JP4144886B2 - Circuit board holding jig - Google Patents

Description

  The present invention positions and holds a circuit board across an electronic component mounting line when mounting the electronic component on a flexible type or rigid type (using a thin glass epoxy board that is difficult to carry by itself). The circuit board holding jig of FIG.

  As is well known, electronic devices such as cellular phones, PDAs (Personal Data Assistants), and notebook computers tend to be compact with high performance and multiple functions. For these electronic devices that tend to be reduced in size, for example, a flexible printed circuit (FPC) substrate having a sheet-like flexibility in which a polyimide film and a wiring circuit conductor are laminated has been widely used.

  This FPC board is a sheet-like resin with various wiring patterns printed on it. Various electronic components (for example, ICs, capacitors, resistors, inductors, filters, connectors, etc.) are placed on the wiring patterns. It consists of what will be implemented. The electronic component mounting process on the FPC board includes a cream solder printing process, an electronic component mounting process, a solder reflow process, a cutting process, and the like. Through the above processes, that is, in the electronic component mounting line, the FPC It is necessary to fix the substrate in a flattened state and transport it within each process and between each process.

  Therefore, in order to handle FPC boards and thin glass epoxy boards that have been difficult to carry by conventional methods in the same way as regular-shaped circuit boards (for example, rigid-type circuit boards made of glass epoxy resin), rigidity is required. It was possible to fix by using a metal fitting on a high board or by attaching a heat resistant tape on a rigid metal plate.

  In the conventional example described above, the work of attaching with a heat-resistant tape has to be performed manually because it is difficult to automate with a robot or the like. Also, when removing the FPC board from the metal flat plate, it must be done manually as well, and the situation was extremely unsatisfactory in terms of mass productivity and cost.

  As a technique for solving this problem, an adhesive layer is formed of silicon resin, which is a weak adhesive, on the surface of a jig corresponding to the above-described metal fitting or metal flat plate, and an FPC is placed on the surface of the adhesive layer. A thin substrate fixing jig to be held has been proposed (for example, Patent Document 1).

  However, in general, a low molecular weight siloxane that has not been polymerized remains even when the silicon resin is polymerized (polymerized). Therefore, when the silicon resin is heated, the remaining low molecular weight siloxane is exposed on the surface of the silicon resin layer. It has the property to do. Therefore, in the electronic component mounting process for mounting the electronic component on the FPC board, the low molecular siloxane contained in the silicon resin is exposed on the surface of the adhesive layer as the temperature rises during the solder reflow process. Vaporize with heat.

  The low molecular weight siloxane exposed on the surface of the adhesive layer is interposed between the adhesive layer and the FPC substrate to be held, and prevents the FPC substrate from being held by the adhesive layer. Even if the FPC substrate can be held, the low-molecular siloxane contaminates the surface of the FPC substrate and the surface of the adhesive layer, and adversely affects the subsequent process. Therefore, the cleaning process of the FPC board and the adhesive layer is required.

  Further, the volatilized low-molecular siloxane adheres to and contaminates the surface of the FPC board that is not in direct contact with the adhesive layer or a member of the mounting apparatus. For this reason, the conductor pattern of the FPC board is damaged, which hinders the joining of electronic components. As a specific example, when low molecular weight siloxane is reattached to the electronic component contact portion of the FPC board, silicon dioxide decomposed and produced acts as an electrical insulator, causing contact failure.

  Furthermore, it volatilizes also in the space in the mounting device and pollutes the mounting atmosphere. This contamination of the mounting atmosphere significantly impairs the product quality after mounting for mounting that requires a clean atmosphere such as a clean room. Therefore, the man-hour and cost for cleaning the mounting atmosphere are inevitable.

In order to solve the above-described problem, a holding and conveying jig in which an adhesive layer is formed of a fluorine-based resin has been proposed (for example, Patent Document 2). That is, since the low molecular weight component that has not been polymerized does not remain in the fluororesin layer, the low molecular weight component is not exposed on the surface of the adhesive layer during heating in the reflow process. Therefore, it is possible to prevent a problem caused by contamination due to exposure and volatilization of low molecular siloxane in the above-described silicon resin. Furthermore, since the use environment temperature of the fluorine-based resin layer is relatively high at about 250 ° C. or more and about 300 ° C. or less, lead-free solder (reflow temperature of 230 ° C. or more and 280 ° C. or less) which has been widely used in environmental measures in recent years Can also respond.
Japanese Patent Laid-Open No. 7-22795 JP 2004-158477 A

As described above, the adhesive layer composed of the fluorine-based resin can solve the problem due to the low molecular weight component. However, it is generally known that a fluorine-based resin is inferior in adhesion, which is an adhesive force per unit, as compared to a silicon-based resin. Specifically, in Patent Document 2, the adhesiveness (14 6 g / cm ^{2 to} 19 8 g / cm ² ) of the adhesive layer made of a fluororesin is the adhesiveness of the adhesive layer made of a silicon resin. Experimental results have been reported to be about one third of (206 g / cm ^{2 to} 584 g / cm ² ).

  As described above, when the adhesiveness is about one third of that of the silicone resin adhesive layer, the FPC board cannot be securely held by the fluorine resin adhesive layer, and the FPC board falls off during the mounting process. Resulting in. Even if it does not fall off, the FPC board is struck particularly by hot air during reflow, which hinders the mounting of electronic components.

  Accordingly, an object of the present invention is to provide a circuit board holding jig provided with an adhesive layer made of a fluororesin that can hold an FPC board with an adhesiveness equivalent to or higher than that of an adhesive layer made of silicon resin. And

The present invention is a circuit board holding jig for positioning and holding the circuit board over an electronic component mounting line for mounting electronic parts on the circuit board,
A base board having a base surface formed in a plate shape;
A circuit board holding layer provided on the base surface and holding the circuit board;
The circuit board holding layer is
A holding surface that has a first surface roughness and adheres to the circuit board with a first adhesive force;
A fixing surface having a second surface roughness and fixed to the base surface with a second adhesive force larger than the first adhesive force.

  In the circuit board holding jig according to the present invention, by forming the circuit board holding layer with a fluorine-based resin instead of the silicon resin, the FPC board can be made siloxane-free with an adhesion degree equal to or higher than that of the silicon resin. Can be retained.

The basic concept of the present invention will be described below before the circuit board holding jig according to the present invention is described in detail based on specific embodiments shown in the drawings. As described above, it is generally recognized that a fluorine-based resin has a lower degree of adhesion than a silicon resin. However, in the present invention, an experiment was performed to determine the relationship between the surface roughness of the fluororesin adhesive layer and the degree of adhesion, and a new fact recognition different from general recognition was obtained.

FIG. 1 shows the relationship between the surface roughness and the degree of adhesion of the fluororesin adhesive layer and the silicon resin adhesive layer, respectively, obtained as a result of the experiment. The experimental conditions were that the probe was pressed against the adhesive layer at a predetermined load using a dedicated adhesion meter, and then the probe was pulled up at a constant speed so that the probe was detached from the adhesive layer. The weight at the time of the determination is determined as the degree of adhesion (gf / cm ² ). The experimental temperature is 25 ° C.

As shown in FIG. 1, it can be seen that the adhesiveness of the fluororesin adhesive layer varies greatly depending on its surface roughness. More specifically, in the range roughness of 0.001Myuemu～0.01Myuemu, tackiness is ^{2000gf / cm 2 ~1800gf / cm 2} . When the surface roughness is in the range of 0.01 μm to 0.1 μm, the adhesion is 1800 gf / cm ^{2 to} 1600 gf / cm ² . When the surface roughness is in the range of 0.10 μm to 0.30 μm, the adhesion is 1600 gf / cm ^{2 to} 1400 gf / cm ² . When the surface roughness is in the range of 0.30 μm to 0.80 μm, the adhesion is 1400 gf / cm ^{2 to} 1000 gf / cm ² . The range roughness of 0.80Myuemu～2.00Myuemu, tackiness is ^{1000gf / cm 2 ~500gf / cm 2} . The range roughness of 2.00Myuemu～5.00Myuemu, tackiness is ^{500gf / cm 2 ~150gf / cm 2} .

On the other hand, the adhesiveness of the silicone resin adhesive layer is significantly smaller due to surface roughness than the adhesiveness of the fluororesin adhesive layer. Specifically, when the surface roughness is in the range of 0.001 μm to 0.30 μm, the adhesion is 1300 gf / cm ^{2 to} 1000 gf / cm ² . The range roughness of 0.30Myuemu～5.0Myuemu, tackiness is ^{1000gf / cm 2 ~500gf / cm 2} .

Thus, in general, the adhesiveness of the fluororesin adhesive layer, which is generally recognized as having a lower adhesiveness than silicon resin, is at least when the surface roughness is less than 0.30 μm. 100 gf / cm ^{2 to} 700 gf / cm ² is larger than the adhesiveness of the layer. If the surface roughness is 0.30Myuemu～0.8Myuemu, large enough 0gf / cm ² ~400gf / cm ² than the tack of the silicone resin adhesive layer. When the surface roughness is in the range of 0.80 μm to 2.0 μm, the adhesiveness of the fluororesin adhesive layer is equivalent to the adhesiveness of the silicone resin adhesive layer. However, when the surface roughness is in the range of 2.0 μm to 5.0 μm, the adhesiveness of the fluororesin adhesive layer is 350 gf / cm ² smaller than the adhesiveness of the silicone resin adhesive layer.

That is, the experimental results shown in FIG. 1 show that the adhesiveness of the fluororesin adhesive layer can be set larger than that of the silicone resin adhesive layer by controlling the surface roughness of the surface, and more finely. It shows that it can be set to a desired degree of adhesion. Moreover, since the experimental conditions in the above-mentioned Patent Document 2 are unknown, the fluorine resin adhesive layer according to the present invention shows the experimental results in Patent Document 2, although it cannot be simply compared with the experimental results in the present invention. It shows that the adhesion degree of fluorine resin is about 10 times the adhesion degree of 14 6 g / cm ^{2 to} 19 8 g / cm ² .

  The degree of adhesion that acts between the adhesive layer (fluorinated resin) and the object (measuring element) is set by the self-adhesiveness of the materials in contact with each other and the air density between the surfaces to be joined. is there. Therefore, if the surface roughness of the surface of the adhesive layer is reduced and brought close to a mirror surface state, it is presumed that the airtightness between the adhesive surface and the adhesive surface of the object increases, thereby increasing the adhesiveness. . However, the experimental results shown in FIG. 1 exceed the recognition that silicon resins have a greater degree of adhesion than fluororesins.

  In addition, the surface roughness which concerns on this invention can be given to the surface of the adhesion layer made from a fluororesin by press molding with a metal mold | die. If the surface side of the adhesive layer of the mold is processed so as to have a surface roughness corresponding to the desired adhesiveness, the surface roughness of the mold is transferred to the surface of the adhesive layer during press molding. As a method for finishing the surface of the mold to a desired surface roughness, known techniques such as shot blasting, etching, and polishing can be used.

  Further, depending on the position on the circuit board holding jig, the object to be held may be different, or a different degree of adhesion may be required. In such a case, the mold may be processed so as to have different surface roughness depending on the site of the adhesive layer. Thus, by press-molding with a mold having a desired surface roughness, a circuit board holding jig having an adhesive layer having a different required adhesiveness for each part can be easily configured.

  In addition to the molding by the mold as described above, after the adhesive layer is formed by screen printing or the like, the surface thereof can be additionally processed to have a desired surface roughness. However, in the method of additionally processing the surface after forming the pressure-sensitive adhesive layer, it is difficult to ensure accuracy and it is very difficult to finish the surface roughness different for each part. Furthermore, the number of man-hours required for the additional work and the number of cleaning steps for the adhesive layer and the circuit board holding jig after the additional work are also required. Molding with a mold is very advantageous because it does not have these problems.

Next, the fluororesin used for forming the adhesive layer in the circuit board holding jig according to the present invention will be described. As described above, the fluororesin used in the present invention is required to have no low molecular weight component remaining and high temperature stability. Such as the fluorine resin, one having a peroxide cross-linked structure, those having a polyol crosslinked structure, and may include those having diamine crosslinking structure. The adhesive layer may be formed of one type of fluorine resin among these three types (peroxide crosslinked structure, polyol crosslinked structure, and diamine crosslinked structure). You may comprise combining.

Hereinafter, FIG. 2 and FIG. 3 exemplify the chemical structure of a fluororesin having such a peroxide cross-linked structure. 2 and 3, “HFP” means hexafluoroprepylene, “VF ₂ ” means vinylidene fluoride, “TFE” means tetrafluoroethylene, and “PMVE” means par It means fluoromethyl vinyl ether, and “CMS” means cure site monomer.

For convenience of explanation, the fluororesins having the peroxide cross-linking structures shown in FIGS. 2 and 3 are identified as the fluororesin FR1 and the fluororesin FR2, respectively. Fluororesin FR2 shown in Figure 3, by replacing the HFP in fluororesin FR1 shown in FIG. 2 at P MVE, by oxygen in PMVE, although the fluorine content is reduced as compared with the fluorine-based resin FR1 The low temperature flexibility has been improved. The chemical structure shown in FIGS. 2 and 3 is merely an example of a fluorine-based resin that can be used for the adhesive layer according to the present invention, and has another chemical structure in which no low molecular weight component remains. Needless to say, a fluororesin can also be used.

Moreover, in FIG. 4, the kind of fluorine resin which has a peroxide bridge | crosslinking structure used for formation of the adhesion layer which concerns on this invention, and the example of the monomer composition are shown. The fluororesin shown in FIG. 4 has a chemical structure in which the monomer composition of the fluororesin FR1 and the fluororesin FR2 is changed . In addition, according to the monomer composition of fluorine resin FR1 and fluorine resin FR2, it distinguishes from fluorine resin FRa, FRb, FRc, and FRd, respectively. In the figure, “◯” means that the corresponding monomer is included, and “ − ” means that the corresponding monomer is not included.

  FIG. 5 shows the relationship between cold resistance and methanol resistance of the fluororesin having the peroxide cross-linking structure shown in FIG. Further, the fluorine resins FRa to FRd shown in FIGS. 4 and 5 show an example of a fluorine resin having a peroxide cross-linking structure that can be used for the adhesive layer according to the present invention, and have similar properties. Needless to say, a fluorine-based resin having the above can be used.

6, 7, and Figure 8, the chemical structure of the fluorine-based resin having a polyol crosslinked structure for use in forming the adhesive layer according to the present invention, monomer composition, and cold resistance and to methanol of the relationship . The meanings of symbols and the like in FIG. 6, FIG. 7, and FIG. 8 are as described with reference to FIG. 2 (FIG. 3), FIG. 4, and FIG. However, as shown in FIG. 6, the fluororesin having a polyol cross-linking structure is identified as the fluororesin FR3. In FIGS. 7 and 8, two types of fluororesin FR3 having a polyol cross-linked structure are represented as fluororesin FRe and fluororesin FRf.

Further, FIG. 9, FIG. 10, and FIG. 11 show the relationship between the chemical structure, monomer composition , cold resistance and methanol resistance of the fluororesin having a diamine cross-linking structure diagram used for forming the adhesive layer according to the present invention. Show. The meanings of symbols and the like in FIG. 6, FIG. 7, and FIG. 8 are as described with reference to FIG. 2 (FIG. 3), FIG. 4, and FIG. However, as shown in FIG. 9, a fluororesin having a polyol cross-linking structure is identified as a fluororesin FR4. In FIGS. 10 and 11, two types of fluororesin FR4 having a polyol cross-linking structure are represented as fluororesin FRg and fluororesin FRh.

Next, the configuration of the circuit board holding jig according to the present invention will be described with reference to FIG. 12, FIG. 13, FIG. 14, and FIG. As described above, the adhesive layer formed on the circuit board holding jig is made of a fluororesin having the above-described composition and a mold prepared to have the above-described desired surface roughness. It is.

  FIG. 12 shows a basic configuration of the circuit board holding jig 1 in a state where the circuit board 11 is held and the electronic component 12 is mounted on the circuit board 11 via the cream solder 8. The circuit board holding jig 1 is configured to position and hold the circuit board 11 across an electronic component mounting line for mounting the electronic component 12 on the circuit board 11. The circuit board 11 includes an FPC board and a thin glass epoxy board that is difficult to carry. The circuit board holding jig 1 includes a rigid base board 2 and a circuit board holding layer 3 provided on one surface 2 a of the base board 2.

  The base board 2 is composed of a mechanically rigid material, for example, a metal plate such as aluminum, copper, and stainless steel, glass epoxy, magnesium board, carbon FRP, ceramic, phenol, polyimide, and the like. It is sufficient if it ensures the sex. The base board 2 is provided with positioning holes 7 as necessary. The positioning hole 7 can be used for positioning when the FPC board 11 is bonded to the base board 2, and when the cream solder 8 is printed on the copper foil pattern of the FPC board 11 or the electronic component 12 is mounted. It can be used for rough positioning. In addition, the position hole 7 can be used to recognize the pattern position mark 13 of the FPC board 11 by the recognition means and use it as a means to correct the positional variation when the FPC board 11 is bonded to the base board 2. .

  The circuit board holding layer 3 is an adhesive layer formed of a fluorine-based resin as described above, and is means for sticking and holding the circuit board 11 with an adhesive degree corresponding to the surface roughness of the surface. As shown in FIG. 13, the circuit board holding layer 3 is fixed to one surface 2 a of the base board 2. For the purpose of adhesively holding the circuit board 11, the adhesive force (hereinafter referred to as “holding surface”) of the surface 3 a of the circuit board holding layer 3, that is, the surface used for holding the circuit board 11 (hereinafter referred to as “holding surface”). F1 is the adhesive strength (hereinafter referred to as “adhesive surface”) of the back surface 3b of the circuit board holding layer 3, that is, the surface fixed to the surface 2a of the base board 2 (hereinafter referred to as “adhesive surface”). If F2 is referred to as “force”, it must be configured such that F1 <F2.

  The holding adhesive force F1 is set to A1 as the degree of adhesion of the holding surface 3a (hereinafter referred to as “holding adhesiveness”), and the area of the holding surface 3a actually used for adhesion to the circuit board 11 (hereinafter referred to as “holding area”). )), S1 is obtained as F1 = A1 × S1. On the other hand, the sticking adhesive force F2 is F2 = A2 × S2 when the sticking degree of the sticking surface 3b is A2, and the area of the sticking surface 3b (hereinafter referred to as “sticking area”) is S2 (S1 = <S2). Desired.

  Therefore, in the case of holding area S1 << fixing area S2, holding adhesiveness A1 and fixing adhesiveness A2 may be substantially the same. That is, when the surface roughness of the holding surface 3a (hereinafter referred to as “holding surface roughness”) is SR1, and the surface roughness of the fixing surface 3b (hereinafter referred to as “fixing surface roughness”) is SR2, the holding surface 3a is held. The circuit board holding layer 3 may be formed so that the surface roughness SR1 and the fixed surface roughness SR2 are substantially the same.

On the other hand, when the holding area S1 = the fixing area S2 or the difference between the holding area S1 and the fixing area S2 is small, the holding adhesiveness A1 << the fixing adhesiveness A2 must be satisfied. That is, the circuit board holding layer 3 may be formed so that the holding surface roughness SR1 >> the fixed surface roughness SR2. The relationship between the holding adhesiveness A1 (holding surface roughness SR1) and the fixing adhesiveness A2 (fixing surface roughness SR2) can be appropriately determined based on the relationship between the holding adhesive strength F1 and the fixing adhesive strength F2. it can.

  The fixing surface roughness SR22 of the fixing surface 3b corresponds to the surface roughness of the surface 2a of the base board 2, and the holding surface roughness SR1 of the holding surface 3a corresponds to the surface roughness of the mold. Therefore, the surface 2a of the base board 2 is processed so as to have a desired fixed surface roughness SR2 by the same method as that for the mold, and then the fluororesin is molded by molding, thereby forming the base board 2 The circuit board holding layer 3 can be correctly formed and fixed thereon. In addition, although the adhesive surface of the circuit board holding layer 3 prepared in advance may be adhered to the surface 2a of the base board 2 with an adhesive or the like, the above-described method is preferable from the viewpoint of work efficiency.

FIG. 14 shows a more specific example of the circuit board holding jig according to the present invention. Figure 15, X in FIG. 14 - shows the X section. The circuit board holding jig 1 in this example is basically configured in the same manner as the circuit board holding jig 1 shown in FIGS. However, as shown in FIG. 15, in this example, there are positioning pin insertion holes 4 for positioning the circuit board 11 with respect to the base board 2 so as to penetrate the base board 2 and the circuit board holding layer 3. Is provided. Further, means for applying an external force to the circuit board 11 when the circuit board 11 is peeled from the circuit board holding layer 3 through the base board 2 and the circuit board holding layer 3 in the region of the circuit board holding layer 3. For example, a through hole 5 that allows insertion of a pressing pin (not shown) is provided.

  An FPC board 11 is detachably bonded and held on a circuit board holding layer 3 provided on the base board 2. As a result, the FPC board 11 is held in close contact with the base board 2 via the circuit board holding layer 3 with nothing projecting upward, and the FPC board 11 is secured to the base board 2 with flatness secured. And can be handled in the same manner as a general rigid-type electronic circuit board in subsequent electronic component mounting lines.

In addition, it has been experimentally derived that the adhesive force (load required for peeling) necessary for holding the FPC is usually about 300 gf. As can be seen from FIG. 1, an adhesive strength of 300 gf can be obtained very easily.

  The circuit board holding jig of the present invention configured as described above positions the circuit board across the electronic component mounting line for mounting the electronic component on the circuit board including the FPC board and the thin glass epoxy board which is difficult to carry by itself. And holding a circuit board holding jig of a siloxane-free specification, especially for an FPC board lacking flatness and a thin glass epoxy board that is difficult to carry, and holding it flat, It can be said that this works extremely effectively in that various operations in the electronic component mounting line can be performed efficiently.

  The circuit board holding jig according to the present invention positions and holds the circuit board over the electronic component mounting line for mounting the electronic parts on the circuit board including the FPC board and the thin glass epoxy board which is difficult to carry. As a thing, it can be used for the mounting process of a siloxane free specification.

Table showing the relationship between the surface roughness of the fluororesin adhesive layer and silicon resin adhesive layer and the degree of adhesion obtained as a result of the experiment The figure which shows an example of the chemical structure of the fluororesin which has a peroxide bridge | crosslinking structure used for formation of the circuit board holding layer of the circuit board holding jig which concerns on embodiment of this invention The figure which shows the example different from FIG. 2 of the chemical structure of the fluororesin which has a peroxide bridge | crosslinking structure used for formation of the circuit board holding layer of the circuit board holding jig concerning embodiment of this invention The figure which shows the kind of fluororesin which has a peroxide bridge | crosslinking structure used for formation of the circuit board holding layer of the circuit board holding jig concerning embodiment of this invention, and its monomer composition The figure which shows the relationship between cold resistance and methanol resistance of the fluororesin shown in FIG. The figure which shows an example of the chemical structure of the fluororesin which has a polyol crosslinked structure used for formation of the circuit board holding layer of the circuit board holding jig which concerns on embodiment of this invention The figure which shows the kind of fluororesin which has the polyol crosslinked structure used for formation of the circuit board holding layer of the circuit board holding jig concerning embodiment of this invention, and its monomer composition The figure which shows the relationship between cold resistance and methanol resistance of the fluororesin shown in FIG. The figure which shows an example of the chemical structure of the fluorine resin which has a diamine bridge | crosslinking structure used for formation of the circuit board holding layer of the circuit board holding jig which concerns on embodiment of this invention The figure which shows the kind of fluorine-type resin which has a diamine bridge | crosslinking structure used for formation of the circuit board holding layer of the circuit board holding jig concerning embodiment of this invention, and its monomer composition The figure which shows the relationship between cold resistance and methanol resistance of the fluororesin shown in FIG. The perspective view which shows the basic structure of the circuit board holding jig which concerns on embodiment of this invention. Sectional drawing which shows the principal part of the circuit board holding jig shown in FIG. The top view which shows the more concrete structure of the circuit board holding jig which concerns on embodiment of this invention XX sectional view in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Circuit board holding jig 2 Base board 2a Upper surface of circuit board 3 Circuit board holding layer 3a Holding surface 3b Adhering surface 4 Positioning pin insertion hole 5 Through hole 7 Position hole 8 Cream solder 11 Circuit board 12 Electronic component 13 Pattern position mark

Claims (4)

A circuit board holding jig for positioning and holding the circuit board over an electronic component mounting line for mounting electronic parts on the circuit board,
A base board formed in a plate shape and having a base surface;
A circuit board holding layer that is formed of a fluororesin on the base surface and holds the circuit board;
A first holding surface having a first surface roughness is formed on the surface of the circuit board holding layer,
The circuit board holding jig is characterized in that the first surface roughness is selected in the range of Ra average roughness of 0.001 μm to 0.3 μm.   The circuit board holding jig according to claim 1, wherein the circuit board holding layer is formed by a mold having a surface having the first surface roughness. The base surface has a second surface roughness;
The circuit board holding jig according to claim 1, wherein the first surface roughness is equal to or higher than the second surface roughness.   2. The circuit according to claim 1, wherein a positioning pin insertion hole is provided through the base board and the circuit board holding layer to position the circuit board with respect to the base board. Substrate holding jig.

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