JPH02209441A - Cu alloy stock for lead frame of semiconductor device having excellent effect of suppressing wear in stamping die - Google Patents

Abstract

PURPOSE:To improve the effect of suppressing wear in a die and to prolong its service life by adding specified amounts of Mg, Ca, Zn, etc., to a conventionally used Cu alloy as the stock for a die used at the time of stamping a lead frame in a semiconductor device. CONSTITUTION:As the stock for a die used at the time of manufacturing a lead frame used in the manufacturing of various semiconductor devices from its sheet material or wire material by stamping, a Cu alloy of which one or more kinds among, by weight, 0.001 to 0.05% Mg, 0.001 to 0.01 % Ca and 0.001 to 1% Zn are further added to a Cu alloy contg. 0.05 to 0.25% Fe, 0.015 to 0.07% P and 0.0005 to 0.01% Pb is used. The effect of suppressing wear in the die is made excellent, so that the die having prolonged service life can be obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a mold used for stamping (punching) lead frames from materials such as plates and strips in the manufacture of various semiconductor devices. C for lead frames of semiconductor devices, which has extremely little wear, that is, has an excellent effect of suppressing the wear of stamping dies, and therefore makes it possible to further extend the service life of stamping dies.
This relates to u-alloy materials.

[Conventional technology]

Previously, the same applicant published JP-A-60-176258 in % by weight (hereinafter % indicates % by weight), F a:o,
05-0.26%, P: 0.015-0.07%
, Pb: 0.001 to 0.01%, and the remainder is Cu and unavoidable impurities. Proposed as a Cu alloy material for lead frames.

[Problem to be solved by the invention]

Although the above-mentioned conventional Cu alloy materials have the strength, repeated bendability, and heat resistance required for lead frames of semiconductor devices, the current situation is that they are still not fully satisfactory in terms of the wear suppression effect of stamping dies. It is.

[Means to solve the problem]

Therefore, from the above-mentioned viewpoint, the present inventors focused on the above-mentioned conventional Cu alloy material and conducted research to further improve the wear-suppressing effect of the stamping die. When containing a small amount of one or more of Mg, Ca, and Zn,
The wear suppression effect of stamping dies has been further improved without compromising the strength, repeated bendability, and heat resistance required for semiconductor device lead frames, making it possible to significantly extend the service life of stamping dies. We obtained the knowledge to do so.

This invention was made based on the above findings, and includes F e:0. o! +-0.25%, P:0.
O12~0.07%, Pb:0.0005~0.01%
, furthermore, Mg: 0.001~0.05%, Ca: 0.001~
0.01%, Zn: 0.001-1%, one or more of them, and the rest is Cu and unavoidable impurities. This Cu alloy material for lead frames of semiconductor devices is characterized by its excellent suppressive effect.

Next, the reason why the composition of the Cu alloy material of the present invention is limited as described above will be explained.

(a) Fe and P Both of these components have the effect of forming Fe-P compounds that precipitate finely on the base material and improving the strength, repeated bendability, and heat resistance of the Cu alloy material. Even if the amount is either Fe or P component, Fe: 0.05
% and P: less than 0.015%, the desired effect cannot be obtained in the above action, and on the other hand, even if the content is either Fe or P component, Fe:o, 25% and P
: If it exceeds 0.07%, the conductivity decreases, so the content is reduced to Fe: 0.05-0.
．． 25%, P: 0. It was set as O12-0.07%.

(b) Pb As mentioned above, the Pb acid component has the function of preventing wear of the mold used for stamping lead frames from Cu alloy materials, but when its content is 0.
．． If the content is less than 0.005%, the desired effect cannot be obtained, while if the content exceeds 0.01%, the amount of Pb precipitated at grain boundaries and inside the grains will increase, resulting in poor repeatability and plating properties. The content was set at 0.0005 to 0.01%.

(c) Mg, Ca, and Zn These components, especially in the coexistence of the PB acid component, can further suppress the wear of the stamping mold and extend its service life, i.e., the mold can reach a specified amount of wear. However, if the content of any component is less than 0.001%, the desired effect will not be achieved. is not obtained, and on the other hand, its content 'h-ffi is Mg
If the Ca content exceeds 0.05%, not only will the viscosity of the molten metal during melting and casting become high, but oxidation will also become severe and ingot defects will occur frequently.
If it exceeds 1%, oxidation consumption will be severe when it is added and the content yield will drop significantly, making it uneconomical. Furthermore, in the case of Zn, if it exceeds 1%, the conductivity will drop significantly. Therefore, the content is Mg+0.0, respectively.
01-0.05%, Ca: 0.001-0.01%, Z
n: determined to be 0.001 to 1%.

In the Cu alloy material of the present invention, it is desirable that the content of oxygen contained as an unavoidable impurity is 50 ppI11 or less, while Ag, Aj7. B.

Even if one or more of components such as Co, Cr, Mn, NI, Si, and Sn are contained, if the total content is 0.2% or less, they will not have any adverse effect on the material properties. isn't it.

〔Example〕

Next, the Cu alloy material of the present invention will be specifically explained with reference to Examples.

Using a normal low-frequency groove melting furnace, prepare Cu alloy molten metals having the respective compositions shown in Table 1, and use a semi-continuous casting method to obtain dimensions of thickness: 150 m + width: 400 m 1 × length: 1500 mm. This ingot was hot rolled at a starting humidity of 2800°C and a finishing temperature of 550°C, and then water-cooled from the finishing temperature to form a plate with a thickness of 1.
A 2mm hot-rolled plate, one side; 0.5m+
After applying each side of s, cold rolling, intermediate annealing, and pickling are performed in one cycle, and this is repeated, and cold rolling is performed under the condition that the final cold rolling rate is 30%,
The present invention C can be achieved by using a cold-rolled plate with a plate thickness of 0.381.
u alloy materials IA-3E and conventional Cu alloy materials 1a-3
c were produced respectively.

Next, in order to evaluate the strength and heat resistance of the various Cu alloy materials obtained as a result, tensile strength, elongation, and softening temperature were measured, and repeated bending tests were conducted. A stamping die wear test was conducted to evaluate the wear suppression effect on the die.

The softening temperature is determined by heating and holding test pieces with dimensions of length: 50 mm x width: 50 mm x thickness: OJ81 m at various temperatures for 1 hour, and measuring the Vickers hardness of the test pieces after heating at each heating temperature. The hardness was measured at the heating temperature at which a sudden decrease in hardness occurred in the test piece.

In addition, in the repeated bending test, length: 200m + sX width =
Insert one end of a test piece with dimensions of 15 mm x thickness: 0.381 + am into a groove with dimensions of width: 0.5 mm x depth of near 0 mm, stand upright, and tighten the test piece. , make alternating strikes of 90″ on both the left and right sides,
This 90'' bend was counted as one bend, and the number of bends until the test piece broke was measured.

Furthermore, the stamping die wear test was conducted using commercially available WC as a die having a composition consisting of 18% Co and the remainder of WC.
This is done by stamping (press punching) a 16-lead lead frame using a base cemented carbide.
The number of times of stamping until a 5 m+m paris was generated was measured. These results are shown in Table 1.

〔Effect of the invention〕

From the results shown in Table 1, the present invention Cu alloy material IA~
3E all contain trace amounts of Mg, Ca, or Zn, which gives stamping molds a much better wear-suppressing effect than conventional Cu alloy materials 1a to 3c that do not contain these components. It is clear that the service life can be extended, and it has also been shown that the strength, heat resistance, and repeated bendability do not decrease due to the inclusion of the above components.

As described above, the Cu alloy material of the present invention not only has the strength, heat resistance, and repeated bendability required for lead frames of semiconductor devices, but also suppresses the wear of stamping dies. It has industrially useful properties such as a significantly long service life.

Claims (1)

[Claims] (1) Fe: 0.05~0.25%, P: 0.015~
0.07%, Pb: 0.0005-0.01%, and further contains Mg: 0.001-0.05%, Ca: 0.001-0
．． 01%, Zn: 0.001 to 1%, and the rest is Cu and unavoidable impurities (weight %). A Cu alloy material for semiconductor device lead frames that has excellent mold wear suppression effects.