JP2011214024A - Circuit board provided with support frame and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit board provided with a support frame, which does not need to form and remove a resist mask when forming a plating part, can suppress a leak of a plating liquid, can reduce a dispersion of the thickness of the plating part and has little loss of plating.SOLUTION: The circuit board provided with the support frame includes a circuit board 10 which is integrated with the support frame 11 in an internal opening region 12 of the support frame 11. The circuit board 10 includes: a metal support substrate 1; an insulating layer 2 formed on the metal support substrate 1; a wiring layer 3 formed on the insulating layer 2; a cover layer 4 which covers the wiring layer 3 and the insulating layer 2; and the plating part 6 formed on the surface of the wiring layer 3 which is not covered with the cover layer 4. The support frame 11 includes: the metal support substrate 1; the insulating layer 2 formed on the metal support substrate 1; a conductor layer 7 formed on the insulating layer 2; and a protective layer 8 which is formed on the conductor layer 7 and is constituted by the same material as that of the cover layer 4.

Description

  The present invention relates to a circuit board with a support frame that does not require the formation or peeling of a resist mask when forming a plating part, can suppress plating leakage, reduces the variation in the thickness of the plating part, and has a small plating loss.

  For example, a suspension board on which elements such as a magnetic head slider are mounted is known as a circuit board used in an HDD (Hard Disk Drive). For example, as shown in FIG. 9, the suspension substrate is formed on the head portion side, and an element mounting region 101 for mounting the elements, and an external circuit substrate connection region formed on the tail portion side for connection to the external circuit substrate. 102 and a wiring layer 103 (103a to 103d) for electrically connecting the element mounting region 101 and the external circuit board connection region 102.

  In manufacturing the suspension substrate, as shown in FIG. 10, first, a sheet (suspension substrate with a support frame) in which a plurality of suspension substrates 110 and a support frame 111 are integrated is manufactured. Thereafter, the suspension substrate 110 is separated from the support frame 111 to obtain a single suspension substrate 110.

  The suspension substrate usually has a basic structure in which a metal support substrate (for example, SUS), an insulating layer (for example, polyimide resin), and a wiring layer (for example, Cu) are laminated in this order. Furthermore, a plating part is usually formed in a part of the wiring layer. This plating part is formed in the terminal part which connects with an element or an external circuit, for example. The plated portion can be formed by, for example, an electrolytic plating method, but it is necessary to use a plating mask in order to prevent plating from being formed on unnecessary portions.

  As an example of the method for forming the plating portion, there is pattern plating using a dry film resist (DFR). This method is a method in which plating is performed by forming a plating mask by laminating, exposing, and developing (in some cases, thermosetting after development) DFR. Another example of the method for forming the plated portion is pattern plating (jig plating) using a jig. This method is a method in which a jig (plating mask) formed in a predetermined pattern is attached to an object to perform plating. Still another example of the method for forming the plating portion is pattern plating using a cover layer. This method is a method of performing plating by using a cover layer that covers the wiring layer as a plating mask, and is described in FIGS.

JP 2008-310946 A

  The three pattern plating methods described above have the following drawbacks. First, in pattern plating using DFR, a lamination process, an exposure process, a development process, and the like are required for forming a plating mask, and after forming a plating portion, a peeling process for peeling the plating mask is required. There is a problem that the number of processes increases. Next, pattern plating using a jig has a problem that the plating solution is likely to leak because the adhesion between the jig (plating mask) and the object is low. Next, in pattern plating using a cover layer, excess plating is formed on the surface of the support frame (the support frame 111 in FIG. 10) that supports the circuit board. There is a problem that the increase in cost becomes remarkable in plating. Moreover, there is a problem in that the thickness of the plated portion varies greatly due to the plating formed on the support frame. It is possible to combine pattern plating using a cover layer with pattern plating using DFR or pattern plating using a jig. However, in the former case, there remains a problem that the number of steps increases. In the latter case, there remains a problem that plating leakage is likely to occur.

  The present invention has been made in view of the above problems, and does not require the formation or peeling of a resist mask during the formation of a plating part, can suppress plating leakage, reduce the variation in the thickness of the plating part, and The main object of the present invention is to provide a circuit board with a support frame with little plating loss.

  In order to solve the above problems, in the present invention, a circuit board with a support frame having a circuit board and a support frame, wherein the circuit board and the support frame are integrated in an internal opening region of the support frame. The circuit board includes a metal support substrate, an insulating layer formed on the metal support substrate, a wiring layer formed on the insulating layer, and a cover layer covering the wiring layer and the insulating layer. A plating portion formed on the surface of the wiring layer not covered with the cover layer, and the support frame includes the metal support substrate and the insulating layer formed on the metal support substrate; Provided is a circuit board with a support frame, comprising: a conductor layer formed on the insulating layer; and a protective layer formed on the conductor layer and made of the same material as the cover layer.

  According to the present invention, by providing a protective layer made of the same material as the cover layer on the conductor layer of the support frame, it is not necessary to form and remove a resist mask when forming the plating portion, and plating leakage is prevented. It is possible to suppress the variation in the thickness of the plating portion, and it is possible to obtain a circuit board with a support frame with little plating loss.

  In the above invention, the circuit board is preferably a suspension board.

  In the said invention, it is preferable that the said protective layer is formed along the internal opening area | region of the said support frame at least. This is because the combination with jig plating becomes easy.

  In the said invention, it is preferable that the material of the said cover layer and the said protective layer is a polyimide resin. This is because it has excellent chemical resistance.

  Further, in the present invention, there is provided a method for manufacturing a circuit board with a support frame, comprising a circuit board and a support frame, wherein the circuit board and the support frame are integrated in an internal opening region of the support frame, A laminate preparation step of preparing a laminate having a metal support substrate, an insulating layer formed on the metal support substrate, and a wiring layer and a conductor layer formed on the insulating layer, and the same material Forming a cover layer that covers the wiring layer and the insulating layer, and forming a protective layer on the conductor layer; a protective layer forming step; and a wiring layer that is not covered by the cover layer. And a plating part forming step of forming a plating part on the surface. A method of manufacturing a circuit board with a supporting frame is provided.

  According to the present invention, by providing a protective layer made of the same material as the cover layer on the conductor layer of the support frame, it is not necessary to form and remove a resist mask when forming the plating portion, and plating leakage is prevented. It is possible to obtain a circuit board with a support frame that can be suppressed, the variation in the thickness of the plating portion is reduced, and the plating loss is small.

  In the above invention, the circuit board is preferably a suspension board.

  In the said invention, it is preferable to form the said protective layer along the internal opening area | region of the said support frame at least. This is because the combination with jig plating becomes easy.

  In the said invention, it is preferable that the material of the said cover layer and the said protective layer is a polyimide resin. This is because it has excellent chemical resistance.

  The circuit board with a support frame of the present invention does not require the formation or peeling of a resist mask when forming a plating portion, can suppress plating leakage, reduces variations in the thickness of the plating portion, and has a small plating loss. There is an effect.

It is a schematic plan view which shows an example of the circuit board with a support frame of this invention. It is a schematic diagram explaining the circuit board with a support frame of this invention. FIG. 3 is a schematic plan view in which a cover layer 4 and a protective layer 8 are removed from FIG. It is a schematic sectional drawing explaining pattern plating using a jig | tool. It is a schematic sectional drawing explaining the circuit board with a support frame of this invention. It is a schematic sectional drawing explaining the circuit board with a support frame of this invention. It is a schematic sectional drawing which shows an example of the manufacturing method of the circuit board with a support frame of this invention. It is a graph which shows distribution of the plating thickness of the circuit board with a support frame obtained in Example 1 and Comparative Example 1. It is a schematic plan view explaining a suspension substrate. It is a schematic plan view explaining a suspension substrate with a support frame.

  Hereinafter, the circuit board with a support frame and the method for manufacturing the circuit board with a support frame of the present invention will be described in detail.

A. Circuit board with support frame The circuit board with support frame of the present invention has a circuit board and a support frame, and the circuit with support frame in which the circuit board and the support frame are integrated in an internal opening region of the support frame. The circuit board includes a metal support substrate, an insulating layer formed on the metal support substrate, a wiring layer formed on the insulating layer, and a cover that covers the wiring layer and the insulating layer. And a plating part formed on the surface of the wiring layer not covered with the cover layer, and the support frame includes the metal support substrate and the insulating layer formed on the metal support substrate. And a conductive layer formed on the insulating layer, and a protective layer formed on the conductive layer and made of the same material as the cover layer.

  FIG. 1 is a schematic plan view showing an example of a circuit board with a support frame of the present invention. For convenience, the description of the cover layer and the protective layer is omitted. A circuit board 20 with a support frame shown in FIG. 1 has a plurality of circuit boards 10 and a support frame 11, and the plurality of circuit boards 10 and the support frame 11 are integrated in an internal opening region 12 of the support frame 11. It is what.

  2A is an enlarged view of a region X in FIG. 1, and FIG. 2B is a cross-sectional view taken along line AA in FIG. 2A. As shown in FIGS. 2A and 2B, a circuit board 10 according to the present invention includes a metal supporting board 1, an insulating layer 2 formed on the metal supporting board 1, and a wiring formed on the insulating layer. It has a layer 3, a cover layer 4 that covers the wiring layer 3 and the insulating layer 2, a terminal part 5 that is a part of the wiring layer 3, and a plating part 6 formed on the surface of the terminal part 5. The support frame 11 according to the present invention is formed on the metal support substrate 1, the insulating layer 2 formed on the metal support substrate 1, the conductor layer 7 formed on the insulating layer 2, and the conductor layer 7. The protective layer 8 is made of the same material as the cover layer 4.

  On the other hand, FIG. 3 is a schematic plan view in which the cover layer 4 and the protective layer 8 are removed from FIG. As shown in FIG. 3, in order to form plating on the terminal portion 5 of the circuit board 10, the terminal portion 5 and the conductor layer 7 of the support frame 11 are electrically connected. In order to prevent the plating on the conductor layer 7, it is necessary to form a plating mask on the conductor layer 7. Conventionally, a DFR or a jig has been used. On the other hand, the present invention is characterized in that the cover layer and the protective layer made of the same material as the cover layer are used as plating masks.

  According to the present invention, by providing a protective layer made of the same material as the cover layer on the conductor layer of the support frame, it is not necessary to form and remove a resist mask when forming the plating portion, and plating leakage is prevented. It is possible to suppress the variation in the thickness of the plating portion, and it is possible to obtain a circuit board with a support frame with little plating loss.

  The circuit board with a support frame of the present invention has the following advantages over the conventional pattern plating. As described above, in conventional pattern plating using DFR, a lamination process, an exposure process, a development process, and the like are required for forming a plating mask. There is a problem that the number of processes increases. On the other hand, in this invention, since DFR is not used, a lamination, an exposure process, a development process, and a peeling process become unnecessary, and the process can be simplified.

  Further, in the conventional pattern plating using DFR, for example, when a cyan bath is used for electrolytic Au plating, there is a problem that the DFR cannot maintain the adhesion for a long time and the plating time is restricted. On the other hand, in the present invention, since the same material as the cover layer is used as the material of the protective layer, the adhesion of the protective layer (plating mask) can be maintained for a long time compared to the conventional DFR. The material of the cover layer needs to have adhesiveness (chemical resistance) to the extent that it does not deteriorate with the plating solution when manufacturing the product. It can be set as a highly protective layer. By improving the adhesion of the protective layer, it becomes easy to lengthen the plating time, and plating with a low current density and a long time can be performed. As a result, the plating thickness variation can be reduced.

  Further, as described above, pattern plating using a conventional jig has a problem that the plating solution is liable to leak because the adhesion between the jig (plating mask) and the object is low. This problem will be described with reference to FIG. In pattern plating using a jig, as shown in FIG. 4, a jig (plating mask) 13 on which a pattern is formed is affixed to a circuit board 20a with a support frame before plating is formed. In this state, plating is formed on the terminal portion 5 by bringing the plating solution 14 into contact therewith. In pattern plating using a jig, since the adhesion between the conductor layer 7 of the support frame and the jig 13 is low, the plating solution easily leaks in the region Y and is unnecessary at the end of the conductor layer 7 of the support frame. There is a problem of forming plating. On the other hand, in the present invention, since the same material as the cover layer is used as the material of the protective layer, the adhesion can be increased compared to the case where a conventional jig is used, and plating leakage is prevented. Can be suppressed.

  Further, pattern plating using a conventional jig has a problem that the jig itself is not suitable for pattern miniaturization and a problem that the accuracy of alignment between the jig and the object is poor. On the other hand, in the present invention, by using the same material as the cover layer as the material of the protective layer, miniaturization is facilitated, and further, the alignment accuracy can be higher than in the case of using a jig. it can. Further, when the circuit board with a support frame of the present invention is manufactured in combination with jig plating, the jig shape can be simplified, so that the jig manufacturing cost can be reduced.

  In addition, as described above, in pattern plating using a cover layer, excessive plating is formed on the surface of the support frame that supports the circuit board, resulting in a large plating loss, and particularly in noble metal plating, an increase in cost. There is a problem that becomes prominent. On the other hand, in the present invention, by forming a protective layer on the surface of the conductor layer of the support frame, unnecessary plating can be prevented and plating loss can be reduced.

  In pattern plating using a cover layer, the plating area of the support frame is much larger than the area of the plated portion of the circuit board, and the arrangement of the support frame is not uniform, so the current density of each circuit board changes. There is a problem that the variation in the thickness of the plated portion becomes large. On the other hand, in the present invention, since the ratio of the area of the plating portion of the circuit board to the total plating area is increased, the variation in the plating thickness of the circuit board can be reduced.

Furthermore, in this invention, it has the advantage that the intensity | strength of the whole circuit board with a support frame improves by forming a protective layer on the conductor layer of a support frame. Moreover, by forming a protective layer on the conductor layer of the support frame, intrusion of foreign matters derived from the conductor layer and melting of the conductor layer can be suppressed in the subsequent steps.
Hereinafter, the circuit board with a support frame of the present invention will be described separately for the members of the circuit board with the support frame and the configuration of the circuit board with the support frame.

1. First, members of the circuit board with a support frame of the present invention will be described. The circuit board with a support frame of the present invention has a circuit board and a support frame. The circuit board has a metal support board, an insulating layer, a wiring layer, a cover layer, and a plating part, and the support frame has a metal support board, an insulating layer, a conductor layer, and a protective layer.

  The material of the metal support substrate in the circuit board and the support frame is preferably selected as appropriate according to the use of the circuit board. When the circuit board is a suspension board, the material of the metal support board is preferably a metal having a spring property. Specific examples include SUS. Moreover, although the thickness of a metal support substrate changes with kinds of the material, it exists in the range of 10 micrometers-20 micrometers, for example.

  The insulating layers in the circuit board and the support frame are each formed on the metal support board. Examples of the material for the insulating layer include polyimide resin (PI). In addition, the material of the insulating layer may be a photosensitive material or a non-photosensitive material. The thickness of the insulating layer is, for example, in the range of 5 μm to 10 μm.

  The wiring layer in the circuit board is formed on the insulating layer. Examples of the material for the wiring layer include metals, and copper (Cu) is preferable among them. The thickness of the wiring layer is, for example, in the range of 5 μm to 18 μm, and preferably in the range of 9 μm to 12 μm.

  The plating part in the circuit board is formed on the surface of the wiring layer not covered with the cover layer. In the present invention, it is preferable that a plating portion is formed in a terminal portion for connection to an element such as a magnetic head or an external circuit. Although the kind of plating part is not specifically limited, For example, Au plating, Ni plating, Ag plating, Cu plating etc. can be mentioned. Especially, in this invention, it is preferable that Ni plating and Au plating are formed from the surface side of the wiring layer. The thickness of the plating portion is, for example, in the range of 0.1 μm to 4.0 μm.

  The conductor layer in the support frame is formed on the insulating layer. The material of the conductor layer is usually composed of the same material as the wiring layer. The preferable range of the thickness of the conductor layer is the same as the preferable range of the thickness of the wiring layer. In particular, in the present invention, the thickness of the conductor layer and the thickness of the wiring layer are preferably the same.

  The cover layer in the circuit board is formed so as to cover the wiring layer and the insulating layer. The material and thickness of the cover layer are not particularly limited, but the following are preferable from the viewpoints of plating resistance and prevention of circuit board warpage. Examples of the material for the cover layer include a resin, and among them, a polyimide resin is preferable. The material of the cover layer may be a photosensitive material or a non-photosensitive material. The thickness of the cover layer is preferably in the range of 2 μm to 30 μm, for example, and more preferably in the range of 2 μm to 10 μm. This is because when the circuit board is a suspension board, the flying height control is not greatly affected if the circuit board is within the above range.

  The polyimide resin in this invention can be shown by following formula (1), for example.

(R ₁ is a tetravalent organic group, R ₂ is a divalent organic group, R ₁ and R ₂ may be a single structure or a combination of two or more types, n is a natural number of 1 or more)

In the formula (1), generally, R ₁ is a structure derived from tetracarboxylic dianhydride, and R ₂ is a structure derived from diamine.

  Examples of the tetracarboxylic dianhydride include pyromellitic dianhydride, merophanic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4. '-Biphenyltetracarboxylic dianhydride, 2,3,3', 4'-biphenyltetracarboxylic dianhydride, 2,3,2 ', 3'-biphenyltetracarboxylic dianhydride, 2,2' , 6,6′-biphenyltetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1, Examples include 3,3,3-hexafluoropropane dianhydride and bis (3,4-dicarboxyphenyl) ether dianhydride.

When an aromatic tetracarboxylic dianhydride is used, there is a merit that it becomes a polyimide having excellent heat resistance and a low linear thermal expansion coefficient. Therefore, in this invention, it is preferable that 33 mol% or more is a structure represented by following formula (2) among R < ₁ > in Formula (1).

The polyimide resin having the structure as described above exhibits high heat resistance and low coefficient of linear thermal expansion. From the viewpoint of high heat resistance and low linear thermal expansion coefficient, it is more preferable that 50 mol% or more of R ₁ in the formula (1) is a structure represented by the formula (2), and 70 mol% or more is the formula. The structure represented by (2) is more preferable.

  On the other hand, the diamine component in the present invention may be one kind of diamine alone or two or more kinds of diamines. The diamine in the present invention is not particularly limited. In the diamine according to the present invention, two or more aromatic rings are bonded by a single bond, and two or more amino groups are bonded to separate aromatic rings directly or as part of a substituent. It may be. As such a diamine, what is shown to following formula (3) can be mentioned, for example.

(A is a natural number of 0 or 1 or more, and the amino group is bonded to the meta position or the para position with respect to the bond between the benzene rings.)
Specific examples of the diamine represented by the formula (3) include benzidine.

Moreover, in this invention, it is preferable that 33 mol% or more is a structure represented by following formula (4) among R < ₂ > in Formula (1).

(R ₃ is a divalent organic group, an oxygen atom, a sulfur atom, or a sulfone group, and R ₄ and R ₅ are a monovalent organic group or a halogen atom.)

When it has the above structure, the heat resistance of the polyimide finally obtained improves and a linear thermal expansion coefficient becomes small. From the viewpoint of high heat resistance and low linear thermal expansion coefficient, it is more preferable that 50 mol% or more of R ₂ in the formula (1) is a structure represented by the formula (4), and 70 mol% or more is the formula. The structure represented by (4) is more preferable.

  The hygroscopic expansion coefficient of the polyimide resin is preferably 30 ppm /% RH or less. The thermal expansion coefficient of the polyimide resin is preferably in the range of 15 ppm / ° C. to 30 ppm / ° C.

  The protective layer in the support frame is formed on the conductor layer and is made of the same material as the cover layer. The preferable range of the thickness of the protective layer is the same as the preferable range of the thickness of the cover layer. Especially, in this invention, it is preferable that the thickness of a protective layer and the thickness of a cover layer are the same.

2. Next, the configuration of the circuit board with a support frame of the present invention will be described. The circuit board with a support frame of the present invention includes a circuit board and a support frame, and the circuit board and the support frame are integrated in an internal opening region of the support frame. In the present invention, as shown in FIG. 5 (a), the support frame 11 may have one inner opening region 12, and as shown in FIG. 5 (b), the support frame 11 has two or more inner portions. It may have an opening region 12. Each internal opening region 12 preferably has two or more circuit boards 10.

  Further, since the protective layer 8 is for preventing plating from being formed on the conductor layer of the support frame, from the viewpoint of preventing the formation of plating, the area where the protective layer covers the conductor layer is larger. Is preferred. On the surface of the support frame, the area of the protective layer relative to the total area is not particularly limited, but is preferably 10% or more, more preferably 30% or more, and 50% or more, for example. Is more preferable. On the other hand, in the present invention, the area and density of the plating region may be adjusted by exposing the conductor layer from the protective layer in order to supply electric power or to suppress variations in plating thickness. Specifically, as shown in FIG. 6A, a conductor layer exposed portion 15 for power feeding may be provided, and as shown in FIG. 6B, a conductor for suppressing variation in plating thickness. A layer exposed portion 16 may be provided. FIG. 6 is a schematic plan view of the circuit board with a support frame before the plating portion is formed.

3. Circuit board with support frame The use of the circuit board in the present invention is not particularly limited as long as it has a metal support substrate, an insulating layer, a wiring layer, a terminal portion, and a plating portion. Especially, it is preferable that the circuit board in this invention is a board | substrate for suspension used for HDD.

B. Next, a method for manufacturing a circuit board with a support frame according to the present invention will be described. The method for manufacturing a circuit board with a support frame of the present invention includes a circuit board and a support frame, and the circuit board with a support frame is integrated with the circuit board and the support frame in an internal opening region of the support frame. A manufacturing method for preparing a laminate including a metal support substrate, an insulating layer formed on the metal support substrate, and a wiring layer and a conductor layer formed on the insulating layer. Forming a cover layer covering the wiring layer and the insulating layer using the same material, and forming a protective layer on the conductor layer; and covering the cover layer And a plating part forming step of forming a plating part on the surface of the wiring layer that is not broken.

  FIG. 7 is a schematic cross-sectional view for explaining an example of a method for producing a circuit board with a support frame of the present invention. FIG. 7 corresponds to FIG. 2 (b). In FIG. 7, first, a laminated member having a metal supporting substrate 1X, an insulating layer 2X formed on the metal supporting substrate 1X, and a conductor layer 3X formed on the insulating layer 2X is prepared (FIG. 7 ( a)). Next, a resist pattern 17 is formed on the surfaces of the metal support substrate 1X and the conductor layer 3X using DFR, and the metal support substrate 1X and the conductor layer 3X exposed from the resist pattern 17 are wet-etched (FIG. 7B). ). Thereby, the wiring layer 3, the terminal part 5, and the conductor layer 7 are formed (FIG.7 (c)).

  Thereafter, the cover layer 7 covering the wiring layer 3 and the insulating layer 2 is formed using the same material, and the protective layer 8 is formed on the conductor layer 7 (FIG. 7D). At this time, the cover layer is not formed on the terminal portion 5 forming the plating portion. Next, a resist pattern is prepared using DFR, and the insulating layer 2X exposed from the resist pattern is wet-etched to form the insulating layer 2 (FIG. 7E). Next, electrolytic plating is performed on the terminal portion 5 exposed from the cover layer 7 to form a plated portion 6 (FIG. 7F). Finally, the metal supporting board 1 is wet-etched again to obtain a circuit board 20 with a supporting frame (FIG. 7G).

According to the present invention, by providing a protective layer made of the same material as the cover layer on the conductor layer of the support frame, it is not necessary to form and remove a resist mask when forming the plating portion, and plating leakage is prevented. It is possible to obtain a circuit board with a support frame that can be suppressed, the variation in the thickness of the plating portion is reduced, and the plating loss is small.
Hereafter, the manufacturing method of the circuit board with a support frame of this invention is demonstrated for every process.

1. Laminated body preparation process The laminated body preparation process in this invention is a laminated body which has a metal support substrate, the insulating layer formed on the said metal support substrate, and the wiring layer and conductor layer which were formed on the said insulating layer. Is a step of preparing

  The method for forming the laminate is not particularly limited as long as the desired laminate can be obtained. As an example of a method for forming a laminated body, a method using a laminated member can be given as shown in FIG.

  When using a laminated member having a metal support substrate, an insulating layer, and a conductor layer, the wiring layer of the circuit board and the conductor layer of the support frame are formed by etching the conductor layer. Although the method for etching the conductor layer is not particularly limited, specific examples include wet etching. The type of etchant used for wet etching is preferably selected as appropriate according to the type of conductor layer. For example, when the material of the conductor layer is copper, an iron chloride-based etchant or the like can be used. In the present invention, a resist pattern is usually formed using DFR or the like, and the conductor layer exposed from the resist pattern is etched.

  7 (g), when the plating part 6 is formed on both surfaces of the terminal part 5, the metal support substrate 1 at the position of the terminal part 5 is etched before the plating part 6 is formed. It is necessary to keep. The method for etching the metal supporting substrate is not particularly limited, and specific examples include wet etching. The type of etchant used for wet etching is preferably selected as appropriate according to the type of metal support substrate. For example, when the material of the metal support substrate is SUS, an iron chloride-based etchant or the like can be used. . In the present invention, a resist pattern is usually formed using DFR or the like, and the metal supporting substrate exposed from the resist pattern is etched.

2. Cover layer-protective layer forming step Next, the cover layer-protective layer forming step in the present invention will be described. The cover layer-protective layer forming step in the present invention is a step of forming a cover layer covering the wiring layer and the insulating layer using the same material, and forming a protective layer on the conductor layer.

  The method for forming the cover layer and the protective layer is preferably selected as appropriate depending on the types of materials of the cover layer and the protective layer. For example, when the material of the cover layer and the protective layer is a photosensitive material, a cover layer having a predetermined pattern can be formed by exposure and development. On the other hand, when the material of the cover layer and the protective layer is a non-photosensitive material, a cover layer having a predetermined pattern can be formed by etching through a resist pattern.

3. Plating part forming step Next, the plating part forming step in the present invention will be described. The plated portion forming step in the present invention is a step of forming a plated portion on the surface of the wiring layer that is not covered with the cover layer.

  In the present invention, the plated portion is usually formed by an electrolytic plating method. Examples of the method for forming the plating portion include immersion plating and jig plating. The type of the plating solution is not particularly limited, and is preferably selected as appropriate according to the type of the plating part.

4). Others In addition to the steps described above, the present invention usually includes an insulating layer etching step for etching the insulating layer. This step can be performed at an arbitrary timing at which a desired circuit board with a support frame can be obtained. The insulating layer can be processed by wet etching, for example. The type of the etching solution is preferably selected as appropriate according to the type of the insulating layer. For example, when the material of the insulating layer is a polyimide resin, an alkaline etching solution or the like can be used. In addition, the circuit board with a support frame obtained by the present invention is the same as the contents described in the above-mentioned “A. Circuit board with support frame”, and therefore description thereof is omitted here.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the technical idea described in the claims of the present invention has substantially the same configuration and exhibits the same function and effect regardless of the case. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be described more specifically with reference to examples.

[Example 1]

  A circuit board with a support frame was produced by the same method as shown in FIG. An insulating layer 2X having a thickness of 10 μm was formed on the metal support substrate 1X, which is SUS304 having a thickness of 20 μm, using the first non-photosensitive polyimide as an insulating layer forming material by a coating method. Furthermore, about 300 nm of Ni—Cr—Cu serving as a seed layer is coated on the insulating layer by a sputtering method, and using this as a conductive medium, a wiring layer 3X which is a Cu plating layer having a thickness of 9 μm is formed by Cu plating. A three-layer laminate was obtained (FIG. 7A).

  Patterning was performed simultaneously using a dry film so that a jig hole whose positional accuracy was important on the SUS side and a desired wiring layer on the Cu plating layer side could be formed. Thereafter, etching was performed using a ferric chloride solution, and a resist film was removed after the etching to obtain a wiring layer 3, a terminal portion 5, and a conductor layer 7 (FIGS. 7B and 7C).

  Next, a non-photosensitive polyimide-based liquid cover layer forming material is coated with a die coater, dried, resist-engraved, and the cover layer forming material is etched at the same time as development, and then cured to form a cover layer forming material (second A cover layer 4 made of a non-photosensitive polyimide) is formed on the wiring layer 3, the terminal portion 5 and the insulating layer 2, and at the same time, a protective layer 8 made of a cover layer forming material (second non-photosensitive polyimide) is formed. It formed on the conductor layer 7 (FIG.7 (d)). The film thickness of the cover layer after curing was 5 μm on the wiring layer. By forming such a cover layer and a protective layer, it is possible to control warpage and reduce rigidity, and to protect the wiring pattern layer.

In addition, the physical property value of the cover layer forming material (second non-photosensitive polyimide) for forming the cover layer herein has a hygroscopic expansion coefficient of 8.0 × 10 ⁻⁶ /% RH, and a thermal expansion coefficient of It was 17 × 10 ⁻⁶ / ° C. Further, the physical property values of the insulating layer forming material (first non-photosensitive polyimide) are a hygroscopic expansion coefficient of 10.7 × 10 ⁻⁶ /% RH and a thermal expansion coefficient of 21 × 10 ⁻⁶ / ° C. A material having a small difference in physical property values between the insulating layer forming material and the cover layer forming material was used.

  Next, a 10 μm-thick polyimide (insulating layer 2X) was resist-engraved and etched using an organic alkali etching solution, and after the etching, the resist was removed to obtain a patterned insulating layer 2 (FIG. 7E). ).

Next, after the terminal portion 5 was acid-washed, electrolytic Ni plating was performed to obtain a plated portion 6 (FIG. 7 (f)). Note that a standard sulfamic acid Ni plating bath was used as the electrolytic Ni plating bath, and the plating conditions were such that the current density was about 5.5 A / dm ² and 80 seconds.

  Next, in order to perform the outer shape processing of SUS, resist engraving is performed again, only the SUS side is etched, and after the etching, resist stripping is performed to obtain an evaluation sample (circuit board with support frame) (FIG. 7G). ).

[Comparative Example 1]
A circuit board with a support frame was obtained in the same manner as in Example 1 except that the protective layer was not formed on the support frame.

[Evaluation 1]
The variation of the plating thickness of the samples for evaluation obtained in Example 1 and Comparative Example 1 was evaluated. The plating thickness was measured with a fluorescent X-ray film thickness meter. The results are shown in Table 1.

  In Table 1, “total piece area” = “plating area of one circuit board (plating area in the circuit board 10)” × “number of circuit boards present in the support frame 11”. As shown in Table 1 and FIG. 8, the circuit board with a support frame of Example 1 in which the support frame was coated was plated as compared with the circuit board with a support frame of Comparative Example 1 in which the support frame was not coated. The thickness variation was reduced.

  DESCRIPTION OF SYMBOLS 1 ... Metal support board, 2 ... Insulating layer, 3 ... Wiring layer, 4 ... Cover layer, 5 ... Terminal part, 6 ... Plating part, 7 ... Conductive layer, 8 ... Protective layer, 10 ... Circuit board, 11 ... Support frame 12 ... Internal opening region, 13 ... Jig (plating mask), 14 ... Plating solution, 15 ... Conductor layer exposed portion, 16 ... Conductor layer exposed portion, 17 ... Resist pattern, 20 ... Circuit board with support frame

Claims (8)

A circuit board and a support frame, and a circuit board with a support frame in which the circuit board and the support frame are integrated in an internal opening region of the support frame,
The circuit board includes a metal supporting board, an insulating layer formed on the metal supporting board, a wiring layer formed on the insulating layer, a cover layer covering the wiring layer and the insulating layer, and the cover Having a plated portion formed on the surface of the wiring layer not covered with the layer,
The support frame is formed on the metal support substrate, the insulating layer formed on the metal support substrate, a conductor layer formed on the insulating layer, and the conductor layer, and is the same as the cover layer And a protective layer made of the above material.   The circuit board with a support frame according to claim 1, wherein the circuit board is a suspension board.   The circuit board with a support frame according to claim 1, wherein the protective layer is formed along at least an internal opening region of the support frame.   The circuit board with a support frame according to any one of claims 1 to 3, wherein a material of the cover layer and the protective layer is a polyimide resin. A method for manufacturing a circuit board with a support frame, comprising a circuit board and a support frame, wherein the circuit board and the support frame are integrated in an internal opening region of the support frame,
A laminate preparation step of preparing a laminate having a metal support substrate, an insulating layer formed on the metal support substrate, and a wiring layer and a conductor layer formed on the insulating layer;
Using the same material, a cover layer that covers the wiring layer and the insulating layer is formed, and a protective layer is formed on the conductor layer.
A plating part forming step of forming a plating part on the surface of the wiring layer not covered with the cover layer;
A method of manufacturing a circuit board with a support frame, comprising:   The method for manufacturing a circuit board with a support frame according to claim 5, wherein the circuit board is a suspension board.   The method for manufacturing a circuit board with a support frame according to claim 5, wherein the protective layer is formed along at least an internal opening region of the support frame.   The method for manufacturing a circuit board with a support frame according to any one of claims 5 to 7, wherein a material of the cover layer and the protective layer is a polyimide resin.

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