JP3275786B2 - Pressure welding tool for IC chip lead material bonding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to
The present invention relates to a pressure welding tool for bonding a lead material of an IC chip, which hardly accumulates residual stress over time, and therefore does not cause cracking of a substrate or peeling of brazing even when the size is increased.

[0002]

2. Description of the Related Art Conventionally, in general, when manufacturing an IC chip, as shown in, for example, a schematic explanatory view of FIG. The tip of a lead material such as a Cu alloy is heated to 500 to 1000 ° C. by a built-in heater via a bump such as an Au-In alloy (solder material) formed on the surface of an IC chip in the same arrangement as the lead material. Bonding is performed by reducing the pressure with a heated pressure welding tool. In addition, as a pressure welding tool used for bonding a lead material of an IC chip,
For example, as described in Japanese Patent No. 2520971, a tool body has a thickness of 0.5 to 5 mm, and
A hot filament method, a microwave plasma CVD method, and a high-frequency plasma CV are applied to the surface of a substrate made of an iC-based sintered body, a Si ₃ N ₄ -based sintered body, or an AlN-based sintered body.
The tool body is formed by forming a polycrystalline diamond film having an average layer thickness of 5 to 300 μm using a vapor phase synthesis method such as the D method.
There is known a structure in which a shank portion containing a heater made of a C-base cemented carbide or the like is joined using a brazing material made of various Cu alloys, Ag alloys, or the like.

[0003]

On the other hand, in recent years, high integration of semiconductor devices has been remarkable, and as a result, the area of IC chips has increased, and the press-fitting tools used for manufacturing the same have tended to increase in size. In addition to the above-mentioned conventional press-welding tools, in many other press-welding tools, the larger the size of the tool, the more likely it is that cracks will occur in the body of the tool body constituting the press-welding tool in practical use,
At present, peeling tends to occur at the brazing portion between the base and the shank portion, and shortening of service life is inevitable.
This is considered to be caused by the repetition of the working mode, that is, the step of pressing the welding tool heated to 500 to 1000 ° C. to the lead material at room temperature and heating the bumps to the melting temperature via this lead material to perform the bonding. In this case, the press-welding tool, especially the substrate constituting the same, is subjected to rapid repetition of heating and cooling. At the same time, the residual stress generated at the same time accumulates over time, and the residual stress in the substrate is reduced by the press-welding tool. It is understood that the larger the size, the larger the size of the residual stress, and finally, the accumulated and increased residual stress causes substrate cracking and brazing peeling.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above-mentioned viewpoints, as a result of researching to develop a pressure welding tool that generates little residual stress and does not accumulate the residual stress over time even when repeatedly subjected to rapid heating and cooling, the base of the pressure welding tool was obtained. Is a solid solution of carbon and nitride of Ti and W (however, the proportion of W is 5-40% of the total amount with Ti).
%): 5 to 60% by weight, and the balance is made of ceramics having a composition of tungsten carbide (hereinafter, referred to as WC) and unavoidable impurities.
g: 5 to 15%, P: 1 to 10%, and if necessary, Ti and / or Zr: 0.5 to 10%, the balance being Cu having a composition consisting of Cu and inevitable impurities. Alloy, and further, the shank portion is Cr: 1
Ni alloy having a composition of 0 to 25% and Fe: 5 to 15%, with the balance being Ni and unavoidable impurities (above,%
Indicates weight%. The same applies to the following)
The resulting pressure welding tool not only has the property that the base does not easily generate residual stress, and the brazing material not only acts to suppress the accumulation of residual stress, but also brazes the base and the shank. It is also excellent in heat resistance, so even if it is made larger, it will not crack or peel off by brazing, and, combined with the excellent heat resistance secured by the shank portion, can be used for a remarkably long period of time. The research result was obtained.

The present invention has been made on the basis of the above-mentioned research results. A tool body formed by vapor-phase synthesis deposition of a polycrystalline diamond film on the surface of a substrate is provided by using a brazing material and a shank having a built-in heater. In the press-welding tool having a structure joined to the portion, the base of the tool main body is formed of a carbon-nitride solid solution of Ti and W in a ratio of 5 to 40% of the total amount of Ti with W (hereinafter, (Ti, W ) Represented by CN): 5 to 60%, the remainder being composed of ceramics having a composition consisting of WC and unavoidable impurities.
5 to 15%, P: 1 to 10%, and, if necessary, Ti and / or Zr: 0.5 to 10%, with the balance having Cu and inevitable impurities. It is composed of a Cu alloy, and further, the shank portion is made of C
r: 10 to 25%, Fe: 5 to 15%, and the remainder is composed of a Ni alloy having a composition of Ni and unavoidable impurities.
The present invention has a feature in a press-contact tool for bonding a lead material of a C chip.

In the pressure welding tool of the present invention, the thickness of the polycrystalline diamond film formed on the surface of the substrate by the ordinary vapor phase synthesis method is such that the thickness of the substrate is 2 to 5 mm, The thickness is desirably 30 to 100 μm. When forming the polycrystalline diamond film, as a pretreatment, the substrate is pressed at a pressure of 10 to 76 μm.
0 torr nitrogen or Ar atmosphere, temperature: 1350-
Heat treatment under the condition of holding at 1550 ° C. for a predetermined time,
A Ti-based carbonitride-enriched layer is formed on the surface of
It is preferable to improve the adhesion of the polycrystalline diamond film by forming an average layer thickness of 0 μm and setting the surface roughness of the substrate to S: 5 to 20 μm.

Next, the reason why the compositions of the base, the brazing material and the shank constituting the press-welding tool of the present invention are determined as described above will be described. (1) Substrate Basically, a ceramic substrate having a two-phase structure of a (Ti, W) CN phase and a WC phase has a property that a residual stress is hardly generated even when subjected to repeated heating and cooling as described above. Has a ratio of 5 to 40%, preferably 10 to 3%, of the ratio of W in (Ti, W) CN to the total amount with Ti.
5%, and the ratio of (Ti, W) CN to the total amount of WC and 5-60%, preferably 15-50%.
i, W) 40% even if the ratio of W in CN is less than 5%
, The ratio of (Ti, W) CN is still 5%.
% Or more than 60%, it is impossible to stably secure the property that the residual stress is hardly generated. These have been obtained empirically and have been determined as described above based on these results.

(2) Brazing filler metal (a) Ag The Ag component has a function of lowering the melting point of the brazing filler metal, thereby increasing the fluidity and enabling satisfactory brazing with a small amount of brazing filler metal. In the coexistence with the Cu component, which is the main component of, there is an effect of absorbing the residual stress, thereby suppressing the accumulation of the residual stress with time, and promoting heat transfer from the heated shank portion to the base. Content is 5%
When the content is less than 15%, the desired effect cannot be obtained. On the other hand, when the content exceeds 15%, the strength of the brazed portion decreases, so that the content is 5 to 15%, preferably 7%. １３13%.

(B) The PP component has the effect of lowering the melting point of the brazing material and improving its own strength, thereby improving the strength of the brazed portion. If the desired effect cannot be obtained in the above-mentioned action, and if the content exceeds 10%, the brazed portion rapidly becomes brittle,
The content was determined to be 1 to 10%, preferably 3 to 8%.

(C) Ti and Zr These components are contained as necessary because they have the function of further improving the wettability of the brazing material to the tool body and the cutting piece and thereby improving the joining strength. If the content is less than 0.5%, the desired effect cannot be obtained in the above-mentioned action,
On the other hand, if the content exceeds 10%, the strength of the brazed portion will decrease, so that the content is 0.5 to
10%, preferably 1 to 6%.

(3) Shank section The shank section has its own 50 heaters by a built-in heater.
It is required to have excellent heat resistance and oxidation resistance because it has a role of heating to 0 to 1000 ° C. and maintaining the temperature of the brazed tool body at the same temperature. Therefore, the Cr component of the Ni alloy constituting the shank portion is:
Although it is contained as a component for improving heat resistance and oxidation resistance, if the proportion is less than 10%, desired heat resistance and oxidation resistance cannot be secured, while the proportion is 25%.
, The strength is reduced, so the ratio is set to 10 to 25%. Similarly, the Fe component has the effect of improving the strength, but the proportion is 5%.
If the ratio is less than 15%, the desired strength cannot be ensured. On the other hand, if the ratio exceeds 15%, the heat resistance and the oxidation resistance tend to decrease.
It was determined to be 5%.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The press-contact tool of the present invention will be specifically described with reference to embodiments. First, for the purpose of manufacturing a substrate, each of the raw material powders has an average particle size of 1.2 μm,
The ratio of W to the total amount with Ti (hereinafter the same) 5
% (Ti, W) CN [weight ratio (the same applies hereinafter), WC /
TiC / TiN = 0.5 / 60/35, hereinafter, (Ti,
(W) CN- (1)) powder, (Ti, W) CN having a W content of 10% [WC / TiC / TiN = 10/50
/ 40, hereafter referred to as (Ti, W) CN- (2)) powder, (Ti, W) CN with 15% W [WC / Ti
C / TiN = 15/45/30, hereinafter, (Ti, W) C
N- (3)) and 20% of W (Ti,
W) CN [WC / TiC / TiN = 20/45/35,
(Ti, W) CN- (4)) (Ti, W) CN [WC / TiC / TiN] in which the proportion of W is 25%
= 25/40/35, hereinafter, (Ti, W) CN- (5)
(Ti, W) CN containing 30% of powder and W
[WC / TiC / TiN = 30/40/30, hereinafter,
(Ti, W) CN- (6)) powder, the proportion of W is 3
5% of (Ti, W) CN [WC / TiC / TiN = 35
/ 40/25, hereafter referred to as (Ti, W) CN- (7)) powder, (Ti, W) CN [WC
/ TiC / TiN = 40/40/20; hereinafter, (Ti,
W) CN- (8)) powder and WC powder having an average particle size of 1.0 μm are prepared, and these raw material powders are respectively blended into the blending composition shown in Table 1, and wet-mixed in a ball mill for 72 hours. Then, after drying, it is press-molded into a green compact at a pressure of 1 ton / cm ² , and the green compact is nitrided under the conditions of N ₂ gas partial pressure: 200 torr, temperature: 1350 ° C., and holding for 1 hour. Similarly, sintering was performed under the conditions shown in Table 1 (however, the holding time at the sintering temperature was 1 hour).
HIP treatment is performed at 1350 ° C. for 1 hour, and the length is further machined to 10 mm × width: 4 mm × thickness:
In a nitrogen atmosphere at a predetermined pressure within a range of 10 to 200 torr, the size is set to 1350 to 150
By subjecting the WC grains on the surface to coarsening heat treatment at a predetermined temperature in the range of 0 ° C. for 0.5 hour,
H were each manufactured.

Next, as a pretreatment, the surfaces of the substrates A to H were first immersed in a 5% nitric acid aqueous solution for 10 minutes to clean the surface, and further dispersed and contained diamond powder having an average particle diameter of 0.5 μm. In a state where the ultrasonic surface damage treatment was performed under the condition of holding in alcohol for 10 minutes, this was charged into a usual microwave plasma CVD apparatus, and the reaction gas composition was CH ₄ (flow rate: 10 cc / min) + H.
₂ (flow rate: 500 cc / min), atmosphere pressure: 50 torr, microwave output: 2 kW, substrate temperature: 900 ° C., and vapor phase synthesis was performed. Tool bodies A to H were each manufactured by forming a polycrystalline diamond film having the average layer thickness shown.

In a graphite crucible, a Cu alloy melt having the composition shown in Table 3 was prepared, cast into an ingot, and hot-rolled into a hot-rolled sheet having a thickness of 0.2 mm. The rolled sheet was subjected to cold rolling to produce brazing materials a to h each having a thickness of 0.1 mm.

Further, in the same graphite crucible, Ni alloy melts having the compositions shown in Table 4 were prepared, precision cast (lost wax method), and then machined to obtain the same dimensions as the surface dimensions of the substrate. The shank parts A to O having the brazing surfaces of No. 1 to No. 3 were manufactured.

Next, the tool body, the brazing material, and the shank are set in a combination shown in Table 5,
The crimping tools 1 to 8 of the present invention were manufactured by brazing the tool main body to the shank portion via a brazing material under the condition of holding at a predetermined temperature in the range of 850 to 1000 ° C. for 10 minutes in an Ar atmosphere. .

For comparison purposes, each of the tool bodies has a polycrystalline diamond film having an average layer thickness of 50 μm, but the substrate is made of Si ₃ N ₄ -5% Y ₂ O ₃ -3.
% Al ₂ Si ₃ N ₄ groups sintered body having a composition consisting of O ₃ (hereinafter referred to as tool body J), AlN-3% Y 2 O 3 -
AlN-based sintered body having a composition of 2% CaO (hereinafter, referred to as tool body K) and SiC-based sintered body having a composition of SiC-2% B ₄ C (hereinafter, tool body L)
And a shank portion of Fe-19.7% N
i-19.3% Co-0.95% Mn The shank portion (hereinafter referred to as shank portion) of a Fe-Ni-Co alloy having a composition of Mn and Cu-32% Z as a brazing material.
Cu-Zn-Ag having a composition consisting of n-30% Ag
The comparative pressure welding tools 1 to 3 were manufactured under the same conditions except that an alloy brazing material (hereinafter, referred to as brazing material i) was used.

With respect to the press-welded tools 1 to 8 of the present invention and the comparative press-welded tools 1 to 3 obtained as described above, the tip surface of the polycrystalline diamond film was machined to a length of 15 mm × width: 5 mm and the surface roughness was set to Rmax. Then, an accelerated durability test was performed under the following conditions in a state of being polished to 0.8 μm. That is, in the accelerated durability test, oxygen-free copper and an Al alloy (containing 2% of Si) were used instead of the IC chip and the lead material shown in FIG. 1, and both had a surface of 20 mm × 10 mm and a thickness of 10 m.
m dimension, one surface dimension is 0.5mm x
Using a water-cooled box in which 0.5 mm is provided and two protrusions each having a height of 3 mm are arranged in two rows along the length direction by 10 pieces, and the above various press-welding tools are provided on the surface of the water-cooled box on which the protrusions are provided. While heating at 600 ° C., one cycle was performed for 8 seconds with a load of 10 kg, and 3 seconds of the cycle was used as a press contact time, and the number of cycles until the service life was reached was measured. Table 5 shows the results of these measurements.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

[Table 4]

[0023]

[Table 5]

[0024]

According to the results shown in Table 5, the press-welding tools 1 to 8 of the present invention can suppress the generation of residual stress by the combination of the base, the brazing material, and the shank as described above.
In addition, since the accumulation of residual stress with time is prevented, excellent durability is exhibited over a long period of time without occurrence of substrate cracking or brazing peeling. It is also clear that the service life can be reached in a relatively short time due to cracking of the substrate or brazing. As described above, the press-welding tool of the present invention can be used for a long period of time without causing cracks in the substrate or peeling off by brazing even if the tool is enlarged, so that it is sufficiently satisfactory for high integration of semiconductor devices. Corresponding.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a use mode of a pressure welding tool.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/60

Claims (2)

(57) [Claims] 1. A press-welding tool having a structure in which a tool body formed by vapor-phase synthetic deposition of a polycrystalline diamond film on a surface of a base is joined to a shank portion with a built-in heater using a brazing material. , A carbon nitride solid solution of Ti and W (where W is 5 to 40% by weight based on the total amount of Ti): 5 to 60% by weight, with the balance being tungsten carbide and inevitable impurities. The brazing material is made of a Cu alloy containing Ag: 5 to 15% by weight, P: 1 to 10% by weight, and the balance being Cu and inevitable impurities. Further, the shank portion is made of a Ni alloy containing Cr: 10 to 25% by weight, Fe: 5 to 15% by weight, and the balance being composed of Ni and unavoidable impurities. Base Crack brazing peeled IC chip lead material bonding crimping tool with no occurrence of. 2. A pressure welding tool having a structure in which a tool body formed by vapor-phase synthetic deposition of a polycrystalline diamond film on a surface of a base is joined to a shank portion containing a heater using a brazing material. , A carbon nitride solid solution of Ti and W (where W is 5 to 40% by weight based on the total amount of Ti): 5 to 60% by weight, with the balance being tungsten carbide and inevitable impurities. And a brazing material comprising: Ag: 5 to 15% by weight, P: 1 to 10% by weight, and Ti and / or Zr: 0.5 to 10% by weight. %, The balance being Cu and a composition consisting of unavoidable impurities
the shank portion is made of a Ni alloy containing Cr: 10 to 25% by weight, Fe: 5 to 15% by weight, and the balance being composed of Ni and unavoidable impurities. A pressure welding tool for bonding a lead material of an IC chip, which is free from cracking of a substrate and peeling of a braze.