WO2022062170A1

WO2022062170A1 - Method for forming solder mask layer on circuit board, circuit board manufacturing method, and circuit board

Info

Publication number: WO2022062170A1
Application number: PCT/CN2020/132937
Authority: WO
Inventors: 吴鹏; 李小新; 熊佳; 魏炜
Original assignee: 深南电路股份有限公司
Priority date: 2020-09-28
Filing date: 2020-11-30
Publication date: 2022-03-31
Also published as: CN114286532A

Abstract

A method for forming a solder mask layer on a circuit board, a circuit board manufacturing method, and a circuit board. The method for forming a solder mask layer on a circuit board comprises: forming a solder mask film on a circuit board (S11), the solder mask film comprising an ink layer (62) and a first protective layer (61) provided on the ink layer (62), wherein the ink layer (62) is in contact with the surface of one side of the circuit board, and the ink layer (62) is made of an epoxy resin; processing the first protective layer (61) to expose an opening region of the ink layer (62) (S12); etching ink in the opening region to manufacture a solder mask opening (S13); and when the solder mask opening is manufactured, curing the ink layer (62) and removing the first protective layer (61) to form a solder mask layer (S14). The solder mask layer formed by the method has strong rigidity and is suitable for ultra-thin substrates.

Description

Method for forming solder resist layer on circuit board, manufacturing method of circuit board and circuit board

【Technical field】

The invention relates to the technical field of circuit boards, in particular to a method for forming a solder resist layer on a circuit board, a manufacturing method of the circuit board and a circuit board.

【Background technique】

In the production process of the PCB board, it is often necessary to provide a solder mask layer on the substrate after the outer layer pattern is produced.

At present, liquid type ink or dry film type ink is generally used to form the solder resist layer; wherein, the liquid type ink is specifically applied to the surface of the substrate by roller coating or screen printing, and then pre-baking, exposing, developing, Post-baking and other processes produce solder mask openings, and then solidify the ink to obtain a solder mask layer; for dry film ink, the roll dry film ink is applied to the surface of the substrate by vacuum filming, and then exposed to light. , development, post-baking and other processes to create a solder mask window, and then solidify the ink to obtain a solder mask layer.

However, the existing liquid type inks and dry film type inks have low glass transition temperature (Tg) and modulus (Modulus), and high coefficient of thermal expansion (CTE), so that the rigidity of the prepared solder resist layer is weaker , has a certain negative impact on the operability of the core board processing process, the warpage of the finished product and the resulting packaging yield, and cannot meet the performance requirements of ultra-thin substrates.

[Content of the invention]

The present application provides a method for forming a solder resist layer on a circuit board, a method for making a circuit board, and a circuit board, which can solve the problems of glass transition temperature (Tg) and modulus (Modulus) of the existing liquid ink and dry film ink. ) is lower and the coefficient of thermal expansion (CTE) is higher, so that the rigidity of the prepared solder mask layer is weak, and the operability of the processing process of the core board, the warpage of the finished product and the resulting packaging yield have a certain degree. The negative impact is that it cannot meet the performance requirements of ultra-thin substrates.

In order to solve the above-mentioned technical problems, a technical solution adopted in the present application is to provide a method for forming a solder resist layer on a circuit board, the method comprising: forming a solder resist film on the circuit board; The first protective layer on the ink layer, wherein the ink layer is in contact with one side surface of the circuit board, and the material of the ink layer is epoxy resin; the first protective layer is processed to expose the window area of the ink layer; The ink in the window area is etched to form a solder resist window; after the solder resist window is manufactured, the ink layer is cured and the first protective layer is removed to form a solder resist layer.

Wherein, the step of forming the solder resist film on the circuit board specifically includes: providing the circuit board and the solder resist film; wherein, the solder resist film includes a first protective layer, a second protective layer, and is provided on the first protective layer and the second protective layer The ink layer between them; remove the second protective layer, and make the ink layer of the solder mask adhere to one side surface of the circuit board.

Wherein, the step of forming the solder mask on the circuit board specifically includes: sticking dry film ink on the circuit board to form an ink layer; wherein, the material of the dry film ink is epoxy resin; A protective film is attached to the side surface to form a first protective layer, and the first protective layer covers the ink layer.

Wherein, the step of forming the solder resist film on the circuit board specifically includes: coating liquid ink on the circuit board to form an ink layer; wherein, the material of the liquid ink is epoxy resin; pre-baking the ink layer to make the ink layer The layer is in a semi-cured state; a protective film is attached to the surface of the ink layer away from the circuit board to form a first protective layer, and the first protective layer covers the ink layer.

Wherein, the step of processing the first protective layer to expose the window area of the ink layer specifically includes: disposing a patterned dry film on the surface of the first protective layer away from the ink layer, and exposing, developing and etching the patterned dry film Treat to expose windowed areas of ink layer; remove graphic dry film.

The step of curing the ink layer and removing the first protective layer to form the solder resist layer specifically includes: baking the ink layer to cure the ink layer, and then removing the first protective layer; or, removing the first protective layer, and then removing the ink layer. layer is baked to cure the ink layer.

The step of removing the first protective layer specifically includes: using an etching process to remove the first protective layer.

Wherein, the first protective layer is a metal layer.

In order to solve the above technical problems, another technical solution adopted in this application is to provide a method for manufacturing a circuit board, the method comprising: providing a core board; forming a solder resist layer on at least one surface of the core board; The step of forming a solder resist layer on at least one surface of the board specifically adopts the above-mentioned method for forming a solder resist layer on a circuit board.

In order to solve the above technical problems, another technical solution adopted in the present application is to provide a circuit board, the circuit board includes a core board and a solder resist layer disposed on at least one surface of the core board; wherein, the solder resist layer adopts the above-mentioned A method of forming a solder resist layer on the related circuit board.

The present application provides a method for forming a solder resist layer on a circuit board, a manufacturing method for the circuit board, and a circuit board, and the method for forming a solder resist layer on the circuit board is formed by forming a resist layer including an ink layer and a first protective layer on the circuit board. Solder film, and make the ink layer contact one side surface of the circuit board; then process the first protective layer to expose the window area of the ink layer; then etch the ink in the window area to make a solder mask window ; After the solder mask opening is made, the ink layer is cured and the first protective layer is removed to form a solder mask. Among them, since the material of the ink layer in the solder mask is epoxy resin, its glass transition temperature (Tg) and modulus (Modulus) are high, and the thermal expansion coefficient (CTE) is low, so that the formed solder mask has It has strong rigidity and can be suitable for the use of ultra-thin substrates; in addition, by further disposing a first protective layer on the surface of the ink layer away from the circuit board, in the process of forming the solder resist layer, it is ensured that the formed solder resist layer has At the same time of strong rigidity, the first protective layer can be processed to form a window area, and then the ink at the corresponding position of the ink layer can be etched to make a window area, thereby forming a solder resist layer.

【Description of drawings】

1 is a flowchart of a method for forming a solder resist layer on a circuit board provided by an embodiment of the present application;

FIG. 2 is a sub-flow chart of step S11 in FIG. 1 provided by a specific embodiment of the present application;

FIG. 3 is a schematic structural diagram of a circuit board provided by an embodiment of the present application;

FIG. 4 is a schematic diagram of a product structure provided by an embodiment of the present application after being processed in step S112;

FIG. 5 is a sub-flow chart of step S11 in FIG. 1 provided by another specific embodiment of the present application;

FIG. 6 is a sub-flow chart of step S11 in FIG. 1 provided by another specific embodiment of the present application;

7 is a schematic diagram of a product structure provided by an embodiment of the present application after being processed in step S12;

8 is a schematic diagram of a product structure provided by an embodiment of the present application after being processed in step S13;

9 is a schematic diagram of a product structure provided by an embodiment of the present application after being processed in step S14;

10 is a flowchart of a method for manufacturing a circuit board provided by an embodiment of the application;

FIG. 11 is a schematic structural diagram of a circuit board provided by an embodiment of the present application.

【detailed description】

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

The terms "first", "second" and "third" in this application are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first", "second", "third" may expressly or implicitly include at least one of that feature. In the description of the present application, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly and specifically defined. All directional indications (such as up, down, left, right, front, rear...) in the embodiments of the present application are only used to explain the relative positional relationship between components under a certain posture (as shown in the accompanying drawings). , motion situation, etc., if the specific posture changes, the directional indication also changes accordingly. Furthermore, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but optionally also includes unlisted steps or units, or optionally also includes For other steps or units inherent to these processes, methods, products or devices.

Reference herein to an "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor a separate or alternative embodiment that is mutually exclusive of other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

The present application will be described in detail below with reference to the accompanying drawings and embodiments.

Please refer to FIG. 1. FIG. 1 is a flowchart of a method for forming a solder resist layer on a circuit board provided by an embodiment of the application; in this embodiment, a method for forming a solder resist layer on a circuit board is provided. The solder mask layer has strong rigidity and is suitable for the use of ultra-thin substrates.

Specifically, the method includes:

Step S11 : forming a solder resist film on the circuit board.

The circuit board may specifically be a semi-finished circuit board, for example, a multilayer core board structure with circuit layers; the solder mask includes an ink layer 62 and a first protective layer 61 disposed on the ink layer 62, wherein the ink layer 62 is in contact with one side surface of the circuit board, and the ink material of the ink layer 62 is epoxy resin.

In a specific embodiment, referring to FIG. 2 , FIG. 2 is a sub-flow chart of step S11 in FIG. 1 provided for a specific embodiment of the present application; in this embodiment, step S11 specifically includes:

Step S111: Provide a circuit board and a solder mask.

3 is a schematic structural diagram of a circuit board provided by an embodiment of the application; the circuit board may specifically be a semi-finished circuit board, and the circuit board may specifically include a substrate 51 and a circuit board disposed on at least one surface of the substrate 51 The metal layer 52 is provided with a circuit layer pattern on the metal layer 52; in this embodiment, the solder mask is an integral structure, which can be directly used as a product; specifically, the solder mask includes a first protective layer 61 , the second protective layer (peeled during use), and the ink layer 62 arranged between the first protective layer 61 and the second protective layer, and the ink material of the ink layer 62 is epoxy resin, and the glass transition temperature of the ink is (Tg) and modulus (Modulus) are higher, and the coefficient of thermal expansion (CTE) is lower, which can make the ink layer 62 more rigid, and reduce the operability in the processing of the core board, the warpage of the finished product and the encapsulation caused by it. The negative impact of yield, suitable for the use of ultra-thin substrates. Specifically, the Tg of the ink layer 62 in the solder mask is 86% higher than that of the existing dry film ink and liquid ink, and the Modulus is 146% higher, but the CTE is only 25% of the ordinary ink, so , The warpage value of the finished substrate (circuit board) made of this ink is only 50%-60% of that of the ordinary ink substrate, which is more suitable for the characteristics of ultra-thin substrates.

Wherein, the first protective layer 61 can be a metal layer, for example, a copper layer; the second protective layer can be a common polyethylene film.

Step S112: removing the second protective layer, and making the ink layer of the solder resist film adhere to one side surface of the circuit board.

Referring to FIG. 4, FIG. 4 is a schematic diagram of the product structure provided by an embodiment of the application after processing in step S112; specifically, the second protective layer in the solder mask is removed to expose the ink layer 62, and then the solder mask is removed The ink layer 62 is attached to one side surface of the circuit board, and is pasted together by a vacuum laminating machine to form the structure shown in FIG. 4 . It can be understood that, after the solder mask is attached to the circuit board, the first protective layer 61 is disposed on the surface of the ink layer 62 on the side away from the circuit board.

In the specific implementation process, a high-temperature oven is further used to pre-bake the product processed in step S112, so that the ink is in a semi-cured state.

In another specific embodiment, referring to FIG. 5 , FIG. 5 is a sub-flow chart of step S11 in FIG. 1 provided for another specific embodiment of the present application; in this embodiment, the solder mask is processed by different layers in stages. The formed structure is not an off-the-shelf product; specifically, in this embodiment, step S11 specifically includes:

Step S121 : sticking dry film ink on the circuit board to form an ink layer; wherein, the material of the dry film ink is epoxy resin.

Wherein, the specific implementation process of step S121 is the same or similar to the specific implementation process of pasting the dry model ink on the circuit board in the prior art, and the same or similar effects can be achieved. For details, please refer to the prior art, which is not repeated here. Repeat.

Step S122 : sticking a protective film on the surface of the ink layer away from the circuit board to form a first protective layer, and the first protective layer covers the ink layer.

In this embodiment, the first protective layer 61 can also be a metal layer, such as a copper layer; and in the specific implementation process, after the protective film is attached to the surface of the ink layer 62, the ink can also be applied by a vacuum laminating machine. The layer 62 , the first protective layer 61 and the circuit board are bonded together; it can be understood that, in this embodiment, the ink layer 62 and the first protective layer 61 after being pressed together are formed as a solder mask.

In the specific implementation process, a high-temperature oven is further used to pre-bake the product processed in step S122, so that the ink is in a semi-cured state.

In yet another specific embodiment, referring to FIG. 6 , FIG. 6 is a sub-flow chart of step S11 in FIG. 1 provided for another specific embodiment of the present application; in this embodiment, the solder mask is also processed in different stages. The structure formed by the layers is not an off-the-shelf product; specifically, in this embodiment, step S11 specifically includes:

Step S131 : coating liquid ink on the circuit board to form an ink layer; wherein, the material of the liquid ink is epoxy resin.

Wherein, the specific implementation process of step S131 is the same or similar to the specific implementation process of coating liquid ink on the circuit board in the prior art, and can achieve the same or similar effects. For details, please refer to the prior art, which will not be repeated here. .

Step S132: Pre-bake the ink layer so that the ink layer is in a semi-cured state.

Specifically, a high-temperature oven may be used to pre-bake the ink layer 62 to pre-cure the ink, so as to facilitate the later attachment of the protective film to form the first protective layer 61 .

Step S133 : sticking a protective film on the surface of the ink layer away from the circuit board to form a first protective layer, and the first protective layer covers the ink layer.

Step S12: Process the first protective layer to expose the window area of the ink layer.

Referring to FIG. 7, FIG. 7 is a schematic diagram of the product structure provided by an embodiment of the application after being processed in step S12; in the specific implementation process, the first protective layer 61 may be processed by means of exposure, development, and etching to form The window area of the ink layer 62; specifically, a patterned dry film is arranged on the surface of the first protective layer 61 away from the ink layer 62, and the patterned dry film is exposed, developed and etched to expose the opening of the ink layer 62. window area; after that, remove the graphic dry film. The graphic on the graphic dry film corresponds to the position on the ink layer 62 where the window needs to be opened.

Step S13 : etching the ink in the window area to make a solder mask window.

Specifically, the product structure after processing in step S13 can be referred to FIG. 8 , which is a schematic diagram of the product structure after processing in step S13 provided by an embodiment of the application; The specific implementation process of etching to produce the solder mask opening is the same or similar, and the same or similar technical effects can be achieved. For details, please refer to the prior art, which will not be repeated here.

Step S14 : after the solder resist window is fabricated, the ink layer is cured and the first protective layer is removed to form a solder resist layer.

Specifically, the product structure after processing in step S14 can be referred to FIG. 9 , which is a schematic diagram of the product structure after processing in step S14 provided by an embodiment of the application; in the specific implementation process, the ink layer 62 can be first Baking to cure the ink layer 62, and then performing an etching process on the first protective layer 61 to remove the first protective layer 61, thereby forming a solder resist layer; or, performing an etching process on the first protective layer 61 to remove the first protective layer 61; and then bake the ink layer 62 to cure the ink layer 62, thereby forming a solder resist layer. Specifically, high-temperature baking can be used to completely cure the ink; and in the process of removing the first protective layer 61, when the first protective layer 61 is a copper layer, a copper etching process can be used to remove the copper layer , Specifically, copper chloride or ferric chloride can be used to remove the copper layer.

In the method for forming a solder resist layer on a circuit board provided by this embodiment, a solder resist film including an ink layer 62 and a first protective layer 61 is formed on the circuit board, and the ink layer 62 is in contact with one side surface of the circuit board; Then, the first protective layer 61 is processed to expose the window area of the ink layer 62; then the ink in the window area is etched to make a solder mask window; after the solder mask window is made, the ink layer 62 is cured And remove the first protective layer 61 to form a solder resist layer. Among them, since the ink material of the ink layer 62 in the solder mask is epoxy resin, the glass transition temperature (Tg) and modulus (Modulus) of the ink are high, and the thermal expansion coefficient (CTE) is low, so that the formed The rigidity of the solder mask layer is strong, and it can be suitable for the use of ultra-thin substrates; in addition, by further disposing the first protective layer 61 on the surface of the ink layer 62 on the side away from the circuit board, in the process of forming the solder mask layer, the While the formed solder resist layer has strong rigidity, the first protective layer 61 can be processed to form a window area, and then the ink at the corresponding position of the ink layer 62 can be etched to create a window area, and then Solder mask is formed.

It should be noted that, the above-mentioned solder resist film can be applied not only to package substrate products, but also to other types of PCB products, which is not limited in this embodiment.

Referring to FIG. 10, FIG. 10 is a flowchart of a method for manufacturing a circuit board provided by an embodiment of the application; in this embodiment, a method for manufacturing a circuit board is provided, and the method includes:

Step S41: Provide a core board.

The core board can be specifically understood as the semi-finished circuit board involved in the above embodiments; the core board can specifically be a multi-layer core board or a single-layer core board, and at least one surface of the core board is provided with a circuit layer pattern. In the specific implementation process, for the specific implementation process of processing the core board, reference may be made to the specific implementation process of processing a multi-layer core board or a single-layer core board in the prior art, which will not be repeated here.

Step S42 : forming a solder resist layer on at least one surface of the core board.

Specifically, the specific implementation process of step S42 is the same or similar to the specific implementation process of the method for forming a solder resist layer on a circuit board provided in the above-mentioned embodiments, and can achieve the same or similar technical effects. For details, please refer to the above-mentioned related Written records will not be repeated here.

In the manufacturing method of the circuit board provided in this embodiment, in the process of forming the solder resist layer on one surface of the core board, the solder resist film including the ink layer 62 and the first protective layer 61 is formed on the core board, and the ink The layer 62 is in contact with one side surface of the core board; then the first protective layer 61 is processed to expose the window area of the ink layer 62; then the ink in the window area is etched to produce a solder mask window; After the solder mask is opened, the ink layer 62 is cured and the first protective layer 61 is removed to form a solder mask. Among them, since the ink material of the ink layer 62 is epoxy resin, the glass transition temperature (Tg) and modulus (Modulus) of the ink are relatively high, and the coefficient of thermal expansion (CTE) is relatively low, so that the rigidity of the formed solder resist layer is increased. It is stronger and has a lower warpage rate, which can be suitable for the use of ultra-thin substrates; in addition, by further disposing the first protective layer 61 on the surface of the ink layer 62 on the side away from the circuit board, in the process of forming the solder resist layer, ensure that the While the formed solder resist layer has strong rigidity, the first protective layer 61 can be processed in the process of forming the solder resist layer to form a window area, and then the ink layer 62 can be treated accordingly. The ink at the location is etched to create a windowed area to form a solder mask.

Please refer to FIG. 11 , which is a schematic structural diagram of a circuit board provided by an embodiment of the application; in this embodiment, a circuit board is provided, and the circuit board 70 includes a core board 71 and at least one circuit board disposed on the core board 71 . Solder mask 72 on the surface.

The core board 71 may be a semi-finished circuit board in the method for forming a solder resist layer on a circuit board provided by the above embodiments. Specifically, the core board 71 may be a single-layer core board or a multi-layer core board. It includes a substrate and a metal layer arranged on at least one surface of the substrate; wherein, a circuit layer pattern is arranged on the metal layer.

Wherein, the solder resist layer 72 can be specifically an ink layer; the ink material of the ink layer is epoxy resin; the glass transition temperature (Tg) and modulus (Modulus) of the ink are relatively high, and the coefficient of thermal expansion (CTE) is relatively low, thereby The rigidity of the solder resist layer 72 is strong, and the warpage value is low, which can be suitable for the use of ultra-thin substrates; in a specific embodiment, the solder resist layer 72 can be formed on the circuit board 70 involved in the above embodiment. The solder resist layer 72 is formed by the method.

The above are only the embodiments of the present application, and are not intended to limit the scope of the patent of the present application. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present application, or directly or indirectly applied in other related technical fields, All are similarly included in the scope of patent protection of the present application.

Claims

A method for forming a solder resist layer on a circuit board, comprising:

A solder resist film is formed on the circuit board; the solder resist film includes an ink layer and a first protective layer disposed on the ink layer, wherein the ink layer is in contact with one side surface of the circuit board, and the The material of the ink layer is epoxy resin;

treating the first protective layer to expose the window area of the ink layer;

etching the ink in the window area to make a solder mask window;

After the solder resist window is fabricated, the ink layer is cured and the first protective layer is removed to form a solder resist layer.
The method for forming a solder resist layer on a circuit board according to claim 1, wherein the step of forming a solder resist film on the circuit board specifically comprises:

A circuit board and a solder mask are provided; wherein, the solder mask includes a first protective layer, a second protective layer, and an ink layer disposed between the first protective layer and the second protective layer;

The second protective layer is removed, and the ink layer of the solder resist film is attached to one side surface of the circuit board.
The method for forming a solder resist layer on a circuit board according to claim 1, wherein the step of forming a solder resist film on the circuit board specifically comprises:

A dry film ink is pasted on the circuit board to form an ink layer; wherein, the material of the dry film ink is epoxy resin;

A protective film is attached to a surface of the ink layer away from the circuit board to form a first protective layer, and the first protective layer covers the ink layer.
The method for forming a solder resist layer on a circuit board according to claim 1, wherein the step of forming a solder resist film on the circuit board specifically comprises:

Coating liquid ink on the circuit board to form an ink layer; wherein, the material of the liquid ink is epoxy resin;

Pre-baking the ink layer so that the ink layer is in a semi-cured state;

A protective film is attached to a surface of the ink layer away from the circuit board to form a first protective layer, and the first protective layer covers the ink layer.
The method for forming a solder resist layer on a circuit board according to claim 1, wherein the step of processing the first protective layer to expose the window area of the ink layer specifically comprises:

A graphic dry film is arranged on the surface of the first protective layer away from the ink layer, and the graphic dry film is exposed, developed and etched to expose the window area of the ink layer;

Remove the graphic dry film.
The method for forming a solder resist layer on a circuit board according to claim 5, wherein the step of curing the ink layer and removing the first protective layer to form the solder resist layer specifically comprises:

Baking the ink layer to cure the ink layer, and then removing the first protective layer; or,

The first protective layer is removed, and then the ink layer is baked to cure the ink layer.
The method for forming a solder resist layer on a circuit board according to claim 6, wherein the step of removing the first protective layer specifically comprises:

The first protective layer is removed by an etching process.
The method for forming a solder resist layer on a circuit board according to claim 7, wherein the first protective layer is a metal layer.
A method for making a circuit board, comprising:

Provide core board;

forming a solder resist layer on at least one surface of the core board;

Wherein, the step of forming a solder resist layer on at least one surface of the core board specifically adopts the method for forming a solder resist layer on a circuit board as claimed in claim 1 .
A circuit board, comprising a core board and a solder resist layer disposed on at least one surface of the core board; wherein, the solder resist layer adopts the solder resist layer formed on the circuit board according to claim 1. method.