder resist (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded. Thus, a solder resist layer 3 having a dry film thickness of 38.0 μm from the surface of the insulating substrate 1 to the solder resist layer surface 9 was formed.

<Process (C1)>
Next, using a photomask 8 having a pattern in which an actinic ray is irradiated in a region other than the region assumed as the electronic component mounting portion, the solder resist layer 3 at an energy of 300 mJ / cm ² with a contact exposure machine. The exposure was carried out.

<Process (B1)>
Next, after peeling off the carrier film, the solder resist layer 3 in the unexposed area is thinned by immersing in a 10% by mass aqueous sodium metasilicate solution (liquid temperature 25 ° C.) for 16 seconds. One opening 11 was formed. When the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured after the micelle removal process, the water washing process, and the drying process, the depth was 15.0 μm, and the opening at the top of the first opening The width 15 was 600 μm, and the opening width 16 at the bottom of the first opening was 600 μm.

<Process (C2)>
Next, using a photomask 8 having a pattern in which actinic rays are irradiated outside the region from the end of the connection portion 2 to the outside to the outside of 100 μm, the contact exposure machine is used to increase the energy to 300 mJ / cm ² . Then, the solder resist layer 3 was exposed.

<Process (B2)>
Next, the solder resist layer 3 of the unexposed part was thinned by immersing in a 10% by mass sodium metasilicate aqueous solution (liquid temperature 25 ° C.) for 12 seconds, and the connecting part 2 was exposed from the solder resist layer 3. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured after the micelle removal process, the water washing process, and the drying process, the depth was 26.0 μm, and the opening above the second opening was The width 17 was 300 μm, and the opening width 18 at the bottom of the second opening was 300 μm. Moreover, since the solder resist layer 3 at the bottom 12 of the first opening was reduced in thickness by the step (B2), when the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured, the depth was It was 15.5 μm. Furthermore, the surface roughness Ra of the solder resist layer surface 9 was 0.03 μm 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 of the bottom 12 of the first opening and the bottom 13 of the second opening was 0.40 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

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 8)
Each part of the printed wiring board produced by the same method as in Example 7 was measured except that the smoothing process (80 ° C., 30 seconds) was performed after the step (B2). When the depth to the bottom 12 of one opening was measured, the depth was 15.5 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening width 16 at the bottom of the first opening was 600 μm. . When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 26.0 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 300 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.40 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. 0.08 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

Example 9
Each part of the printed wiring board produced by the same method as in Example 7 was measured except that the smoothing process (80 ° C., 30 seconds) was performed after the step (B1). When the depth to the bottom 12 of one opening was measured, the depth was 15.5 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening width 16 at the bottom of the first opening was 600 μm. . When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 26.0 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 300 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.08 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. .40 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 10)
Solder resist was measured when each part of the printed wiring board produced by the same method as in Example 7 was performed except that the smoothing treatment (80 ° C., 30 seconds) was performed after the steps (B1) and (B2). When the depth from the layer surface 9 to the bottom 12 of the first opening was measured, the depth was 15.5 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening width 16 at the bottom of the first opening. Was 600 μm. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 26.0 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 300 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.08 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. 0.08 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 11)
When each part of the printed wiring board produced by the same method as in Example 7 was measured except that the exposure amount in the step (C2) was 200 mJ / cm ² , the first opening portion from the solder resist layer surface 9 was measured. When the depth to the bottom 12 was measured, the depth was 16.0 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening width 16 at the bottom of the first opening was 600 μm. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 26.0 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 320 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.40 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. .40 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 12)
The printed wiring board produced by the method similar to Example 7 except performing the exposure amount of a process (C2) at 200 mJ / cm < ² >, and performing a smoothing process (80 degreeC, 30 second) after a process (B2). When each part was measured, when the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured, the depth was 16.0 μm, and the opening width 15 at the top of the first opening was 600 μm. The opening width 16 at the bottom of the first opening was 600 μm. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 26.0 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 320 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.40 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. 0.08 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 13)
The printed wiring board produced by the method similar to Example 7 except performing the exposure amount of a process (C2) at 200 mJ / cm < ² >, and performing a smoothing process (80 degreeC, 30 second) after a process (B1). When each part was measured, when the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured, the depth was 16.0 μm, and the opening width 15 at the top of the first opening was 600 μm. The opening width 16 at the bottom of the first opening was 600 μm. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 26.0 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 320 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.08 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. .40 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 14)
Produced in the same manner as in Example 7 except that the exposure amount in the step (C2) is 200 mJ / cm ² and the smoothing treatment (80 ° C., 30 seconds) is performed after the steps (B1) and (B2). As a result of measuring each part of the printed wiring board, the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured, and the depth was 16.0 μm. The opening width 15 was 600 μm, and the opening width 16 at the bottom of the first opening was 600 μm. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 26 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening width 18 at the bottom of the second opening was 18 μm. Was 320 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.08 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. 0.08 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 15)
When each part of the printed wiring board produced by the same method as in Example 7 was measured except that the exposure amount in the step (C1) was 200 mJ / cm ² , the first opening portion from the solder resist layer surface 9 was measured. When the depth to the bottom 12 was measured, the depth was 15.5 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening width 16 at the bottom of the first opening was 620 μm. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 26.0 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 300 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.40 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. .40 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 16)
The printed wiring board produced by the method similar to Example 7 except performing the exposure amount of a process (C1) at 200 mJ / cm < ² >, and performing a smoothing process (80 degreeC, 30 second) after a process (B2). When each part was measured, the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured. The depth was 15.5 μm, and the opening width 15 at the top of the first opening was 600 μm. The opening width 16 at the bottom of the first opening was 620 μm. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 26.0 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 300 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.40 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. 0.08 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 17)
The printed wiring board produced by the method similar to Example 7 except performing the exposure amount of a process (C1) at 200 mJ / cm < ² >, and performing a smoothing process (80 degreeC, 30 second) after a process (B1). When each part was measured, the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured. The depth was 15.5 μm, and the opening width 15 at the top of the first opening was 600 μm. The opening width 16 at the bottom of the first opening was 620 μm. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 26.0 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 300 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.08 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. .40 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 18)
Produced in the same manner as in Example 7 except that the exposure amount in the step (C1) is 200 mJ / cm ² and the smoothing treatment (80 ° C., 30 seconds) is performed after the steps (B1) and (B2). When each part of the printed wiring board was measured, the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured, and the depth was 15.5 μm. The opening width 15 was 600 μm, and the opening width 16 at the bottom of the first opening was 620 μm. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 26.0 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 300 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.08 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. 0.08 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 19)
When each part of the printed wiring board produced by the same method as in Example 7 was measured except that the exposure amount in the step (C1) and the step (C2) was 200 mJ / cm ² , the solder resist layer surface 9 was measured. When the depth of the first opening to the bottom 12 was measured, the depth was 16.0 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening width 16 at the bottom of the first opening was 620 μm. It was. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 26.0 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 320 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.40 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. .40 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 20)
Produced in the same manner as in Example 7 except that the exposure amount in the step (C1) and the step (C2) is 200 mJ / cm ² and the smoothing treatment (80 ° C., 30 seconds) is performed after the step (B2). As a result of measuring each part of the printed wiring board, the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured, and the depth was 16.0 μm. The opening width 15 was 600 μm, and the opening width 16 at the bottom of the first opening was 620 μm. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 26.0 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 320 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.40 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. 0.08 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 21)
Produced in the same manner as in Example 7 except that the exposure amount in the step (C1) and the step (C2) is 200 mJ / cm ² and a smoothing treatment (80 ° C., 30 seconds) is performed after the step (B1). As a result of measuring each part of the printed wiring board, the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured, and the depth was 16.0 μm. The opening width 15 was 600 μm, and the opening width 16 at the bottom of the first opening was 620 μm. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 26.0 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 320 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.08 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. .40 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 22)
Example 7 with the exception of performing the exposure doses in steps (C1) and (C2) at 200 mJ / cm ² and performing a smoothing treatment (80 ° C., 30 seconds) after steps (B1) and (B2). When each part of the printed wiring board produced by the same method was measured, when the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured, the depth was 16.0 μm. The opening width 15 at the top of one opening was 600 μm, and the opening width 16 at the bottom of the first opening was 620 μm. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 26.0 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 320 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.08 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. 0.08 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

  In Examples 7 to 22, a printed wiring board having a structure A in which the opening width 15 at the top of the first opening of the solder resist layer 3 was equal to or less than the opening width 16 at the bottom of the first opening was obtained. In these printed wiring boards, since the adhesive strength between the solder resist layer 3 and the underfill is improved, the effect of improving the insulation reliability of the printed wiring board can be obtained. The printed wiring board manufactured according to Examples 7 to 22 has a structure A in which the opening width 15 at the top of the opening in the first opening 11 of the solder resist layer 3 is equal to or less than the opening width 16 at the bottom of the opening. In addition, the adhesive strength between the solder resist layer 3 and the underfill is improved by having the structure B in which the opening width 17 at the top of the opening in the second opening 14 is equal to or less than the opening width 18 at the bottom of the opening. Therefore, since the insulation reliability of the printed wiring board can be improved and the adhesive strength between the solder and the connection portion 2 is improved, the electronic components are connected via the solder balls arranged in the connection portion 2. In this case, high connection reliability can be obtained between the two.

  Further, since the opening width 15 at the top of the opening in the first opening 11 of the solder resist layer 3 is smaller than the opening width 16 at the bottom of the opening, the solder resist layer 3 bites into the underfill, and the anchor effect causes the fifteenth embodiment. The printed wiring boards of ˜22 have higher insulation than the printed wiring boards of Examples 7-14, in which the opening width 15 at the top of the opening in the first opening 11 of the solder resist layer 3 is equal to the opening width 16 at the bottom of the opening. Reliability is obtained. Moreover, since the opening width 17 of the upper part of the opening part in the 2nd opening part 14 of the soldering resist layer 3 is smaller than the opening width 18 of the opening part bottom part, the soldering resist layer 3 bites into solder, and Examples 11-14 by the anchor effect The printed wiring boards of Examples 19 to 22 are Examples 7 to 10 and Examples 15 to 15 in which the opening width 17 at the top of the opening in the second opening 14 of the solder resist layer 3 is equal to the opening width 18 at the bottom of the opening. Higher connection reliability than 18 printed wiring boards can be obtained.

  In addition, the surface roughness Ra of the bottom portion 12 of the first opening was reduced by the smoothing process, and the surface roughness Ra of the printed wiring board of Examples 9, 13, 17, and 21 and the bottom portion 13 of the second opening was reduced. Printed wiring boards of Examples 8, 12, 16, and 20, and printed wirings of Examples 10, 14, 18, and 22 in which the surface roughness Ra of the bottom 12 of the first opening and the bottom 13 of the second opening is reduced The board has higher strength of the solder resist layer 3 than the printed wiring boards of Examples 7, 11, 15, and 19, and can improve the reliability of the printed wiring board.

  In Examples 23 to 26, a printed wiring board is manufactured by the manufacturing method of FIG.

(Example 23)
<Process (A1)>
Set an area assuming a part of a copper-clad laminate (area 170 mm x 200 mm, copper foil thickness 18 μm, substrate thickness 0.4 mm) as an electronic component mounting part of 600 μm x 600 μm, and use an etching resist in that area A circuit board having a circular connection portion 2 having a diameter of 100 μm was produced by the subtractive method. Next, a dry film solder resist (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded. As a result, a first solder resist layer 3-1 having a dry film thickness of 38.0 μm was formed on the surface of the insulating substrate 1.

<Process (C1)>
Next, using a photomask 8 having a pattern in which actinic rays are irradiated outside the region from the end of the connection portion 2 to the outside to the outside of 100 μm, the contact exposure machine is used to increase the energy to 300 mJ / cm ² . Then, the first solder resist layer 3-1 was exposed.

<Process (B)>
Next, after peeling off the carrier film, the first solder resist layer 3-1 in the unexposed area is thinned by immersing in a 10% by mass sodium metasilicate aqueous solution (liquid temperature 25 ° C.) for 26 seconds. It was. Then, the micelle removal process, the water washing process, and the drying process were performed, and the connection part 2 was exposed from the 1st soldering resist layer 3-1. When the depth from the surface of the 1st soldering resist layer 3-1 to the bottom part 13 of a 2nd opening part was measured, the depth was 25.0 micrometers.

<Process (C2)>
Next, using a photomask 8 having a pattern in which actinic rays are irradiated to an area from the end of the connection portion 2 to the outside by 100 μm, using a contact exposure machine with an energy of 300 mJ / cm ² . The first solder resist layer 3-1 was exposed.

<Process (A2)>
Next, a solder resist film (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded from above the first solder resist layer 3-1 in which the step (C2) was completed. As a result, a second solder resist layer 3-2 having a dry film thickness of 18.0 μm is formed on the surface of the first solder resist layer 3-1, and the dry film thickness from the surface of the insulating substrate 1 to the solder resist layer surface 9 is 56. It became 0 μm.

<Process (C3)>
Next, using a photomask 8 having a pattern in which an actinic ray is irradiated in a region other than the region assumed as the electronic component mounting portion, the second solder resist at an energy of 300 mJ / cm ² using a contact exposure machine. Layer 3-2 was exposed.

<Process (D)>
By performing a development process for 50 seconds using a 1% by mass sodium carbonate aqueous solution (liquid temperature 30 ° C., spray pressure 0.15 MPa), the second solder resist layer 3-2 in the unexposed area is removed, and the first opening The part 11 is formed and the first solder resist layer 3-1 around the connection part 2 and the connection part 2 exposed from the first solder resist layer 3-1 covered with the second solder resist layer 3-2. Exposed again. When the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured, the depth was 18.0 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening at the bottom of the first opening The width 16 was 600 μm. Moreover, since the 1st soldering resist layer 3-1 of the bottom part 13 of a 2nd opening part reduced 0.5 micrometer film | membrane by process (D), the depth from the soldering resist layer surface 9 to the bottom part 13 of a 2nd opening part is The opening width 17 at the top of the second opening was 300 μm, and the opening width 18 at the bottom of the second opening was 300 μm.

  Further, when the surface roughness was measured using an ultra-deep shape measuring microscope (manufactured by KEYENCE, product number “VK-8500”), the surface roughness Ra of the solder resist layer surface 9 was 0.03 μm. The surface roughness Ra of the bottom 12 of the first opening was 0.05 μm, and the surface roughness Ra of the bottom 13 of the second opening was 0.40 μm. Furthermore, when the solder resist layer surface 9, the bottom 12 of the first opening, and the bottom 13 of the second opening were observed with a microscope, no smear remained.

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 24)
Each part of the printed wiring board produced by the same method as in Example 23 was measured except that the smoothing treatment (80 ° C., 30 seconds) was performed after the step (B). When the depth to the bottom 12 of one opening was measured, the depth was 18.0 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening width 16 at the bottom of the first opening was 600 μm. . When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 43.5 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 300 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.05 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. 0.08 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 25)
When each part of the printed wiring board produced by the same method as in Example 23 was measured except that the exposure amount in the step (C1) was 200 mJ / cm ² , the first opening portion from the solder resist layer surface 9 was measured. When the depth to the bottom 12 was measured, the depth was 18.0 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening width 16 at the bottom of the first opening was 600 μm. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 43.5 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 320 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.05 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. .40 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 26)
The printed wiring board produced by the method similar to Example 23 except performing the exposure amount of a process (C1) at 200 mJ / cm < ² >, and performing a smoothing process (80 degreeC, 30 second) after a process (B). When each part was measured, the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured. The depth was 18.0 μm, and the opening width 15 at the top of the first opening was 600 μm. The opening width 16 at the bottom of the first opening was 600 μm. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 43.5 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 320 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.05 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. 0.08 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

  In Examples 23 to 26, a printed wiring board having a structure A in which the opening width 15 at the upper part of the first opening of the solder resist layer 3 is equal to or smaller than the opening width 16 at the bottom of the first opening is obtained. In these printed wiring boards, since the adhesive strength between the solder resist layer 3 and the underfill is improved, the effect of improving the insulation reliability of the printed wiring board can be obtained. Further, the printed wiring board manufactured according to Examples 23 to 26 has a structure A in which the opening width 15 at the top of the opening in the first opening 11 of the solder resist layer 3 is equal to or less than the opening width 16 at the bottom of the opening. In addition, the adhesive strength between the solder resist layer 3 and the underfill is improved by having the structure B in which the opening width 17 at the top of the opening in the second opening 14 is equal to or less than the opening width 18 at the bottom of the opening. Therefore, since the insulation reliability of the printed wiring board can be improved and the adhesive strength between the solder and the connection portion 2 is improved, the electronic components are connected via the solder balls arranged in the connection portion 2. In this case, high connection reliability can be obtained between the two.

  In addition, since the opening width 17 at the top of the opening in the second opening 14 of the solder resist layer 3 is smaller than the opening width 18 at the bottom of the opening, the solder resist layer 3 bites into the solder, and the anchor effect causes Example 25. In the printed wiring board of Example 26, the opening width 17 at the top of the second opening 14 of the solder resist layer 3 is equal to the opening width 18 at the bottom of the opening. However, high connection reliability can be obtained. Further, the printed wiring boards of Example 24 and Example 26 in which the surface roughness Ra of the bottom portion 13 of the second opening was reduced by the smoothing treatment were more solder resist than the printed wiring boards of Examples 23 and 25. The strength of the layer 3 is high, and the reliability of the printed wiring board can be improved.

  In Examples 27 to 34, a printed wiring board is manufactured by the manufacturing method of FIG.

(Example 27)
<Process (A1)>
A region assuming a part of a copper-clad laminate (area 170 mm × 200 mm, copper foil thickness 18 μm, substrate thickness 0.4 mm) as a component mounting portion of 600 μm × 600 μm was set, and an etching resist was used in the region. A circuit board having a circular connection portion 2 having a diameter of 100 μm was manufactured by the subtractive method. Next, a dry film solder resist (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded. As a result, a first solder resist layer 3-1 having a dry film thickness of 38.0 μm was formed on the surface of the insulating substrate 1.

<Process (B1)>
Next, after peeling off the carrier film, the first solder resist layer 3-1 was thinned by being immersed in a 10% by mass aqueous sodium metasilicate solution (liquid temperature: 25 ° C.) for 26 seconds. Then, the micelle removal process, the water washing process, and the drying process were performed, and the connection part 2 was exposed from the 1st soldering resist layer 3-1. When the height from the surface of the first solder resist layer 3-1 after the thinning treatment to the upper part of the connection part 2 was measured, the height was 5.0 μm.

<Process (C1)>
Next, the entire surface of the first solder resist layer 3-1 was exposed with an energy of 300 mJ / cm ² using a contact exposure machine.

<Process (A2)>
Next, a solder resist film (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded from above the first solder resist layer 3-1 in which the step (C1) was completed. As a result, a second solder resist layer 3-2 having a dry film thickness of 28.0 μm is formed on the surface of the first solder resist layer 3-1, and dryness from the surface of the insulating substrate 1 to the surface of the second solder resist layer 3-2 is performed. The film thickness was 41.0 μm.

<Process (C2)>
Next, using a photomask 8 having a pattern in which an actinic ray is irradiated in a region other than the region assumed as the electronic component mounting portion, the second solder resist at an energy of 300 mJ / cm ² using a contact exposure machine. Layer 3-2 was exposed.

<Process (B2)>
Next, after the carrier film is peeled off, the second solder resist layer 3-2 in the unexposed area is thinned by being immersed in a 10% by mass aqueous sodium metasilicate solution (liquid temperature 25 ° C.) for 19 seconds. It was. Then, the micelle removal process, the water washing process, and the drying process were performed, and the 1st opening part 11 was formed. When the depth from the surface of the second solder resist layer 3-2 to the bottom 12 of the first opening was measured, the depth was 18.0 μm.

<Process (C3)>
Next, using a photomask 8 having a pattern in which actinic rays are irradiated outside the region from the end of the connection portion 2 to the outside to the outside of 100 μm, the contact exposure machine is used to increase the energy to 300 mJ / cm ² . Then, the second solder resist layer 3-2 was exposed.

<Process (D)>
The second solder resist layer 3-2 in the unexposed area is removed by performing development for 15 seconds using a 1% by mass sodium carbonate aqueous solution (liquid temperature 30 ° C., spray pressure 0.15 MPa), and the second solder The connection part 2 exposed from the first solder resist layer 3-1 covered with the resist layer 3-2 and the first solder resist layer 3-1 around the connection part are exposed again, and the first opening part is exposed. The second solder resist layer 3-2 at the bottom 12 and the first solder resist layer 3-1 at the bottom 13 of the second opening were reduced. The depth from the bottom 12 of the first opening to the bottom 13 of the second opening is 10.0 μm, and the depth from the solder resist layer surface 9 to the bottom 12 of the first opening is measured. Was 18.5 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening width 16 at the bottom of the first opening was 600 μm. The depth from the solder resist layer surface 9 to the bottom 13 of the second opening is 28.5 μm, the opening width 17 at the top of the second opening is 300 μm, and the opening width 18 at the bottom of the second opening is 300 μm. there were.

  Further, when the surface roughness was measured using an ultra-deep shape measuring microscope (manufactured by KEYENCE, product number “VK-8500”), the surface roughness Ra of the solder resist layer surface 9 was 0.03 μm. The surface roughness Ra of the bottom 12 of the first opening was 0.40 μm, and the surface roughness Ra of the bottom 13 of the second opening was 0.42 μm. Furthermore, when the solder resist layer surface 9, the bottom 12 of the first opening, and the bottom 13 of the second opening were observed with a microscope, no smear remained.

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 28)
Each part of the printed wiring board produced by the same method as in Example 27 was measured except that the smoothing process (80 ° C., 30 seconds) was performed after the step (B1). When the depth to the bottom 12 of one opening was measured, the depth was 18.5 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening width 16 at the bottom of the first opening was 600 μm. . When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 28.5 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 300 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.40 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. .10 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 29)
Each part of the printed wiring board produced by the same method as in Example 27 was measured except that the smoothing process (80 ° C., 30 seconds) was performed after the step (B2). When the depth to the bottom 12 of one opening was measured, the depth was 18.5 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening width 16 at the bottom of the first opening was 600 μm. . When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 28.5 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 300 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.08 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. .40 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 30)
When each part of the printed wiring board produced by the same method as Example 27 was measured except performing the smoothing process (80 ° C., 30 seconds) after the steps (B1) and (B2), the solder resist When the depth from the layer surface 9 to the bottom 12 of the first opening was measured, the depth was 18.5 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening width 16 at the bottom of the first opening. Was 600 μm. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 28.5 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 300 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.08 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. .10 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 31)
When each part of the printed wiring board produced by the same method as in Example 27 was measured except that the exposure amount in the step (C2) was 200 mJ / cm ² , the first opening portion from the solder resist layer surface 9 was measured. When the depth to the bottom 12 was measured, the depth was 18.5 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening width 16 at the bottom of the first opening was 620 μm. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 28.5 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 300 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.40 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. .40 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 32)
The printed wiring board produced by the method similar to Example 27 except performing a smoothing process (80 degreeC, 30 second) after a process (B1), and performing the exposure amount of a process (C2) at 200 mJ / cm < ² >. When each part was measured, the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured, the depth was 18.5 μm, and the opening width 15 at the top of the first opening was 600 μm. The opening width 16 at the bottom of the first opening was 620 μm. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 28.5 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 300 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.40 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. .10 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 33)
The printed wiring board produced by the method similar to Example 27 except performing the exposure amount of a process (C2) at 200 mJ / cm < ² >, and performing a smoothing process (80 degreeC, 30 second) after a process (B2). When each part was measured, the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured, the depth was 18.5 μm, and the opening width 15 at the top of the first opening was 600 μm. The opening width 16 at the bottom of the first opening was 620 μm. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 28.5 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 300 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.08 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. .40 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 34)
Fabricated in the same manner as in Example 27, except that smoothing treatment (80 ° C., 30 seconds) is performed after step (B1) and step (B2), and the exposure amount in step (C2) is performed at 200 mJ / cm ^2. As a result of measuring each part of the printed wiring board, when measuring the depth from the solder resist layer surface 9 to the bottom 12 of the first opening, the depth is 18.5 μm, The opening width 15 was 600 μm, and the opening width 16 at the bottom of the first opening was 620 μm. When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 28.5 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 300 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.08 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. .10 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

  In Examples 27 to 34, printed wiring boards having a structure A in which the opening width 15 at the top of the first opening of the solder resist layer 3 was equal to or less than the opening width 16 at the bottom of the first opening were obtained. In these printed wiring boards, since the adhesive strength between the solder resist layer 3 and the underfill is improved, the effect of improving the insulation reliability of the printed wiring board can be obtained. Further, the printed wiring board manufactured according to Examples 27 to 34 has a structure A in which the opening width 15 at the top of the opening in the first opening 11 of the solder resist layer 3 is equal to or less than the opening width 16 at the bottom of the opening. In addition, the adhesive strength between the solder resist layer 3 and the underfill is improved by having the structure B in which the opening width 17 at the top of the opening in the second opening 14 is equal to or less than the opening width 18 at the bottom of the opening. Therefore, since the insulation reliability of the printed wiring board can be improved and the adhesive strength between the solder and the connection portion 2 is improved, the electronic components are connected via the solder balls arranged in the connection portion 2. In this case, high connection reliability can be obtained between the two.

  Further, since the opening width 15 at the top of the opening in the first opening 11 of the solder resist layer 3 is smaller than the opening width 16 at the bottom of the opening, the solder resist layer 3 bites into the underfill, and the anchor effect causes Example 31. The printed wiring boards of .about.34 have higher insulation than the printed wiring boards of Examples 27 to 30, in which the opening width 15 at the top of the opening in the first opening 11 of the solder resist layer 3 is equal to the opening width 16 at the bottom of the opening. Reliability is obtained. In addition, the printed wiring board of Examples 29 and 33 in which the surface roughness Ra of the bottom 12 of the first opening was reduced by the smoothing process, and the Example 28 in which the surface roughness Ra of the bottom 13 of the second opening was reduced. 32, and the printed wiring boards of Examples 30 and 34 in which the surface roughness Ra of the bottom 12 of the first opening and the bottom 13 of the second opening is reduced are the printed wiring boards of Examples 27 and 31. The strength of the solder resist layer 3 is higher than that, and the reliability of the printed wiring board can be improved.

  In Examples 35 to 36, a printed wiring board is manufactured by the manufacturing method of FIG.

(Example 35)
<Process (A1)>
Set an area assuming a part of a copper-clad laminate (area 170 mm x 200 mm, copper foil thickness 18 μm, substrate thickness 0.4 mm) as an electronic component mounting part of 600 μm x 600 μm, and use an etching resist in that area A circuit board having a circular connection portion 2 having a diameter of 100 μm was manufactured by the subtractive method. Next, a dry film solder resist (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded. As a result, a first solder resist layer 3-1 having a dry film thickness of 38.0 μm was formed on the surface of the insulating substrate 1.

<Process (B1)>
Next, after peeling off the carrier film, the first solder resist layer 3-1 was thinned by being immersed in a 10% by mass aqueous sodium metasilicate solution (liquid temperature: 25 ° C.) for 26 seconds. Then, the micelle removal process, the water washing process, and the drying process were performed, and the connection part 2 was exposed from the 1st soldering resist layer 3-1. When the height from the surface of the first solder resist layer 3-1 after the thinning treatment to the upper part of the connection part 2 was measured, the height was 5.0 μm.

<Process (C1)>
Next, the entire surface of the first solder resist layer 3-1 was exposed with an energy of 300 mJ / cm ² using a contact exposure machine.

<Process (A2)>
Next, a solder resist film (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded from above the first solder resist layer 3-1 in which the step (C1) was completed. As a result, a second solder resist layer 3-2 having a dry film thickness of 18.0 μm is formed on the surface of the first solder resist layer 3-1, and dryness from the surface of the insulating substrate 1 to the surface of the second solder resist layer 3-2 is performed. The film thickness was 31.0 μm.

<Process (C2)>
Next, using a photomask 8 having a pattern in which actinic rays are irradiated outside the region from the end of the connection portion 2 to the outside to the outside of 100 μm, the contact exposure machine is used to increase the energy to 300 mJ / cm ² . Then, the second solder resist layer 3-2 was exposed.

<Process (D1)>
Next, after peeling off the carrier film, the second solder resist layer in the unexposed area is developed for 22 seconds using a 1% by mass sodium carbonate aqueous solution (liquid temperature 30 ° C., spray pressure 0.15 MPa). The connection part 2 exposed from the first solder resist layer 3-1 and the first solder resist layer 3-1 around the connection part, which have been removed by 3-2 and covered with the second solder resist layer 3-2. Was exposed again, and the film of the first solder resist layer 3-1 at the bottom 13 of the second opening was reduced. The depth from the surface of the second solder resist layer 3-2 to the bottom 13 of the second opening is 18.5 μm, the opening width 17 at the top of the second opening is 300 μm, and the opening width 18 at the bottom of the second opening is It was 300 μm.

<Process (A3)>
Next, a solder resist film (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) is formed on the first solder resist layer 3-1 and the second solder resist layer 3-2 that have completed the step (D1). Vacuum thermocompression bonding was performed. As a result, a third solder resist layer 3-3 having a dry film thickness of 18.0 μm is formed on the surfaces of the first solder resist layer 3-1 and the second solder resist layer 3-2. The dry film thickness up to the surface of the resist layer 3-3 was 49.0 μm.

<Process (C3)>
Next, using a photomask 8 having a pattern in which actinic rays are irradiated in a region other than the region assumed as the electronic component mounting portion, the third solder resist is applied at an energy of 300 mJ / cm ² with a contact exposure machine. Layer 3-3 was exposed.

<Process (D2)>
The third solder resist layer 3-3 in the unexposed area is removed by performing a development process for 36 seconds using a 1 mass% aqueous sodium carbonate solution (liquid temperature 30 ° C., spray pressure 0.15 MPa), and the third solder is removed. The bottom 12 of the first opening that was the surface of the second solder resist layer, which was covered with the resist layer 3-3, is exposed and connected to the connection portion 2 exposed from the first solder resist layer 3-1. The first solder resist layer 3-1 (the bottom 13 of the second opening) around the part was exposed again. The depth from the solder resist layer surface 9 which is the surface of the third solder resist layer 3-3 to the bottom 12 of the first opening is 18.0 μm, the opening width 15 at the top of the first opening is 600 μm, the first The opening width 16 at the bottom of the opening was 600 μm. The depth from the solder resist layer surface 9 to the bottom 13 of the second opening was 36.5 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening width 18 at the bottom of the second opening was 300 μm. .

  Further, when the surface roughness was measured using an ultra-deep shape measuring microscope (manufactured by Keyence Corporation, product number “VK-8500”), the surface roughness of the solder resist layer surface 9 and the bottom 12 of the first opening was measured. The thickness Ra was 0.03 μm, and the surface roughness Ra of the bottom 13 of the second opening was 0.42 μm. Furthermore, when the solder resist layer surface 9, the bottom 12 of the first opening, and the bottom 13 of the second opening were observed with a microscope, no smear remained.

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 36)
Each part of the printed wiring board produced by the same method as in Example 35 was measured except that the smoothing treatment (80 ° C., 30 seconds) was performed after the step (B1). When the depth to the bottom 12 of one opening was measured, the depth was 18.0 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening width 16 at the bottom of the first opening was 600 μm. . When the depth from the solder resist layer surface 9 to the bottom 13 of the second opening was measured, the depth was 36.5 μm, the opening width 17 at the top of the second opening was 300 μm, and the opening at the bottom of the second opening The width 18 was 300 μm. The surface roughness Ra of the solder resist layer surface 9 is 0.03 μm, the surface roughness Ra of the bottom 12 of the first opening is 0.03 μm, and the surface roughness Ra of the bottom 13 of the second opening is 0. 0.08 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

  In Examples 35 and 36, a printed wiring board having a structure A in which the opening width 15 at the top of the first opening of the solder resist layer 3 is equal to or less than the opening width 16 at the bottom of the first opening was obtained. In these printed wiring boards, since the adhesive strength between the solder resist layer 3 and the underfill is improved, the effect of improving the insulation reliability of the printed wiring board can be obtained. Further, the printed wiring board manufactured according to Examples 35 and 36 has a structure A in which the opening width 15 at the top of the opening in the first opening 11 of the solder resist layer 3 is equal to or less than the opening width 16 at the bottom of the opening. In addition, the adhesive strength between the solder resist layer 3 and the underfill is improved by having the structure B in which the opening width 17 at the top of the opening in the second opening 14 is equal to or less than the opening width 18 at the bottom of the opening. Therefore, since the insulation reliability of the printed wiring board can be improved and the adhesive strength between the solder and the connection portion 2 is improved, the electronic components are connected via the solder balls arranged in the connection portion 2. In this case, high connection reliability can be obtained between the two.

  In addition, the printed wiring board of Example 36 in which the surface roughness Ra of the bottom portion 13 of the second opening is reduced by the smoothing treatment has higher strength of the solder resist layer 3 than the printed wiring board of Example 35, and the printed wiring board. Can improve the reliability of

(Comparative Example 3)
Set an area assuming a part of a copper-clad laminate (area 170 mm x 200 mm, copper foil thickness 18 μm, substrate thickness 0.4 mm) as an electronic component mounting part of 600 μm x 600 μm, and use an etching resist in that area A circuit board having a circular connection portion 2 having a diameter of 100 μm was manufactured by the subtractive method. Next, a dry film solder resist (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded. Thereby, the solder resist layer 3 having a dry film thickness of 41.0 μm from the surface of the insulating substrate 1 to the solder resist layer surface 9 was formed. Thereafter, the entire surface of the solder resist layer 3 was exposed with an energy of 1000 mJ / cm ² using a contact exposure machine, and further heated at 150 ° C. for 30 minutes using a hot air dryer.

  Next, excimer laser light (wavelength 248 nm, output 50 W) was irradiated to the region assumed as the electronic component mounting portion, and the first opening 11 was formed in the solder resist layer 3.

  Next, an excimer laser beam (wavelength 248 nm, output 50 W) was irradiated to an area from the end portion of the connection portion 2 to the outside by 100 μm to expose the connection portion 2 from the solder resist layer 3.

  When the solder resist layer surface 9 irradiated with the laser beam was observed with a microscope, the solder resist layer surface 9 and the bottom portion 12 of the first opening portion were formed by forming the first opening 11 and irradiating the connecting portion 2 with the laser beam. In addition, smear was generated at the upper part of the connection part 2 and the bottom part 13 of the second opening.

  Next, a solution containing sodium hydroxide as a main component (manufactured by Meltex Co., Ltd., trade name: ENPLATE (registered trademark) MLB-496A) and a solution containing 1-methoxy-2-propanol (Meltex) Made by Tex Co., Ltd., trade name: ENPLATE (registered trademark) MLB-496B) and a mixed solution of distilled water, the solder resist layer 3 in which smear is generated is immersed at 60 ° C. for 15 minutes to swell the smear It was. Next, a solution containing sodium permanganate as a main component (Meltex Co., Ltd., trade name: ENPLATE (registered trademark) MLB-497A) and a solution containing sodium hydroxide as a main component (Meltex Co., Ltd.) The product was soaked in a mixed solution of ENPLATE (registered trademark) MLB-497B) and distilled water at 80 ° C. for 10 minutes to decompose and remove the swollen smear.

  Further, when the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured, the depth was 18.0 μm, the opening width 15 at the top of the first opening was 600 μm, and the bottom of the first opening The opening width 16 was 590 μm. Moreover, when the depth from the bottom 12 of the first opening to the bottom 13 of the second opening around the connecting portion 2 was measured, the depth was 10.0 μm, and the opening width 17 at the top of the second opening was The opening width 18 at the bottom of the second opening was 300 μm and 290 μm. Moreover, the surface roughness Ra of the solder resist layer surface 9 was 0.80 μm, and the surface roughness Ra of the bottom 12 of the first opening and the bottom 13 of the second opening was 0.90 μm. Further, when the surface of the solder resist layer 9 around the first opening 11, the first opening 11, and the bottom 13 of the second opening around the connecting portion 2 were observed with a microscope, the entire surface of the solder resist layer 3 was roughened. It had been.

(Comparative Example 4)
Set an area assuming a part of a copper-clad laminate (area 170 mm x 200 mm, copper foil thickness 18 μm, substrate thickness 0.4 mm) as an electronic component mounting part of 600 μm x 600 μm, and use an etching resist in that area A circuit board having a circular connection portion 2 having a diameter of 100 μm was manufactured by the subtractive method. Next, a solder resist film (trade name: PFR-800 AUS410, manufactured by Taiyo Ink Manufacturing Co., Ltd.) was subjected to vacuum thermocompression bonding. Thereby, the solder resist layer 3 having a dry film thickness of 41.0 μm from the surface of the insulating substrate 1 to the solder resist layer surface 9 was formed. Thereafter, the entire surface of the solder resist layer 3 was exposed with an energy of 1000 mJ / cm ² using a contact exposure machine, and further heated at 150 ° C. for 30 minutes using a hot air dryer.

Next, a resist film for blasting (trade name: MS7100, manufactured by Mitsubishi Paper Industries Co., Ltd.) was thermocompression bonded. Next, using a photomask 8 having a pattern in which an actinic ray is irradiated in a region other than the region assumed as the electronic component mounting portion, a blast resist film at an energy of 100 mJ / cm ² using a contact exposure machine The film was exposed to light and then developed, and the unexposed blast resist film was removed.

  Next, sandblast treatment (abrasive material: SiC # 800, blast pressure 0.15 MPa) was performed on the blast resist film to form the first opening 11 in the solder resist layer 3, and then the blast resist film was peeled off. .

Next, a resist film for blasting (trade name: MS7100, manufactured by Mitsubishi Paper Industries Co., Ltd.) was vacuum thermocompression bonded. Next, using a photomask 8 having a pattern in which actinic rays are irradiated outside the region from the end of the connecting portion 2 to the outside of 100 μm, the contact exposure machine is used to increase the energy to 100 mJ / cm ² . The blast resist film was exposed to light, and then developed to remove the unexposed blast resist film.

  Next, sandblasting (abrasive material: SiC # 800, blast pressure 0.15 MPa) is performed on the resist film for blasting, an opening is formed in the solder resist layer 3 at the bottom 12 of the first opening, and the connection portion 2 is formed. After the exposure, the resist film for blasting was peeled off. When the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured, the depth was 18.0 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening at the bottom of the first opening The width 16 was 580 μm. Moreover, when the depth from the bottom 12 of the first opening to the bottom 13 of the second opening around the connecting portion 2 was measured, the depth was 10.0 μm, and the opening width 17 at the top of the second opening was The opening width 18 at the bottom of the second opening was 300 μm and 280 μm. Further, the surface roughness Ra of the solder resist layer surface 9 was 0.03 μm, and the surface roughness Ra of the bottom 12 of the first opening and the bottom 13 of the second opening was 1.20 μm. Further, when the solder resist layer 3 at the bottom 12 of the first opening and the bottom 13 of the second opening was observed with a microscope, the entire surface was roughened.

  The printed wiring boards manufactured by Examples 7 to 36 and Comparative Examples 3 and 4 have the first opening 11 formed in the electronic component mounting portion and the solder resist layer 3 around the electronic component mounting portion, and Since the connection portion 2 is partially exposed from the solder resist layer 3 by the second opening portion 14 formed in the bottom portion 12 of the first opening portion, flip-chip connection is performed using this printed wiring board. In such a case, when sufficient underfill is injected to ensure the connection reliability between the electronic component and the circuit board, the underfill overflows from the gap between the electronic component and the circuit board and adversely affects the electrical operation. In the printed wiring board in which the connection portions 2 are arranged at a high density, the bonding strength between the connection portions 2 and the insulating substrate 1 and the bonding strength between the connection portions 2 and the solder are also possible. Is increased, high connection reliability is obtained.

  Furthermore, the printed wiring boards manufactured according to Examples 7 to 36 are Comparative Example 3 and Comparative Example 4 in which the first opening 11 and the second opening 14 are formed in the solder resist layer by laser processing, desmear processing, and sandblasting. Compared with the printed wiring board, the strength of the solder resist layer 3 is high, and high connection reliability is obtained.

  Examples 37-40 manufacture the printed wiring board with the manufacturing method of FIG.

(Example 37)
<Process (A)>
Set an area assuming a part of a copper-clad laminate (area 170 mm x 200 mm, copper foil thickness 18 μm, substrate thickness 0.4 mm) as an electronic component mounting part of 600 μm x 600 μm, and use an etching resist in that area A circuit board having a circular connection portion 2 having a diameter of 100 μm was produced by the subtractive method. Next, a dry film shape solder resist (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded. Thus, a solder resist layer 3 having a dry film thickness of 38.0 μm from the surface of the insulating substrate 1 to the solder resist layer surface 9 was formed.

<Process (C1)>
Next, using a photomask 8 having a pattern in which an actinic ray is irradiated in a region other than the region assumed as the electronic component mounting portion, the solder resist layer 3 at an energy of 300 mJ / cm ² with a contact exposure machine. The exposure was carried out.

<Process (B)>
Next, after peeling off the carrier film, the solder resist layer 3 in the unexposed area is thinned by immersing in a 10% by mass aqueous sodium metasilicate solution (liquid temperature 25 ° C.) for 16 seconds. One opening 11 was formed. When the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured after the micelle removal process, the water washing process, and the drying process, the depth was 15.0 μm, and the opening at the top of the first opening The width 15 was 600 μm, and the opening width 16 at the bottom of the first opening was 600 μm.

<Process (C2)>
Next, using a photomask 8 having a pattern in which actinic rays are irradiated outside the region from the end of the connection portion 2 to the outside to the outside of 100 μm, the contact exposure machine is used to increase the energy to 300 mJ / cm ² . Then, the solder resist layer 3 was exposed.

<Process (D)>
By performing development processing for 50 seconds using a 1% by mass aqueous sodium carbonate solution (liquid temperature 30 ° C., spray pressure 0.15 MPa), the unexposed solder resist layer 3 is removed and the second opening 14 is formed. At the same time, the connecting portion 2 was exposed from the solder resist layer 3, and the solder resist layer 3 at the bottom 12 of the first opening was reduced. When the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured, the depth was 15.5 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening at the bottom of the first opening The width 16 was 600 μm. Further, when the depth from the bottom 12 of the first opening to the surface of the insulating substrate 1 was measured, the depth was 22.5 μm, the opening width 17 at the top of the second opening was 300 μm, and the bottom of the second opening was The opening width 18 was 300 μm. Further, when the surface roughness was measured using an ultra-deep shape measuring microscope (manufactured by KEYENCE, product number “VK-8500”), the surface roughness Ra of the solder resist layer surface 9 was 0.03 μm. The surface roughness Ra of the bottom 12 of the first opening was 0.40 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

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 38)
Each part of the printed wiring board produced by the same method as in Example 37 was measured except that the smoothing treatment (80 ° C., 30 seconds) was performed after the step (B). When the depth to the bottom 12 of one opening was measured, the depth was 15.5 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening width 16 at the bottom of the first opening was 600 μm. . Further, when the depth from the bottom 12 of the first opening to the surface of the insulating substrate 1 was measured, the depth was 22.5 μm, the opening width 17 at the top of the second opening was 300 μm, and the bottom of the second opening was The opening width 18 was 300 μm. The surface roughness Ra of the solder resist layer surface 9 was 0.03 μm, and the surface roughness Ra of the bottom 12 of the first opening was 0.08 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 39)
Measurement of each part of the printed wiring board produced in the same manner as in Example 37 except that the exposure amount in the step (C1) was performed at 200 mJ / cm ² revealed that the first opening portion from the solder resist layer surface 9 was measured. When the depth to the bottom 12 was measured, the depth was 15.5 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening width 16 at the bottom of the first opening was 620 μm. Further, when the depth from the bottom 12 of the first opening to the surface of the insulating substrate 1 was measured, the depth was 22.5 μm, the opening width 17 at the top of the second opening was 300 μm, and the bottom of the second opening was The opening width 18 was 300 μm. The surface roughness Ra of the solder resist layer surface 9 was 0.03 μm, and the surface roughness Ra of the bottom 12 of the first opening was 0.40 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

(Example 40)
The printed wiring board produced by the method similar to Example 37 except performing the exposure amount of a process (C1) at 200 mJ / cm < ² >, and performing a smoothing process (80 degreeC, 30 second) after a process (B). When each part was measured, the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured. The depth was 15.5 μm, and the opening width 15 at the top of the first opening was 600 μm. The opening width 16 at the bottom of the first opening was 620 μm. Further, when the depth from the bottom 12 of the first opening to the surface of the insulating substrate 1 was measured, the depth was 22.5 μm, the opening width 17 at the top of the second opening was 300 μm, and the bottom of the second opening was The opening width 18 was 300 μm. The surface roughness Ra of the solder resist layer surface 9 was 0.03 μm, and the surface roughness Ra of the bottom 12 of the first opening was 0.08 μm. Furthermore, when the periphery of the opening of the solder resist layer 3 and the bottom 12 of the first opening and the bottom 13 of the second opening were observed with a microscope, no smear remained.

  In Examples 37 to 40, printed wiring boards having a structure A in which the opening width 15 at the top of the first opening of the solder resist layer 3 was equal to or less than the opening width 16 at the bottom of the first opening were obtained. In these printed wiring boards, since the adhesive strength between the solder resist layer 3 and the underfill is improved, the effect of improving the insulation reliability of the printed wiring board can be obtained. Moreover, the printed wiring board manufactured by Examples 37 to 40 has a structure A in which the opening width 15 at the top of the opening in the first opening 11 of the solder resist layer 3 is equal to or less than the opening width 16 at the bottom of the opening. In addition, the adhesive strength between the solder resist layer 3 and the underfill is improved by having the structure B in which the opening width 17 at the top of the opening in the second opening 14 is equal to or less than the opening width 18 at the bottom of the opening. Therefore, since the insulation reliability of the printed wiring board can be improved and the adhesive strength between the solder and the connection portion 2 is improved, the electronic components are connected via the solder balls arranged in the connection portion 2. In this case, high connection reliability can be obtained between the two.

  Further, since the opening width 15 at the top of the opening in the first opening 11 of the solder resist layer 3 is smaller than the opening width 16 at the bottom of the opening, the solder resist layer 3 bites into the underfill. , 40 is higher in insulation than the printed wiring boards of Examples 37 and 38 in which the opening width 15 at the top of the opening in the first opening 11 of the solder resist layer 3 is equal to the opening width 16 at the bottom of the opening. Reliability is obtained.

  In addition, the printed wiring boards of Examples 38 and 40 in which the surface roughness Ra of the bottom 12 of the first opening is reduced by the smoothing treatment are stronger than the printed wiring boards of Examples 37 and 39. The reliability of the printed wiring board can be improved.

(Comparative Example 5)
Set an area assuming a part of a copper-clad laminate (area 170 mm x 200 mm, copper foil thickness 18 μm, substrate thickness 0.4 mm) as an electronic component mounting part of 600 μm x 600 μm, and use an etching resist in that area A circuit board having a circular connection portion 2 having a diameter of 100 μm was manufactured by the subtractive method. Next, a dry film solder resist (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PFR-800 AUS410) was vacuum thermocompression bonded. Thereby, the solder resist layer 3 having a dry film thickness of 41.0 μm from the surface of the insulating substrate 1 to the solder resist layer surface 9 was formed. Thereafter, the entire surface of the solder resist layer 3 was exposed with an energy of 1000 mJ / cm ² using a contact exposure machine, and further heated at 150 ° C. for 30 minutes using a hot air dryer.

  Next, excimer laser light (wavelength 248 nm, output 50 W) was irradiated to the region assumed as the electronic component mounting portion, and the first opening 11 was formed in the solder resist layer 3.

  Next, an excimer laser beam (wavelength 248 nm, output 50 W) was irradiated to an area from the end of the connection part 2 to the outside by 100 μm, so that the connection part 2 was completely exposed from the solder resist layer 3.

  When the solder resist layer surface 9 irradiated with the laser beam was observed with a microscope, the solder resist layer surface 9 and the bottom portion 12 of the first opening portion were formed by forming the first opening 11 and irradiating the connecting portion 2 with the laser beam. In addition, smear was generated at the upper part of the connection part 2 and the bottom part 13 of the second opening.

  Next, a solution containing sodium hydroxide as a main component (manufactured by Meltex Co., Ltd., trade name: ENPLATE (registered trademark) MLB-496A) and a solution containing 1-methoxy-2-propanol (Meltex) Made by Tex Co., Ltd., trade name: ENPLATE (registered trademark) MLB-496B) and a mixed solution of distilled water, the solder resist layer 3 in which smear is generated is immersed at 60 ° C. for 15 minutes to swell the smear It was. Next, a solution containing sodium permanganate as a main component (Meltex Co., Ltd., trade name: ENPLATE (registered trademark) MLB-497A) and a solution containing sodium hydroxide as a main component (Meltex Co., Ltd.) The product was soaked in a mixed solution of ENPLATE (registered trademark) MLB-497B) and distilled water at 80 ° C. for 10 minutes to decompose and remove the swollen smear.

  Further, when the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured, the depth was 18.0 μm, the opening width 15 at the top of the first opening was 600 μm, and the bottom of the first opening The opening width 16 was 590 μm. Further, when the depth from the bottom 12 of the first opening to the surface of the insulating substrate 1 was measured, the depth was 23.0 μm, the opening width 17 at the top of the second opening was 300 μm, and the bottom of the second opening was The opening width 18 was 290 μm. Further, the surface roughness Ra of the solder resist layer surface 9 was 0.80 μm, and the surface roughness Ra of the bottom 12 of the first opening was 0.90 μm. Furthermore, when the solder resist layer surface 9 and the first opening 11 around the first opening 11 were observed with a microscope, the entire surface of the solder resist layer 3 was roughened.

(Comparative Example 6)
Set an area assuming a part of a copper-clad laminate (area 170 mm x 200 mm, copper foil thickness 18 μm, substrate thickness 0.4 mm) as an electronic component mounting part of 600 μm x 600 μm, and use an etching resist in that area A circuit board having a circular connection portion 2 having a diameter of 100 μm was manufactured by the subtractive method. Next, a solder resist film (trade name: PFR-800 AUS410, manufactured by Taiyo Ink Manufacturing Co., Ltd.) was subjected to vacuum thermocompression bonding. Thereby, the solder resist layer 3 having a dry film thickness of 41.0 μm from the surface of the insulating substrate 1 to the solder resist layer surface 9 was formed. Thereafter, the entire surface of the solder resist layer 3 was exposed with an energy of 1000 mJ / cm ² using a contact exposure machine, and further heated at 150 ° C. for 30 minutes using a hot air dryer.

Next, a resist film for blasting (trade name: MS7100, manufactured by Mitsubishi Paper Industries Co., Ltd.) was thermocompression bonded. Next, using a photomask 8 having a pattern in which an actinic ray is irradiated in a region other than the region assumed as the electronic component mounting portion, a blast resist film at an energy of 100 mJ / cm ² using a contact exposure machine Layer 3 was exposed and then developed to remove the unexposed blast resist film.

  Next, sandblast treatment (abrasive material: SiC # 800, blast pressure 0.15 MPa) was performed on the blast resist film to form the first opening 11 in the solder resist layer 3, and then the blast resist film was peeled off. .

Next, a resist film for blasting (trade name: MS7100, manufactured by Mitsubishi Paper Industries Co., Ltd.) was vacuum thermocompression bonded. Next, using a photomask 8 having a pattern in which actinic rays are irradiated outside the region from the end of the connecting portion 2 to the outside of 100 μm, the contact exposure machine is used to increase the energy to 100 mJ / cm ² . The blast resist film was exposed to light, and then developed to remove the unexposed blast resist film.

  Next, sandblasting (abrasive material: SiC # 800, blast pressure 0.15 MPa) is performed on the resist film for blasting, an opening is formed in the solder resist layer 3 at the bottom 12 of the first opening, and the connection portion 2 is formed. After the exposure, the resist film for blasting was peeled off. When the depth from the solder resist layer surface 9 to the bottom 12 of the first opening was measured, the depth was 18.0 μm, the opening width 15 at the top of the first opening was 600 μm, and the opening at the bottom of the first opening The width 16 was 580 μm. Further, when the depth from the bottom 12 of the first opening to the surface of the insulating substrate 1 was measured, the depth was 23.0 μm, the opening width 17 at the top of the second opening was 300 μm, and the bottom of the second opening was The opening width 18 was 280 μm. Further, the surface roughness Ra of the solder resist layer surface 9 was 0.03 μm, and the surface roughness Ra of the bottom 12 of the first opening was 1.20 μm. Furthermore, when the solder resist layer 3 at the bottom 12 of the first opening was observed with a microscope, the entire surface was roughened.

  The printed wiring boards manufactured in Examples 37 to 40 and Comparative Examples 5 to 6 have the first opening 11 formed in the electronic component mounting portion and the solder resist layer 3 around the electronic component mounting portion, and the first Since the connection part 2 is exposed from the solder resist layer 3 by the second opening part 14 formed in the bottom part 12 of the opening part, when flip chip connection is performed using this printed wiring board, an electronic component When sufficient underfill is injected to ensure the connection reliability between the circuit board and the circuit board, the underfill may overflow from the gap between the electronic component and the circuit board and adversely affect the electrical operation. In addition, even in a printed wiring board in which the connection portions 2 are arranged at a high density, the bonding strength between the connection portions 2 and the solder is increased, and high connection reliability is obtained.

  Furthermore, the printed wiring boards manufactured according to Examples 37 to 40 are printed in Comparative Examples 5 and 6 in which the first opening 11 and the second opening 14 are formed in the solder resist layer by laser processing, desmearing, and sandblasting. Compared with the wiring board, the strength of the solder resist layer 3 is high, and high connection reliability is obtained.

  The present invention can be used for a printed wiring board provided with a connecting portion for connecting electronic components.

1 Insulating substrate 2 Conductor circuit (connection part)
DESCRIPTION OF SYMBOLS 3 Solder resist layer 4 Opening part 5 Opening width 6 of upper part of opening part Opening width 7 of opening part bottom part Actinic ray 8 Photomask 9 Solder resist layer surface 10 Solder resist layer opening part bottom part 11 First opening part 12 First opening part The bottom 13 The bottom 14 of the second opening 14 The second opening 15 The opening width 16 at the top of the first opening 16 The opening width 17 at the bottom of the first opening 18 The opening width 18 at the top of the second opening 19 The opening width 19 of the bottom of the second opening Conductor circuit 20 Dam structure

Claims (5)

  It has a circuit board on which a connection part for connecting electronic components is formed on an insulating substrate, and has a solder resist layer having an opening on the surface of the circuit board, and the connection part is partially exposed from the solder resist layer in the opening. What is claimed is: 1. A printed wiring board having a structure in which an opening width of an upper portion of an opening of a solder resist layer is equal to or smaller than an opening width of a bottom of the opening.   The printed wiring board according to claim 1, wherein the surface roughness Ra of the solder resist layer surface and the bottom of the solder resist layer opening is 0.50 μm or less.   A circuit board having a connection part for connecting an electronic component formed on an insulating substrate, having a solder resist layer on the surface of the circuit board, and an electronic component mounting part and a surrounding solder resist layer being opened Printed wiring having an opening, a second opening formed by opening a part of the solder resist layer at the bottom of the first opening, and a connecting portion exposed from the solder resist layer in the second opening A structure in which the opening width at the top of the opening in the first opening is equal to or less than the opening width at the bottom of the opening, and the opening width at the top of the opening in the second opening is equal to or less than the opening width of the bottom of the opening. A printed wiring board having at least one structure selected from the group consisting of a certain structure B.   4. The printed wiring board according to claim 3, wherein the surface roughness Ra of at least one surface selected from the group consisting of the surface of the solder resist layer, the bottom of the first opening, and the bottom of the second opening is 0.50 [mu] m or less.   5. The printed wiring board according to claim 3, wherein in the second opening, the entire surface and a part of the side surface of the connection portion are exposed from the solder resist layer.