JP3465541B2 - Lead frame material manufacturing method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor component
The present invention relates to a method for manufacturing a lead frame material used for a lead frame . 2. Description of the Related Art As the integration density of semiconductor integrated circuits increases, the number of pins in a lead frame material and the pin width and pin pitch are reduced. These multi-pin lead frames include:
It is necessary to reduce the thickness of the material, and a copper alloy having high strength capable of coping with this and heat radiation capable of coping with increased power consumption is used. [0003] Cu-Ni-Si based copper alloys are precipitation hardening alloys. When a compound of Ni and Si is deposited in a fine shape by heat treatment, high strength and good thermal and electrical conductivity are obtained. Therefore, it is suitable as a material for a multi-pin lead frame. [0004] In general, a method for producing a precipitation-hardenable copper alloy such as a Cu-Ni-Si system is to form a copper alloy material by forming a copper alloy ingot and heat the copper alloy material to a high temperature (solution treatment). Treatment) to dissolve the alloy element (precipitated element) which is non-uniformly precipitated in the Cu matrix,
Thereafter, the copper alloy material is subjected to primary cold working, and then heated (aged) to a predetermined temperature to uniformly precipitate solid-solution elements in the Cu matrix. Is applied. For example, after performing a solution treatment at a temperature of 700 ° C. or more so that the crystal grain size is 5 μm or more,
Cold working with a working degree of 95% or less, aging treatment at 350 to 700 ° C, cold working with a working degree of 20 to 95%, and 150 to
There is a method of performing a heat treatment at 800 ° C.
No. 250154). The solution treatment in the conventional method for producing a Cu—Ni—Si precipitation hardenable copper alloy is performed at a high temperature (900 ° C.) for the purpose of promoting solid solution of the precipitated element in the matrix.
Degree). In addition, since the subsequent cold working and aging treatment conditions are often selected only for the purpose of improving the electrical conductivity and strength of the Cu—Ni—Si-based precipitation-hardening copper alloy, a relatively high temperature (500 to (600 ° C.). The external processing of the lead frame includes a stamping method and an etching method. In the case of a high-density multi-pin frame having more than 200 pins, an etching method in which fine processing is relatively easy is used. In a high-density multi-pin frame, the pin width of the inner lead is narrow, which almost reaches the limit of the pin width required for wire bonding, and the pin pitch is also narrow. It is important to precisely control the dimensional accuracy. However, the linearity and dimensional accuracy of the inner leads are greatly affected by the crystal structure and the form of precipitates of the material in addition to the etching processing conditions. Due to the difference in the etching property between the boundary portion and the inside of the crystal grain, the material in which the crystal grain has grown greatly tends to have irregularities in the texture pattern on the etched surface. Further, the size of the precipitate also affects the etching property, and when the precipitate is large, irregularities are likely to be formed on the etched surface. Due to the occurrence of such irregularities, the linearity and dimensional accuracy of the inner lead are deteriorated. A Cu—Ni—Si precipitation hardenable copper alloy requires a heat treatment step for solution and aging.
At that time, there is a possibility that the crystal grains become coarse or precipitates grow large. That is, in the conventional manufacturing method, the solution treatment is often performed at a high temperature (about 900 ° C.) for the purpose of promoting solid solution of the precipitated element in the matrix. It is likely to grow to a coarse crystal structure. In the aging treatment, heating is often performed at a relatively high temperature in order to sufficiently promote the precipitation of solid solution elements. Therefore, there is a possibility that crystal grains may grow excessively and become a coarse crystal structure. , Precipitate size tends to be large. Accordingly, the present invention solves the above-mentioned problems, and provides a lead foil having excellent lead formability by etching and having fine crystal grains and precipitates in a matrix.
An object of the present invention is to provide a method for manufacturing a frame material . [0014] In order to solve the above-mentioned problems, the invention according to claim 1 includes at least 1.0 to 5.0 wt% of Ni and at least
0.2-1.0 wt%, Zn 1.0-5.0 wt%,
P contains 0.003-0.3 wt% and Ni
A method for producing a lead frame material, comprising subjecting a copper alloy having a weight ratio of 4.5 / 5.5 to a solution treatment and an aging treatment, wherein the copper alloy is treated at a temperature range of 750-810 ° C. After the solution treatment, the copper alloy has a working rate of 6%.
First cold working of 0% or more, and then first aging treatment of the copper alloy at 370 to 470 ° C. × 0.5 to 3 hours, and then working rate of 50% or less again for the copper alloy Second
Next, cold working is performed, and then the copper alloy is subjected to 400 to 50
The second aging treatment is performed at 0 ° C. × 0.5 to 3 hours. The reason for defining the above numerical range will be described below. The temperature range of the solution treatment is 750 to 810 ° C.
The reason is that if the solution treatment temperature is lower than 750 ° C., the solution does not proceed sufficiently, and in the subsequent aging treatment, coarsening of the precipitated elements that could not be dissolved completely occurs, and high strength is obtained. This is because not only is not possible, but also the lead formability of the etching is reduced. If the solution treatment temperature is higher than 810 ° C., the solid solution of the precipitated element proceeds sufficiently, but the crystal grains become coarse, and fine crystal grains cannot be obtained in the final material, and lead forming of etching is performed. This is because the property is reduced. The reason why the working ratio of the first cold working is defined as 60% or more is that if the working ratio is lower than 60%, the crystal grains may be insufficiently refined, and the next aging treatment may be performed. This is because precipitation of fine precipitates in the process may be insufficient. The first aging treatment is performed at 370-470 ° C. × 0.
The aging treatment temperature and the time of 37 hours were specified as 5 to 3 hours.
If the temperature is lower than 0 ° C. or shorter than 0.5 hour, precipitation of solid solution elements due to aging does not sufficiently proceed, and good strength and electrical conductivity cannot be obtained in the final material. Also,
If the aging treatment temperature / time is higher than 470 ° C. or longer than 3 hours, aging causes precipitation of coarse precipitates, and high strength cannot be obtained in the final material, and recrystallization proceeds to reduce the crystal grain size. It is because it becomes big. The reason why the working ratio of the second cold working is specified to be 50% or less is that if the working ratio is higher than 50%, coarse precipitates are liable to precipitate by the next aging treatment, and the final material This is because the residual strain increases and warpage occurs during lead molding. The second aging treatment is performed at 400 to 500 ° C. × 0.
The aging treatment temperature and the time of 40 to 40 hours are specified as 5 to 3 hours.
If the temperature is lower than 0 ° C. or shorter than 0.5 hour, the precipitation of new precipitates does not sufficiently proceed, the residual strain increases, and warpage tends to occur during lead molding. If the aging treatment temperature / time is higher than 500 ° C. or longer than 3 hours, precipitation of coarse precipitates occurs due to aging, and high strength cannot be obtained in the final material, and recrystallization proceeds and crystal grains This is because the diameter increases. The added amounts of Ni and Si are set to 1.
The reason for defining the amounts to be 0 to 5.0 wt% and 0.2 to 1.0 wt% is to reduce the amount of solid solution elements after aging treatment.
If the addition amount is less than 1.0 wt% and 0.2 wt%, respectively, the high strength due to precipitation is not sufficient, and if the addition amount is more than 5.0 wt% and 1.0 wt%, respectively, precipitation cannot be completed. This is because the amount of solid solution elements increases. The reason why the weight ratio of Ni / Si is defined as 4.5 to 5.5 is that Ni and Si are precipitated as Ni ₂ Si, and the amount of Ni or Si existing as excess is reduced. That's why. Zn has the effect of preventing interfacial delamination during soldering, and the addition amount of Zn is specified to be 1.0 to 5.0 wt%. The above-mentioned effect is obtained when the addition amount is less than 1.0 wt%. Is not sufficient, and if the addition amount is more than 5.0 wt%, the conductivity is particularly lowered. P has an effect as a deoxidizing material and also has an effect of preventing an adverse effect due to oxidation of Si during casting.
The reason why the addition amount of P is defined as 0.003 to 0.3 wt% is that if the addition amount is less than 0.003 wt%, the above-mentioned effect is not sufficient, and if the addition amount is more than 0.3 wt%, it is particularly large. This is for reducing the conductivity. According to the above configuration, at least Ni and S
In a method for manufacturing a lead frame material comprising subjecting a copper alloy containing i to a solution treatment and an aging treatment, the copper alloy is subjected to the solution treatment in a temperature range of 750 to 810 ° C. Is subjected to a first cold working at a working ratio of 60% or more, and then the copper alloy is subjected to 370-470 ° C. × 0.
After the first aging treatment for 5 to 3 hours, the copper alloy is again subjected to a second cold working at a working ratio of 50% or less, and then the copper alloy is 400 to 500 ° C. × 0.5 to 3 hours. By performing the second aging treatment, it is possible to obtain a lead frame material which is excellent in lead formability by etching and has a fine crystal grain and precipitate size in a matrix. Embodiments of the present invention will be described below. The method for producing a lead frame material of the present invention comprises:
First, a copper alloy ingot having a predetermined chemical composition is subjected to molding (extrusion, cold working, etc.) to form a copper alloy material. The copper alloy ingot contains at least 1.0-5.0 wt% of Ni, 0.2-1.0 wt% of Si,
1.0 to 5.0 wt% of Zn and 0.003 to 0.3 of P
wt.%, and the weight ratio of Ni / Si is 4.
5 to 5.5. Here, a particularly preferable chemical composition range is 1.5 to 2.5 wt% of Ni and 0.3 to 0.2 wt% of Si.
5 wt%, Zn is 1.5-3.0 wt%, P is 0.01
~ 0.05 wt%. In order to prevent crystal grains from being coarsened in this copper alloy material and to sufficiently dissolve the precipitated elements, 750-500
A solution treatment is performed in a temperature range of 810 ° C. Here, a particularly preferable temperature range of the solution treatment is 780 to 800 ° C. After that, the solution-treated copper alloy material is
A first cold working with a working ratio of 60% or more is performed. This primary cold working refines the crystal grains of the copper alloy material, introduces lattice defects that serve as starting points for solid solution element precipitation, and promotes the formation of fine precipitates during the first aging treatment. . In particular, in order to improve the lead formability at the time of etching, it is necessary to sufficiently refine the crystal grains of the copper alloy material. The effect of miniaturization increases. Then, the copper alloy material after the first cold working is
A first aging process is performed. In the first aging treatment, it is important to precipitate a large amount of solid solution elements in a fine shape. However, in the present invention, since the working ratio of the first cold working is high, the precipitation of the solid solution elements is high. Progresses easily, and coarse precipitates easily precipitate. For this reason, the temperature and time conditions of the first aging treatment are set to 370 to 470 ° C. × 0.5 to 3 hours.
In addition to suppressing the precipitation of coarse precipitates, a large amount of solid solution elements is precipitated in a fine shape. Here, particularly preferred temperature and time conditions for the first aging treatment are 440 to 460 ° C ×
1 to 2 hours. Since the solid solution elements in the matrix cannot be completely precipitated only by the first aging treatment, some alloying elements remain in a solid solution state even after the first aging treatment. For this reason,
As it is, it is insufficient to achieve good electrical conductivity in the final material. Therefore, in order to introduce lattice defects serving as starting points for precipitating alloying elements remaining in a solid solution state, a second cold working with a working ratio of 50% or less is performed on the copper alloy material after the first aging treatment. Apply. Then, the copper alloy material after the second cold working is
A second aging process is performed. In the second aging treatment, it is important to suppress the generation of coarse precipitates, generate new precipitates, and reduce the amount of solid solution elements while keeping the crystal grain size fine. Therefore, the temperature of the second aging treatment
The time condition is 400-500 ° C. × 0.5-3 hr.
Here, a particularly preferred temperature and time condition of the second aging treatment is 400 to 460 ° C. × 1 to 2 hours. By subjecting the copper alloy material to the second aging treatment, a copper alloy material for electronic equipment, which is the final material, is obtained. That is, according to the lead frame material manufacturing method of the present invention, the solution treatment temperature for the copper alloy material, the working ratio of each cold working, and the processing temperature of each aging treatment are specified. The resulting copper alloy material for a lead frame is excellent in lead formability by etching, and has a fine crystal grain and precipitate size in a matrix. Further, since the crystal grains and precipitates in the matrix are fine, they have high strength and good electric and thermal conductivity. Further, since the lead formability by etching is excellent, the copper alloy material for electronic equipment obtained by the manufacturing method of the present invention can be used as a material for a smaller and more multi-pin lead frame. Example 1 While oxygen-free copper was melted in a high-frequency melting furnace, Ni, Si, Zn, and P were added as appropriate, and the molten metal was poured into a mold to be 30 mm in diameter and 250 mm in length. And the chemical composition is Ni: 2.5 wt%, Si: 0.5 wt%,
Zn: 1.5 wt%, P: 0.03 wt%, Ni / Si
A copper alloy ingot (sample A) having a weight ratio of 5.0 is cast. (Example 2) In the same manner as in Example 1, the diameter 3
0 mm, length 250 mm, and the chemical composition is Ni:
3.5 wt%, Si: 0.7 wt%, Zn: 3.5 wt
%, P: 0.03 wt%, weight ratio of Ni / Si: 5.0
Is cast (sample B). (Comparative Example 1) In the same manner as in Example 1, the diameter 3
0 mm, length 250 mm, and the chemical composition is Ni:
6.0 wt%, Si: 1.2 wt%, Zn: 1.5 wt
%, P: 0.03 wt%, weight ratio of Ni / Si: 5.0
Of the copper alloy ingot (sample C). (Comparative Example 2) As in Example 1, the diameter was 3
0 mm, length 250 mm, and the chemical composition is Ni:
2.0 wt%, Si: 0.5 wt%, Zn: 1.5 wt
%, P: 0.03 wt%, weight ratio of Ni / Si: 4.0
Is cast (sample D). (Comparative example 3)
0 mm, length 250 mm, and the chemical composition is Ni:
3.0 wt%, Si: 0.5 wt%, Zn: 1.5 wt
%, P: 0.03 wt%, weight ratio of Ni / Si: 6.0
Of the copper alloy ingot (sample E). Example 1,
Table 1 shows the chemical compositions of the copper alloy ingots of Comparative Example 2 and Comparative Examples 1 to 3. [Table 1] Next, using the copper alloy ingots of Samples A to E, a copper alloy material for electronic equipment is manufactured. Example 3 The copper alloy ingot of Example 1 was heated to 850 ° C., and the copper alloy ingot was extruded to form a plate having a width of 20 mm and a thickness of 8 mm. This plate-shaped copper alloy material is cold-rolled to a thickness of 0.1 mm.
It is formed into a 7 mm thin plate copper alloy material. Next, after heating the sheet-shaped copper alloy material to 800 ° C., the sheet-shaped copper alloy material is rapidly cooled by being put into water, and the sheet-shaped copper alloy material is subjected to a solution treatment. Processing rate 7 for sheet-like copper alloy material after solution heat treatment
The first cold rolling of 0% is performed to form a thickness of 0.21 mm. Thereafter, the sheet-shaped copper alloy material was heated at 460 ° C. ×
A 1 hour primary aging process is performed. This sheet-like copper alloy material is subjected to a second cold rolling process at a processing rate of about 29% to a thickness of 0.1%.
Formed to 15 mm. Thereafter, the sheet-like copper alloy material was heated at 400 ° C. ×
A 1 hour secondary aging treatment is performed to produce a copper alloy material for electronic devices (Sample No. 1). Example 4 Using the copper alloy ingot of Example 1, the same procedure as in Example 3 was performed except that the first aging treatment was 440 ° C. × 1 hr and the second aging treatment was 420 ° C. × 1 hr. A copper alloy material for electronic equipment (sample No. 2) is manufactured. Example 5 The same procedure as in Example 3 was performed except that the first aging treatment was performed at 400 ° C. × 1 hr and the second aging treatment was performed at 450 ° C. × 1 hr using the copper alloy ingot of Example 1. A copper alloy material for electronic equipment (sample No. 3) is manufactured. Comparative Example 4 A copper alloy material for electronic equipment (sample No. 4) was produced in the same manner as in Example 3 except that the solution treatment temperature was 830 ° C. using the copper alloy ingot of Example 1. I do. Comparative Example 5 A copper alloy material for electronic equipment (sample No. 5) was prepared in the same manner as in Example 3 except that the solution heat treatment temperature was 740 ° C. using the copper alloy ingot of Example 1. I do. (Comparative Example 6) A copper alloy material for electronic equipment (sample No. 3) was prepared in the same manner as in Example 3 except that the working rate of the first cold working was changed to 50% using the copper alloy ingot of Example 1. .
6) is prepared. Comparative Example 7 Using the copper alloy ingot of Example 1, the same procedure as in Example 3 was performed except that the first aging treatment was 480 ° C. × 1 hr, and the second aging treatment was 380 ° C. × 1 hr. A copper alloy material for electronic equipment (Sample No. 7) is manufactured. Comparative Example 8 Using the copper alloy ingot of Example 1, the same procedure as in Example 3 was performed except that the first aging treatment was 360 ° C. × 1 hr and the second aging treatment was 460 ° C. × 1 hr. A copper alloy material for electronic equipment (sample No. 8) is manufactured. (Comparative Example 9) A copper alloy ingot for electronic equipment (sample No. 9) was produced in the same manner as in Example 3 except that the copper alloy ingot of Example 1 was used and the working ratio of the second cold working was set to 60%. .
9) is prepared. Comparative Example 10 A copper alloy material for electronic equipment (sample N) was prepared in the same manner as in Example 3 except that the copper alloy ingot of Example 1 was used and the secondary aging treatment was performed at 380 ° C. × 1 hr.
o. 10) is manufactured. (Comparative Example 11) A copper alloy material for electronic equipment (sample N) was prepared in the same manner as in Example 3 except that the copper alloy ingot of Example 1 was used and the secondary aging treatment was performed at 520 ° C. × 1 hr.
o. 11) is prepared. Example 6 Using the copper alloy ingot of Example 2, a copper alloy material for electronic equipment (Sample No. 12) was produced in the same manner as in Example 3. Comparative Example 11 Using the copper alloy ingot of Comparative Example 1, a copper alloy material for electronic equipment (sample No. 13) was produced in the same manner as in Example 3. Comparative Example 12 Using the copper alloy ingot of Comparative Example 2, a copper alloy material for electronic equipment (Sample No. 14) was produced in the same manner as in Example 3. Comparative Example 13 Using the copper alloy ingot of Comparative Example 3, a copper alloy material for electronic equipment (Sample No. 14) was produced in the same manner as in Example 3. Table 2 shows the manufacturing conditions of the copper alloy materials for electronic devices of Examples 3 to 6 and Comparative Examples 4 to 14. [Table 2] Next, the sample No. For 1 to 14, tensile strength (MPa), conductivity (% IACS), crystal grain size (μ
m) was measured. Table 3 shows the measurement results. [Table 3] As shown in Table 3, material No. Since 1 to 3 and 12 are manufactured based on the method for manufacturing a lead frame material of the present invention, a tensile strength of 700 MPa or more,
Conductivity of 40% IACS or more and fine crystal grains were obtained. On the other hand, the sample No. Samples 4 and 5 have a solution treatment temperature (830 ° C., 740 ° C.) within a specified range (750 ° C.).
-810 ° C), the solution temperature was too high. In Sample No. 4, the crystal grains were coarse (200 μm), and conversely, the sample N in which the solution treatment temperature was too low
o. 5, the tensile strength was 700 MPa or less (628
MPa) and the electrical conductivity is 40% IACS or less (38.0% IACS). Sample No. In No. 6, since the working ratio (50%) of the first cold working is out of the specified range (60% or more), the crystal grains are coarse (120 μm). Sample No. 7 and 8, the primary aging treatment temperature (480 ° C., 360 ° C.) is within a specified range (370 to 470).
° C), the temperature of the first aging treatment is too high. 7, the tensile strength was 700 MPa or less (63
6 MPa) and coarse crystal grains (120 μm)
On the contrary, the sample No. 1 in which the first aging treatment temperature was too low. 8, the tensile strength was 700 MPa or less (6
10 MPa), and the conductivity is 40% IACS or less (39.6
% IACS) and the crystal grains are coarse (12 IACS).
0 μm). Sample No. No. 9 has a tensile strength of 700 MPa or less (630 MPa) because the working ratio (60%) of the second cold working is out of the specified range (50% or less). Sample No. 10 and 11, the secondary aging temperature (380 ° C., 520 ° C.) is within a specified range (400 to 50 ° C.).
0 ° C.), the sample temperature is too low for the second aging treatment. In Sample No. 10, the conductivity was 40% IACS or less (39.2% IACS), and conversely, Sample No. 10 in which the secondary aging temperature was too high. In No. 11, the tensile strength is 700 MPa or less (580 MPa) and the crystal grains are coarse (200 μm). Sample No. In the chemical composition of the copper alloy material used in No. 13, the Ni / Si weight ratio (5.0) is within the specified range (4.5 to 5.5), but the contents of Ni and Si (6 respectively) 0.0 wt% and 1.2 wt%) are within specified ranges (1.0 to 5.0 wt% and 0.2 to 0.2 wt%, respectively).
1.0 wt%), the conductivity is 40% IACS.
Below (36.4% IACS). Sample No. In the chemical composition of the copper alloy used in No. 14, the contents of Ni and Si (each of 2.
0 wt% and 0.5 wt%) are within specified ranges (1.
0-5.0 wt%, 0.2-1.0 wt%), but the weight ratio of Ni / Si (4.0) is within the specified range (4.
5 to 5.5), the tensile strength is 700 MPa or less (656 MPa). Sample No. In the chemical composition of the copper alloy material used in No. 15, the contents of Ni and Si (3.
0 wt% and 0.5 wt%) are within specified ranges (1.
0-5.0 wt%, 0.2-1.0 wt%), but the Ni / Si weight ratio (6.0) is within the specified range (4.
5 to 5.5), the tensile strength is 700 MPa or less (680 MPa) and the conductivity is 40 MPa.
% IACS or less (38.8% IACS). [0077] According to the above summary the present invention, the solution treatment temperature of the copper alloy material, the working ratio of the nuclear cold working, and by defining the processing temperature of each aging treatment, obtained Lee
The frame material is excellent in lead formability by etching, and exhibits an excellent effect that crystal grains and precipitate size in the matrix are fine.

────────────────────────────────────────────────── ─── front page continued (51) Int.Cl. ⁷ identifications FI C22F 1/00 661 C22F 1/00 661A 682 682 683 683 685 685 686 686Z 691 691B 691C 694 694A (56) references JP Akira 61 -250154 (JP, A) JP-A-6-17209 (JP, A) JP-A-5-171378 (JP, A) JP-A-6-41660 (JP, A) JP-A-8-296012 (JP, A) JP-A-2-205645 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C22F 1/08 C22C 9/00-9/10

Claims (1)

(57) [Claims 1] At least 1.0 to 5.0 wt% of Ni,
0.2 to 1.0 wt% of Si and 1.0 to 5.0 watts of Zn
t and P are contained at 0.003-0.3 wt%.
In a method for producing a lead frame material obtained by subjecting a copper alloy having a weight ratio of Ni / Si of 4.5 to 5.5 to a solution treatment and an aging treatment, the copper alloy is subjected to 750 to 810 ° C.
After performing the above solution treatment in the temperature range described above, the copper alloy is subjected to a first cold working at a working ratio of 60% or more, and then the copper alloy is subjected to a 370-470 ° C. × 0.5-3 hr. After the first aging treatment, the copper alloy is again subjected to a second cold working at a working ratio of 50% or less, and then the copper alloy is subjected to 40% or less cold working.
A method for manufacturing a lead frame material, comprising performing a second aging treatment at 0 to 500C for 0.5 to 3 hours.