TW202302250A - Bonding tool with high flatness comprising polycrystalline diamond tip unified on top of carbide body - Google Patents

Abstract

A bonding tool configured to be used for mounting a semiconductor element is disclosed. The present disclosure provides a bonding tool which is coupled to a holder of a bonding device to thermally press a wiring element and a semiconductor element, the bonding tool including: a single carbide body having a holder coupling part formed on one side thereof to be coupled to the holder of the bonding device, the single carbide body having a heater insertion hole formed therein; and a polycrystalline diamond tip coupled to the other side of the carbide body. The present disclosure may provide an integrated bonding tool which minimizes the difference in a coefficient of thermal expansion in the manufacturing process or use environment.

Description

High flatness bonding tool consisting of a polycrystalline diamond tip integrated on top of a carbide body

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

Tape automated bonding (TAB) or chip-on-film (COF) technology uses bonding tools to thermally press semiconductor components, such as display driver ICs (display driver ICs, DDI) and thin film on wires, thereby bonding them.

Figure 1 shows an example of a typical conventional bonding tool.

As shown in FIG. 1, the bonding tool includes a body portion 12 coupled to a frame of a bonding device, and a front end portion secured to the body portion. The front part can be made of diamond, such as chemical vapor deposition (Chemical Vapor Deposition, CVD) diamond, monocrystalline diamond (monocrystalline diamond) or diamond sintered body (diamond sintered body), in order to achieve tool surface flatness, wear resistance, Uniformity of temperature distribution, things like that.

In FIG. 1 , for example, using a substrate 14 having a CVD diamond 15 formed as a front end portion, the substrate 14 is coupled to the main body 12 in a welding or brazing manner by using solder 13 (or adhesive).

The main body 12 is made of molybdenum, carbide alloy, nickel-based alloy, tungsten or tungsten alloy, iron-nickel cobalt alloy, stainless steel, iron-nickel alloy, titanium or titanium alloy and other metal materials.

Such conventional bonding tools use heterogeneous materials including body, solder 13 (or adhesive), substrate, and diamond. A problem with using heterogeneous materials in this way is that the different coefficients of thermal expansion can cause thermal distortion (eg warping or bending) during high temperature manufacturing or in high temperature service environments (400-500ºC). Thermal deformation prevents the tip of the bonding tool from maintaining the desired flatness.

Problems related to flatness caused by thermal deformation are a major obstacle in the manufacture of bonding tools with large-area diamond tips, and thermal compression type bonding tools used in high-temperature environments are difficult to ensure the flatness of a large number of bumps heated/compressed at the same time .

In some cases, a coupling mechanism (eg, bolt) can be used instead of the solder 13 to couple the body and tip of the joining tool, but using dissimilar materials (eg, bolt) will inevitably lead to thermal deformation.

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

Another embodiment of the present invention provides a bonding tool that can be easily manufactured and processed in an integrated type, and can achieve a high degree of flatness through processing.

Another embodiment of the present invention provides a bonding tool that ensures a high degree of flatness even in a high temperature environment.

Another embodiment of the present invention provides a bonding tool capable of suppressing thermal deformation at high temperature in a manufacturing process or a use environment.

Another embodiment of the present invention provides a bonding tool having a large area diamond tip.

Another embodiment of the present invention provides a method suitable for manufacturing the bonding tool described above.

According to one embodiment, the present invention provides a bonding tool, which is coupled to a frame of a bonding device to thermally press a wiring element and a semiconductor element, the bonding tool comprising: a single carbide body having a body formed on a bracket coupling portion on one side thereof to be coupled to the bracket of the engaging device, the single carbide body having a heater insertion hole formed therein; and a bracket coupled to the other side of the carbide body Polycrystalline diamond tip.

In the present invention, the carbide body has a non-joint structure.

In the present invention, the polycrystalline diamond tip is preferably joined to the carbide body by high temperature and pressure sintering. At this point, the polycrystalline diamond tip is joined by metal diffusion in the carbide body.

In the present invention, the carbide body has a protrusion disposed on its other side such that the polycrystalline diamond tip is mounted on the protrusion. At this point, the protrusion has the shape of a band extending across the surface of the carbide body.

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

According to another embodiment, the present invention provides a method of manufacturing a bonding tool coupled to a holder of a bonding device for thermally pressing a wiring element and a semiconductor element, the method comprising: laminating diamond powder on a carbide substrate, followed by sintering at high temperature and pressure to prepare a sintered body comprising a laminated structure of the carbide substrate and a polycrystalline diamond layer; planarizing the sintered body; and Machining, wherein the machining includes: machining the shape of the sintered body; and machining holes on the sintered body.

In the present invention, the diamond powder does not contain a metal binder.

In this case, machining includes machining the polycrystalline diamond layer to form a polycrystalline diamond tip, and the polycrystalline diamond tip is disposed on a carbide body and has a ribbon shape extending across the surface of the carbide body.

In the present invention, machining includes electrical discharge machining.

In the present invention, mechanical processing includes laser processing.

In the present invention, high temperature and high pressure sintering 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 for minimizing the difference in coefficient of thermal expansion in a manufacturing process or use environment. In addition, the present invention can provide a bonding tool that can be easily manufactured and processed in an integrated form, and can achieve a high level of flatness through processing. Furthermore, according to the present invention, thermal deformation can be suppressed at high temperatures in a manufacturing process or in a use environment, whereby a high degree of flatness can be ensured even in a high temperature environment. Therefore, the present invention can provide a bonding tool having a large-area diamond tip.

The present invention can be variously modified and includes various exemplary embodiments which will be described in detail below. However, the specific exemplary embodiments are not intended to limit the present invention, but cover all modifications, equivalent replacements, and replacements belonging to the concept and technical scope of the present invention.

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

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

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

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

A polycrystalline diamond tip 120 is disposed on one side of the carbide body 110 , and a portion of the upper surface of the carbide body protrudes to form a protrusion 118 for mounting the polycrystalline diamond tip 120 . For example, the protrusion 118 has a band shape extending longitudinally while forming the platform-like structure of the polycrystalline diamond tip 120 . In the present invention, the shape of the tip is exemplary, and may be a shape following a bump arrangement shape of a semiconductor element. Furthermore, in the bonding tool of the present invention, two or more rows of band heaters as shown may be provided.

According to the present invention, the polycrystalline diamond tip of the bonding tool has a room-temperature flatness and high-temperature flatness of 2 μm or less in a region corresponding to a tip length of 25 mm, 30 mm, 35 mm or more, or at an area equivalent to ¹³⁵ m In the area of the tip area above, the room temperature flatness and the high temperature flatness are 2 μm or less. In the present invention, the surface of the polycrystalline diamond tip may have a convex shape or a concave shape. Preferably, the surface of the polycrystalline diamond tip has a concave shape at high temperature to prevent bumps of lead circuits on the film and semiconductor element bumps at both ends of the tip from bumping open.

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

Heater insertion holes (heater insertion holes) 112A, 112B arranged in parallel with the polycrystalline diamond tip 120 are provided inside the carbide body 110, that is, at the center of the carbide body 110, and the heater insertion holes 112A, 112B Temperature sensors (temperature sensors) 113A, 113B are arranged between the polycrystalline diamond tip 120 . A heater (not shown) and a temperature sensor (not shown) such as a thermocouple (thermocouple) are respectively inserted into the heater insertion holes 112A, 112B, and the temperature sensors 113A, 113B to control the temperature of the bonding tool. temperature.

On the other hand, on the other side of the carbide main body 110, there are provided a fastening part (fastening part) 115A and a fastening part 115A as a coupling mechanism for mounting the carbide main body 110 on a bracket (not shown in the figure) of the engaging device. Section 115B. The fastening portion 115A and the fastening portion 115B can have threaded holes as shown in the figure and can be locked to the bracket by means such as bolts. In the present invention, the fastening portion 115A and the fastening portion 115B protrude from the side of the carbide body 110 , but the present invention is not limited thereto, and the shape of the fastening portion may be implemented in various ways.

In addition, a vacuum hole 114 may be provided inside the carbide body 110 . The vacuum hole 114 forms a flow path from the polycrystalline diamond tip 120 of the carbide body 110 through the carbide body. The vacuum holes 114 allow semiconductor devices such as driver ICs to be vacuumed when in contact with the polycrystalline diamond tip 120 .

Additionally, additional holes may be formed in the carbide body 110, such as a position fixing hole 116 configured to set a bracket fixing position.

In the bonding tool of the present invention, the carbide body 110 is set as a single component. Here, "single" refers to two or more components, which are neither homogeneous nor heterogeneous, and neither chemically nor mechanically bonded to each other. The carbide body 110 is in contrast to the conventional bonding tool described in FIG. 1 , which is not formed as a single component by bonding the body 12 and the substrate 14 . In contrast, the carbide body 110 of the present invention is obtained by machining a single homogeneous carbide member, as described below.

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 carbide body 110 . As described below, the polycrystalline diamond tip 120 is sintered and integrated without the use of a separate adhesive thereon.

Fig. 3 shows an example of a bonding tool using the present invention.

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

The bonding tool 100 of the polycrystalline diamond tip 120 vacuum picks up a semiconductor device, such as a display driver IC (hereinafter referred to as DDI 10 ), for example. The bonding apparatus transports and aligns the bonding tool 100 on the film 20 on which the metal wires such as leads are formed.

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

The carbide substrate of the bonding tool described above is heated to a temperature of about 400-500ºC. When the bonding tool is heated, the carbide body constituting the bonding tool and the polycrystalline diamond tip 120 are heated separately. At this time, thermal deformation occurs due to the difference in thermal expansion of the components. During this process, the thermal deformation of the polycrystalline diamond tip can be viewed in two elements. One of the two elements is ① the deformation parallel to the pressure axis, and the other ② is the deformation perpendicular to the pressure axis.

Of the two elements, the former acts uniformly over the entire contact surface of the polycrystalline diamond tip 120, while the latter does not. Since the thermal expansion coefficients of the carbide substrate and the polycrystalline diamond tip 120 are different, during the heating process, the polycrystalline diamond tip is thermally deformed in a direction perpendicular to the pressure axis, so the polycrystalline diamond tip 120 is warped. This warping affects the flatness of the polycrystalline diamond tip.

According to the present invention, the occurrence of warpage in the carbide body is suppressed by using a single-component carbide body, unlike the prior art in which a joined body is produced by joining or mechanically joining two or more components of. Furthermore, by minimizing the metal binder of the polycrystalline diamond tip, the interface between the carbide body 110 and the polycrystalline diamond tip 120 does not become a heterogeneous component.

A method of manufacturing the bonding tool of the present invention will be described below.

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

Referring to FIG. 4, a diamond powder compact is prepared (S110). Diamond powder compacts can be produced by mixing diamond powder with an organic binder to prepare a slurry, followed by shaping and drying. For example, a diamond powder compact can be formed into a sheet. In this case, diamond powder with a particle size in the range of 0.5 to 50 μm can be used. In addition, the diamond powder compact is substantially free of metal binders.

The compacted body of diamond powder is laminated on the carbide substrate, and sintered through high-temperature and high-pressure (HTHP) (steps S120 and S130 ).

This process is carried out under high temperature and high pressure where diamond exists in a stable state, by filling the pressed body with a material with a melting point of 2000 or higher (such as tantalum (Ta), molybdenum (Mo), niobium (Nb), etc. ) made of refractory crucible (refractory crucible). At this time, the metal binder (eg cobalt (Co)) in the carbide substrate will melt at the sintering temperature to form a liquid phase, and the pressure applied during the sintering process will separate the metal liquid phase from the carbide The matrix is extruded and infiltrated into the pores between the compacted diamond powder. Diamond powder compacts are liquid-phase sintered by infiltration of the liquid phase. In the present invention, high temperature and high pressure sintering can be carried out at a temperature of 1300-1700°C and a pressure of 5-10 GPa.

Next, machining is performed on the prepared sintered body (S140). The machining process of the sintered body for obtaining the bonding tool in the present invention is as follows. However, each machining process described below is not necessarily performed, and the order of each machining process can also be changed.

[Grinding and polishing of sintered body]

The upper and/or lower surface of the sintered body is ground and polished. In the present invention, since the polycrystalline diamond layer and the underlying carbide substrate are integrated with each other through sintering, the flatness of the entire sintered body can be improved through grinding and polishing.

Fig. 5 is a photograph of a sintered body manufactured according to an embodiment of the present invention after planar processing. The diameter of the sintered body in the figure is about 60mm, the thickness is about 20 to 30mm, and the thickness of the polycrystalline diamond tip is 0.5mm. According to the present invention, large-area bonding tools with a maximum diameter of 60 mm and a thickness of 20 to 30 mm can be manufactured.

[Shape Machining]

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

[Hole Machining]

The carbide portion is machined by electrical discharge machining to have a heater insertion hole 112A, a heater insertion hole 112B, a temperature sensor 113A, a temperature sensor 113B, and a vacuum hole 114 as shown in FIGS. 2A and 2B , and perform tap machining.

Vacuum hole processing and cavity processing are performed on the polycrystalline diamond part through laser processing.

[post-processing processing]

Remove the discharge machining marks by grinding, and apply titanium nitride (TiN), titanium nitride carbide (TiCN), titanium aluminum nitride (TiAlN), and high aluminum nitride titanium on the tool through the PVD coating method of physical vapor deposition (AlTiN), aluminum chromium nitride (AlCrN), chromium nitride (CrN), or aluminum chromium nitride (CrAlN) coating.

FIG. 6 is a photo of the bonding tool manufactured according to the sintering and machining processes of the present invention.

＜Manufacturing example 1＞

The diamond powder compacted body with a particle size of 0.5-50 μm and the WC-Co carbide substrate are loaded into a refractory crucible, and sintered at a high temperature of 1500 ° C and a pressure of 7 GPa to prepare a sintered body.

The prepared sintered body is ground and polished. Specifically, the carbide body is ground using a diamond wheel in a surface grinder, and the polycrystalline diamond layer is ground and polished using a diamond slurry in a grinder and polisher. The bonding tool shown in FIG. 6 is manufactured by shape machining and hole machining. The thickness of the fabricated bonding tool was 25mm, and the size of the polycrystalline diamond tip was 35(W)*5(L)*0.5(T)mm.

＜Test example 1＞

The room temperature flatness of the bonding tool manufactured in Manufacturing Example 1 was measured by a white light scanning interferometer on an area of 34(W)mm*4(L)mm at the tip of the polycrystalline diamond. The measurement method and conditions are as follows. - Measuring device: Bruker Alicona Alicona InfiniteFocusSL - Measurement standard: ISO/TS 12781-1, 12781-2

According to the measurement results, the flatness at room temperature is 1.6 μm.

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

＜Test example 2＞

The high-temperature (480°C) flatness of the bonding tool manufactured in Manufacturing Example 1 was measured. The high-temperature flatness of a polycrystalline diamond tip with an area of 34(W)*4(L)mm was measured by phase shifting interferometry (PSI).

According to the measurement results, the room temperature flatness is 1.6 µm and the high temperature flatness is 1.3 µm.

＜Test example 3＞

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

[Table 1] project Test Conditions operating temperature 400°C-500°C work pressure 7-25kgf/ ^cm2 a cycle time 2.3sec/time

The flatness at room temperature before the test, after 2 million tests, and after 4 million tests was measured by a white light scanning interferometer according to the above conditions, as shown in Table 2.

[Table 2] category Flatness at room temperature (µm) before testing 1.6 After 2 million tests 1.4 After 4 million tests 1.8

Although the preferred embodiments of the present invention have been described above, the technical spirit of the present invention is not limited to the above preferred embodiments, and can be implemented in various ways without departing from the technical spirit of the present invention embodied in the scope of the patent application.

10: Display driver IC 12: Bump 13: Solder 14: Substrate 15: CVD diamond 100:Joint tool 110: carbide body 112A: heater insertion hole 112B: heater insertion hole 113A: temperature sensor 113B: temperature sensor 114: vacuum hole 115A: fastening part 118:Protrusion 120: Polycrystalline diamond tip 115B: fastening part 20: Membrane 22: metal wire 200: bracket S110: Preparation of diamond powder compact S120: Lamination of diamond powder compacts on carbide substrates S130: High temperature and high pressure (HTHP) sintering S140: Machining the sintered body

The above and other embodiments, features, and advantages of the present invention will become more apparent after the following detailed description in conjunction with the accompanying drawings, wherein: Figure 1 shows an example of a typical bonding tool known in the art; 2A is a perspective view of a bonding tool according to an embodiment of the present invention, and FIG. 2B is a bottom view of a bonding tool according to an embodiment of the present invention; Figure 3 shows an example of a bonding tool using an embodiment of the present invention; FIG. 4 is a flowchart of a manufacturing method of a bonding tool according to an embodiment of the present invention; Fig. 5 shows the photograph that the sintered body of an embodiment of the present invention is manufactured with plane processing; And FIG. 6 is a photograph of the bonding tool of the present invention manufactured according to the sintering and machining process.

100:Joint tool

110: carbide body

112A: heater insertion hole

112B: heater insertion hole

113A: temperature sensor

113B: temperature sensor

114: vacuum hole

115A: fastening part

118:Protrusion

120: Polycrystalline diamond tip

Claims (13)

A bonding tool, coupled to a frame of a bonding device to thermally press a wiring element and a semiconductor element, the bonding tool includes: a single carbide body having a bracket coupling portion formed on one side thereof to be coupled to the bracket of the engaging device, the single carbide body having a heater insertion hole formed therein; and A polycrystalline diamond tip is coupled to the other side of the carbide body. The joining tool according to claim 1, wherein the carbide body has a non-joining structure. The bonding tool according to claim 1, wherein the polycrystalline diamond tip is bonded to the carbide body by high temperature and high pressure sintering. The bonding tool of claim 3, wherein the polycrystalline diamond tip is bonded by metal diffusion in the carbide body. The bonding tool as claimed in claim 1, wherein the carbide body has a protrusion disposed on the other side thereof so that the polycrystalline diamond tip is mounted on the protrusion. The bonding tool of claim 5, wherein the protrusion has a band shape extending across the surface of the carbide body. The bonding tool as claimed in claim 1, wherein when the polycrystalline diamond tip has a length of 25 mm or more, the bonding tool has a flatness of 2 μm or less. A method of manufacturing a bonding tool coupled to a frame of a bonding device to thermally press a wiring element and a semiconductor element, the method comprising: laminating a diamond powder on a carbide substrate, and then sintering at high temperature and pressure to prepare a sintered body comprising a laminated structure of the carbide substrate and a polycrystalline diamond layer; planarizing the sintered body; and performing a mechanical process on the sintered body; Among them, the mechanical processing includes: machining the outer shape of the sintered body; and Holes were machined into the sintered body. The method according to claim 8, wherein the diamond powders do not contain metal binders. The method of claim 8, wherein the machining comprises machining the polycrystalline diamond layer to form a polycrystalline diamond tip, and the polycrystalline diamond tip is disposed on a carbide body and has an extension transverse The shape of the band across the surface of the carbide body. The method as claimed in claim 8, wherein the machining includes electrical discharge machining. The method according to claim 8, wherein the mechanical processing includes laser processing. The method according to claim 8, wherein the high temperature and high pressure sintering is carried out at a temperature of 1300-1700° C. and a pressure of 5-10 GPa.

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