KR20080013355A - Metallic laminate and method for preparing thereof - Google Patents

Abstract

A metallic laminate and a manufacturing method thereof are provided to install a COF(Chip On Film) chip even at fine pitch below 40 micrometers by optimizing a process window by using a polyimide resin layer. A metallic laminate is composed of: a metal layer; a low thermal expansion polyimide resin layer laminated on the metal layer and provided with a thermal expansion coefficient below 20ppm/deg.C; and a high thermal expansion polyimide resin layer laminated on the low thermal expansion polyimide resin layer and provided with a thermal expansion coefficient over 20ppm/deg.C. The thermal expansion coefficient of an MD(Machine Direction) of the low thermal expansion polyimide resin layer is 16~19ppm/deg.C and the thermal expansion coefficient of a TD(Transverse Direction) is 17~20ppm/deg.C.

Description

Metal lamination and manufacturing method thereof {METALLIC LAMINATE AND METHOD FOR PREPARING THEREOF}

1 is a good photograph of the position shift does not occur during chip mounting.

2 is a photograph of a non-defective product in which position shift does not occur during chip mounting.

3 is a photograph in which position shift occurs at the time of chip mounting.

4 is a photograph showing a position shift when mounting a chip.

The present invention relates to a metal laminate and a method of manufacturing the same, and more particularly, to a metal laminate and a method of manufacturing the same that can minimize the displacement between the bump portion and the inner lead during chip mounting.

Recently, with the rapid development of the degree of integration of semiconductor integrated circuits and the development of surface-mounting technology for directly mounting small chip components, the thin and light reduction of electronic products is rapidly progressing, and thus, in electronic products rather than conventional rigid printed circuit boards. BACKGROUND OF THE INVENTION The use of flexible printed circuit boards that are easy to install in a space is becoming common.

In general, metal laminates for printed circuit boards used in large LCDs (liquid crystal displays) are required to have excellent reliability and chemical resistance in terms of dimensional stability against temperature change, adhesion, and planarity before and after etching.

In addition, the higher density required than the conventional flexible printed circuit (Flexible Printed Circuit) is required because the narrow line width is required, due to such characteristics, the copper foil is thin, the polyimide layer has a structural characteristic that is thick.

As a result, the circuit line width having a density of 40 μm or less has a pitch of 40 μm or less, resulting in a defect caused by displacement between the bump part and the inner lead during chip mounting. In particular, in the case of a three-layer substrate, when the misalignment occurs, the inner lead is pushed into the adhesive layer, and even if a slight misalignment occurs during chip mounting due to the bias, a short circuit or a short circuit occurs between the neighbors. Can be.

An object of the present invention is to provide a metal laminate and a method of manufacturing the same that can minimize the displacement between the bump portion and the inner lead during chip mounting.

The present invention provides a metal layer, a low thermal expansion polyimide resin layer having a thermal expansion coefficient of 20 ppm / ° C. or less laminated on the metal layer, and a high thermal expansion polyimide resin layer having a thermal expansion coefficient of 20 ppm / ° C. or more laminated on the low thermal expansion polyimide resin layer. To include, the low thermal expansion polyimide resin layer of the thermal expansion coefficient of the MD (Machine Direction) direction of 16 to 19ppm / ℃, the thermal expansion coefficient of the TD (Transverse Direction) direction to provide a metal laminate plate do.

The present invention,

a) low thermal expansion polyimide having a thermal expansion coefficient of 20 ppm / ° C. or lower, a thermal expansion coefficient of 16 to 19 ppm / ° C. in the MD direction, and a thermal expansion coefficient of 17 to 20 ppm / ° C. in the TD direction using a polyimide precursor solution on the metal layer; Forming a layer; And

b) forming a high thermal expansion polyimide layer having a thermal expansion coefficient of 20 ppm / ° C. or more using a polyimide precursor solution on the low thermal expansion polyimide layer.

The present invention provides a printed circuit board including the metal laminate.

Hereinafter, the present invention will be described in detail.

In the metal laminate according to the present invention, the thermal expansion coefficient of the polyimide resin layer directly laminated on the metal layer is 20 ppm / ° C. or lower, the thermal expansion coefficient in the MD direction is 16 to 19 ppm / ° C., and the thermal expansion coefficient in the TD direction is 17 to 20 ppm / ° C. It is characterized by the above-mentioned.

Here, MD direction means the movement direction (vertical direction) on the machine which manufactures the said polyimide resin layer at the time of manufacture of a polyimide resin layer, and TD direction means its vertical direction (lateral direction).

In the present invention, the thermal expansion coefficient in the MD direction of the low thermal expansion polyimide resin layer is 16 to 19 ppm / ° C., and the thermal expansion coefficient in the TD direction is 17 to 20 ppm / ° C., thereby optimizing the process window during chip mounting, between the bump part and the inner lead. Position shift can be minimized, and chip mounting can be performed even at intervals between inner leads according to densification of a printed circuit board, that is, a fine pitch of 40 μm or less.

In addition, in the case of Dimensional Stability of the polyimide resin layer including the low thermally expandable polyimide resin layer and the high thermally expandable polyimide resin layer, the MD direction and the TD direction in the stage B (the numerical stability of the metal laminate due to the metal layer removal) The difference in expansion rate is 0.03% or less, and it is preferable that the expansion rate difference in the MD direction and the TD direction is also 0.03% or less in Stage C (the numerical stability of the metal laminate due to heat). When the expansion ratio difference in the MD and TD directions exceeds 0.03%, a position shift may occur between the bump and the inner lead when the chip is mounted, and a short circuit or short circuit may occur. The stretch rate of the present invention was measured by the method of measuring the tensile stretchability described in the IPC-FC-241C regulation book.

Stage B measurement method according to the IPC-FC-241C regulation book,

a) After cutting the polyimide resin of the present invention into 27 cm x 29 cm to prepare a specimen, the upper left portion is made by drawing a line or making a hole at a position of 1.25 cm in the horizontal direction and 1.25 cm in the vertical direction from the edge of the specimen. From A, B, C and D, respectively;

b) measuring the distance of each of A, B, C, D after stabilizing the prepared specimen at 23 ± 2 ° C., 50 ± 5% RH for 24 hours;

c) After etching, except for the target portion of the specimen prepared above, for example, a square portion of 13 cm x 13 cm from the center portion, it is washed and dried. After stabilizing the specimen at 23 ± 2 ° C., 50 ± 5% RH for 24 hours, measuring the distance of A, B, C, and D, respectively.

d) The measurement method of Stage C is also left for 30 ± 2 minutes in an oven at 150 ± 2 ° C. for 30 hours at 23 ± 2 ° C. and 50 ± 5% RH after the specimens used in Stage B are above A, B, C D, measuring the distance of each.

The elasticity of the MD and TD directions may be calculated by substituting the measured value into Equation 1 below.

[Equation 1]

Where I is the value measured in step b) and F is the value measured in step c) or d).

In the present invention, the thermal expansion coefficient of the low thermal expansion polyimide resin layer is preferably 5 to 20 ppm / ° C, and the thermal expansion coefficient of the high thermal expansion polyimide resin layer is preferably 30 to 50 ppm / ° C.

In the present invention, the sum of the low thermally expandable polyimide resin layer and the high thermally expandable polyimide resin layer thickness is preferably 30 to 50 µm.

The low thermally expandable polyimide resin layer and the high thermally expandable polyimide resin layer of the present invention are prepared by a polyimide precursor solution, and the polyimide precursor solution is preferably in the form of a varnish in which an dianhydride, diamine and an organic solvent are mixed. The dianhydride and diamine are preferably mixed in a molar ratio of 1: 0.9 to 1: 1.1.

Specific examples of the dianhydride include PMDA (pyromellitic dianhydride), BPDA (3,3 ', 4,4'-biphenyltetracarboxylic dianhydride) and BTDA (3,3', 4,4 '). Benzophenonetetracarboxylic dianhydride) may be used, but is not limited thereto.

Specific examples of the diamine include p-PDA (p-phenylenediamine), m-PDA (m-phenylenediamine), 4,4'-ODA (4,4'-oxydianiline), 3,4'- ODA (3,4'-oxydianiline), TPE-R (1,3-bis (4-aminophenoxy) benzene), BAPP (2,2-bis (4- [4-aminophenoxy] -phenyl ) Propane) and HAB (3,3'-dihydroxy-4,4'-diaminobiphenyl) may be used, but is not limited thereto.

The organic solvent is N-methylpyrrolidinone (NMP), N, N-dimethylacetamide (DMAc), tetrahydrofuran (THF), N, N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO) , Cyclohexane, acetonitrile and mixtures thereof may be selected from the group consisting of, but is not limited thereto.

The polyimide precursor is preferably 10 to 30% by weight based on the total weight of the total solution. If the polyimide precursor is less than 10% by weight, use of unnecessary solvents increases, and if it exceeds 30% by weight, the viscosity of the solution becomes too high and there is a problem that it is difficult to apply uniformly.

This invention can also add small amount of dianhydride, diamine, or another compound other than the said compound as needed.

In addition, an additive such as an antifoaming agent, an antigelling agent, a curing accelerator, or the like may be further added to facilitate coating or curing or to improve other physical properties.

In the present invention, the thermal expansion coefficient and the expansion ratio of the polyimide resin layer can be adjusted by adjusting the type, composition, and additives of the dianhydride and the diamine.

The metal layer may be made of various metals such as copper, aluminum, iron, nickel, silver, palladium, chromium, molybdenum and tungsten or alloys thereof, and is preferably copper.

The present invention,

a) low thermal expansion polyimide having a thermal expansion coefficient of 20 ppm / ° C. or lower, a thermal expansion coefficient of 16 to 19 ppm / ° C. in the MD direction, and a thermal expansion coefficient of 17 to 20 ppm / ° C. in the TD direction using a polyimide precursor solution on the metal layer; Forming a layer;

b) forming a high thermally expandable polyimide layer having a thermal expansion coefficient of 20 ppm / ° C. or more using a polyimide precursor solution on the low thermally expandable polyimide;

It provides a method for producing a metal laminate comprising a.

When coating the polyimide precursor solution, a die coater, a comma coater, a reverse comma coater, a gravure coater, or the like can be used. The coating technique used in the field may be used. Drying of the coated varnish depends on the structure and conditions of the oven, but can be dried at 50 to 350 ° C, more preferably 80 to 250 ° C, which is usually lower than the boiling point of the solvent.

As described above, the polyimide precursor is coated on one end of the metal layer and dried, and then cured. The curing temperature may be, for example, about 390 ° C. The curing may be carried out by gradually raising the temperature in an oven under a nitrogen atmosphere or a vacuum, or hardening by continuously passing a high temperature in a nitrogen atmosphere.

In the present invention, a method of forming, drying, and curing a high thermally expandable polyimide resin layer after forming, drying, and curing a low thermally expandable polyimide resin layer may be used, and a low thermally expandable polyimide resin layer and a high thermally expandable polyimide resin layer may be used. After formation, it can dry and harden collectively, after forming a low thermally expansible polyimide resin layer and drying, after forming a high thermally expansible polyimide layer on it, you may dry and harden collectively.

In addition, the present invention provides a printed circuit board including the metal laminate.

In addition, the present invention provides a method of manufacturing a printed circuit board comprising the step of chip mounting on the metal laminate.

Except for the metal laminate in the configuration and manufacturing method of the printed circuit board can use a technique known in the art.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are for illustrating the present invention, and the scope of the present invention is not limited thereto.

Synthesis Example 1

2.41 g of p-PDA (phenylene diamine) and 4.47 g of 4,4'- ODA (Oxydianiline) were dissolved in 162 ml of N-methylpyrrolidinone. I was. At this time, the polymerization temperature was 5 ° C. The polymerized solution was sequentially dried at 90 ° C, 110 ° C, and 140 ° C on copper foil, and then heated up to 350 ° C to produce a film having a thickness of 40 µm. The coefficient of linear expansion was measured using TMA (Thermomechanical Analysis) while heating the film at a rate of 10 ° C./min. The average linear expansion coefficient of the MD direction was 32 ppm / ° C. in the temperature range of 100 ° C. to 200 ° C., and the TD direction The average coefficient of thermal expansion was 33 ppm / 占 폚.

Synthesis Example 2-11

To prepare a polyimide precursor solution in the same manner as in Synthesis Example 1 using a dianhydride and diamine as shown in Table 1.

Dianhydride (g) Diamine (g) Thermal expansion coefficient × 10 ^-6 (1 / ℃)       MD        TD Synthesis Example 1 BPDA PMDA BTDA p-PDA 4,4'-ODA 32 33 13.06 2.41 4.47 Synthesis Example 2 BPDA PMDA BTDA p-PDA ODA 16 17 14.39 5.05 0.49 Synthesis Example 3 BPDA PMDA BTDA p-PDA ODA 19 20 2.94 3.27 8.05 5.16 0.50 Synthesis Example 4 BPDA PMDA BTDA p-PDA ODA 18 18 2.90 2.15 9.52 5.35 Synthesis Example 5 BPDA PMDA BTDA p-PDA 4,4'-ODA 17 18 7.02 7.68 5.13 0.10 Synthesis Example 6 BPDA PMDA BTDA p-PDA ODA 18 18 6.50 7.10 3.30 3.00 Synthesis Example 7 BPDA PMDA BTDA p-PDA 4,4'-ODA 29 31 13.47 3.23 3.23 Synthesis Example 8 BPDA PMDA BTDA p-PDA 4,4'-ODA 13 15 13.18 0.54 0.80 5.41

Example 1

The polyimide precursor solution prepared in Synthesis Example 2 was applied to the copper foil, and the thickness after curing was as shown in Table 2 below. Thereafter, the mixture was dried at 90 ° C., 110 ° C., and 140 ° C. in sequence, and the polyimide precursor solution prepared in Synthesis Example 2 was applied in the same manner to contact the cured polyimide precursor solution, followed by drying in the same manner, followed by drying at 350 ° C. Hardening up to and then the expansion ratio was measured as described above. As a result of confirming that the position shift occurs at the time of chip mounting, it was confirmed through FIG. 1 that the position shift did not occur at the time of chip mounting.

Example 2-7

After using the polyimide precursor solution as shown in Table 2 below to produce a two-layer copper foil laminate in the same manner as in Example 1, the expansion ratio was measured as follows. As a result of confirming that position shift occurs at the time of chip mounting, it was confirmed that position shift occurred at the time of chip mounting.

First floor Second floor Expansion rate liquid Thickness (㎛) liquid Thickness (㎛) Stage b Stage C Example 1 Synthesis Example 2 32 Synthesis Example 1 8 MD +0.01 MD -0.03 TD +0.00 TD -0.05 Example 2 Synthesis Example 2 30 Synthesis Example 7 10 MD +0.00 MD -0.03 TD +0.00 TD -0.04 Example 3 Synthesis Example 3 35 Synthesis Example 7 5 MD +0.01 MD -0.04 TD +0.00 TD -0.06 Example 4 Synthesis Example 4 31 Synthesis Example 1 9 MD +0.03 MD -0.02 TD +0.00 TD -0.05 Example 5 Synthesis Example 5 33 Synthesis Example 7 7 MD +0.02 MD -0.03 TD +0.00 TD -0.04 Example 6 Synthesis Example 6 31 Synthesis Example 1 9 MD -0.01 MD -0.05 TD +0.00 TD -0.04 Example 7 Synthesis Example 6 33 Synthesis Example 8 7 MD +0.00 MD -0.03 TD +0.00 TD -0.04

 Comparative Example 1

The polyimide precursor solution manufactured by the synthesis example 1 was apply | coated to copper foil so that it might become 10 micrometers in thickness after hardening. Thereafter, the polyimide precursor solution prepared in Synthesis Example 2 was dried in the same manner so as to dry at 90 ° C., 110 ° C., and 140 ° C. in order, and then applied to have a thickness of 30 μm. After drying in turn, the temperature was raised to 350 ° C. to cure the thin film. At this time, after fabricating the manufactured two-layer copper-clad laminate, the stretching ratio was measured. In Stage B, the MD stretching ratio was +0.04 and the TD stretching ratio was -0.01, and in Stage C, the MD stretching ratio was -0.04 and the TD stretching direction. The rate of -0.06 was found, and as a result of confirming that the position shift occurred at the time of chip mounting, it was confirmed through FIG. 3 that the position shift occurred.

Comparative Example 2

The polyimide precursor solution manufactured by the synthesis example 8 was apply | coated to copper foil so that thickness might be 34 micrometers after hardening. Thereafter, the polyimide precursor solution prepared in Synthesis Example 1 was dried at 90 ° C., 110 ° C., and 140 ° C. in order to contact the cured polyimide precursor solution. It dried and it heated up to 350 degreeC, and hardened the thin film. In the case of the manufactured two-layer copper clad laminate, the expansion ratio was measured, and the MD direction expansion ratio in the stage B was +0.02 and the TD direction expansion ratio was +0.03, and in stage C, the MD direction expansion ratio was -0.01 and the TD direction expansion ratio. It came out as -0.04, and as a result of confirming the positional shift during chip mounting, it was confirmed through Figure 4 that the positional shift occurs.

As described above, when the polyimide resin layer according to the present invention is used, the printed circuit is minimized by optimizing a process window when mounting a chip-on-film chip to minimize the positional shift between the bump part and the inner lead. Chip mounting is possible even at intervals between inner leads according to the densification of the substrate, that is, a fine pitch of 40 μm or less.

Claims (13)

A metal layer, a low thermal expansion polyimide resin layer having a thermal expansion coefficient of 20 ppm / ° C. or less laminated on the metal layer, and a high thermal expansion polyimide resin layer having a thermal expansion coefficient of 20 ppm / ° C. or more laminated on the low thermal expansion polyimide resin layer, A metal laminate having a thermal expansion coefficient in the direction of MD (Machine Direction) of the low thermal expansion polyimide resin layer and a thermal expansion coefficient in the direction of TD (Transverse Direction) of 17 to 20 ppm / ° C. The stretching ratio difference between the MD direction and the TD direction in Stage B of the polyimide resin layer including the low thermally expandable polyimide and the high thermally expandable polyimide resin layer is 0.03. The metal laminate is less than or equal to%. The stretching ratio difference between the MD direction and the TD direction is 0.03% or less in Stage C of the polyimide resin layer including the low thermally expandable polyimide and the high thermally expandable polyimide resin layer. Metal laminate. The metal laminated plate of Claim 1 whose thickness of the polyimide resin layer containing the said low thermally expandable polyimide resin layer and the said high thermally expandable polyimide resin layer is 30-50 micrometers. The metal laminate of claim 1, wherein the low thermally expandable polyimide resin layer and the high thermally expandable polyimide resin layer are made from a polyimide precursor solution containing dianhydride and diamine in a molar ratio of 1: 0.9 to 1: 1.1. The method of claim 5, wherein the dianhydride is PMDA (pyromellitic dianhydride), BPDA (3,3 ', 4,4'-biphenyltetracarboxylic dianhydride) and BTDA (3,3', 4, 4'-benzophenonetetracarboxylic dianhydride) is one or more metal laminates selected from the group consisting of. The method of claim 5, wherein the diamine is p-PDA (p-phenylenediamine), m-PDA (m-phenylenediamine), 4,4'-ODA (4,4'-oxydianiline), 3,4 '-ODA (3,4'-oxydianiline), TPE-R (1,3-bis (4-aminophenoxy) benzene), BAPP (2,2-bis (4- [4-aminophenoxy] -Phenyl) propane), HAB (3,3'-dihydroxy-4,4'-diaminobiphenyl) at least one metal laminate selected from the group consisting of. The metal laminate of claim 5, wherein the polyimide precursor solution comprises 10 to 30 wt% of the polyimide precursor relative to the total weight of the polyimide precursor solution. The metal laminate of claim 5, wherein the polyimide precursor solution further comprises at least one of an antifoaming agent, a gel inhibitor, and a curing accelerator. The metal laminate of claim 1, wherein the metal layer is made of a material selected from copper, aluminum, iron, nickel, silver, palladium, chromium, molybdenum and tungsten or alloys thereof. a) a low thermal expansion polyimide having a thermal expansion coefficient of 20 ppm / ° C. or lower, a thermal expansion coefficient of 16 to 19 ppm / ° C. in the MD direction, and a thermal expansion coefficient of 17 to 20 ppm / ° C. in the TD direction using a low thermal expansion polyimide precursor on the metal layer Forming a layer; And b) forming a high thermal expansion polyimide layer having a thermal expansion coefficient of 20 ppm / ° C. or more using a high thermal expansion polyimide precursor on the low thermal expansion polyimide; Method for producing a metal laminate comprising a. A metal layer, a low thermal expansion polyimide resin layer having a thermal expansion coefficient of 20 ppm / ° C. or less laminated on the metal layer, and a high thermal expansion polyimide resin layer having a thermal expansion coefficient of 20 ppm / ° C. or more laminated on the low thermal expansion polyimide resin layer, A printed circuit board comprising a metal laminate, wherein the coefficient of thermal expansion in the MD direction of the low thermal expansion polyimide resin layer is 16 to 19 ppm / 占 폚, and the coefficient of thermal expansion in the TD direction is 17 to 20 ppm / 占 폚. A metal layer, a low thermal expansion polyimide resin layer having a thermal expansion coefficient of 20 ppm / ° C. or less laminated on the metal layer, and a high thermal expansion polyimide resin layer having a thermal expansion coefficient of 20 ppm / ° C. or more laminated on the low thermal expansion polyimide resin layer, A printed circuit board comprising the step of mounting a chip on a metal laminate in which the thermal expansion coefficient in the MD direction of the low thermal expansion polyimide resin layer is 16 to 19 ppm / 占 폚 and the thermal expansion coefficient in the TD direction is 17 to 20 ppm / 占 폚. Manufacturing method.

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