JPH05299479A - Bonding tool and its manufacture - Google Patents

Abstract

PURPOSE:To provide a bonding tool which will not easily cause the peeling-off or cracking of a film having a tip surface for pressing by applying a coating film on a shank member. CONSTITUTION:In a bonding tool having a film 14 containing gas phase synthesis diamond covering the surface of a tool body 11, at least a portion 13 forming the tip surface for thermocompression bonding of the film 14 is made of gas phase synthesis diamond, and a portion 12 in close contact with the tool body 11 at the film 14 is a tool where a metal, ceramics and gas phase synthesis diamond are mixed together.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a TAB bonding tool used in a semiconductor chip manufacturing process and a manufacturing method thereof.

[0002]

PRIOR ART AND PROBLEMS TO BE SOLVED BY THE INVENTION LS
In implementing I, the TAB method has begun to be used rapidly. The TAB method is a method of collectively joining a large number of electrodes formed on an LSI chip and lead wires on a film carrier tape with a heated bonding tool.

Since the bonding tool used in the TAB method is required to have high reliability to withstand repeated use at high temperature for a long time, it is necessary to use a material having excellent heat resistance and wear resistance. Will be.

In order to satisfy these required characteristics, a synthetic or natural diamond single crystal, a binderless cBN crystal body, a diamond sintered body or the like has been conventionally bonded and used at the tip portion of a bonding tool.

However, the natural diamond single crystal has a large variation in performance due to the fact that it contains a large amount of impurities and the crystal orientations are not uniform.
It was difficult to supply a large size of mm square or more.

On the other hand, although synthetic diamond single crystals are the most excellent material in terms of performance, they are very expensive as compared with other materials, so that they are used only in limited applications. is there.

In addition, the binderless cBN sintered body and the diamond sintered body are inferior in wear resistance to the material containing diamond as a main component, and the latter contain a binder, so that the tip end at a high temperature. There is a problem that the surface is largely warped and the lead wire cannot be uniformly pressed, and it is not always satisfactory for the user.

On the other hand, since vapor-phase-synthesized polycrystalline diamond (hereinafter abbreviated as vapor-phase synthetic diamond) does not contain a binder, the characteristics of the diamond material can be fully utilized and the size is large. Products can be supplied inexpensively and stably. For these reasons, vapor-phase synthetic diamond has recently been used as a suitable material for bonding tools.

Such vapor-phase synthetic diamond is produced by chemical vapor deposition (CVD) in which a raw material gas containing hydrocarbons such as methane and hydrogen as main components is decomposed and excited under a low pressure.

As a bonding tool using vapor phase synthetic diamond, for example, one obtained by brazing diamond obtained by vapor phase synthesis on a shank material can be mentioned. In such tools, the diamond is either brazed directly to the shank material, or deposited on a suitable substrate and brazed through this substrate.

On the other hand, a bonding tool has been developed in which a shank material is directly coated with diamond by vapor phase synthesis. For example, Japanese Unexamined Patent Publication No. 64-5026 discloses a tool in which a diamond film is formed by CVD on the surface of an integral stainless material to form a tip surface for pressure bonding. Such a tool can be manufactured in a smaller number of steps than a tool in which diamond is brazed to a shank material, and the cost can be kept low.

However, a tool in which a shank material is coated with diamond by vapor phase synthesis has low adhesion strength to the shank material of the diamond film, so that peeling or cracking of the film is likely to occur during use, resulting in poor durability. It was

It is an object of the present invention to provide a bonding tool having a shank material provided with a coating film and having a tip surface for pressure bonding, in which peeling or cracking of the film is unlikely to occur and which is more durable. To do.

[0014]

A bonding tool according to a first aspect of the present invention is a tool in which the surface of a tool base is covered with a coating containing vapor phase synthetic diamond, and the coating forms at least a tip surface for crimping. The part is composed of vapor-phase synthetic diamond, and the part of the above film that is involved in the adhesion with the tool substrate has a reduced content of vapor-phase synthetic diamond and has a thermal expansion coefficient closer to that of the tool substrate than diamond. It contains at least one of metal and ceramics.

Also provided is a method for manufacturing a bonding tool according to the first invention.

A method of manufacturing a bonding tool according to a second aspect of the present invention is a method of manufacturing a bonding tool in which the surface of a tool base is covered with a film containing vapor phase synthetic diamond, the tool base having a surface on which the film is to be formed. And a powder is formed on the above surface by vapor phase synthesis while supplying at least one powder of metal and ceramics having a thermal expansion coefficient closer to that of the tool substrate than diamond, to form a film. And a step of stopping the supply of metals and ceramics, continuing only the deposition of diamond by vapor phase synthesis, and completing the formation of the film.

In the first and second aspects of the invention, the material forming the tool base is, for example, Mo, W, Fe-N.
i alloy (for example, Invar), Fe-Ni-Co alloy (for example, Super Invar), Fe-Co-Cr alloy (for example, Stainless Invar), Fe-Pt alloy, F
e-Pd alloy, Kovar (29% Ni, 17% Co, F
e balance), Cu-W alloy, WC-Co alloy, WC-Ti
C-Co alloy, W-Ni alloy, stainless steel, etc. can be used.

In the first and second inventions, the metal contained in the film is, for example, Mo, W, Cr or C.
For example, SiC, Si ₃ N ₄ , WC and BN can be used as the ceramics.
Etc. can be used.

According to the present invention, the material contained in the portion involved in the adhesion with the tool substrate is selected from the above metals and ceramics in consideration of the adhesion with diamond, the adhesion with the tool substrate and the coefficient of thermal expansion. Therefore, it is desirable that appropriate ones be appropriately selected or combined.

Regarding the adhesiveness with the vapor phase synthetic diamond, SiC, Si ₃ N ₄ , WC, BN, Mo and W are more preferable, and the adhesiveness with diamond is SiC, Si ₃
Excellent in the order of N ₄ , WC, BN, Mo, W.

On the other hand, regarding the adhesion to the tool base made of the above-mentioned materials, Mo, W, Cr, Co, Ni, Fe
Is more preferable.

From the above, for example, a portion of the coating closer to the tool base contains a large amount of Mo, W, Cr, Co, Ni or Fe, which has excellent adhesion to the tool base, while the coating contains a gas. It is also preferable that a large amount of SiC, Si ₃ N ₄ , WC, BN, Mo or W is present in the portion closer to the phase-synthesized diamond.

In the first and second inventions, various vapor phase methods can be applied to the formation of diamond by vapor phase synthesis. For example, CVD using a thermoelectron emission or plasma discharge to decompose and excite a source gas, or C using a combustion flame
VD is valid.

As the raw material gas, for example, a gas containing a mixture of hydrocarbons such as methane, ethane and propane, organic carbon compounds such as alcohols and esters such as methanol and ethanol and hydrogen, and hydrogen can be used. .. In addition to these, an inert gas such as argon, oxygen, carbon monoxide, water, etc. may be contained in the raw material within a range not impairing the synthetic reaction of diamond and its characteristics.

In the present invention, the thickness of the film covering the tool substrate and containing the vapor-phase synthetic diamond is, for example, 5 to 1
0000 μm is preferable, and 200 to 1000 μm is more preferable.

In this coating, the thickness of the part which is made of vapor phase synthetic diamond and constitutes the tip surface of the tool is preferably, for example, 5% to 95% of the thickness of the entire coating.
0% to 60% is more preferable.

On the other hand, in this coating, the thickness of the portion that is involved in the adhesion to the tool substrate and contains metal or ceramics is, for example, preferably 5 to 95%, more preferably 40 to 80% of the thickness of the entire coating. ..

Further, in the present invention, the metal or ceramics may be contained in the portion of the coating which is in close contact with the tool substrate at a volume ratio of 20%, for example.

In the second invention, the powder of metal or ceramics contained in the coating is, for example, 0.1 to 10.
A particle size of 300 μm is preferable, and 0.2 to 60 μm.
It is more preferable that the particle size is

This powder can be brought into close contact with the diamond on the tool base by supplying it to the flow of the raw material gas used for the vapor phase synthesis of diamond. On this occasion,
The powder may be completely melted once, may be semi-molten, or may not be melted at all. Since the high temperature plasma jet has a temperature distribution, the state of the powder can be easily adjusted depending on where the powder is supplied. Furthermore, since the heat capacity varies depending on the size of the powder, the same control can be performed by changing the size.

The film formation while supplying such a powder can be carried out, for example, by a known CVD, but it is more preferably carried out by a thermal spraying process using high temperature plasma CVD.

[0032]

In the bonding tool according to the first aspect of the present invention, in the coating covering the surface of the tool base, the part constituting the tip surface is made of vapor phase synthetic diamond and is excellent in heat resistance, wear resistance and fracture resistance. ing.

Moreover, the portion forming the tip surface is bonded to the tool base through the portion in which metal or ceramics and vapor phase synthetic diamond are mixed.

The portion in which the metal or ceramics and diamond are mixed adheres to the tool base more strongly than diamond alone. Further, since the vapor-phase synthetic diamond contained in this portion follows the vapor-phase synthetic diamond constituting the tip surface, this portion and the portion constituting the tip surface are integrated as a film. Therefore, in the bonding tool of the present invention, a film having excellent heat resistance, wear resistance and chipping resistance is firmly adhered to the tool base on the surface thereof.

In addition, since the contained metals and ceramics have a coefficient of thermal expansion closer to that of the tool substrate than diamond, the coating contains the metal or ceramics, and the portion which is in close contact with the tool substrate has a difference in coefficient of thermal expansion during use. The internal stress caused by is smaller than before and plays a role in preventing peeling of the coating during use.

The portion containing metal or ceramics also plays a role in alleviating the difference in the coefficient of thermal expansion between the diamond forming the tip surface and the tool base. For this reason,
Repeated heat shock during use prevents the film from peeling or cracking.

Further, since the portion containing metal or ceramics improves the toughness of the coating, the coating is more excellent in wear resistance and fracture resistance.

As described above, in the bonding tool according to the first invention, the coating adheres more strongly to the tool base than the conventional tool directly coated with diamond, and the heat resistance and wear resistance of the operating surface are better. It has been improved. Such tools are more durable than conventional.

According to the manufacturing method of the second invention, first, diamond is deposited by vapor phase synthesis on the surface of the tool base while supplying powder of metal or ceramics having a thermal expansion coefficient closer to that of the tool base than diamond. Continue
A layer in which metal or ceramics and diamond are mixed is formed. As described above, this layer has excellent adhesion to the tool base and also plays a role of alleviating the difference in thermal expansion coefficient between the diamond and the tool base.

When the powder is supplied under the condition that the powder does not melt, it is also possible to grow diamond with the particles of the powder as nuclei, and a mixed phase with the supplied powder in which vapor phase synthetic diamond serves as a binder is obtained. The adhesion between diamond and powder is also very good.

In this manufacturing method, after the mixed layer is formed on the tool substrate to have an appropriate thickness, the powder supply is stopped and the diamond vapor phase growth is continued. Thereby, the tool tip surface made of diamond can be formed. As described above, this tip surface has excellent heat resistance, wear resistance, and fracture resistance.

Further, by stopping the supply of powder and continuing the vapor phase synthesis of diamond, a film in which the mixed layer and the diamond layer are integrated can be formed, and this film has been described above. It strongly adheres to the tool base and has excellent durability.

The above steps are also useful, for example, when forming a tool in which a film is strongly adhered to a curved surface.

Further, such a film forming step is a series of steps, and once the tool substrate is set in, for example, a CVD apparatus, the diamond is deposited while the powder supply timing is appropriately set to perform the bonding operation. It is possible to complete a bonding tool in which the film forming the surface is strongly adhered to the tool base.

As described above, according to this manufacturing method,
With a very simple process, a bonding tool with excellent durability can be manufactured, and the cost thereof can be suppressed.

[0046]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows an apparatus for forming a coating on a tool substrate in manufacturing the bonding tool of the present invention.

A method of manufacturing a tool according to the present invention will be described below with reference to the drawings. The apparatus shown in FIG. 1 is for performing high temperature plasma CVD and has an exhaust port 5
A cathode 2 for discharging into a vacuum chamber 1 that can be evacuated from
And an anode 3 is provided. Between the cathode 2 and the anode 3,
A DC voltage is applied by the power supply 4.

As shown by the arrow in the figure, the raw material gas for synthesizing diamond is supplied through between the electrodes, and is decomposed and excited by the discharge at the supply port 6 to generate plasma. In the series of operations from plasma generation to diamond formation, the vacuum chamber 1
The inside is under low pressure.

The generated plasma hits the surface of the shank 8 provided in the moving direction of the shank 8 and set in the holder 7 to grow diamond. When metal or ceramic fine powder is supplied onto the shank 8 through the pipe 9 simultaneously with the diamond growth, a layer in which the metal or ceramic and diamond are mixed is formed on the shank surface. At this time, by adjusting the supply position of the powder, the powder can be supplied to the surface of the base material in any of the molten, semi-molten and unmelted states.

When this layer has an appropriate thickness, the supply of metal or ceramics is stopped, diamond deposition is further continued, and a diamond layer is deposited with an appropriate thickness.

As described above, the tip end surface is made of at least diamond, and a film in which metal or ceramics and diamond are mixed is formed at the contact portion with the shank.

Using the above apparatus, a known high temperature plasma C
According to the VD method, first, a diamond composite layer having a thickness of about 100 μm was formed on a shank made of Mo. The formation conditions are as follows.

Raw material gas (flow rate): CH ₄ / H ₂ = 2%, Ar / H ₂ =
100%, total flow rate 3000 cc Pressure: 150 Torr Substrate temperature: 900 ° C. Discharge voltage: 60 V Discharge current: 60 A Supply powder: SiC and Mo having a particle size of 20 to 30 μm Supply amount: 1 g / min, total amount 30 g At this time, Mo is melted , SiC was supplied as a powder under the condition that it was not melted.

Next, under the above conditions, only the powder supply was stopped and diamond was deposited to a thickness of about 200 μm.

Thereafter, the shank coated with the film was taken out from the apparatus and the diamond surface at the tip was lapped to form a tip surface with R _max = 0.1.

The main part of the tool thus produced is as shown in FIG. 2A, and in the bonding tool 10, the diamond composite layer 12 and the diamond layer 13 containing SiC and Mo on the shank 11 are provided.
A coating film 14 is sequentially deposited.

The overall shape of the bonding tool 10 is as shown in FIG. 2 (b), and the coating 14 is provided on the tip of the shank 11 of the integral body made of Mo.

A durability test of the bonding tool constructed as described above was carried out by mounting it on a bonding apparatus, and it was able to withstand 1.2 million uses.

Comparative Example On the other hand, a diamond film was formed on the shank of the same material under the following conditions using the same apparatus as in the above-mentioned example without supplying powder.

Raw material gas (flow rate): CH ₄ / H ₂ = 3%, Ar / H ₂ =
100%, total flow rate 3000 cc Pressure: 200 Torr Substrate temperature: 880 ° C. Discharge voltage: 70 V Discharge current: 62 A Attempts to form a diamond film of about 150 μm on the shank under the above conditions. Peeled off from the shank material made of Mo.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an apparatus for manufacturing a bonding tool according to the present invention.

2 (a) is a sectional view and FIG. 2 (b) is a side view showing a specific example of a bonding tool according to the present invention.

[Explanation of symbols]

 1 Vacuum Chamber 2 Cathode 3 Anode 4 Power Supply 5 Exhaust Port 7 Holder 8 Shank 10 Bonding Tool 11 Shank 12 Diamond Composite Layer 13 Diamond Layer 14 Film

Claims (2)

[Claims] 1. A bonding tool in which the surface of a tool substrate is covered with a film containing polycrystalline diamond that has been vapor-phase synthesized, and at least a portion of the film that constitutes the tip surface for pressure bonding is made of vapor-phase synthetic diamond. And, the portion of the coating involved in the adhesion with the tool substrate, the content of the polycrystalline diamond is reduced, and at least one of metal and ceramics having a thermal expansion coefficient closer to the tool substrate than diamond. Contains or
Bonding tool. 2. A method of manufacturing a bonding tool, which comprises covering the surface of a tool substrate with a film containing polycrystalline diamond that has been vapor-phase synthesized, the method comprising the step of preparing a tool substrate having a surface on which the film is to be formed. On the surface, while supplying at least one powder of metal and ceramics having a thermal expansion coefficient closer to the tool base than diamond, a step of depositing diamond by vapor phase synthesis to form the film, A method of manufacturing a bonding tool, comprising the steps of stopping the supply of the metal and ceramics, continuing only the deposition of diamond by vapor phase synthesis, and completing the formation of the film.