JPH08181173A - Flip-chip bonding tool and its manufacture and mounting method using the same - Google Patents

Abstract

PURPOSE: To prevent thermal damage of surface roughness and flatness of a tool surface and maintain the excellent state for a long term, by specifying the surface roughness, the flatness and the maximum temperature difference of a pressing surface at the tip of a tool which is composed of diamond and has a vacuum suction hole. CONSTITUTION: A tool is used in mounting of a flip-chip bonding method which directly mounts an LSI on a board. The tool tip surface acting as a pressing surface at the time of mounting is coated with diamond 3. The temperature of the pressing surface is controlled to be equal to the application temperature of the tool in the range of 200-400 deg.C. In this state, polishing is performed in the manner in which the flatness of the pressing surface in the range that the highest temperature of the pressing surface is 230-400 deg.C is 5μm or lower, and the surface is in the state of a mirror surface whose Rmax designation is 0.1μm or lower. At least a vacuum suction hole 4 which is opened in the pressing surface at the tool tip is installed, and the maximum temperature difference in the pressing surface is made 30 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flip chip type mounting tool for directly mounting an LSI on a printed wiring board or a glass substrate.

[0002]

2. Description of the Related Art In recent years, various electronic devices using semiconductor elements have been developed, and the technological progress in this field is remarkable. In order to bring out the electrical characteristics of the electronic components that make up these electronic devices and to bring out their full performance, it is necessary to join the joining members.

Among various mounting methods, recently, a mounting method using a wireless bonding technique which does not use a bonding wire has been attracting attention due to its excellent features such as high mounting efficiency and flexibility in package design. .

Among the wireless bonding methods, particularly in the flip-chip mounting method, bumps formed on an LSI are used to directly bond to the substrate, so that it is possible to cope with a narrower pitch of substrate leads and to improve the mounting efficiency. Technology is being developed as a possible mounting method.

Actually, this mounting method is adopted for mounting an MPU such as a workstation or a personal computer, or mounting a driver LSI on a glass substrate in manufacturing a liquid crystal panel.

In the mounting of the MPU, since the bumps made of solder are melted and bonded, a tool heated directly or indirectly to a temperature range of 200 to 400 ° C. is used to vacuum-adsorb the LSI, and then the LSI is fixed. Press for a time, then 20
A mounting method is adopted in which the pressure is released after cooling to 0 ° C. or less.

In the liquid crystal panel manufacturing process, since the driver LSI is mounted on the glass substrate via the thermosetting ACF (anisotropic conductive sheet), other than the above method, 200 to 400 ° C. In a mounting method in which the LSI is vacuum-sucked and conveyed, and then pressed for a certain period of time while being directly or indirectly always heated to the temperature range.

[0008]

In any of the mounting methods, the temperature is constantly or intermittently set to a high temperature, so that excellent heat resistance is required as a characteristic of the tool. That is, since the tool needs to directly press the LSI without damaging the LSI, the surface roughness and flatness of the tool tip surface need to be kept in a good state for a long time without being damaged by heat. However, the metal tools such as Invar alloy and Mo that have been conventionally used have a problem that their characteristics are gradually deteriorated.

Furthermore, since the heated and sublimated solder and resin solidify and adhere to the tool surface, it is necessary to clean it regularly. Cleaning is performed by directly removing the deposits from the tool surface mechanically.However, in the case of conventional tools, the tip surface is scraped off and the shape changes,
Another problem is that good mounting work cannot be continued.

In order to solve the above problems, the present inventor has conducted extensive studies based on the prior art described in Japanese Patent Application No. 6-62905, and as a result, has completed a tool that meets the demands of the market. .

[0011]

The present invention includes the following (1) to (1).
A mounting tool having the feature (4), a method for manufacturing the mounting tool, and a mounting method are provided.

(1) A tool used in the mounting of a flip chip mounting method for directly mounting an LSI on a substrate, wherein the pressing surface at the tip of the tool has a surface roughness of 0.1 μm or less in Rmax display. Which is made of polycrystalline diamond according to the method and has at least one vacuum suction hole opened in the surface, and the flatness of the pressing surface in the maximum temperature range of 230 to 400 ° C. 5
A flip-chip mounting tool characterized in that it has a characteristic that the maximum temperature difference in the pressing surface is 30 μC or less, and the μm or less.

(2) The step of coating the tool tip surface, which is the pressing surface at the time of mounting, with polycrystalline diamond, and the temperature of the pressing surface is controlled to be the same as the tool operating temperature in the range of 200 to 400 ° C. However, the maximum temperature of the pressing surface is 230 ~
A method of manufacturing a flip-chip mounting tool, which comprises at least a flatness of the pressing surface in a range of 400 ° C. of 5 μm or less, and a polishing step of making the surface into a mirror surface state of 0.1 μm or less in Rmax display. .

(3) The pressing surface is made of polycrystalline diamond by the vapor phase synthesis method, and the surface is 0.1 μm in Rmax display.
In the following mirror state, and the maximum temperature of the pressing surface is 230-4
The flatness of the pressing surface under the condition of 00 ° C. is 5 μm or less,
A tool having a characteristic that the maximum temperature difference in the pressing surface is 30 ° C or less is directly or indirectly heated to a temperature range of 200 to 400 ° C, and is pressed for a certain period of time after vacuum suctioning and transferring the LSI. By doing so, the flip-chip mounting method is characterized in that it is mounted on the substrate via a bonding member.

(4) The pressing surface is made of polycrystalline diamond by the vapor phase synthesis method, and the surface has a Rmax value of 0.1 μm.
In the following mirror state, and the maximum temperature of the pressing surface is 230-4
The flatness of the pressing surface under the condition of 00 ° C. is 5 μm or less,
A tool having a characteristic that the maximum temperature difference within the pressing surface is 30 ° C. or less is directly or indirectly heated to a temperature range of 200 to 400 ° C., and the LSI is vacuum-sucked and conveyed, and then pressed for a certain period of time. Then, the flip-chip mounting method is characterized in that the substrate is mounted on the substrate via a bonding member by releasing the pressure after cooling to 200 ° C. or less.

[0016]

In carrying out the present invention, it is essential that the mounting pressing surface at the tip of the tool is made of polycrystalline diamond by the vapor phase synthesis method. That is, the polycrystalline diamond produced by the vapor phase synthesis method has excellent heat resistance and wear resistance,
The advantage is that it can be manufactured at low cost.

Further, in order to meet the demands of the market, the pressing surface at the tip of the tool is composed of polycrystalline diamond by a vapor phase synthesis method having a surface roughness of 0.1 μm or less in Rmax, and is opened in the surface. It has at least one vacuum suction hole, and the maximum temperature of the pressing surface is 230
It is necessary that the flatness of the pressing surface in the range of up to 400 ° C. is 5 μm or less and the maximum temperature difference in the pressing surface is 30 ° C. or less.

When manufacturing the above tool, it is preferable to adopt the tool structure described in Japanese Patent Application No. 6-62905. That is, a structure in which polycrystalline diamond is directly coated on a specific cemented carbide shank, or a specific cemented carbide substrate is coated with polycrystalline diamond, and then the polycrystalline diamond-coated cemented carbide is formed into a metal or alloy. It is a structure that is joined to a manufactured shank by means such as brazing. In particular, the latter structure is a more preferable structure because it has a high degree of freedom in terms of shank workability and tool characteristics.

The cemented carbide for coating polycrystalline diamond has microscopic projections of hard carbide and / or hard carbonitride on at least one surface of the coated surface,
The linear expansion coefficient from room temperature to 400 ° C is 4.0 × 10 ^-6 ~
A cemented carbide of 5.5 × 10 ⁻⁶ / ° C. is used.

When such a substrate is coated with polycrystalline diamond according to the specifications described below, a tool material having high adhesion strength between the coated polycrystalline diamond and the substrate and excellent strength and thermal response is realized. be able to.

It is considered that the reason why the adhesion strength is improved with this substrate is that since the surface of the cemented carbide having microscopic projections is coated with polycrystalline diamond, the peeling resistance is enhanced by the so-called anchor effect. Further, the coefficient of linear expansion of the cemented carbide from room temperature to 400 ° C. is 4.0 × 10 ^{−6 to} 5.5.
By defining × 10 ^-6 / ° C, it becomes possible to suppress the thermal stress due to the difference in thermal expansion between the coated polycrystalline diamond and the base material to a small level, and this excellent adhesion can be achieved even at high temperatures when the bonding tool is used. The strength can be maintained.

More specifically, the material of the cemented carbide as the base material is composed of hard carbides of carbides of the IVa.Va.VIa group elements of the periodic table and / or solid solutions thereof, and has a WC of 70 to 70%. 95% by weight, periodic table other than WC IV
It can be expressed as containing 2 to 25% by weight of carbides of a.Va.VIa group elements and the remaining% by weight of iron group metals.
Within this composition range, microscopic projections of hard carbide and / or hard carbonitride can be generated by the heat treatment described later, and the anchor effect can be effectively exhibited. In addition, regarding the coefficient of linear expansion,
4.0 × 10 ^{−6 to} 5.5 × 10 ⁻⁶ / in the range up to 00 ° C.
It can be controlled in the range of ° C. In addition, as the iron group metal to be contained, it is particularly preferable to use Co from the viewpoint of wettability with a hard carbide that affects sinterability.

The length of the microscopic projections composed of hard carbide and / or hard carbonitride on the surface of the cemented carbide after heat treatment is preferably 2 to 10 μm. When the length of the protrusions is regulated within this range, a remarkable anchor effect is not seen when the length is shorter than 2 μm, and when the length is longer than 10 μm, a large amount of space is left between the protrusions when the polycrystalline diamond is coated in the subsequent step. This is because it becomes difficult to generate crystalline diamond, and on the contrary, high adhesion strength cannot be obtained.

In order to form such microscopic projections of hard carbide and / or hard carbonitride on the surface, the linear expansion coefficient from room temperature to 400 ° C. is 4.0 × 10 ^{-6 to} 5.5. ×
10 ⁻⁶ / ° C., and as hard carbide, IVa of the periodic table
-Va / VIa group element carbide and / or solid solution thereof, and its composition is 70 to 95% by weight of WC, and 2 to 25 weight% of IVa / Va / VIa group element carbide other than WC. %, And a cemented carbide containing an iron group metal in a residual weight% of N ₂ or CO atmosphere of 10 to 760 Torr at a temperature of 900 to 1,500 ° C. for 0.5 to 3 hours, and then N ₂ , CO, an inert gas, or a heat treatment for cooling to room temperature in a vacuum atmosphere is required. By this treatment, the periodic table IVa, Va, which is a constituent of cemented carbide,
The carbide of the VIa group element moves to the surface of the cemented carbide and is further recrystallized to grow into microscopic projections. The microscopic protrusions may partly be nitrided by the heating atmosphere and eventually become carbonitride or a mixed phase of carbide and carbonitride, but the adhesion strength is only carbide. As good as.

Here, if the pressure / gas atmosphere in the heating conditions is out of the above specified range, no microscopic protrusions of hard carbide and / or hard carbonitride are generated, or the length is within the above range. It is not preferable because it will not be possible. Further, the heating temperature and the holding time thereof are regulated at a temperature lower than 900 ° C. or a holding time shorter than 0.5 hours, in which carbides of the IVa, Va, and VIa group elements of the periodic table are superhard. This is because it is difficult to move to the surface of the alloy, and the formation of protrusions becomes insufficient. On the other hand, if the temperature is higher than 1,500 ° C. or the holding time is longer than 3 hours, the grain growth of hard carbides and / or hard carbonitrides growing on the surface becomes remarkable and the strength is lowered, which is not preferable.

Incidentally, with the formation of microscopic projections by the above heat treatment, the iron group metal, which was the binder of the cemented carbide, is also eluted on the surface. This iron group metal no longer acts as a binder for cemented carbide, and in the coating step of polycrystalline diamond described below, it has the effect of converting precipitated diamond into graphite, so remove it before the coating step. is necessary. For removing the iron group metal on the surface, a method of immersing the heat-treated cemented carbide in an acid to dissolve it is preferable. As the acid that can be used in this case, hydrochloric acid, nitric acid or the like or a mixed acid thereof which does not dissolve the carbide or carbonitride but dissolves only the iron group metal is effective. The dissolution treatment can be carried out at room temperature, but the treatment can be carried out more efficiently by heating under pressure. Since the microscopic projections generated by the heat treatment of the cemented carbide in the present invention are formed in layers so as to completely cover the surface of the cemented carbide, the acid that dissolves the iron group metal on the surface is As a result, the iron group metal that is the binder of the cemented carbide is not dissolved by penetrating into the inside.

Before performing these heat treatments, it is necessary to previously make a hole through the surface opposite to the surface to be coated with polycrystalline diamond. This is the LSI when mounting
Is a hole for vacuum adsorption, and it is not preferable because the property of the surface created by the heat treatment may be affected in the processing after the heat treatment. Further, even after the coating treatment of the polycrystalline diamond, the polycrystalline diamond may be damaged due to processing, which is not preferable.

The cemented carbide surface-modified by the above method is used as a base material, and the surface having microscopic projections is coated with polycrystalline diamond by a vapor phase synthesis method. Here, a known method can be applied as the vapor phase synthesis method performed for coating the polycrystalline diamond. That is, various kinds of CVD (Chemical Vapor Deposition) method and thermal burning flame method which cause decomposition / excitation of the raw material gas by utilizing plasma discharge or thermionic emission can be used. As the raw material gas, for example, a mixed gas of hydrogen with a substance containing carbon as a constituent element such as hydrocarbons such as methane, ethane, propane, alcohols such as methanol and ethanol, or organic carbon compounds such as esters is used. Is common. In addition to hydrogen, an inert gas such as argon, oxygen, carbon monoxide, water, etc. may be contained within a range that does not interfere with the diamond formation reaction.

The coating thickness of the polycrystalline diamond is 15 to 15.
It is important that it is 100 μm. Minimum value of 15 μm
The preferable range of the length of the microscopic projections on the surface of the cemented carbide is 2 to 10 μm, and therefore, when the projections are the longest, they are completely covered and after that, a mirror surface state is obtained. This is a value that allows for the allowance in the polishing process. The maximum value is defined as 100 μm because if it is thicker than this, the thermal stress due to the difference in thermal expansion between the base material and the coated polycrystalline diamond becomes remarkable, and the effect of improving the adhesion strength due to the anchor effect is weakened.

Further, regarding the purity of polycrystalline diamond, it is important that the peak ratio (Y / X) of diamond carbon (X) and non-diamond carbon (Y) by Raman spectroscopy is 0.2 or less. If the quality of the film is not such high purity, thermal deterioration of the tip surface during use will be remarkable and a satisfactory life cannot be obtained.

Here, in more detail about the interface between the cemented carbide surface and the coated polycrystalline diamond, "the microscopic protrusions on the cemented carbide surface penetrate into the polycrystalline diamond layer to be coated". Can be expressed. With the base material specification of the present invention, coating having such a cross-sectional structure is possible, and the anchor effect can be effectively exhibited.

After the coating treatment of the polycrystalline diamond, the coated surface is mirror-finished to be the tool pressing surface. Here, the mirror surface state means a state where the surface roughness Rmax is 0.1 μm or less. The surface can be processed by polishing with a grinding wheel that is generally adopted as a method for processing sintered diamond or polycrystalline diamond by vapor phase synthesis. However, the maximum temperature of the pressing surface, which is a general tool usage condition, is 230 to 400 ° C.
Under the above condition, it is necessary to polish so that the flatness is 5 μm or less. As the means, for example, polishing is performed while controlling the temperature of the central portion of the pressing surface to be the same as the tool use temperature in the range of 200 to 400 ° C.

Particularly in this step, the polycrystalline diamond is (100) plane and / or (110) plane in the thickness direction.
When the surface is oriented, it is preferable because the processing efficiency of this mirror surface processing can be enhanced.

The polycrystalline diamond-coated cemented carbide obtained by such a method can be used as it is or as a tool for flip chip mounting by processing the cemented carbide portion into a required shape. it can.

Further, as a more preferable structure as described above, in the case where a polycrystalline diamond-coated cemented carbide is used as a tool material and bonded to a specific shank, the following steps are required.

That is, as the shank material, the coefficient of linear expansion from room temperature to 400 ° C. is 4.0 × 10 ^{−6 to} 5.5 × 1.
It is necessary to use at least one selected from the group consisting of metals, alloys and / or cemented carbides having a temperature of 0 ^-6 / ° C. This is specified because the generation of thermal stress due to the difference in thermal expansion from the tool material is suppressed as much as possible. Specifically, cemented carbide, Mo, W, Cu-W alloy, Cu-Mo
Alloy, W-Ni alloy, Kovar alloy, Invar alloy material.

The tool material and the shank can be joined by any known method, but in particular, 650 to 1,2.
The method of joining through a joining metal having a melting point of 00 ° C. is effective. Specifically, means such as brazing with a brazing material having a melting point in such a temperature range and thermocompression bonding with Au can be used. Here, the brazing material is Au, Ag, C
A material containing at least one selected from u, Pt, Pd, Ni, etc. as a main component, and elements other than these as long as the characteristics of the brazing material are not impaired is used. Further, in the case of thermocompression bonding with Au, it is preferable to previously coat one or more metal thin films of Ti, Pt, Au, Ni, Mo, etc. on the joint surface between the tool material and the shank. These coating treatments have the effect of increasing the thermocompression bonding strength of Au.

The reason for setting the lower limit of the melting point of the bonding for bonding to 650 ° C. is that the solder layer must be resistant to thermal deformation and thermal deterioration when the tool is used under heating.
The upper limit of 1,200 ° C. is because the polycrystalline diamond is likely to be thermally deteriorated when bonded at a temperature higher than this.

It is preferable that the polishing of the tool surface is performed after joining, from the viewpoint of ensuring accuracy, and the above-described polishing method is applied.

In the tool manufactured by the above method, the pressing surface is composed of polycrystalline diamond.
The maximum temperature difference in the pressing surface in the temperature range of 0 to 400 ° C. is 30 ° C. or less, and good characteristics can be exhibited. In particular, the shank design as shown in Fig. 1 is more excellent in terms of temperature distribution and flatness.

[0041]

EXAMPLES The present invention will be specifically described below with reference to examples.

Example 1 A cemented carbide containing 87% by weight of WC, 7.2% by weight of TiC and 5.8% by weight of Co was ground into a shape of 20 mm × 3 mm × 2 mm.
Next, a through hole having a diameter of 1 mm was vertically formed in the center of a 20 mm × 3 mm surface by electric discharge machining.

Thereafter, this cemented carbide was held at a temperature of 1,390 ° C. for 1 hour in a CO atmosphere of 160 Torr, and then heat-treated to cool it to room temperature in a vacuum atmosphere.
By this heat treatment, microscopic protrusions made of a solid solution carbide of W and Ti are generated on the surface, and the gap between these protrusions is filled with Co eluted from the inside of the cemented carbide. Became clear.

This cemented carbide was dipped in nitric acid kept at 60 ° C. to dissolve and remove only Co that was eluted, so that the surface was formed with microscopic projections of (W, Ti) C having a length of 3 μm. Cemented Carbide covered with was produced. The coefficient of linear expansion of this surface-modified cemented carbide is 4.4 × 10 ⁻⁶ / ° C. in the range from room temperature to 400 ° C., which is similar to that of the cemented carbide before heat treatment. I was able to confirm that.

Next, using this cemented carbide as a base material, the 20 mm × 3 mm surface to be the tool tip is placed inside the hot filament CVD apparatus, and the polycrystalline diamond is coated for 50 hours. It was Table 1 shows the synthesis conditions.

[0046]

[Table 1]

The surface of the recovered cemented carbide has a thickness of 70 μm.
It was revealed that m of polycrystalline diamond was coated. Further, this polycrystalline diamond has a peak ratio (Y / X) of diamond carbon (X) and non-diamond carbon (Y) of 0.07 in Raman spectroscopic analysis, and it can be confirmed that the polycrystalline diamond is extremely high in purity. It was Furthermore, when the orientation of the diamond crystal was confirmed by X-ray diffraction, it was revealed that the diamond crystal had a (100) orientation in the film thickness direction.

This tool material and (Fe-29 wt% Ni
-17 wt% Co) -based alloy shank is joined with a silver solder having a melting point of 820 ° C., while heating so that the central portion of the tool pressing surface reaches a temperature of 250 ° C.,
The polycrystalline diamond coated surface was polished with a diamond grindstone. As a result, the surface is 0.07μ in Rmax display.
It was possible to obtain a mirror surface state of m, and a tool having the shape shown in FIG. Where 1 is a shank, 2 is a cemented carbide substrate, 3
Is polycrystalline diamond, 4 is a vacuum suction hole, and 5 is a brazing material. The thickness of the polycrystalline diamond 3 after mirror-finishing was 40 μm.

In order to evaluate the characteristics of the tool (A) manufactured by the above method, the flatness in the longitudinal direction of the pressing surface and the inside of the pressing surface when the temperature near the center of the tool pressing surface is 250 ° C. The temperature distribution was measured. For comparison, a tool (B) made of a single Super Invar of the same shape was also manufactured and evaluated.

Here, for the measurement of the flatness, the method described in JP-A-5-326642 was applied. That is, first, φ0.1 is placed on a cemented carbide substrate whose surface is flat.
A measurement jig in which 20 Au wires of No. 1 were arranged in parallel was prepared.
Next, each tool whose center temperature of the pressing surface was 250 ° C
After arranging so that the length direction of these 20 Au lines and the tool longitudinal direction are orthogonal to each other, press the tool against the Au lines to
The u-line was deformed and the amount of deformation was measured. The temperature distribution in the pressing surface was measured with an infrared radiation thermometer.

The results are shown in Table 2. As is clear from this table, it was found that the conventional Super Invar tools had insufficient properties in all of them. On the contrary,
It was confirmed that if the tool material according to the present invention is used as the tool material, such a requirement for high accuracy is sufficiently satisfied.

[0052]

[Table 2]

Further, a liquid crystal panel drive driver LSI was mounted on a glass substrate using these tools. Note that mounting was performed by a steady heating method via an ACF made of a thermosetting resin. Further, the tool was cleaned by rubbing the surface of the tool with sandpaper of # 400 every 1,000 times of mounting to remove the attached matter.

As a result, with the tool A according to the present invention, uniform and good joining was possible 50,000 times, and it was possible to continue mounting, but with the comparative tool B, after 10,000 times mounting. Joining located near both ends of the tool pressing surface became insufficient, resulting in poor joining.

Example 2 A cemented carbide shank 6 having a shape shown in FIG. 2 was prepared by grinding and electric discharge machining a cemented carbide containing 90% by weight of WC, 5% by weight of TaC and 5% by weight of Co.
And Here, the size of the surface 7 which is a tool tip surface by being coated with polycrystalline diamond is 25 mm × 15 mm.

Thereafter, this cemented carbide was held at a temperature of 1,390 ° C. for 2 hours in an N ₂ atmosphere of 110 Torr and then heat-treated to cool it to room temperature in a vacuum atmosphere.
By this heat treatment, microscopic projections made of solid solution carbides of W and Ta are generated on the surface, and the gaps between these projections are filled with Co eluted from the inside of the cemented carbide. Became clear.

This cemented carbide was immersed in hydrochloric acid at 50 ° C.,
By dissolving and removing only the eluted Co, the length is 4μ
A cemented carbide having a surface covered with microscopic projections of (W, Ta) C of m could be produced. The surface-modified cemented carbide has a coefficient of linear expansion of 4.5 × 10 ⁻⁶ / ° C. in the range from room temperature to 400 ° C., which is similar to that of the cemented carbide before heat treatment. I was able to confirm that.

Next, using this cemented carbide as a base material, the 25 mm × 15 mm surface 7 to be the tool tip is placed inside the microwave plasma CVD apparatus so that the polycrystalline diamond coating is coated with 32. I went on time. Table 3 shows the synthesis conditions.

[0059]

[Table 3]

The surface of the recovered cemented carbide has a thickness of 60 μm.
It was revealed that the above-mentioned polycrystalline diamond was coated. In addition, this polycrystalline diamond has diamond carbon (X) and non-diamond (Y) by Raman spectroscopic analysis.
The peak ratio (Y / X) was 0.06, and it was confirmed that the purity was extremely high. Furthermore, when the orientation of the diamond crystal was confirmed by X-ray diffraction, it was revealed that the diamond crystal had a (110) orientation in the film thickness direction.

Next, while heating the polycrystalline diamond-coated cemented carbide so that the temperature near the center of the polycrystalline diamond-coated surface serving as the tool pressing surface is 380 ° C.,
Polished with a diamond grindstone. As a result, the surface can be made into a mirror surface state of 0.07 μm in Rmax display, and the thickness of the polycrystalline diamond after mirror surface processing is 20 μm.
Became.

With respect to this tool, the thermal response, the temperature distribution on the tool pressing surface, and the flatness of the tool pressing surface were evaluated.

As for the above, the temperature rising time from the energization of the tool at room temperature to 380 ° C. and the cooling time from the energization stop to 380 ° C. to 200 ° C. were measured and evaluated. In addition, with respect to, the temperature of each part of the tool pressing surface when the central part of the tool tip surface was set to 380 ° C. was measured by the same method as in Example 1, and the maximum temperature difference was evaluated. For, the maximum warpage size of the tool surface was measured and evaluated in the same manner as in Example 1 at room temperature and at the center of the tool tip surface of 380 ° C. For comparison, Mo Tool (D) and Super Inver Tool (E)
Was also evaluated.

The results are shown in Table 4. From this, it has been clarified that the tool according to the present invention exceeds the performance of the conventional tool in terms of thermal response, uniformity of temperature distribution, and flatness.

[0065]

[Table 4]

Further, an attempt was made to mount an MPU for a personal computer on a printed wiring board using these tools. Since the mounting is performed by melting and solidifying the Pb-Sn solder bumps formed on the surface of the MPU, the pulse heating method was used in which the maximum tool temperature was 380 ° C. The tool cleaning was performed in the same manner as in Example 1.

As a result, with the tool C according to the present invention, uniform and good joining was possible 100,000 times, and it was possible to continue mounting, but with the comparative tools D and E, 10,000 times mounting was possible. After that, the joints located near both ends of the tool pressing surface became insufficient, resulting in defective joints.

[0068]

As described above, the flip-chip mounting tool adopting the constitution of the present invention can maintain the surface roughness and flatness of the tool tip end surface in a good condition for a long time without being damaged by heat. Therefore, better flip chip mounting can be realized as compared with the case of using the conventional tool.

[Brief description of drawings]

1 is a perspective view of a tool of the present invention in Embodiment 1. FIG.

FIG. 2 is a perspective view of a polycrystalline diamond-coated substrate produced in Example 2.

[Explanation of symbols]

 1 Shank 2 Cemented Carbide Base Material 3 Polycrystalline Diamond 4 Vacuum Adsorption Hole 5 Brazing Material 6 Cemented Carbide Shank 7 Surface to be coated with polycrystalline diamond

Claims (12)

[Claims] 1. A tool used in flip-chip mounting method for directly mounting an LSI on a substrate, wherein a pressing surface at the tip of the tool has a surface roughness of 0.1 μm or less in Rmax display. According to the present invention, and has at least one vacuum suction hole opened in the surface, and the maximum temperature of the pressing surface is 23
A flip-chip mounting tool characterized in that the flatness of the pressing surface in the range of 0 to 400 ° C. is 5 μm or less, and the maximum temperature difference in the pressing surface is 30 ° C. or less. 2. A tool comprises a polycrystalline diamond-coated cemented carbide tip and a metal or alloy shank, and these components are joined through a joining metal having a melting point of 650 to 1,200 ° C. The flip-chip mounting tool according to claim 1, wherein: 3. The flip chip mounting tool according to claim 1, wherein the polycrystalline diamond is directly coated on the tip pressing surface of the shank made of cemented carbide. 4. The thickness of polycrystalline diamond is 15 to 1
The flip chip mounting tool according to any one of claims 1 to 3, wherein the flip chip mounting tool has a thickness of 00 m. 5. A part or all of the shank is cemented carbide, Mo, W, Cu-W alloy, Cu-Mo alloy, W-N.
The flip chip mounting tool according to any one of claims 1 to 4, which is made of an i alloy, a Kovar alloy, or an Invar alloy. 6. A step of coating polycrystalline diamond on a tool tip surface which is a pressing surface at the time of mounting, and a temperature of the pressing surface is set to 2
The maximum temperature of the pressing surface is 230-40 while controlling it so that it is the same as the tool operating temperature in the range of 00-400 ° C.
A method of manufacturing a flip-chip mounting tool, which comprises at least a flatness of a pressing surface in a range of 0 ° C. of 5 μm or less, and a polishing step of making the surface into a mirror surface state of 0.1 μm or less in Rmax display. . 7. A tip portion made of a polycrystalline diamond-coated cemented carbide and a shank made of a metal or an alloy are made of 650.
7. The method of manufacturing a flip chip mounting tool according to claim 6, further comprising a step of joining through a joining metal having a melting point of ˜1,200 ° C. 8. The method for manufacturing a flip chip mounting tool according to claim 6, wherein the polycrystalline diamond is directly coated on the shank made of cemented carbide. 9. The thickness of polycrystalline diamond is 15 to 1
It is 00 micrometers, The manufacturing method of the flip-chip mounting tool in any one of Claims 6-8. 10. A part or all of the shank is cemented carbide, Mo, W, Cu-W alloy, Cu-Mo alloy, W-N.
10. The method for manufacturing a flip chip mounting tool according to claim 6, wherein the flip chip mounting tool is made of an i alloy, a Kovar alloy, or an Invar alloy. 11. The pressing surface is made of polycrystalline diamond by a vapor phase synthesis method, the surface is a mirror surface state of 0.1 μm or less in terms of Rmax, and the maximum temperature of the pressing surface is 230 to 40.
A tool having the characteristics that the flatness of the pressing surface is 5 μm or less and the maximum temperature difference within the pressing surface is 30 ° C. or less under the condition of 0 ° C. is always directly or indirectly heated to a temperature range of 200 to 400 ° C. In this state, the LSI is vacuum-sucked, conveyed, and then pressed for a certain period of time to mount the LSI via a bonding member on the substrate. 12. The pressing surface is made of polycrystalline diamond by a vapor phase synthesis method, the surface is a mirror surface state of 0.1 μm or less in terms of Rmax, and the maximum temperature of the pressing surface is 230 to 40.
A tool having characteristics that the flatness of the pressing surface under the condition of 0 ° C. is 5 μm or less and the maximum temperature difference within the pressing surface is 30 ° C. or less is directly or indirectly heated to a temperature range of 200 to 400 ° C. In this state, the LSI is vacuum-sucked, conveyed, and then pressed for a certain period of time, then cooled to 200 ° C. or lower and then released from the pressing, whereby the flip-chip is mounted through a bonding member on the substrate. How to implement.