WO2022211370A1 - Bonding tool having high flatness and provided with polycrystalline diamond tip integrated with cemented carbide body - Google Patents

Abstract

A bonding tool used for mounting a semiconductor device is disclosed. The present invention provides a bonding tool which is coupled to a holder of a bonding device so as to heat-compress a semiconductor device and a wire device, wherein the bonding tool comprises: a single cemented carbide body including a holder coupling part provided at one side thereof to be coupled to the holder of the bonding device and a heater insertion hole provided therein; and a polycrystalline diamond tip coupled to the other side of the cemented carbide body. According to the present invention, an integrated bonding tool, which minimizes a difference in a thermal expansion coefficient in a manufacturing process or a use environment, can be provided.

Description

High-flat bonding tool with polycrystalline diamond tip integrated into a carbide body

The present invention relates to a bonding tool, and more particularly, to a bonding tool used for mounting a semiconductor device.

In Tape Automated Bonding (TAB) or Chip on Film (COF) technology, a bonding tool is used to bond a semiconductor device such as a Distplay Driver IC (DDI) and a lead on a film by thermocompression bonding.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically an example of a conventional typical bonding tool.

Referring to FIG. 1 , the bonding tool includes a body portion 12 coupled to a holder of the bonding device and a tip portion joined to the body portion. At this time, for the tip portion, diamond, for example, vapor-phase synthetic diamond, diamond single crystal, or diamond sintered body may be used in order to obtain flatness of the tool surface, wear resistance, uniformity of temperature distribution, and the like.

For example, in FIG. 1 , a substrate 14 having a CVD diamond 15 formed thereon is used. At this time, the substrate 14 is coupled to the body 12 by soldering or brazing via soldering (or bonding material).

Meanwhile, as the body 12 , a metal material made of molybdenum, cemented carbide, nickel base alloy, tungsten or tungsten alloy, iron-nickel cobalt alloy, stainless steel, iron-nickel alloy, titanium or titanium alloy, etc. is used.

As described above, heterogeneous materials such as a body, a solder (or bonding material), a substrate, and a diamond are used in a conventional bonding tool. Since these dissimilar materials have different coefficients of thermal expansion, thermal deformation such as distortion or warpage occurs in a high-temperature manufacturing process or in a high-temperature use environment (400~500℃), and due to such thermal deformation, the tip of the bonding tool is required There is a problem in that the flatness cannot be maintained.

The flatness problem due to such thermal deformation is a practical obstacle to the manufacture of a bonding tool having a large-area diamond tip. It becomes difficult to obtain

On the other hand, there are cases in which a coupling mechanism such as a bolt is used instead of a solder when the body and the tip of the bonding tool are combined.

In order to solve the problems of the prior art, an object of the present invention is to provide an integrated bonding tool for minimizing a difference in thermal expansion coefficient in a manufacturing process or a use environment.

In addition, an object of the present invention is to provide a bonding tool that is easy to manufacture and process in one piece and can achieve high flatness by processing.

Another object of the present invention is to provide a bonding tool having high flatness even in a high-temperature use environment.

Another object of the present invention is to provide a bonding tool capable of suppressing thermal deformation at a high temperature in a manufacturing process or a use environment.

Another object of the present invention is to provide a bonding tool having a large-area diamond tip.

Another object of the present invention is to provide a manufacturing method suitable for manufacturing the above-described bonding tool.

In order to achieve the above technical object, the present invention provides a bonding tool for coupling to a holder of a bonding device for thermocompression bonding a semiconductor device and a wiring device, wherein the bonding tool is coupled to a holder for coupling with the holder of the bonding device on one side. a single carbide body having a portion and a heater insertion hole therein; And it provides a bonding tool comprising a polycrystalline diamond tip coupled to the other side of the carbide body.

In the present invention, the cemented carbide body preferably has a non-bonding structure.

In addition, in the present invention, the polycrystalline diamond tip is preferably coupled to the cemented carbide body by high-temperature and high-pressure sintering. At this time, the polycrystalline diamond tip may be coupled by diffusion of the metal binder in the carbide body.

In addition, in the present invention, the other side of the cemented carbide body may be provided with a protrusion for mounting the polycrystalline diamond tip. At this time, the protrusion may be in the shape of a band extending across the surface of the carbide body.

In the present invention, the bonding tool preferably has room temperature and high temperature flatness of 2 μm or less at a length of 25 mm or more of the polycrystalline diamond tip.

In order to achieve the above other technical problem, the present invention provides a method for manufacturing a bonding tool for bonding a semiconductor element and a wiring element to a holder of a bonding apparatus for thermocompression bonding, laminating a diamond powder compact on a cemented carbide base material and sintering at high temperature and high pressure to prepare a sintered body having a laminate structure including a cemented carbide base material and a polycrystalline diamond layer; planarizing the sintered body; and processing the sintered body, wherein the processing step includes processing an outer shape of the sintered body; And it provides a method of manufacturing a bonding tool comprising the step of processing the hole in the sintered body.

In the present invention, the diamond powder compact preferably does not include a metal binder.

In this case, the processing step may include processing the polycrystalline diamond layer to form a polycrystalline diamond tip, and the polycrystalline diamond tip may have a band shape extending across the surface of the cemented carbide body on the cemented carbide body.

In the present invention, the processing step may include electric discharge machining or laser machining.

In the present invention, the high-temperature and high-pressure sintering step is preferably performed at a temperature of 1300-1700° C. and a pressure of 5-10 GPa.

According to the present invention, it is possible to provide an integrated bonding tool that minimizes the difference in the coefficient of thermal expansion in the manufacturing process or the use environment. In addition, the present invention can provide a bonding tool that is easy to manufacture and process in one piece, and can achieve high flatness by processing. In addition, the present invention can exhibit high flatness even in a high-temperature environment by suppressing thermal deformation at a high temperature in a manufacturing process or a use environment. Accordingly, the present invention can provide a bonding tool having a large-area diamond tip.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically an example of a conventional typical bonding tool.

2A and 2B are a perspective view and a bottom perspective view of a bonding tool according to an embodiment of the present invention, respectively.

3 is a view for explaining an example of using a bonding tool according to an embodiment of the present invention.

4 is a flowchart schematically illustrating a method of manufacturing a bonding tool according to an embodiment of the present invention.

5 is a photograph taken after flat processing of the sintered body manufactured according to an embodiment of the present invention.

6 is a photograph taken of the bonding tool of the present invention manufactured according to the sintering and machining process.

Hereinafter, the present invention will be described in detail by describing preferred embodiments of the present invention with reference to the drawings.

2A and 2B are a perspective view and a bottom perspective view, respectively, according to an embodiment of the present invention.

2A and 2B , the bonding tool 100 includes a carbide body 110 and a polycrystalline diamond tip 120 .

The carbide body 110 has a hexahedral outline as shown, but the present invention is not limited thereto.

A polycrystalline diamond tip 120 is provided on one side of the carbide body 110 , and a portion of the upper surface of the carbide body protrudes for mounting the tip 120 to form a protrusion 118 . Exemplarily, the protrusion 118 has a band shape extending in the longitudinal direction while forming the mesa structure of the tip 120 . In the present invention, the shape of the tip is exemplary, and may be a shape that follows the bump arrangement shape of the semiconductor device. In addition, it goes without saying that two or more rows of band-shaped heaters may be arranged in the bonding tool of the present invention.

According to the present invention, the bonding tool has room temperature flatness or high temperature flatness of the polycrystalline diamond tip of 2 μm or less in the area of 25 mm, 30 mm, or 35 mm tip length or more. Or, it is preferable to have room temperature flatness and high temperature flatness of 2 μm or less in an area of 135 m ² or more with a tip area. In the present invention, the surface of the polycrystalline diamond tip may have a convex or concave shape. Preferably, the surface of the polycrystalline diamond tip has a concave shape at a high temperature to prevent bump open of the semiconductor element at both ends of the tip and the lead circuit on the film.

In this case, the high-temperature flatness is based on a value measured at a temperature of 480°C, and the flatness may be measured by either white light scanning interferometry (WSI) or phase shift interferometry (PSI). Preferably, the flatness may be measured by white light scanning interferometry. In addition, in the present invention, room temperature and high temperature flatness of the bonding tool may have a value of, for example, 1.5 μm or more.

Heater insertion holes 112A and 112B arranged parallel to the tip 120 are provided on the inner side of the carbide body 110, that is, in the middle, and a temperature sensor is inserted between the heater insertion holes 112A and 112B and the tip. Holes 113A and 113B are provided. A heater (not shown) and a temperature sensor (not shown) such as a thermocouple are inserted into the insertion holes 112A, 112B, 113A, and 113B, respectively, and are used to control the temperature of the bonding tool.

On the other hand, the other side of the carbide body 110 is provided with fastening parts (115A, 115B) as a coupling mechanism for mounting to a holder (not shown) of the bonding device. The fastening parts 115A and 115B may have screw holes as shown and be fastened to the holder by means such as bolts. In the present invention, the fastening parts (115A, 115B) protrude to the side of the carbide body, but the present invention is not limited thereto, and the shape of the fastening part may be implemented in various ways.

In addition, a vacuum hole 114 may be provided inside the cemented carbide body 110 . The vacuum hole 114 forms a flow path passing through the carbide body at the tip 120 of the carbide body 110 . The vacuum hole 114 allows a semiconductor device such as a driver IC in contact with the tip 120 to be vacuum-adsorbed.

In addition, additional holes such as a position fixing hole 116 for setting a holder fixing position may be formed in the carbide body.

In the bonding tool of the present invention, the carbide body 110 is composed of a single component. Here, 'single' means that two or more components, either homogeneous or heterogeneous, are chemically bonded or not mechanically bonded. This is compared to the conventional bonding tool described with reference to FIG. 1, wherein the body 12 and the substrate 14 are formed by bonding and are not a single component. In contrast, as will be described later, the cemented carbide body 110 of the present invention is obtained by processing a single homogeneous cemented carbide member.

In the present invention, the polycrystalline diamond tip 120 is a sintered body including polycrystalline diamond and a metal binder. According to a preferred embodiment of the present invention, the metal binder of the polycrystalline diamond tip 120 may be derived from the cemented carbide body 110 . More preferably, the polycrystalline diamond tip 120 is sintered and integrated without using a separate binder. This will be described later.

3 is a view for explaining an example of using the bonding tool of the present invention.

Referring to FIG. 3 , a bonding tool 100 is mounted on a holder 200 of a bonding apparatus (not shown). A heater is mounted inside the bonding tool 100 .

The polycrystalline diamond tip 120 of the bonding tool 100 vacuum-adsorbs a semiconductor device such as, for example, a display driver IC (hereinafter referred to as 'DDI'; 10). The bonding device transports the bonding tool 100 and aligns it on the film 20 on which metal wiring such as a lead is formed.

The heater built into the bonding tool 100 is heated according to the driving of the bonding device, and the holder of the device presses the bonding tool 100 to bond the bump 12 of the DDI to the metal wiring 22 on the film. do.

The cemented carbide base material of the above-described bonding tool is heated to a temperature of about 400 ~ 500 ℃. When the bonding tool is heated, the cemented carbide body and the polycrystalline diamond tip 120, which are each component constituting the bonding tool, are heated, respectively. At this time, thermal deformation occurs due to the difference in thermal expansion of each component. The thermal strain generated in the polycrystalline diamond tip generated in this process can be divided into two components. One is a deformation component in a direction parallel to the pressing axis (①), and the other is a deformation component in a direction perpendicular to the pressing axis. It is (②).

Of the two components, the former acts uniformly across the contact surface of the polycrystalline diamond tip, whereas the latter does not. Due to the difference in the coefficient of thermal expansion between the cemented carbide base material and the polycrystalline diamond tip 120 , thermal deformation in a direction perpendicular to the pressure axis occurs during heating, and accordingly, the polycrystalline diamond tip causes warpage. This bending deformation affects the flatness of the polycrystalline diamond tip.

According to the present invention, the bending deformation occurring in the carbide body is suppressed by using a carbide body of a single component, unlike the conventional method of manufacturing a bonding body by bonding or mechanically combining two or more components. In addition, by minimizing the metal binder in the polycrystalline diamond tip, the interface between the cemented carbide body and the polycrystalline diamond tip does not act as a heterogeneous component.

Hereinafter, a method of manufacturing the bonding tool of the present invention will be described.

4 is a flowchart schematically illustrating a method of manufacturing a bonding tool according to an embodiment of the present invention.

Referring to FIG. 4 , a diamond powder compact is manufactured ( S110 ). The diamond powder compact may be manufactured by mixing diamond powder and an organic binder to prepare a slurry, then molding and drying the slurry. Illustratively, the diamond powder compact may be formed in a sheet form. In this case, it is preferable to use a diamond powder having a particle diameter in the range of 0.5 to 50 μm. In addition, the diamond powder compact contains substantially no metal binder.

After the diamond powder compact is laminated on a cemented carbide base material, high temperature and high pressure (HTHP) sintering is performed (S120, S130).

This process is carried out under high temperature and pressure in which the diamond exists in a stable state by charging the compact into a refractory crucible made of a high-melting-point material (eg, Ta, Mo, Nb, etc.) of 2000°C or higher. At this time, the metal binder (for example, Co) in the cemented carbide base material is melted at the sintering temperature to form a liquid phase, and the metal liquid phase is squeezed out from the cemented carbide base material by the pressure applied during the sintering process to form a liquid phase between the diamond powder of the molded body. infiltration into the pores. The diamond powder compact is liquid-phase sintered by liquid-phase penetration. In the present invention, high-temperature and high-pressure sintering may be performed at a temperature and pressure of 1300-1700° C. and 5-10 GPa.

Then, the manufactured sintered body is processed (S140). The sintered compact processing process for obtaining a bonding tool in the present invention is as follows. However, each processing process described below does not necessarily have to be performed, and it goes without saying that the order of each processing process may be changed.

① Sintered compact grinding and lapping

The upper and/or lower surfaces of the sintered body are ground and lapped. In the present invention, since the polycrystalline diamond layer and the underlying cemented carbide base material are integrated by sintering, the flatness of the entire sintered body can be improved by lapping and grinding.

5 is a photograph taken after flat processing of the sintered body manufactured according to an embodiment of the present invention. The diameter of the sintered body in the picture is about 60 mm, the thickness is about 20-30 mm, and the thickness of the polycrystalline diamond tip is 0.5 mm. According to the present invention, it is possible to manufacture a large-area bonding tool having a maximum diameter of 60 mm and a thickness of 20 to 30 mm.

② Shape processing

The sintered body is machined according to the predetermined shape of the bonding tool as shown in FIGS. 2A and 2B . This machining can be performed, for example, by wire cut electric discharge machining (WEDM).

③ Hole processing

The holes 112A, 112B, 113A, 113B, and 114 of FIGS. 2A and 2B are machined in the carbide part by electric discharge machining, and other tap machining is performed.

Vacuum hole processing, chamfer processing, etc. are performed on the polycrystalline diamond part by laser processing.

④ Post-processing

The electric discharge machining marks are removed by polishing and coated. As for the coating, TiN, TiCN, TiAlN, AlTiN, AlCrN, CrN or CrAlN can be coated on the tool using the PVD coating method, which is a physical vapor deposition method.

6 is a photograph taken of the bonding tool of the present invention manufactured according to the sintering and machining process.

<Production Example 1>

A sintered body was prepared by charging a diamond powder compact with a particle diameter of 0.5-50 μm and a WC-Co cemented carbide base material into a refractory crucible and sintering at 1,500° C. and 7 GPa at high temperature and high pressure.

The prepared sintered body was ground and lapped. Specifically, the carbide body was ground by using a diamond wheel in a planar grinding machine, and the polycrystalline diamond layer was subjected to lapping and polishing using a diamond slurry in a lapping machine and a polishing machine. A bonding tool as shown in FIG. 6 was manufactured through shape processing and hole processing. The manufactured bonding tool had a thickness of 25mm, and the polycrystalline diamond tip was 35(W)mm*5(L)mm*0.5(T)mm.

<Test Example 1>

The room-temperature flatness of the bonding tool manufactured in Preparation Example 1 was measured by white-light scanning interferometry in an area of 34(W)mm*4(L)mm of the polycrystalline diamond tip. The measurement method and conditions are as follows.

- Measuring device: Bruker Alicona Alicona InfiniteFocusSL

- Measurement standard: ISO/TS 12781-1, 12781-2

As a result of the measurement, the room temperature flatness was 1.6 μm.

The high temperature (480° C.) flatness of the manufactured bonding tool was measured. The high-temperature flatness was measured using a phase shifting interferometry (PSI) method for a polycrystalline diamond tip 34(W)mm*4(L)mm area.

<Test Example 2>

A polycrystalline diamond tip 34(W)mm*4(L)mm area was measured by phase shifting interferometry (PSI) for room temperature and high temperature (480° C.) flatness of the bonding tool manufactured in Preparation Example 1.

As a result of the measurement, the room temperature flatness was 1.6 µm and the high temperature flatness was 1.3 µm.

<Test Example 3>

The bonding tool prepared in Preparation Example 1 was repeatedly tested by pressing at a high temperature. The test conditions are as follows.

Item	test requirements
operating temperature	400℃ ~ 500℃
working pressure	7~25kgf/cm 2
1 cycle time	2.3sec/time

According to the above conditions, the room temperature flatness before the test, after 2 million tests, and after 4 million tests was measured by white-light scanning interferometry, and is shown in Table 2 below.

division	Room temperature flatness (㎛)
before test	1.6
After 2 million tests	1.4
After 4 million tests	1.8

Although the preferred embodiment of the present invention has been described above, the technical spirit of the present invention is not limited to the above-described preferred embodiment, and can be implemented in various ways without departing from the technical spirit of the present invention embodied in the claims. have.

The present invention is applicable to a bonding tool used for mounting a semiconductor device.

Claims (13)

1. A bonding tool for bonding a semiconductor element and a wiring element to a holder of a bonding apparatus for thermocompression bonding, the bonding tool comprising:

   The bonding tool is

   A single cemented carbide body having a holder coupling part for coupling with the holder of the bonding device on one side, and having a heater insertion hole therein; and

   A bonding tool comprising a polycrystalline diamond tip coupled to the other side of the carbide body.
2. According to claim 1,

   The carbide body is a bonding tool, characterized in that having a non-bonding structure.
3. According to claim 1,

   The polycrystalline diamond tip is a bonding tool, characterized in that bonded to the carbide body by high-temperature and high-pressure sintering.
4. 4. The method of claim 3,

   The polycrystalline diamond tip is bonded by diffusion of metal in the carbide body.
5. The method of claim 1,

   The cemented carbide body is a bonding tool, characterized in that provided with a protrusion for mounting the polycrystalline diamond tip on the other side.
6. 6. The method of claim 5,

   wherein the protrusion is in the shape of a band extending across the surface of the carbide body.
7. According to claim 1,

   The bonding tool is a bonding tool, characterized in that it has a flatness of 2㎛ or less at a length of 25mm or more of the polycrystalline diamond tip.
8. A method of manufacturing a bonding tool for bonding a semiconductor element and a wiring element to a holder of a bonding apparatus for thermocompression bonding, the method comprising:

   Laminating diamond powder on a cemented carbide base material and sintering at high temperature and high pressure to prepare a sintered body having a laminate structure including a cemented carbide base material and a polycrystalline diamond layer;

   planarizing the sintered body; and

   Including processing the sintered body,

   The processing step is

   processing the outer shape of the sintered body; and

   Method of manufacturing a bonding tool comprising the step of hole processing the sintered body.
9. 9. The method of claim 8,

   The diamond powder manufacturing method of a bonding tool, characterized in that it does not contain a metal binder.
10. 9. The method of claim 8,

    The processing step comprises processing the polycrystalline diamond layer to form a polycrystalline diamond tip,

    wherein the polycrystalline diamond tip is in the shape of a band extending across the surface of the carbide body on the carbide body.
11. 9. The method of claim 8,

    The machining step is a method of manufacturing a bonding tool, characterized in that it comprises electric discharge machining.
12. 9. The method of claim 8,

    The processing step is a method of manufacturing a bonding tool, characterized in that it comprises laser processing.
13. 9. The method of claim 8,

    The high-temperature and high-pressure sintering step is a method of manufacturing a bonding tool, characterized in that it is performed at a temperature of 1300 ~ 1700 ℃ and a pressure of 5 ~ 10 GPa.

Images