KR20120079131A - Method of manufacturing double-sided copper-clad laminate, and pair of copper or copper alloy foil sheets used thereupon - Google Patents

Abstract

This invention provides the manufacturing method of the double-sided copper clad laminated board which suppressed wrinkles and bending, and a set of copper foil used for the manufacturing method. This invention has the 1st process which forms a resin layer on the single side | surface of a 1st copper foil, and the 2nd process which laminates and heats a 2nd copper foil on this resin layer, and obtains a double-sided copper clad laminated board, 1st copper foil Stress σ _A = E _A × E _B / (E _A + E _B ) × (ΔL _A -ΔL _B ) × 1000, and the stress of the second copper foil σ _B = E _A × E _B / (E _A + E _B ) × (ΔL _B − ΔL _A ) × 1000, where σ _Y is the negative value of σ _A and σ _B , where 10 × σ _Y ≦≦ YS _Y It is a manufacturing method using the 1st copper foil and 2nd copper foil which become. However, E _A : Young's modulus in the width direction when hold | maintaining 1st copper foil for 30 minutes at 350 degreeC, cooling to room temperature, then maintaining it again at 350 degreeC for 30 minutes, and ΔL _A : width of 1st copper foil Directional change rate of dimension, YS _Y : It is set as the 0.2% yield strength of copper foil in a tensile test.

Description

METHOD OF MANUFACTURING DOUBLE-SIDED COPPER-CLAD LAMINATE, AND PAIR OF COPPER OR COPPER ALLOY FOIL SHEETS USED THEREUPON}

This invention is used for a flexible wiring board (FPC: Flexible Printed Circuit), for example, The manufacturing method of the double-sided copper clad laminated board by which copper or copper alloy foil was laminated | stacked on both surfaces of the resin layer, and one set of it used for it It relates to copper or copper alloy foil.

Examples of the copper clad laminate (CCL) used for the flexible wiring board (FPC) include a single-sided copper clad laminate in which copper foil is laminated on one side of the resin layer, and a double-sided copper clad laminate in which copper foil is laminated on both sides of the resin layer (hereinafter referred to as "double-sided CCL"). ) Is used. The circuit formed on the double-sided CCL is a double-sided flexible wiring board, and the use of the double-sided CCL tends to increase due to the fact that finer circuits and space savings of the FPC can be easily realized.

As a manufacturing method of such a double-sided CCL, the varnish of a resin composition is cast on the single side | surface of copper foil, and the method of thermopressing another copper foil on the resin surface after heat-hardening is known (patent document 1). Moreover, the method opposite to copper foil on the front and back of the polyimide film which has a thermoplastic polyimide layer on both surfaces simultaneously, and thermocompression bonding copper foil on the single side | surface of the polyimide film which has a thermoplastic polyimide layer, the opposite side to copper foil The resin surface on the opposite side to copper foil after apply | coating a thermoplastic polyimide layer to the polyimide film surface of this, and heat-compressing another copper foil on the surface, and casting varnish which is a precursor of polyimide to one side of copper foil, and hardening | curing And a method of forming a thermoplastic polyimide layer on the surface, and thermocompression bonding other copper foil on the surface thereof.

Japanese Patent Application Laid-Open No. 05-212824

Here, except the case where copper foil is laminated simultaneously on both surfaces of a resin layer (the said polyimide film etc.), the copper foil (1st copper foil) laminated | stacked for the first time is the temperature of 300 degreeC or more at the time of initial lamination | stacking. It is heated to once and cooled. Moreover, when laminating | stacking another copper foil (2nd copper foil) on the opposite surface of a resin layer after that, the 1st copper foil is also reheated similarly and is cooled.

However, after laminating | stacking and heating a 2nd copper foil, when cooling, wrinkles and bending may arise in parallel in the longitudinal direction of a 1st copper foil, and usually in the width direction center position. It is difficult to completely eliminate this wrinkle and bending, even if it adjusts the lamination conditions of 2nd copper foil, or the heating conditions (thermal crimping conditions, tension | tensile_pressure, etc.) at the time of lamination | stacking. And since the heat history at the time of lamination | stacking applied to a 1st copper foil and a 2nd copper foil differs, such wrinkles and bending are due to the temperature change at the time of cooling after laminating | stacking and heating a 2nd copper foil. It is thought that it arises when the dimensional change rate of both copper foil which exists across a resin layer differs, and copper foil cannot tolerate the stress which arises by it.

That is, this invention was made | formed in order to solve said subject, and an object of this invention is to provide the manufacturing method of the double-sided copper clad laminated board which suppressed wrinkles and bending, and the set of copper or copper alloy foil used for it.

MEANS TO SOLVE THE PROBLEM As a result of various examinations, when manufacturing double-sided CCL, even if stress generate | occur | produced by the difference of the dimensional change of both copper foils, by adjusting the characteristic of both copper foils so that a copper foil does not bend, wrinkles and bending are suppressed. I found something I could do.

In order to achieve the said objective, the manufacturing method of the double-sided copper clad laminated board of this invention provides the 1st process of forming a resin layer in the single side | surface of 1st copper or copper alloy foil, and obtaining a single-sided copper clad laminated board, and the said single-sided copper clad laminated board. the resin layer side by heating by laminating a second copper or copper alloy foil and a second step for obtaining a double-sided copper-clad laminate, wherein the first copper or copper stress of the alloy foil _{σ a = E a × E B} / (E a + E _B ) × (ΔL _A -ΔL _B ) × 1000, and the stress σ _B = E _A × E _B / (E _A + E _B ) × (ΔL _B -ΔL _{A of} the second copper or copper alloy foil ) as × 1000, and when the side of the σ _a and σ _B of the portion (負) as _{σ Y, | 10 × σ Y} | ≤ YS Y is, the first copper or copper alloy foil and the second copper Or copper alloy foil is used.

However, E _A : Young's modulus in the width direction when the said 1st copper or copper alloy foil is hold | maintained at 350 degreeC for 30 minutes, cooled to room temperature, and then maintained again at 350 degreeC for 30 minutes, and cooled to room temperature (unit is ㎬), E _B : Young's modulus in the width direction when the second copper or copper alloy foil was kept at 350 ° C. for 30 minutes and cooled to room temperature (unit: kPa), ΔL _A : The temperature was raised to 350 ° C. at room temperature, and maintained for 30 minutes. Based on the dimension at the time of cooling to room temperature, it hold | maintains again at 350 degreeC for 30 minutes, and the rate of dimensional change of the width direction of the said 1st copper or copper alloy foil after cooling to room temperature (unit is ppm, shrinkage of positive) Value), ΔL _B : the rate of dimensional change in the width direction of the second copper or copper alloy foil after being heated to 350 ° C. at room temperature, held for 30 minutes, and cooled to room temperature (unit is ppm, shrinkage being a positive value) , YS _Y ： In tensile test YS _A (unit is MPa) is selected if the negative side of σ _A and σ _B is _A, and YS _B (unit is MPa), otherwise YS _A : Tension 0.2% yield strength of the said 1st copper or copper alloy foil in a test, YS _B : 0.2% yield strength of the said 2nd copper or copper alloy foil in a tensile test

Copper or copper alloy foil of one set of this invention is used for the manufacturing method of the said double-sided copper clad laminated boards, and consists of a combination of the said 1st copper or copper alloy foil, and the said 2nd copper or copper alloy foil.

In one set of copper or copper alloy foil of the present invention, it is preferable that ΔL _B of the second copper or copper alloy foil is 145 ppm or less.

According to this invention, when manufacturing a double-sided copper clad laminated board, wrinkles and a bending of copper or copper alloy foil can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the manufacturing method of the double-sided copper clad laminated board which concerns on embodiment of this invention.
It is sectional drawing which shows the structural example of a double-sided copper clad laminated board.
It is a figure which shows the state which wrinkles (bending) generate | occur | produce in 1st copper or copper alloy foil by the heat applied at the time of manufacture of a double-sided copper clad laminated board.

Hereinafter, the manufacturing method of the double-sided copper clad laminated board which concerns on embodiment of this invention is demonstrated. In addition, in this invention,% shall represent the mass% unless there is particular notice. 1 shows a method for producing the double-sided copper clad laminate 8.

In FIG. 1, first, the coil-shaped 1st copper foil 4 is unwound continuously, and the application roll 10, 11, etc. are made to the single side | surface of the unwound 1st copper or copper alloy foil 4, and so on. The varnish-like resin composition (2a) is continuously applied to a predetermined thickness using a. The resin composition (2a) becomes the resin layer (2) after hardening. Next, the 1st copper or copper alloy foil 4 which apply | coated the resin composition 2a is introduce | transduced into the drying apparatus 15, and the resin composition 2a is hardened (or semi-hardened). In this way, a resin layer is formed on one side of the first copper or copper alloy foil 4 to obtain a one side copper clad laminate (first step). Here, after completion | finish of a 1st process, it may wind up in a coil form and may advance to a 2nd process. In addition, although heating is carried out when forming a resin layer on the single side | surface of the 1st copper or copper alloy foil 4, it heats after apply | coating the above-mentioned resin composition, and it is already made into a resin layer like a resin film, for example. May be thermocompression-bonded to one surface of the first copper or copper alloy foil 4. Moreover, normally, the heating temperature in a 1st process becomes temperature more than the heating temperature in a 2nd process. Next, the coil 2nd copper or copper alloy foil 6 is unwound continuously, for example, 350? The 1st copper or copper alloy foil 4 and the 2nd copper or copper alloy foil 6 are continuously passed through between the lamination rolls 20 and 21 heated at 400 degreeC. At this time, the second copper or copper alloy foil 6 is laminated and heated on the resin layer 2 side of the first copper or copper alloy foil 4 to obtain a double-sided copper clad laminate 8 (second step) . The double-sided copper clad laminate 8 is appropriately wound by a coil.

And as shown in FIG. 2, the double-sided copper clad laminated board 8 is comprised by laminating | stacking the 2nd copper or copper alloy foil 6 on the resin layer 2 side of the 1st copper or copper alloy foil 4. .

As the 1st copper or copper alloy foil 4 and the 2nd copper or copper alloy foil 6, For example, pure copper, tough pitch copper (JIS-1100), oxygen-free copper (JIS-1020), Sn and / or Ag are added to these pure copper, tough pitch copper, and oxygen-free copper in total at 40? The thing which added 2000 mass ppm is mentioned. Here, when both the composition of the 1st copper or copper alloy foil 4 and the 2nd copper or copper alloy foil 6 contain Sn and / or Ag more than 400 ppm in total, flexibility is required. If either of the foils 4, 6 contains more than 400 ppm of Sn and / or Ag in total, the foil is removed by etching from the double-sided CCL and the other foil is left. Flexibility does not deteriorate. The thickness of the 1st copper or copper alloy foil 4 and the 2nd copper or copper alloy foil 6 is 6? It can be about 18 micrometers. Although the composition of the 1st copper or copper alloy foil 4 and the 2nd copper or copper alloy foil 6 may differ, normally, the thing of the same composition is used. The first copper or copper alloy foil 4 and the second copper or copper alloy foil 6 may be rolled foil or an electrolytic foil.

As the resin layer 2, although thermoplastic resins, such as polyimide, PET (polyethylene terephthalate), an epoxy resin, a phenol resin, and saturated polyester resin, can be used, It is not limited to these. Moreover, the varnish (for example, the polyamic-acid solution of a polyimide precursor) which melt | dissolved the components of these resin layers in the solvent is apply | coated to the single side | surface of the 1st copper or copper alloy foil 4, and it heats, removes a solvent, and reacts ( For example, you may advance and harden imidation reaction. The thickness of the resin layer 2 is 1? It may be about 15 µm.

Next, the characteristic of the 1st copper or copper alloy foil 4 which is a characteristic part of this invention, and the 2nd copper or copper alloy foil 6 is demonstrated.

After forming a resin layer on the single side | surface of the 1st copper or copper alloy foil 4, when laminating | stacking 2nd copper or copper alloy foil 6 and manufacturing double-sided CCL, two copper or copper which sandwiched resin was sandwiched. The stress produced by the difference in the dimensional change of the alloy foils 4 and 6 is shown below.

First of all, the temperature T ₁ (T ₁ It is first laminated on both sides of CCL at a heating temperature at the time of laminating a second copper or copper alloy foil (6)), T ₂ In the case where it is cooled to, the stress σ _A applied to the first copper or copper alloy foil 4 is

σ _A = E _A × E _B / (E _A + E _B ) × (α _B × (T ₁ -T ₂ ) + ΔL _B- (α _A × (T ₁ -T ₂ ) + ΔL _A )) × 1000 (1). In addition, dimensional change (DELTA) makes shrinkage positive, and makes it a change of the width direction (coil width direction at the time of manufacturing CCL continuously from the coil of copper or copper alloy foil).

Here, since the copper or copper alloy foil used for CCL is close to pure copper, thermal expansion coefficient (alpha) (subscripts A and B are 1st copper or copper alloy foil (4), 2nd copper or The copper alloy foil 6) can be considered to be the same (α _A ≒ α _B ). Therefore, Equation 1 is

sigma _A = E _A x E _B / (E _A + E _B ) x (ΔL _A -ΔL _B ) x 1000 (2).

However, E _A : said 1st copper or copper by the 1st heat history which hold | maintains the said 1st copper or copper alloy foil at 350 degreeC for 30 minutes, and then cooled to room temperature, and then maintains it again at 350 degreeC for 30 minutes and cools to room temperature the Young's modulus in the width direction of the alloy foil (in ㎬), E _B: the second copper or copper alloy foil to and maintained at 350 ℃ 30 bungan to cool to room temperature, a second thermal history and the second copper or copper alloy foil according to the Young's modulus in the width direction of the unit (㎬), ΔL _A : Based on the dimension when it heated up at 350 degreeC at room temperature, hold | maintained for 30 minutes, and cooled to room temperature, it hold | maintained again at 350 degreeC for 30 minutes, and the dimension of the width direction of the said 1st copper or copper alloy foil after cooling to room temperature Rate of change (units are ppm, shrinkage is positive), ΔL _B : It is the temperature change rate from room temperature to 350 degreeC, hold | maintains for 30 minutes, and is the dimension change rate (unit is ppm, shrinkage as a positive value) of the width direction of the said 2nd copper or copper alloy foil after cooling to room temperature.

In addition, room temperature is 25? 35 ° C. (typically 25 ° C.).

That is, if the Young's modulus of both copper or copper alloy foils 4 and 6 is made small, and the difference (ΔL _A -ΔL _B ) of the dimensional change rate of copper or copper alloy foils 4 and 6 is made small, stress σ _A will become It becomes small, and wrinkles and bending at the time of manufacture of double-sided CCL are hard to occur.

Here, even if the same thing is used for both copper or copper alloy foils 4 and 6, the difference (ΔL _A -ΔL _B ) of the dimensional change rate occurs, and it is clear that this difference is not due to thermal expansion. When heat is applied to the metal, a change in the structure such as recrystallization or recovery occurs. Therefore, when the metal is heated and cooled, it becomes shorter (heat shrinkage) or longer (heat extension) than the original dimension. Moreover, even if it heats and cools the metal once heated and cooled again below the same temperature, neither heat shrink nor thermal expansion will arise. In addition, these phenomena occur in either of the rolled foil and the electrolytic foil, but the rolled foil has a large deformation due to rolling, and depending on the component of the foil, recrystallized structure in the rolled structure due to the heat applied at the time of manufacturing CCL. Heat shrink or heat elongation is increased.

FIG. 3 shows a state in which the above-described thermal elongation or heat shrinkage occurs due to the heat applied at the time of CCL production, and wrinkles (bending) 100 are generated in the first copper or copper alloy foil 4.

First, when manufacturing a single-sided copper clad laminate in the first step, when the first copper or copper alloy foil 4 is heated and cooled, it is heat shrinked smaller than the original length. Next, when manufacturing a double-sided copper clad laminated board in the said 2nd process, when 2nd copper or copper alloy foil 6 is heated and cooled, it will try to heat shrink smaller than the original length (arrow of FIG. 3). On the other hand, the first copper or copper alloy foil 4 which has already been heat shrinked in the first step is hardly heat shrinked in the second step (arrow of FIG. 3).

Therefore, at the time of cooling after the heating in a 2nd process, compressive stress is applied to the 1st copper or copper alloy foil 4 by the force which the 2nd copper or copper alloy foil 6 is about to shrink | contract. And the 1st copper or copper alloy foil 4 bends without wrinkles (compression and bending generate | occur | produce).

However, in the case where compressive stress is applied to the first copper or copper alloy foil 4 side, if the proof strength of the copper foil is greater than the compressive stress (σ _{A in} Equation 2), it does not bend, so that wrinkles and bending do not occur easily. do. Usually, although the strength with respect to the compression of a copper foil cannot be calculated | required, the boundary value of whether it bends can be substituted by the strength of bearing YS against tension. That is, when 1st copper or copper alloy foil 4 is selected so that YS may be more than (sigma) _A , it is thought that wrinkles and bending do not arise.

And the present inventors calculated | required the conditions which a wrinkle and bending do not produce when manufacturing a double-sided copper clad laminated board by experiment, As a result, about (sigma) _A of Formula (2),

10 × σ _A | ≤ YS _A (3)

When the 1st copper or copper alloy foil 4 was selected so that it might become it, it turned out that wrinkles and a bending do not arise easily.

On the other hand, when compressive stress is applied to 2nd copper or copper alloy foil 6, with respect to (sigma) _B of Formula 2,

| 10 × σ _B | ≤ YS _B (4)

When the 2nd copper or copper alloy foil 6 was selected so that it might become this, it turned out that wrinkles and a bending do not arise easily. However, it is common for compressive stress to be applied to the 1st copper or copper alloy foil 4.

In order to satisfy Equation 3 (or Equation 4), σ _A (σ _B ), that is, the difference in dimensional change rate (ΔL _A) -The smaller the ΔL _B ) is, the better the difference between the heat received by the first copper or copper alloy foil 4 in the first step and the heat received by the second copper or copper alloy foil 6 in the second step. It becomes preferable. Moreover, the smaller the deformation which the 1st copper or copper alloy foil 4 receives in a 1st process, the difference in dimensional change rate ((DELTA) L _A ΔL _B ) is also reduced.

In this regard, as a specific method for satisfying the equations 3 and 4, 1) heating the first copper or copper alloy foil 4 and the second copper or copper alloy foil 6 in advance, 2) the first copper or In the case where the copper alloy foil 4 and the second copper or copper alloy foil 6 are rolled foils, rolling is carried out at a low porosity, and 3) excessively excessive tension in rolling is set from the thickness and mechanical properties of the foils. The thing which does not, 4) using an electrolytic foil for the 1st copper or copper alloy foil 4, and the 2nd copper or copper alloy foil 6 is mentioned. However, considering that it is common to apply compressive stress to the first copper or copper alloy foil 4 side, the methods of 1) to 4) may be performed only on the second copper or copper alloy foil 6.

In the method of 1) above, pure copper is a metal having a face-centered cubic structure. It is known that when recrystallized by heating, a cubic orientation develops and the bendability is improved. The copper foil with the cubic orientation developed has a low Young's modulus and a low 0.2% yield strength in the tensile test. That is, it can be said that the copper foil in which such a cubic orientation developed developed that bending and wrinkles are most likely to occur at the time of manufacturing the double-sided CCL (when performing the second step). For example, when the pure copper foil was kept at 350 ° C. for 30 minutes and cooled, it was found in the experiments of the present inventors that the Young's modulus was about 70 GPa and the 0.2% yield strength was about 50 MPa. Thus, even if it heats and cools small copper or copper alloy foil to about 350 degreeC again, it is thought that a dimensional change is almost zero.

Thus, the first to the copper or copper alloy foil (4), and a second copper or copper alloy foil (6) using the same _{(E A ≒ E B, |} σ A | ≒ | σ B |), ΔL A When approximating to ≒ 0, equation 2 is

σ _A = (E _A × ΔL _B ) / 2 × 1000 (5)

. And from equation 3 and equation 5,

｜ 10000 × (E _A × ΔL _B X / 2) | ≤ YS _A (6)

ΔL _B = 143 (ppm) is obtained by substituting E _A = 70 kHz and YS _A = 50 MPa from the above experimental result into the equation (5). That is, at least the 2nd copper or copper alloy foil 6 is heated before use, and if it uses what is (DELTA) L < _{B =} 143 (ppm), it will have flexibility, and bending and wrinkles will not arise easily. Heating conditions of the 2nd copper or copper alloy foil 6 are 50 degreeC? 1 second at 200 ℃? Although it may be about 10 hours, it is not limited to this. For example, the heating conditions include a 3 hour hold at 60 ° C and a 3 second hold at 130 ° C. Of course, the 0.2% when strength is using a high copper foil, but even if L _B exceeds 143 ppm, the 0.2% on either side of the copper or copper alloy foil (4), and a second copper or copper alloy foil (6) Strength When this high copper foil is used, flexibility cannot be obtained. Therefore, it is preferable to use one having ΔL _B ≦ 143 (ppm) on the second copper or copper alloy foil 6 side.

Next, about the method of said 2), the deformation | transformation of a rolled foil changes with the rolling work degree after final annealing, the rolling reduction of one pass, tension, processing temperature, etc. However, it is difficult to define the amount of reduction and tension uniformly depending on the thickness of the foil to be processed and the performance of the rolling mill. In addition, the deformation becomes smaller as the processing temperature is higher, but the rolling oil plays a role of the coolant during rolling, and it is difficult to define the instantaneous processing temperature.

Therefore, the conditions required for foil with a rolling workability are prescribed | regulated. If the rolling degree is made small, the deformation of the foil becomes small. However, since the cube orientation becomes difficult to develop and the flexibility decreases when recrystallization, it is not preferable. On the other hand, if the crystal grain diameter before rolling is made small, a cube orientation will develop even if it rolls with the same process degree. Based on the above findings, the present inventors have conducted the final cold rolling work as long as R (%) was 93.0 ≤ R, and the average grain size GS (µm) after the final annealing was GS ≤ 3.08 × R-260. It has been found that it is possible to suppress the occurrence of bending and wrinkles without inhibiting the stiffness. In addition, when using double-sided CCL in a bending part, the copper foil of either one (the inferior bendability) is removed by etching, and since only a curved part is set to single-sided CCL type | mold, 1st copper or copper alloy foil 4 And any of the second copper or copper alloy foils 6 may satisfy the above formula (GS ≦ 3.08 × R−260).

In addition, the said Formula 1? Equation 3 is a formula when compressive stress occurs on the first copper or copper alloy foil 4 side, and in general, stress σ _A = E _A × E _B / (E _A + of the first copper or copper alloy foil E _B ) × (ΔL _A −ΔL _B ), and the stress σ _B = E _A × E _B / (E _A + E _B ) × (ΔL _B ? ΔL _A ) of the second copper or copper alloy foil, When the negative side of σ _A and σ _B is σ _Y , | 10 × σ _Y | ≤ YS _Y 1st copper or copper alloy foil and 2nd copper or copper alloy foil are selected so that it may become.

YS _Y ： YS _A (unit is MPa) is selected if the negative side of σ _A and σ _B is _A, and YS _B (unit is MPa), otherwise YS _A : Tensile wherein said 0.2% proof stress of the copper or copper alloy foil in the test, YS _B: a second copper or 0.2% proof stress of the copper alloy foil in a tensile test.

Example

The double-sided CCL was manufactured as shown in FIG. 1, combining the 1st copper foil 4 and the 2nd copper foil 6 of the composition shown in Table 1. Where is Experimental Example 1? 3, 10, the comparative examples 1, and 2 made the 1st copper foil 4 and the 2nd copper foil 6 the same. The experimental example and the comparative example other than that used the copper foil different from the 1st copper foil 4 and the 2nd copper foil 6, respectively. In Table 1, in Experimental Example 6, since compressive stress was applied to the second copper foil 6 side and sigma _B was added, sigma _B became sigma _Y , and between | 10 × sigma _Y | and YS _Y Evaluated the magnitude. In other experimental examples and comparative examples, since the compressive stress was applied to the first copper foil 4 and σ _A was added, σ _A became σ _Y , and the magnitude between 사이 10 × σ _Y ｜ and YS _Y was reduced. Evaluated.

In addition, some copper foil adjusted the average grain size GS and workability R as shown in Table 1, and performed preheat treatment. In addition, although preliminary heat processing was performed after the following chemical processing (plating), you may perform after final rolling or just before CCL manufacture.

First, the single side | surface of the 1st copper foil 4 was chemically treated (plated), and the precursor varnish (U-heungsan-made U- varnish A) of polyimide resin was apply | coated to this surface so that it might be set to thickness of 25 micrometers. Thereafter, the mixture was dried for 30 minutes in a hot air circulation type high temperature bath set at 130 ° C, gradually heated to 350 ° C over 2000 seconds, cured (imidized) to form a resin layer (2), and single sided CCL was produced. . Next, after apply | coating a thermoplastic polyimide (adhesive layer) to the resin side surface of single sided CCL, and drying it, the 2nd copper foil 6 was laminated | stacked and thermally crimped for 10 minutes by the press heated at 350 degreeC, and double-sided CCL was manufactured. Thereafter, the double-sided CCL was cooled to room temperature, and the occurrence of bending and wrinkles was visually determined.

ΔL _A and ΔL _B Cut the 1st copper foil 4 and the 2nd copper foil 6 into 150 mm in the width direction, and 12.5 mm in the length direction, respectively, and the mark of 80 mm of rating intervals with a Vickers hardness tester. Iii), the distance L before applying heat was calculated | required by measuring the coordinates of both attritions. In addition, in the case of the copper foil sample previously heat-treated before lamination, the distance was similarly calculated | required after this heat processing. Next, after hold | maintaining a sample for 30 minutes in 350 degreeC oven, it took out, and after cooling to room temperature, the coordinates of both pins were measured and distance L 'was calculated | required. ΔL _A and ΔL _B Can be calculated as (L-L ') / L, respectively, and shrinkage becomes a positive value. Further, from the definitions of ΔL _A and ΔL _B , ΔL _A Once the temperature was raised to 350 deg. C at room temperature, the dimension at the time of holding for 30 minutes and cooling to room temperature was set to L, and the coordinates of both marks when heated again were set to L '.

Moreover, Young's modulus E _A and E _{B of} the 1st copper foil 4 and the 2nd copper foil 6 Is obtained by the vibration method according to JIS-Z2280-1993, 0.2% yield strength YS _A , YS _B Was calculated | required according to JIS-Z2241-1998 using the tensile tester.

Flexibility was evaluated as follows. First, any one of the 1st copper foil 4 or the 2nd copper foil 6 is removed using the photolithographic technique already known, the wiring of 200 micrometers of circuit widths is formed in the other copper foil, and the wiring The polyimide film to which the epoxy type adhesive agent was apply | coated was thermo-compressed as a coverlay, and the FPC for bending test was produced. At this time, the thickness of the resin layer 2 was 15 micrometers, the coverlay was 12.5 micrometers, and the thickness of the contact bonding layer on copper foil was 2.5 micrometers. In addition, when using double-sided CCL in a bending part, the copper foil of either one (the inferior bendability) is removed by etching, and only a curved part is set to single-sided CCL type, The 1st copper foil 4 or 2nd The test at the time of removing one side of the copper foil 6 was performed.

The bending test used the IPC (American Printed Circuit Industry Association) sliding bending tester, and the bending radius was 1.5 mm when the copper foil thickness was 18 µm, and 1 mm when the copper foil thickness was 12 µm. Flexibility improves as the thickness of the copper foil becomes thinner, so that the bending radius may be changed in accordance with the thickness of the copper foil in order to evaluate the same criteria. Then, 100 repetitive slidings per minute were loaded on the FPC test piece, and the number of bends in which the electrical resistance of the wiring rose 10% from the beginning was used as the end point. Here, the case where this bending frequency | count exceeds 100,000 times was made into good ((circle)), less than 50,000 times were made into bad (x), and 50,000 or more times and less than 100,000 times were determined as usable (△) according to bending conditions. .

The obtained results are shown in Table 1. In addition, in Table 1, "the flexibility of the 1st copper foil of Experimental example 1" shows the evaluation when 2nd copper foil was removed by etching from the double-sided CCL of Experimental example 1, and 1st copper foil was left. .

As is clear from Table 1, in the case of Experimental Examples 1 and 2, which were previously heat-treated to the first copper foil 4 and the second copper foil 6, | 10 x σ _Y | ≤ YS _Y The obtained double-sided CCL had no wrinkles or bends and was excellent in flexibility.

Moreover, also in the case of Experimental Example 3 which adjusted the rolling conditions of the 1st copper foil 4 which is rolled foil, and the 2nd copper foil 6, and made GS <3.08 * R-260 while making R 93.0% or more. , | 10 × σ _Y | ≤ YS _Y The obtained double-sided CCL had no wrinkles or bends and was excellent in flexibility.

On the other hand, Experimental example 4 which used different copper foil for the 1st copper foil 4 and the 2nd copper foil 6? In the case of 9, | 10 x σ _Y | ≤ YS _Y There were no wrinkles or bending in the obtained double-sided CCL. However, the flexibility was different depending on which foil of the first copper foil 4 and the second copper foil 6 was left. For example, in the case of the second copper foil 6 of Experimental Example 6 and the first copper foil 4 of Experimental Example 7, the addition amount of Sn was large (2000 ppm), and the flexibility was inferior. In the case of the 1st copper foil 4 of Experimental Example 8 and the 2nd copper foil 6 of Experimental Example 9, electrolytic copper foil was used without preheating, but bendability was inferior.

Moreover, also in the case of Experimental Example 10 using the same copper foil for the 1st copper foil 4 and the 2nd copper foil 6, | 10 * (sigma) _Y | <= YS _Y There were no wrinkles or bending in the obtained double-sided CCL. However, since both foils were GS> 3.08xR-260, even if any foil was left, the bendability was (triangle | delta).

In the case of the comparative examples 1 and 2, since the combination of foil was not suitable, | 10 * σ _Y |> YS _Y Wrinkles and bending occurred in the obtained double-sided CCL.

Moreover, since the rolling conditions became GS> 3.08 * R-260, in the case of the comparative example 3 which used the tough pitch copper which is a commercial item as it was for the 1st copper foil 4 and the 2nd copper foil 6, flexibility is inferior lost.

2: resin layer
2a: resin composition
4: first copper or copper alloy foil
6: 2nd copper or copper alloy foil
8: double-sided copper clad laminate

Claims (3)

The 1st process of forming a resin layer in the single side | surface of 1st copper or copper alloy foil, and obtaining a single-sided copper clad laminated board, and laminating | stacking and heating a 2nd copper or copper alloy foil in the said resin layer side of the said single-sided copper clad laminated board, and double-sided copper sheet As a manufacturing method of a double-sided copper clad laminated board which has a 2nd process of obtaining a laminated board,
Stress σ _A of the first copper or copper alloy foil is set to E = E _A x E _B / (E _A + E _B ) x (ΔL _A -ΔL _B ) × 1000, and stress σ of the second copper or copper alloy foil _{When B} = E _A x E _B / (E _A + E _B ) x (ΔL _B -ΔL _A ) × 1000 and the negative side of σ _A and σ _B is σ _Y , | 10 × σ _Y | ≤ YS _Y Become,
(However, E _A : Young's modulus in the width direction when the first copper or copper alloy foil is maintained at 350 ° C. for 30 minutes and cooled to room temperature, and then maintained at 350 ° C. for 30 minutes and cooled to room temperature (unit is ㎬) ,
E _B : Young's modulus in the width direction when the second copper or copper alloy foil was kept at 350 ° C. for 30 minutes and cooled to room temperature (unit is ㎬),
ΔL _A : The width direction of the first copper or copper alloy foil after the temperature was raised to 350 ° C. at room temperature, held for 30 minutes, and maintained at 350 ° C. for 30 minutes based on the dimensions when cooled to room temperature again. Rate of change of dimensions (unit is ppm, shrinkage is positive),
ΔL _B : The rate of dimensional change in the width direction of the second copper or copper alloy foil after being heated to 350 ° C. at room temperature, held for 30 minutes, and cooled to room temperature (unit is ppm and shrinkage is defined as a positive value),
YS _Y : With 0.2% yield strength in tensile test, select YS _A (unit is MPa) if the negative side of σ _A and σ _B is A, otherwise select YS _B (unit is MPa).
YS _A : 0.2% yield strength of said 1st copper or copper alloy foil in a tensile test,
YS _B : 0.2% yield strength of said 2nd copper or copper alloy foil in a tensile test)
The manufacturing method of the double-sided copper clad laminated board which uses the said 1st copper or copper alloy foil and the said 2nd copper or copper alloy foil. It is used for the manufacturing method of the double-sided copper clad laminated board of Claim 1, One set of copper or copper alloy foil which consists of a combination of the said 1st copper or copper alloy foil, and the said 2nd copper or copper alloy foil. The method of claim 2,
ΔL _B of the second copper or copper alloy foil 1 set of copper or copper alloy foil whose value is 145 ppm or less.

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