JPS6231059B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to lead frame materials for semiconductors such as ICs and LSIs, and a method for manufacturing the same, and more specifically to leads for semiconductors that have excellent strength, stiffness, repeated bendability, heat resistance, and electrical conductivity. The present invention relates to a semiconductor lead frame material made of a copper alloy suitable as a frame material and a method for manufacturing the same. [Prior art] Conventionally, lead frame materials for semiconductors include Fe, which has a coefficient of linear expansion similar to that of elements and ceramics.
-42wt%Ni alloy has been used, but in recent years, with improvements in device bonding technology and sealing materials, it is being replaced by copper-based materials, which have excellent heat dissipation properties and are relatively inexpensive. However, Fe-42wt% is used as a lead frame material for semiconductors such as ICs and LSIs that require high reliability.
No copper-based material has yet been developed that can satisfy the properties of Ni alloys, ie, excellent strength, repeated bendability, and heat resistance.Therefore, a copper-based material having the above-mentioned properties has been desired. [Problems to be Solved by the Invention] The present invention has been made in view of the prior art described above, and as a result of the inventor's intensive research, Fe
-42wt%Ni alloy has excellent properties as a lead frame material for semiconductors, namely high strength, good repeated bending properties, and high heat resistance, as well as electrical conductivity, corrosion resistance, stress corrosion cracking resistance, We have developed a lead frame material for semiconductors that has excellent solderability, heat-resistant peeling of plated tin and solder, and excellent hot workability, as well as a method for manufacturing the same. [Means for Solving the Problems] The semiconductor lead frame material and the manufacturing method thereof according to the present invention are as follows: (1) Ni 1.0 to 3.5 wt%, Si 0.2 to 0.9 wt%, Mn 0.02 to
1.0wt%, Zn0.1~5.0wt%, Sn0.1~2.0wt%,
Contains Mg0.001~0.01wt%, and further contains one or two selected from Cr, Ti, and Zr.
The first invention provides a semiconductor lead frame material characterized by containing at least 0.001 to 0.01 wt% of Cu, and the remainder substantially consisting of Cu, (2) 1.0 to 3.5 wt% of Ni, 0.2 to 0.2 wt% of Si; 0.9wt%, Mn0.02~
1.0wt%, Zn0.1~5.0wt%, Sn0.1~2.0wt%,
Contains Mg0.001~0.01wt%, and further contains one or two selected from Cr, Ti, and Zr.
After hot rolling an alloy ingot containing 0.001 to 0.01 wt% of copper with the remainder substantially consisting of Cu, it is heated at 5°C/
Cooling at a speed of more than seconds, 400~600℃ after cold working
A semiconductor characterized by performing annealing at a temperature of 400 to 600°C for 5 minutes to 4 hours, followed by temper finish rolling, and then short-time annealing at a temperature of 400 to 600°C for 5 to 60 seconds. This invention consists of two inventions, with the second invention being a method for manufacturing a lead frame material for use. The semiconductor lead frame material and the manufacturing method thereof according to the present invention will be described in detail below. First, the components and component ratios of the semiconductor lead frame material according to the present invention will be explained. Ni is an element that gives strength, and the content is
If Si is less than 1.0wt%, the strength and heat resistance will not improve even if Si is contained at 0.2 to 0.9wt%;
If the content exceeds %, the conductivity decreases, and
It is uneconomical. Therefore, the Ni content is 1.0~3.5wt%
shall be. Si is an element that imparts strength together with Ni, and if the content is less than 0.2wt%, the strength and heat resistance will not improve even if Ni is contained in 1.0 to 3.5wt%.
If the content exceeds 0.9 wt%, the conductivity will decrease and hot workability will deteriorate. Therefore, the Si content is set to 0.2 to 0.9 wt%. Mn is an element that improves hot workability, and if the content is less than 0.02wt%, this effect will be small, and if the content exceeds 1.0wt%, the flowability during agglomeration will deteriorate. Lump yield decreases. Then,
The Mn content is 0.02 to 1.0 wt%. Zn is an element that significantly improves the heat peeling properties of plated tin and solder, and its content is 0.1wt.
If the content is less than 5.0 wt%, this effect will be small, and if the content exceeds 5.0 wt%, solderability will deteriorate. Therefore, the Zn content is set to 0.1 to 5.0 wt%. Sn is an element that contributes to improving strength, stiffness, and repeated bendability.
Below 0.1wt%, these effects are small, and
If the content exceeds 2.0wt%, conductivity, heat resistance, and hot workability will be reduced. Therefore, the Sn content is set to 0.1 to 2.0 wt%. Mg is a stable Mg that replaces the unavoidable S.
It is an essential element to enable hot processing by fixing it in the matrix in the form of a compound with
At less than 0.001wt%, S does not form a stable MgS compound; S exists as it is or in the form of MnS; If the content exceeds 0.01wt%, Cu + MgCu ₂ eutectic (melting point 722℃) will form in the ingot.
When heated to a temperature of 722°C or higher, cracks occur, the molten metal oxidizes, the flowability deteriorates, the ingot becomes unsound, and the yield of ingots decreases. Then,
The Mg content is 0.001 to 0.01wt%. Cr, Ti, and Zr are all elements that improve hot workability, and if the content is less than 0.001wt%, this effect will be small, and if the content exceeds 0.01wt%, the flow during ingot formation will be affected. The properties deteriorate and the agglomeration yield decreases. Therefore, the Cr, Ti, and Zr contents are 0.001~
The content shall be 0.01wt%. Furthermore, when two or more of Cr, Ti, and Zr are contained, the total content is set to 0.001 to 0.01 wt% for the same reason as explained above. Next, a method for manufacturing a semiconductor lead frame material according to the present invention will be explained. The purpose of cooling the cast alloy ingot having the above-mentioned ingredients and ratios after hot rolling from a temperature of 600°C or more at a rate of 5°C/second or more is for solution treatment. When cooling from a temperature below 600°C, even if the cooling rate is 5°C/sec or more, precipitation has already occurred before cooling begins, and a sufficient solution treatment effect cannot be obtained, resulting in poor cold workability. Furthermore, even when cooling from a temperature of 600°C or higher, if the cooling rate is less than 5°C/sec, precipitation will occur during cooling, and a sufficient solution treatment effect will not be obtained, resulting in poor subsequent cold workability. This is because it worsens the Next, after cold working, at a temperature of 400 to 600℃ for 5 minutes to 4
The purpose of annealing is to precipitate Ni and Si compounds.
The precipitation of Ni and Si compounds is insufficient even with an annealing time of 300°F, and precipitation does not occur at temperatures exceeding 600°C, and most of the Ni and Si remain in solid solution. The annealing temperature must be between 400 and 600°C, and the annealing time of less than 5 minutes will result in insufficient precipitation, since Ni and Si in solid solution will significantly deteriorate the heat peeling properties of plated tin and solder. Therefore, it is uneconomical if it exceeds 4 hours, so 5 minutes ~
It is best to set it to 4 hours. Next, after performing temper finishing rolling,
Annealing for a short time of 5 to 60 seconds at a temperature of
The purpose is to recover the elongation decreased by rolling, reduce residual stress, and make it uniform.
At temperatures below 400°C, even if annealing is performed for 5 to 60 seconds, this effect is insufficient, and at temperatures above 600°C, the precipitated Ni and Si compounds re-dissolve into solid solution, making it difficult to meet the requirements. The annealing temperature must be between 400 and 600°C, since the properties of the annealing deteriorate, and if the annealing time is less than 5 seconds, the effects of elongation recovery and residual stress reduction and uniformity are insufficient, and Since this type of heat treatment is generally carried out in a continuous heat treatment line, if the annealing time exceeds 60 seconds, the productivity decreases and is uneconomical, so the annealing time is set to 5 to 60 seconds. [Example] An example of a semiconductor lead frame material and a manufacturing method thereof according to the present invention will be described. Example A copper alloy having the ingredients and proportions shown in Table 1 was melted in the atmosphere under charcoal coating using a Kryptor furnace, and then melted in a cast iron book mold.
After casting an ingot of 45mmT x 80mmW x 200mmL,
After facing the front and back sides of this ingot by 2.5mm, hot rolling at a temperature of 850℃ to 10mmT, cooling with water at a speed of 30℃/sec from a temperature of 600℃ or higher, removing scale, and rolling to a thickness of 0.5mmT. After cold rolling, it was annealed at a temperature of 500°C for 120 minutes, and then cold rolled to obtain a plate material of 0.25 mmT, and further,
Short-time annealing was carried out using a saltpetre furnace at a temperature of 500°C for 20 seconds. The test results for these samples are shown in Table 2. The test method is as explained below. (1) Tensile test was performed using JIS13 cut parallel to the rolling direction.
A No. B test piece was used, and the hardness was measured using a micro-Vickers hardness meter. (2) Repeated bendability was determined by punching out a 0.5 mm wide lead using a press as a test piece, suspending a 227 g weight from one end, and bending the test piece 90 degrees back and forth in one direction. It was counted as one time and was calculated as the average value of 5 samples. The bending axis is perpendicular to the rolling direction. (3) Stiffness strength was measured using a 0.25mmT x 10mmW x 60mmL test piece cut parallel to the rolling direction.
Bending was applied with a bending radius of 40 mm, and the bending moment was determined when the displacement angle was 10°. (4) Heat resistance was determined as hardness when heated at 450°C for 5 minutes using a saltpetre furnace. (5) The heat peeling property of solder was measured by using a weakly activated flux and soldering a sample in a Sn60-Pb40 solder bath at a temperature of 230°C, holding it at a temperature of 150°C for 500 hours, and then bending it 90°. The adhesion of the solder was examined.

【table】

[Table] As is clear from Table 2, No. 1 to No. 1 of the present invention.
It can be seen that No. 4 has overall excellent performance as a semiconductor lead frame material. Furthermore, it can be seen that the results are improved compared to Comparative Examples No. 5 and No. 6 as explained below. That is, since No. 1 of the present invention contains Sn, the strength, stiffness strength, and repeated bendability are improved compared to Comparative Example No. 5, and
Since it contains Mn, Mg, and Cr, hot workability is improved, and furthermore, because it contains Zn, the heat peeling resistance of the solder is improved. No. 2, No. 3, and No. 4 of the present invention contain Sn, so they have improved strength, stiffness strength, and repeated bendability compared to Comparative Example No. 6. Furthermore, since it contains one of Cr, Ti, and Zr, its hot workability is improved, and furthermore, because it contains Zn, its heat-resistant peelability is also improved. [Effects of the Invention] As explained above, the lead frame material for semiconductors and the method for manufacturing the same according to the present invention have the above-described configuration, and therefore have high strength and stiffness, and can withstand repeated bending. It has excellent properties such as excellent properties, high heat resistance, excellent heat peeling properties of solder, and excellent hot workability.

Claims (1)

[Claims] 1 Ni1.0~3.5wt%, Si0.2~0.9wt%, Mn0.02~
1.0wt%, Zn0.1~5.0wt%, Sn0.1~2.0wt%,
It is characterized by containing 0.001 to 0.01 wt% of Mg, further containing 0.001 to 0.01 wt% of one or more selected from Cr, Ti, and Zr, and the remainder substantially consisting of Cu. Lead frame material for semiconductors. 2 Ni1.0~3.5wt%, Si0.2~0.9wt%, Mn0.02~
1.0wt%, Zn0.1~5.0wt%, Sn0.1~2.0wt%,
An alloy ingot containing 0.001 to 0.01 wt% of Mg, and 0.001 to 0.01 wt% of one or more selected from Cr, Ti, and Zr, with the remainder substantially consisting of Cu. After hot rolling, cooling from a temperature of 600°C or more at a rate of 5°C/second or more, and after cold working, annealing at a temperature of 400 to 600°C for 5 minutes to 4 hours, followed by temper finish rolling. 1. A method for producing a lead frame material for semiconductors, which comprises performing short-time annealing for 5 to 60 seconds at a temperature of 400 to 600°C.