Method for manufacturing circuit pattern assembly with release film, method for manufacturing circuit board, and circuit pattern assembly with release film

Abstract

The invention provides a method for manufacturing a circuit pattern assembly with a release film, which can prevent bad conditions caused by etching from the surface. In the method for manufacturing the circuit pattern assembly with the release film, the circuit pattern assembly (2) comprises dummy patterns (4) arranged in gaps (G) between a plurality of circuit patterns (3) and first gaps (G1) between the dummy patterns (4) and the circuit patterns (3). The method for manufacturing the circuit pattern assembly with the release film comprises the following steps of: providing a first back surface concave part (G1R) corresponding to the first gap (G1) and a second back surface concave part (G2R) corresponding to the second gap (G2) between the conductive patterns (3a) on the back surface of the metal plate (9); a step for attaching a release film (5) to the rear surface of the metal plate (9) provided with the first rear surface recess (G1R) and the second rear surface recess (G2R); and a step for removing, by etching, a first region corresponding to the first rear surface recess (G1R) and a second region corresponding to the second rear surface recess (G2R) on the surface of the metal plate (9).

Description

Technical Field

[0001] This invention relates to a method for manufacturing a circuit pattern assembly with a release film, a method for manufacturing a circuit board, and a circuit pattern assembly with a release film. Background Technology

[0002] Various circuit boards have been used throughout history. For example, Patent Document 1 shows a method for manufacturing a circuit board for mounting electronic components used in power modules, etc.

[0003] In the manufacturing method of Patent Document 1, after bonding a metal plate to a ceramic substrate and printing a resist in the shape of a circuit pattern on the metal plate, unwanted portions are removed by etching to form a circuit pattern. Then, a coating is applied to the surface of the circuit pattern to form a circuit substrate.

[0004] On the other hand, due to the high heat generation of electronic components in power modules, research is being conducted on circuit boards in which circuit patterns are stacked on metal substrates such as heat sinks through insulating layers to improve heat dissipation. Furthermore, the increasing demand for high-current power modules in recent years has also created a strong need to develop circuit patterns with a thickness exceeding 0.5 mm.

[0005] Here, Patent Document 2 illustrates a technique where an electrolytic metal foil is peelably disposed relative to a transfer sheet (release film), the electrolytic metal foil is etched to form a circuit pattern, the formed circuit pattern is brought into close contact with the object, and the transfer sheet is peeled off, thereby transferring the circuit pattern to the object. Furthermore, Patent Document 3 illustrates a technique where a thick circuit pattern can be formed by etching both the surface and back of a metal plate. Therefore, by utilizing these techniques, it is possible to obtain a circuit board as described above.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent No. 3795354

[0009] Patent Document 2: Japanese Patent No. 2572071

[0010] Patent Document 3: Japanese Patent Application Publication No. 10-178256 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] Furthermore, depending on the circuit board, there may be multiple circuit patterns configured to perform a predetermined function when electronic components are mounted on a single substrate. In such cases, a relatively large gap is generally maintained between adjacent circuit patterns (for example, about 10 mm). Here, when transferring an assembly of multiple circuit patterns onto a substrate using techniques such as those in Patent Documents 2 and 3, defects were observed during etching. (See also...) Figure 6A This point will be explained later.

[0013] Figure 6A The metal plate 101 shown is ultimately formed as Figure 6B , Figure 6C The circuit pattern assembly 102 shown (in this embodiment, it includes three circuit patterns 106). Here, Figure 6A This is a side view of the metal plate 101. Additionally, Figure 6B This is a side view showing the circuit pattern assembly 102 formed by the metal plate 101. Figure 6C Shown from below Figure 6B The bottom view of the circuit pattern assembly 102. (See figure) Figure 6D As shown, a circuit pattern assembly 102 is laminated on a substrate 104, such as a heat sink, via an insulating layer 103 to form a circuit board 105. The circuit pattern assembly 102 shown includes a plurality of circuit patterns 106 (three in this embodiment), with gaps 107 provided between adjacent circuit patterns 106. In addition, each circuit pattern 106 includes a plurality of conductive patterns 108, and a second gap 109 is provided between the conductive patterns 108.

[0014] exist Figure 6A The metal plate 101 shown is, for example, etched onto the surface (in...) Figure 6A The middle is the lower surface) and the back (in Figure 6A The upper surface (in the middle) has a recess. Among the recesses shown here, the wider recess (the recess on the back is called the back recess 107R, and the recess on the surface is called the surface recess 107F) eventually becomes the gap 107, and the narrower recess (the recess on the back is called the second back recess 109R, and the recess on the surface is called the second surface recess 109F) eventually becomes the second gap 109.

[0015] Then, with the release film 110 attached to the back of the metal plate 101 as shown in the figure, the surface of the metal plate 101 is etched. When attaching the release film 110 to the back of the metal plate 101, a lamination apparatus is typically used to facilitate mass production. The lamination apparatus includes a circular roller that presses the strip-shaped release film 110 onto the back of the metal plate 101, configured to simultaneously feed the release film 110 and the metal plate 101 while rotating the roller to attach the release film 110 to the metal plate 101. Furthermore, although not shown in the figure, the surface of the metal plate 101, except for the surface recesses 107F and the second surface recess 109F, is covered with a hardened dry film obtained through an exposure process before etching. Then, for example, when etching is performed by a device that sprays etchant toward the surface of the metal plate 101, since the parts other than those covered by the hardened dry film (surface recess 107F and second surface recess 109F) dissolve in the thickness direction, surface recess 107F connects to back recess 107R, and second surface recess 109F connects to second back recess 109R, thereby forming Figure 6B The circuit pattern assembly shown is 102.

[0016] also, Figure 6B , Figure 6C With a release film 110 attached to the back of the circuit pattern assembly 102, a transfer body (not shown) is pressed onto the surface of the circuit pattern assembly 102 to transfer the circuit pattern onto the transfer body. Then, the release film 110 is peeled off from the circuit pattern assembly 102 transferred to the transfer body, and the circuit pattern assembly 102 is transferred from the transfer body to the insulating layer 103 laminated on the substrate 104, thereby forming... Figure 6D The circuit board 105 shown.

[0017] However, when etching is performed with the release film 110 attached to the back of the metal plate 101, a portion of the back side of the circuit pattern 106 adjacent to the gap 107 may sometimes dissolve. If this dissolution occurs, there is a possibility that the circuit pattern 106 may not be properly bonded to the insulating layer 103.

[0018] In view of these problems, the object of the present invention is to provide a method for manufacturing a circuit pattern assembly with a release film, which can prevent defects caused by surface etching, in relation to a circuit pattern assembly with a release film attached to the back. At the same time, a method for manufacturing a circuit board using technology related to the method for manufacturing the circuit pattern assembly with a release film, and a circuit pattern assembly with a release film are also provided.

[0019] Technical means to solve the problem

[0020] The present invention is a method for manufacturing a circuit pattern, comprising: a step of applying a coating to a predetermined portion of the surface of a metal plate; a step of attaching a release film to the back of the metal plate to which the coating has been applied; a step of setting a resist pattern covering the coating on the surface of the metal plate; and a step of forming a circuit pattern attached to the release film by etching the metal plate to which the resist pattern is set.

[0021] In addition, the present invention is also a method for manufacturing a circuit board, wherein the circuit pattern obtained by the circuit pattern manufacturing method described above is laminated on an insulating layer laminated on a substrate. The method for manufacturing the circuit board includes: a step of transferring the circuit pattern to a transfer body, a step of peeling the release film from the circuit pattern, and a step of transferring the circuit pattern from the transfer body to the insulating layer.

[0022] In addition, the present invention is also a circuit pattern assembly with a release film, formed of a metal plate, and with a release film attached to the back. The circuit pattern assembly with the release film is composed of multiple circuit patterns, dummy patterns, and a first gap. The multiple circuit patterns include conductive patterns. The dummy patterns are disposed in the gaps between the multiple circuit patterns. The first gap is located between the dummy pattern and the circuit pattern adjacent to the dummy pattern.

[0023] The dummy pattern is preferably a portion extending outward from the outer side of the circuit pattern assembly.

[0024] The gap between the plurality of said circuit patterns is preferably greater than 2 mm, and the first gap is preferably greater than 0.8 mm and less than 3 mm.

[0025] The effects of the invention

[0026] The inventors of this application conducted repeated studies and discovered that, because the gaps between adjacent circuit patterns are generally relatively large, when the release film is attached to the back side of a metal plate with a back recess, the release film is attached in a manner that it is embedded in the back recess. As a result, the release film is not sufficiently adhered near the edge of the metal plate adjacent to the back recess. When etching is performed from the surface in this state, the etching solution seeps into the gap between the stacked metal plates and the release film from near the edge of the metal plate adjacent to the back recess, resulting in the dissolution of the back side of the metal plate.

[0027] On the other hand, according to the method for manufacturing a circuit pattern assembly with a release film, the method for manufacturing a circuit board, and the circuit pattern assembly with a release film according to the present invention, since dummy patterns are provided in the gaps between adjacent circuit patterns, the release film is not attached in a way that is recessed into the back side as before, and the release film is well attached to the back side of the metal plate all over the entire surface. Therefore, when etching the circuit pattern assembly with a release film on the back side with the release film attached thereto from the surface, the undesirable condition of partial dissolution of the back side of the circuit pattern can be prevented. Attached Figure Description

[0028] [ Figure 1A [Illustration 1] is a side view showing one embodiment of the circuit pattern assembly with release film of the present invention.

[0029] [ Figure 1B ]yes Figure 1A The bottom view of the circuit pattern assembly with the stripping film shown.

[0030] [ Figure 1C [Is with] the use Figure 1A A side view of a circuit board containing a circuit pattern assembly with a release film.

[0031] [ Figure 2A [ ] is a diagram related to the manufacturing method of the circuit pattern assembly with release film of the present invention (a diagram related to process S1).

[0032] [ Figure 2B [ ] is a diagram related to the manufacturing method of the circuit pattern assembly with release film of the present invention (a diagram related to process S2).

[0033] [ Figure 2C [ ] is a diagram related to the manufacturing method of the circuit pattern assembly with release film of the present invention (a diagram related to step S3).

[0034] [ Figure 2D [ ] is a diagram related to the manufacturing method of the circuit pattern assembly with release film of the present invention (a diagram related to step S4).

[0035] [ Figure 3A [ ] is a diagram related to the manufacturing method of the circuit pattern assembly with release film of the present invention (a diagram related to step S5).

[0036] [ Figure 3B [ ] is a diagram related to the manufacturing method of the circuit pattern assembly with release film of the present invention (a diagram related to step S6).

[0037] [ Figure 3C [ ] is a diagram related to the manufacturing method of the circuit pattern assembly with release film of the present invention (a diagram related to step S9).

[0038] [ Figure 4A [ ] is a diagram related to the manufacturing method of the circuit board of the present invention (a diagram related to process S11).

[0039] [ Figure 4B [ ] is a diagram related to the manufacturing method of the circuit board of the present invention (a diagram related to process S12).

[0040] [ Figure 4C [ ] is a diagram related to the manufacturing method of the circuit board of the present invention (a diagram related to process S13).

[0041] [ Figure 4D [ ] is a diagram related to the manufacturing method of the circuit board of the present invention (a diagram related to process S14).

[0042] [ Figure 5 [Illustration] is a diagram showing the steps related to the method for manufacturing the circuit pattern and the method for manufacturing the circuit board of the present invention.

[0043] [ Figure 6A [This is a side view related to the metal plate based on Patent Document 2 and Patent Document 3.]

[0044] [ Figure 6B ] is by Figure 6A A side view of a circuit pattern assembly formed by metal plates.

[0045] [ Figure 6C ]yes Figure 6B The bottom view of the circuit pattern assembly shown.

[0046] [ Figure 6D [Is with] the use Figure 6B A side view of the circuit board related to the circuit pattern assembly. Detailed Implementation

[0047] Hereinafter, the manufacturing method of the circuit pattern assembly with release film, the manufacturing method of the circuit board, and one embodiment of the circuit pattern assembly with release film of the present invention will be described with reference to the accompanying drawings. Furthermore, the figures shown in the accompanying drawings are illustrative, and the thickness or width of each part, the ratio of each part to the other, etc., may sometimes differ from the actual implementation.

[0048] First, an example of a manufacture based on the manufacturing method of the circuit pattern assembly with release film in this embodiment, namely a circuit pattern assembly with release film, and an example of a manufacture based on the manufacturing method of the circuit board in this embodiment, namely a circuit board, will be described. Figure 1A , Figure 1BThe circuit pattern assembly 1 with release film shown is formed by attaching release film 5 to the back of circuit pattern assembly 2. Furthermore, in the description of this embodiment, Figure 1A The upper surface of the circuit pattern assembly 2 shown is called the back surface of the circuit pattern assembly 2. Figure 1A The lower surface of the circuit pattern assembly 2 shown is called the surface of the circuit pattern assembly 2.

[0049] The circuit pattern assembly 2 is formed by etching a metal plate into a specified pattern as described below. The circuit pattern assembly 2 is formed by etching a relatively thick copper plate (rolled copper). The thickness of the circuit pattern assembly 2 (the thickness of the thick copper) can be appropriately selected according to the application, but in this embodiment it is selected in the range of 0.3 mm to 2.5 mm.

[0050] The circuit pattern assembly 2 of this embodiment includes a total of three circuit patterns 3 as shown in the figure. Furthermore, while the number of circuit patterns 3 in this embodiment is only one example, the circuit pattern assembly 2 may include multiple circuit patterns 3. Each circuit pattern 3 is configured to perform a predetermined function when electronic components are installed. In the circuit pattern assembly 2 of this embodiment, the three circuit patterns 3 are arranged horizontally in a row, and a dummy pattern 4 (more specifically, a separating portion 4a extending to separate adjacent circuit patterns 3) is provided in the gap G between adjacent circuit patterns 3. The dummy pattern 4 of this embodiment includes an outer portion 4b connected to the separating portion 4a and extending to the outside of the circuit pattern assembly 2. The outer portion 4b of this embodiment is as follows... Figure 1B It is formed into a rectangular frame as shown. Furthermore, the dummy pattern 4 is separate from the circuit pattern 3 and is electrically independent of the circuit pattern 3. Moreover, the circuit pattern 3 comprises multiple electrically independent conductive patterns 3a.

[0051] Here, the gap between the dummy pattern 4 and the circuit pattern 3 adjacent to the dummy pattern 4 is referred to as the first gap G1. The gap between the conductive patterns 3a is referred to as the second gap G2. As shown, the dummy pattern 4 is located between adjacent first gaps G1 (between adjacent first gaps G1 at the portion between two first gaps G1 excluding the second gap G2). Furthermore, the width of gap G is wider than the width of second gap G2. For example, the width of gap G is 10 mm, the width of first gap G1 is 1 mm, and the width of second gap G2 is 1 mm. The width of first gap G1 is preferably 0.8 mm or more and 3 mm or less, more preferably 0.8 mm or more and 2 mm or less, and even more preferably 0.8 mm or more and 1 mm or less, as described later. The width of second gap G2 is preferably set to 1 mm or more and 3 mm or less, more preferably 1 mm or more and 2.5 mm or less, and even more preferably 1 mm or more and 2 mm or less. When the second gap G2 exceeds 3 mm, it is preferable to arrange another dummy pattern, such as dummy pattern 4, which is electrically independent of the circuit pattern 3, in the second gap G2, making the second gap G2 1 mm or more and 3 mm or less. Furthermore, regarding the gap G, there are no particular limitations as long as the first gap G1 can be set within the stated range. However, if the gap G is too small, the width of the dummy pattern 4 also becomes smaller, making the manufacture of the circuit pattern assembly 2 difficult. Therefore, the gap G is generally greater than 2 mm, and typically 3 mm or more.

[0052] The release film 5 is, for example, a film whose initial adhesive force can be reduced by applying heat or irradiating with ultraviolet light. The release film 5 of this embodiment is an ultraviolet (UV) film with the property that the initial adhesive force is reduced by ultraviolet irradiation.

[0053] When the circuit pattern assembly 1 with the release film is used to implement the circuit board manufacturing method described later, it is possible to manufacture... Figure 1C The circuit board 6 shown is an example of a circuit board 6 in this embodiment. The circuit board 6 is sequentially stacked with the circuit pattern assembly 2 described above, the insulating layer 7, and the substrate 8. Furthermore, by implementing the circuit board manufacturing method described later, a circuit pattern assembly 2 in which the dummy pattern 4 has been removed is provided on the circuit board 6.

[0054] The insulating layer 7 is formed from an insulating raw material and serves to electrically insulate the circuit pattern assembly 2 from the substrate 8, and also to allow them to adhere to each other. Furthermore, when the circuit pattern assembly 2 houses electronic components such as power modules, the insulating layer 7 preferably possesses high heat resistance to heat generated by the electronic components and high heat transfer properties to transfer the heat to the substrate 8. The insulating layer 7 may cover the entire surface of the substrate 8 or only a portion of its surface.

[0055] As an example of the raw material for the insulating layer 7, a resin composition containing a thermosetting resin can be cited. Examples of thermosetting resins include epoxy resin, phenolic resin, melamine resin, urea resin, unsaturated polyester resin, alkyd resin, and cyanate ester resin. One thermosetting resin can be used alone, or two or more can be used in combination. In addition to the thermosetting resin, a curing agent can be included as a component in the resin composition. The curing agent is selected according to the type of thermosetting resin, and there are no particular limitations as long as it reacts with the resin. For example, as a curing agent when using epoxy resin, amine-based curing agents, imidazole-based curing agents, and phenolic curing agents can be included. Furthermore, the resin composition may also contain fillers (inorganic fillers). As fillers, fillers with excellent insulation and high thermal conductivity are preferred, such as alumina, silica, aluminum nitride, boron nitride, silicon nitride, and magnesium oxide. Furthermore, the resin composition may also contain curing accelerators, stabilizers, ion scavengers, and solvents. Additionally, the resin composition may also contain a flexibility-improving material.

[0056] The substrate 8 can be formed from various raw materials, but is particularly preferably formed from a raw material with high thermal conductivity, such as copper, aluminum, iron, or other metals (which can be elemental metals or alloys). In this embodiment, the substrate 8 is formed of copper. The substrate 8 shown has fins to improve the effect of heat release to the outside, but it can also be a plate without fins. The substrate 8 is not limited to containing a single component; it can also be constructed by combining multiple components. The substrate 8 may include structures that further improve the effect of heat release to the outside, and may, for example, have a vapor chamber or heat pipe embedded in a metal plate.

[0057] Next, refer to Figures 2A to 5 The manufacturing method of the circuit pattern assembly with release film and the manufacturing method of the circuit board in this embodiment will be described.

[0058] First of all, Figure 2A Dry film 10 is attached to both the surface and back of the metal plate 9 shown. Figure 5In process S1). The metal plate 9 is a plate made of metal such as aluminum or copper, and in this embodiment, a copper plate with a thickness of 0.5 mm to 2.0 mm is used as described above. As an example, the dry film 10 uses a dry film with a thickness of about 25 μm to 150 μm. The dry film 10 is preferably attached to the metal plate 9 using a method such as... Figure 2A As shown, a laminating apparatus includes rollers R on both the surface and back sides of the metal plate 9. In the laminating apparatus, dry film 10 is disposed on both the surface and back sides of the metal plate 9. Then, while pressing the surface-side dry film 10 onto the surface of the metal plate 9 using the surface-side rollers R and pressing the back-side dry film 10 onto the back side of the metal plate 9 using the back-side rollers R, each roller R is rotated. Thus, dry film 10 can be adhered to both the surface and back sides of the metal plate 9.

[0059] Next, as Figure 2B As shown, an exposure film 11 is disposed on the dry film 10 on the surface side and the dry film 10 on the back side. The exposure film 11 is at least in contact with... Figure 1A The portions corresponding to the conductive pattern 3a and the dummy pattern 4 in the circuit pattern 3 shown (in other words, the portions other than those corresponding to the first gap G1 and the second gap G2) have openings. Then, the exposure film 11 is exposed by irradiating it with light from the exposure apparatus. Figure 5 (In step S2). During exposure, the portion of the dry film 10 directly below the opening of the exposure film 11 is hardened by the light passing through the opening.

[0060] Then, for example, through a developing device, such as Figure 2C The development process, as shown, removes the portions of the dry film 10 that have not hardened due to exposure. Figure 5 (Process S3 in the process). Thus, it becomes the following state: on the surface and back of the metal plate 9, in contact with... Figure 1A The portions corresponding to conductive pattern 3a in the circuit pattern 3 shown, and the portions corresponding to dummy pattern 4, retain portions of the dry film 10 that have been cured by exposure (see reference). Figure 2C Hereinafter, the dry film 10 remaining on the surface of the developed metal plate 9 will be referred to as the resist pattern 12. The openings of the resist pattern 12 are located at... Figure 1A The portions corresponding to the first gap G1 and the second gap G2 shown.

[0061] Then, etching is performed on the metal plate 9, including the resist pattern 12. Figure 5 In process S4 of the embodiment, double-sided etching is performed, etching from both the surface side and the back side of the metal plate 9 (see reference). Figure 2DWhen performing this double-sided etching, an etching apparatus that sprays etching solution from both the surface and back sides of the metal plate 9 can be used (e.g., refer to International Publication No. 2022 / 102357). As a result, in the portion of the resist pattern 12 where openings are provided, the surface and back sides of the metal plate 9 dissolve in the thickness direction. In this double-sided etching, etching continues until only the middle portion of the metal plate 9 remains in the thickness direction. As a result, recesses are formed on the surface and back sides of the metal plate 9, one corresponding to the first gap G1 and the other corresponding to the second gap G2. Here, the surface recess in the recess corresponding to the first gap G1 is referred to as the first surface recess G1F, and the back recess is referred to as the first back recess G1R. Similarly, the surface recess in the recess corresponding to the second gap G2 is referred to as the second surface recess G2F, and the back recess is referred to as the second back recess G2R. Figure 1A The dividing portion 4a of the dummy pattern 4 shown is located between adjacent first surface recesses G1F (between adjacent first back recesses G1R).

[0062] Then, using an alkaline stripping device, the resist pattern 12 on the surface and back of the metal plate 9 is removed by using an alkaline solution. Figure 5 (Process S5 in the process). Therefore, as... Figure 3A As shown, a metal plate 9 is formed with a first surface recess G1F and a second surface recess G2F on its surface, and a first back recess G1R and a second back recess G2R on its back.

[0063] Next, as Figure 3B As shown, a dry film 10 is attached to the surface of the metal plate 9, and a reference film is attached to the back of the metal plate 9. Figure 1A The peeling membrane 5 (explained) Figure 5 In process S6), the dry film 10 and the release film 5 are preferably attached to the metal plate 9 using a method such as... Figure 2A As shown, a laminating device includes rollers R on both the surface and back sides of the metal plate 9. Then, while pressing the dry film 10 onto the surface of the metal plate 9 using the surface-side rollers R and pressing the release film 5 onto the back side of the metal plate 9 using the back-side rollers R, each roller R is rotated. This allows the dry film 10 to adhere to the surface of the metal plate 9, and the release film 5 to adhere to the back side of the metal plate 9. Here, in... Figures 6B-6CWhen the circuit pattern assembly 102 shown does not have a dummy pattern, the release film 5 is attached to the back side of the metal plate 101 in a manner that is recessed into the back side recess 107R. As a result, the release film 5 is sometimes not sufficiently adhered to the back side of the metal plate 9. On the other hand, when the first back side recess G1R is provided to form the dummy pattern 4, the defective situation of the release film 5 being attached in a recessed manner can be prevented, and the release film 5 can be sufficiently adhered to the back side of the metal plate 9.

[0064] Then, with Figure 2B Similarly, the exposure process on the surface side of the metal plate 9 shown is performed on... Figure 3B The dry film 10 on the surface side shown is provided with an exposure film 11, and is exposed by irradiating the exposure film 11 with light from the exposure device. Figure 5 (Step S7 in the process). Furthermore, illustrations of step S7 are omitted. In the exposure step of step S7, the same exposure film 11 as in step S2 is used. Therefore, when exposure is performed in step S7, the dry film 10 attached to the surface of the metal plate 9 and... Figure 2B Similarly, at least the portion corresponding to the conductive pattern 3a in the circuit pattern 3 and the portion corresponding to the dummy pattern 4 (in other words, the portion other than the portion corresponding to the first gap G1 and the second gap G2) is hardened.

[0065] Then, with Figure 2C Similarly, the development process on the surface side of the metal plate 9 shown involves removing the portion of the dry film 10 attached to the surface of the metal plate 9 that has not hardened due to exposure. Figure 5 (Process S8 in the process). Thus, it becomes the following state: on the surface of the metal plate 9, with... Figure 2B Similarly, in the portions corresponding to the conductive pattern 3a in circuit pattern 3 and the portions corresponding to the dummy pattern 4, the portions of the dry film 10 that have been hardened by exposure remain. Furthermore, although the illustration of process S8 is omitted, in the developing step of process S8, a similar pattern is also provided on the surface of the developed metal plate 9. Figure 2B The resist pattern 12 shown is as shown.

[0066] Next, as Figure 3C As shown, the metal plate 9, including the resist pattern 12, is etched from the surface side. Figure 5 In this embodiment, process S9 is used as follows. Figure 2B An etching apparatus as shown, such as Figure 3CThe etching solution is sprayed only from the surface side, as shown. Consequently, in the portion of the resist pattern 12 where the openings are located (the portion where the first surface recess G1F and the second surface recess G2F are situated), the surface of the metal plate 9 dissolves in the thickness direction. Therefore, the first surface recess G1F connects to the first back recess G1R, and the second surface recess G2F connects to the second back recess G2R, forming a first gap G1 and a second gap G2 on the metal plate 9. As described above, by providing the first back recess G1R to form the dummy pattern 4, the release film 5 is sufficiently adhered to the back side of the metal plate 9, thus preventing the etching solution sprayed from the etching apparatus from seeping into the space between the release film 5 and the metal plate 9, thus preventing adverse conditions.

[0067] Here, the width of the first gap G1 (i.e., the width of the first surface recess G1F and the first back recess G1R) will be described in detail. The inventors of this application conducted repeated studies and found that if the first gap G1 is too small, there are difficulties in mass production during etching or in the workability of removing the dummy pattern 4 described later; if the first gap G1 is too large, there is a possibility that the release film 5 may not be able to adequately adhere to the periphery of the first back recess G1R. On the other hand, when the width of the first gap G1 is 0.8 mm or more and 3 mm or less, not only is the aforementioned mass production or workability good, but the adhesion of the release film 5 is also good. Further repeated studies revealed that 0.8 mm or more and 2 mm or less is more preferred, and even more preferably 0.8 mm or more and 1 mm or less.

[0068] Then, with Figure 2B Similarly, the alkaline stripping process on the surface side of the metal plate 9 shown uses an alkaline solution to remove the surface layer of the metal plate. Figure 3C The resist pattern 12 on the surface of the metal plate 9 shown is removed. Figure 5 Process S10 in the process). Thus, it is formed in Figure 1A The circuit pattern assembly 2 shown has a release film 5 attached to the back of the circuit pattern assembly 1.

[0069] After forming the circuit pattern assembly 1 with the release film, as follows Figure 4A Perform the operation of removing the dummy pattern 4 from the circuit pattern assembly 2 as shown. Figure 5In step S11 of the process. When removing the dummy pattern 4, for example, a robot's chuck can be used to grasp a portion of the dummy pattern 4 and lift it to peel the dummy pattern 4 from the release film 5, or an operator can perform the operation instead of the robot. In this embodiment, the dummy pattern 4 includes an outer portion 4b extending outside the circuit pattern assembly 2. The outer portion 4b can be grasped, thus preventing the undesirable situation of disordered arrangement of the conductive patterns 3a constituting the circuit pattern 3 when removing the dummy pattern 4. In particular, the outer portion 4b of this embodiment is formed into a rectangular frame shape, and the outer portion 4b can be grasped by clamping the outer peripheral surfaces of the opposing sides of the four sides constituting the frame (e.g., in Figure 4A In the middle, the outer part 4b can be grasped by clamping the right side of the outer part 4b located on the right and the left side of the outer part 4b located on the left, so the operation of removing the dummy pattern 4 can be easily performed.

[0070] Then, as Figure 4B The process of pressing the transfer body 13 onto the surface of the circuit pattern assembly 2 is carried out as shown. Figure 5 (Process S12). The transfer body 13 includes, for example, a urethane cushioning material with an adhesive layer on its surface, and a back plate laminated on the back of the cushioning material. By pressing the surface of the transfer body 13 with the adhesive layer onto the surface of the circuit pattern assembly 2, the circuit pattern assembly 2 is held in place by attachment on the transfer body 13.

[0071] Next, ultraviolet light is irradiated onto the back of the release film 5 attached to the circuit pattern assembly 2 to reduce the adhesion of the release film 5, and the release film 5 is then peeled off from the circuit pattern assembly 2. Figure 5 (Step S13). That is, by performing steps S12 and S13, the circuit pattern assembly 2 held by the release film 5 is transferred to the transfer body 13.

[0072] Then, as Figure 4C As shown, the circuit pattern assembly 2 held by the transfer body 13 is pressed onto the insulating layer 7 stacked on the substrate 8 and heated. In this embodiment, a vacuum pressing device is used to press the transfer body 13 in a vacuum environment at a predetermined temperature. Then, as... Figure 4C As shown, the circuit pattern assembly 2 is transferred to the insulating layer 7 by peeling off the transfer body 13 after the insulating layer 7 has hardened. Figure 5 (Process S14). After this process, the circuit board 6 is completed.

[0073] The foregoing has described one embodiment of the present invention, but the present invention is not limited to this specific embodiment. Various modifications and alterations can be made within the scope of the spirit of the invention as set forth in the claims, unless otherwise specified in the description. For example, the structure of the embodiment can be appropriately added to or deleted from, and the structure of one embodiment can also be incorporated into other embodiments. Furthermore, the effects described in the embodiments are merely illustrative of the effects produced by the present invention and do not imply that the effects based on the present invention are limited to those described.

[0074] For example, the dummy pattern 4 preferably includes a portion extending outside the circuit pattern assembly 2 as described above, such as the outer portion 4b, but it may also be merely a separating portion 4a. Furthermore, the outer portion 4b is not limited to being formed in the described rectangular frame shape; for example, it may consist of only... Figure 1B The outer portion 4b shown is formed by the two long sides of the outer portion 4b connecting to one of the two short sides and the long side that separates the portion 4a. Additionally, Figure 4A The operation of removing the dummy pattern 4 shown can also be performed as follows: Figure 4C The process is performed after transferring the circuit pattern assembly 2 onto the transfer body 13 and peeling off the release film 5, as shown. Furthermore, in the aforementioned embodiment, in... Figure 3C As shown, when etching a metal plate 9 with a release film 5 attached to its back side from the surface side, a first surface recess G1F and a second surface recess G2F are provided on the surface of the metal plate 9. However, the present invention also includes the case where a metal plate 9 without recesses such as the first surface recess G1F or the second surface recess G2F is used.

[0075] Explanation of icon numbers

[0076] 1: A circuit pattern assembly with a release film

[0077] 2: Circuit pattern assembly

[0078] 3: Circuit diagram

[0079] 3a: Conductive pattern

[0080] 4: Fictitious pattern

[0081] 5: Peel-off film

[0082] 6: Circuit board

[0083] 7: Insulation layer

[0084] 8: Substrate

[0085] 9: Metal plate

[0086] G: Gap

[0087] G1: First gap

[0088] G1R: First rear recess

[0089] G2: Second gap

[0090] G2R: Second rear recess

Claims

1. A method for manufacturing a circuit pattern assembly with a release film, wherein the circuit pattern assembly with the release film is formed from a metal plate and has a release film attached to its back side, wherein, The circuit pattern assembly comprises multiple circuit patterns, dummy patterns, and a first gap. The multiple circuit patterns include conductive patterns. The dummy patterns are disposed in the gaps between the multiple circuit patterns. The first gap is located between the dummy pattern and the circuit pattern adjacent to the dummy pattern. The method for manufacturing the circuit pattern assembly with a release film includes the following steps: The process of providing a first back recess corresponding to the first gap and a second back recess corresponding to the second gap between the conductive patterns on the back of the metal plate; The process of attaching the release film to the back of the metal plate having the first back recess and the second back recess; as well as The process of removing the first portion corresponding to the first back recess and the second portion corresponding to the second back recess from the surface of the metal plate by etching.

2. A method for manufacturing a circuit board, wherein the circuit pattern assembly obtained by the method for manufacturing a circuit pattern assembly with a release film as described in claim 1 is laminated onto an insulating layer laminated on a substrate, the method for manufacturing the circuit board comprising the following steps: The process of transferring the circuit pattern assembly onto the transfer body; The process of peeling the release film off the transferred circuit pattern assembly; The process of removing the dummy pattern from the circuit pattern assembly before transferring the circuit pattern assembly to the transfer body, or after peeling off the release film from the circuit pattern assembly; and The process of transferring the circuit pattern assembly after removing the dummy pattern from the transfer body to the insulating layer.

3. A circuit pattern assembly with a release film, formed of a metal plate, wherein a release film is attached to the back side, wherein the circuit pattern assembly with the release film contains... The circuit pattern assembly comprises multiple circuit patterns, dummy patterns, and a first gap. The multiple circuit patterns include conductive patterns. The dummy patterns are disposed in the gaps between the multiple circuit patterns. The first gap is located between the dummy pattern and the circuit pattern adjacent to the dummy pattern.

4. The circuit pattern assembly with a release film according to claim 3, wherein, The dummy pattern is included in the portion extending outward from the assembly of circuit patterns.

5. The circuit pattern assembly with a release film according to claim 3, wherein, The gap between the plurality of said circuit patterns is greater than 2 mm. The first gap is greater than 0.8 mm and less than 3 mm.

Images