CN210223961U - Hardware configuration, module and system for eutectic bonding of wafers at room temperature - Google Patents

Abstract

The utility model discloses a room temperature wafer eutectic bonding hardware configuration, a module and a system, wherein the room temperature wafer eutectic bonding hardware configuration comprises an upper wafer, and the lower surface of the upper wafer is provided with a first semi-metal film; a lower wafer having a second metal film on an upper surface thereof; and a platen disposed above the upper surface of the upper wafer; wherein the first semi-metal film and the pressing plate are transparent to infrared light; the first half metal film and the second metal film form a eutectic metal by eutectic bonding. The room temperature wafer eutectic bonding module adopts the room temperature wafer eutectic bonding hardware configuration, and the room temperature wafer eutectic bonding system adopts the room temperature wafer eutectic bonding module.

Description

Hardware configuration, module and system for eutectic bonding of wafers at room temperature

RELATED APPLICATIONS

The utility model discloses the application requires that the application date of singapore patent application number 10201900578Q 2019 be 01 month 23 the priority date of the utility model. The singapore priority patent application is entitled "hardware configuration and method for room temperature aluminum germanium (AlGe) eutectic bonding. (i.e., the original English title A Hardware Configuration and AMethodologyne for from Temperature arrangement AlGe European binding). The entire or pertinent contents of the singapore priority patent application are incorporated by reference herein.

Technical Field

The present application is in the field of semiconductor manufacturing. More particularly, the present application relates to a hardware configuration and module and system for room temperature wafer eutectic bonding.

Background

Wafer level or chip level bonding using eutectic metals is one of the processes in the semiconductor industry today for the fabrication of micro-electromechanical systems (MEMS) devices. These eutectic metal bonds are used to (i) provide electrical connection between the lower and upper wafers, or (ii) to peripherally seal the MEMS device.

When using existing bonding equipment, wafer alignment and wafer bonding are performed in two separate alignment chambers and bonding chambers, respectively. Within the alignment chamber, the two wafers are aligned using a suitable alignment technique, e.g., face-to-face alignment or face-to-back alignment. After the alignment process is completed, the wafer stack is clamped to a metal plate so that the wafers do not become misaligned prior to bonding in the bonding chamber.

Fig. 1 shows the bonding of two wafers, an upper wafer 1 and a lower wafer 2, which are aligned with each other and clamped to the metal plate 3. For the sake of simplicity, the clamping tool of the metal sheet 3 is not shown in fig. 1. Some metal plates 3 also contain spacers 4 placed between the two wafers 1, 2 so that the gap between the two wafers 1, 2 can be effectively evacuated prior to bonding. Alternatively, if the gasket 4 is not used in the clamping step, the same degree of vacuum can also be obtained by pulling a vacuum for a long time. The two wafers have a metal or metal alloy of pre-deposited and patterned germanium (Ge)5 and aluminum (Al)6, respectively, so that metal bonding, such as aluminum germanium (AlGe) bonding, can be performed.

Fig. 2 shows a conventional bonding arrangement with a bonding chuck 3, two aligned wafers 1, 2 placed on a bottom stage (also called wafer table) 7. The bonding chamber also includes a load/lock door 10 and a vacuum system 11. During bonding, the bonding chamber is evacuated and then the pad 4 is removed. Next, the top platform 8 is lowered by applying pressure on the top platform 8 by means of a piston 9. Wafers 1, 2 have pre-deposited germanium aluminum (GeAl) metals 5, 6, respectively, i.e., typically one of the metals on the upper wafer 1 and the other metal on the lower wafer 2. The bottom stage (wafer table) 7 is heated to slightly below the eutectic melting point so that the two metals diffuse into each other and react to form an inter-metallic compound (imc) bonding the two wafers together. Generally, metals first transition to the liquid phase when forming eutectic alloys. This bonding method also allows for the formation of hermetically sealed bonding structures as the reaction proceeds through the liquid phase, and thus can be used to vacuum seal around the device.

Fig. 3a, 3b, 4a and 4b show that there is a layout of germanium (Ge) lines 5 and a layout of aluminum (Al) lines 6 around a micro-electromechanical systems (MEMS) device 12 for hermetic bonding of the micro-electromechanical systems (MEMS) device 12 with or without vacuum. It should be noted that in the conventional bonding method, aluminum (Al) and germanium (Ge) do not need to be separated on the upper and lower wafers 1 and 2, but an aluminum germanium (AlGe) alloy may be deposited on both wafers. During bonding, the alloy melts and bonds hermetically. The thickness and width of each metal line is not particularly required, and may be in the range of 0.5 to 2 micrometers (um) and 20 to 100 micrometers (um), respectively.

However, when using existing bonding equipment, it is necessary to heat the entire wafer to a higher temperature, such as a eutectic temperature. Such high temperatures can cause problems such as (i) the pre-deposited film is stressed due to over-hardening (curing); (ii) layering a pre-deposited film; (iii) wafer warpage due to film stress; and (iv) wafer fracture caused by higher internal stress during or just after bonding.

In order to make the bonding uniform, the temperature of the entire wafer needs to be the same. However, it is very difficult to obtain satisfactory uniformity across the wafer. For a typical bonding configuration, the non-uniformity of the actual temperature of the wafer table is in the range of 3% to 10% with respect to the set temperature. If the temperature of the wafer table is increased, the non-uniformity thereof is also increased. Thus, in the case of aluminum germanium (AlGe) bonding, the temperature variation across a 300 millimeter (mm) wafer can be as high as 10 ℃ to 40 ℃ relative to the set temperature. This can lead to problems in that if the wafer table temperature is set close to the eutectic temperature, certain portions of the wafer will not be heated to the eutectic temperature and therefore these portions of the wafer will not bond. If the temperature is set well above the eutectic temperature to compensate for the non-uniformity of the wafer temperature, these portions of the wafer can overheat, causing aluminum (Al) to splash around the bonding region. And aluminum splattering around the bonding area may cause electrical connections within the die to short. Both of these problems result in a reduction in the throughput of the equipment.

Fig. 5a and 5b specifically explain the above-described splashing of aluminum (Al). Fig. 5a shows a cross-sectional view of a bonding wire before a bonding process is performed, wherein the upper wafer 1 has a germanium (Ge) wire 5; and the lower wafer 2 has aluminum (Al) lines 6. During the bonding process, the wafers 1, 2 are heated from the bond chuck 3, so that heat flow is conducted from the bond chuck 3 to the lower wafer 2 and then from the lower wafer 2 to the upper wafer 1. In order to heat the germanium (Ge)5 on the upper wafer 1 to the eutectic temperature, the lower wafer 2 must be heated to slightly above the eutectic temperature. After the germanium (Ge)5 is heated, diffusion into the aluminum (Al)6 starts. It is noted that, since the entire aluminum (Al) wire 6 is heated to above the eutectic temperature, once the germanium (Ge)5 starts to diffuse, the aluminum (Al)6 diffuses from the aluminum germanium (Al/Ge) bonding interface to the aluminum silicon (Al/Si) interface. If the ratio of aluminum to germanium (Al: Ge) reaches 49:51 (weight ratio), a molten aluminum germanium (AlGe) alloy is formed. Since the bonding interface is under the force of the bonding force, once the molten aluminum germanium (AlGe) alloy is formed, it diffuses from its boundary into the device region (see fig. 5 b). This may damage the device, resulting in a reduction in yield.

Another problem with heating the entire wafer is that the wafer may contain high stresses and even warp after bonding. Since the wafer is bonded at a relatively high temperature (440 ℃), the wafer will thermally expand and thus contain stresses when the wafer is cooled to room temperature. This can lead to wafer bowing and may even lead to debonding, cracking or breaking of the wafers, especially if one of the wafers is thin.

A third disadvantage of heating the entire wafer is that bonding at high temperatures, the upper wafer 1 and the lower wafer 2 may not be aligned. In order to obtain accurate alignment, the upper wafer 1 and the lower wafer 2 must be at exactly the same temperature. However, in practice, this is very difficult, and there is typically a temperature difference of 1 ℃ to 4 ℃ between the upper wafer 1 and the lower wafer 2. Such temperature variations may generate run-out misalignment (run-out misalignment) which may be in the range of 2 to 10 micrometers (μm), particularly at the edge position of the wafer, due to differences in the coefficient of thermal expansion.

A fourth disadvantage of heating the entire wafer is that some devices requiring bonding may not be heated to high temperatures, for example, aluminum germanium (AlGe) bonding temperatures up to 430 ℃, due to the presence of pre-deposited films, such as polyamide or other carbon films. Most carbon films, generally cannot be heated above 200 ℃. Therefore, it is not possible to heat the entire wafer to the aluminum germanium (AlGe) eutectic bonding temperature, or it is necessary to change the materials used to fabricate the devices.

It is therefore an object of the present application to address the above-mentioned problems of (i) maintaining good temperature uniformity across the wafer; (ii) reducing the stress of the wafer; (iii) the wafer warpage is reduced; (iv) more accurate alignment; and (v) heating the wafer containing the organic thin film to an elevated temperature.

SUMMERY OF THE UTILITY MODEL

In view of the above-mentioned problems with the prior art, the present invention describes a hardware configuration and method for aluminum germanium (AlGe) eutectic bonding that features only local heating of the metal bonding wires by Infrared (IR) radiation without the need to heat the wafer (e.g., silicon wafer or glass wafer) to the eutectic temperature.

According to a first aspect of the present application, the utility model provides a room temperature wafer eutectic bonding's hardware configuration.

The room-temperature wafer eutectic bonding hardware configuration comprises an upper wafer, wherein the lower surface of the upper wafer is provided with a first semi-metal film; a lower wafer having a second metal film on an upper surface thereof; and a platen disposed above the upper surface of the upper wafer; wherein the first semi-metal film and the pressing plate are transparent to infrared light; the first half metal film and the second metal film form a eutectic metal by eutectic bonding. The infrared light has a wavelength in a range of 0.8 micrometers (μm) to 1.5 micrometers (μm).

The selection of the appropriate eutectic metal is based on the application scenario, the pre-deposited material on the wafer, and additional processing steps downstream. Optionally, the eutectic metal includes silver tin (AgSn), copper tin (CuSn), or indium tin (InSn).

Preferably, the first semi-metal film is a germanium (Ge) film and is located on the lower surface of the upper wafer; the second metal film is an aluminum (Al) film and is positioned on the upper surface of the lower wafer. Aluminum germanium (AlGe) is compatible with Complementary Metal Oxide Semiconductor (CMOS). The eutectic temperature of aluminum germanium (AlGe) is relatively high and is 419 ℃.

More preferably, the germanium film and the aluminum film have a shape of a line or dot of thin and patterned germanium and aluminum.

Optionally, the platen is a quartz (quartz) plate. Since a pressure is generally applied to the edge position of the quartz plate, the thickness thereof must be sufficient to withstand the pressure. The thickness of the quartz plate may be in a range of 10 millimeters (mm) to 20 mm.

Optionally, the hardware configuration for eutectic bonding of the room temperature wafer further includes a bonding chuck for clamping the upper wafer and the lower wafer.

Optionally, the hardware configuration for room temperature wafer eutectic bonding further comprises a force application piston for applying a pressure to the pressure plate (e.g., quartz plate).

When the room-temperature wafer eutectic bonding hardware configuration is adopted, the upper wafer and the lower wafer are integrally aligned, placed in a vacuum chamber and extruded by a thick quartz plate. Infrared light passes through a quartz plate, an upper wafer of silicon (Si), and a germanium (Ge) film, focuses on an aluminum film at a bond interface (bond interface), and heats the aluminum film to a temperature slightly above the aluminum germanium (AlGe) eutectic temperature. The heated aluminum film in turn heats the germanium film, causing the germanium film and the aluminum film to interdiffuse and react to form an aluminum germanium (AlGe) eutectic alloy, thereby bonding the upper and lower wafers together. This method can heat only the bonding interface (bonding interface) and the region of several micrometers around it, so that the amount of heat transferred to the silicon (Si) wafer is small, and it is considered that the entire silicon (Si) wafer is not heated. The surface area of the aluminum germanium (AlGe) bonding lines or dots is very small compared to the total surface area of the silicon (Si) wafer, so there is little increase in the overall temperature of the silicon (Si) wafer.

According to a second aspect of the present application, the utility model provides a room temperature wafer eutectic bonding's module.

The module for the room-temperature wafer eutectic bonding comprises the hardware configuration for the room-temperature wafer eutectic bonding; an infrared generator for generating an infrared beam; and an infrared scanner for detecting the first half metal film and the second metal film in the hardware configuration.

Optionally, the infrared scanner further includes an infrared camera for recognizing the first half metal film and the second metal film.

Optionally, the infrared scanner further comprises an optical module for guiding and adjusting the infrared beam.

Optionally, the infrared scanner further comprises a piston plate, the piston plate is connected with the force application piston in the hardware configuration, so as to conduct the bonding force generated by the force application piston to the pressure plate in the hardware configuration; and an electromechanical unit for rotating the piston plate. Wherein the piston plate further comprises a linear groove for passing the infrared beam.

According to a third aspect of the present application, the utility model provides a room temperature wafer eutectic bonding's system.

The system for eutectic bonding of the wafers at the room temperature comprises a module for eutectic bonding of the wafers at the room temperature; a wafer pre-cleaning module for cleaning contaminants, particularly metal oxides, on the surfaces of the upper and lower wafers; a wafer alignment and clamping module for aligning and securing the upper wafer and the lower wafer together; a wafer de-chucking module for removing a wafer stack formed by the upper and lower wafers from the fixture after bonding; a wafer automated processing front end module for automatically transferring the upper and lower wafers.

Drawings

FIG. 1 shows a cross-sectional view of two wafer bonds;

FIG. 2 shows a cross-sectional view of a prior art bonding apparatus;

FIG. 3a is a cross-sectional view of a lower wafer and an aluminum film in a conventional bonding apparatus;

FIG. 3b is a top view of the lower wafer and an aluminum film in a conventional bonding apparatus;

FIG. 4a shows a cross-sectional view of an upper wafer and a germanium film in a prior art bonding apparatus;

FIG. 4b shows a top view of an upper wafer and a germanium film in a prior art bonding apparatus;

FIG. 5a shows a cross-sectional view of a bonding wire before a bonding process is performed;

FIG. 5b is a cross-sectional view showing aluminum film splashing in the conventional bonding apparatus;

FIG. 6 illustrates a cross-sectional view of a hardware configuration of room temperature wafer eutectic bonding of the present application;

FIGS. 7a and 7b are cross-sectional views of a room temperature wafer eutectic bonding hardware configuration of the present application to prevent aluminum film splattering;

FIG. 8 illustrates a cross-sectional view of a first embodiment of a room temperature wafer eutectic bonding module of the present application;

FIG. 9 illustrates a side view of a second embodiment of a room temperature wafer eutectic bonding module of the present application;

fig. 10 shows a system for room temperature wafer eutectic bonding.

The numbers in the figures are as follows: 1. upper wafer, 2, lower wafer, 3, metal plate (bonding chuck), 4, gasket, 5, germanium (wire), 6, aluminum (wire), 7, bottom platform (wafer table), 8, top platform, 9, piston, 10, load/lock gate, 11, vacuum system, 12, Micro Electro Mechanical System (MEMS), 13, aluminum germanium alloy;

101. an upper wafer, 102, a lower wafer, 103, a bonding chuck, 104, a germanium wire, 105, an aluminum wire, 106, a quartz plate, 107, a bonding stage, 108, a cylindrical metal ring, 109, an infrared scanner, 110, an infrared beam, 111, a top piston, 112, a vacuum system, 113, a piston plate, 114, a linear groove, 115, a width of the linear groove, 116a, 116b, a knee, 117, an electromechanical unit, 118, a force piston, 119, a wafer pre-cleaning module, 120, a wafer alignment and clamping module, 121, a wafer bonding module, 122, a wafer de-clamping module, 123, a front end module of a wafer handling robot, 124, a wafer box, 125, a wafer, 126, a wafer transfer module, 127, a functional device, 128, an aluminum germanium (AlGe) alloy.

Detailed Description

The technical solution of the present invention will be further clearly and completely described below with reference to the accompanying drawings and examples.

Hardware configuration for eutectic bonding of wafers at room temperature

Fig. 6 and fig. 7a and 7b are diagrams for explaining the hardware configuration of the room temperature wafer eutectic bonding and how to prevent the aluminum film from splashing. Fig. 6 shows two aligned wafers 101, 102 clamped to a bond chuck 103. The upper wafer 101 may be silicon (Si) or glass depending on device requirements. In particular, the upper wafer 101 needs to be transparent to Infrared (IR) radiation having a wavelength in the range of 0.8 to 1.5 micrometers (μm). Aluminum (Al) lines 105 and germanium (Ge) lines 104 are deposited on the lower wafer 102 and upper wafer 101, respectively, and patterned accordingly. After the two wafers 101, 102 are aligned, a quartz plate 106 is placed over the upper wafer 101 and clamped to hold the two wafers 101, 102 stationary until bonding is complete.

The key point of the present application is that aluminum germanium (AlGe) sputtering does not occur when aluminum germanium (AlGe) wires (104, 105) are bonded. This is explained in detail in fig. 7a and 7 b. The heating process starts from the surface of the aluminum (Al) line 105 at the aluminum germanium (AlGe) bond interface, rather than from the aluminum silicon (AlSi) interface. Therefore, heat flows from the surface of the aluminum wire 105 to the germanium (Ge) wire 104, and the aluminum wire 105 and the germanium wire 104 are in better physical contact by applying pressure. As the bonding interface temperature increases, the interdiffusion between aluminum and germanium increases. When the bonding interface temperature reaches 423 ℃, the aluminum germanium (AlGe) alloy 128 begins to melt and form an aluminum germanium eutectic (AlGe). By controlling the width of the infrared beam 110 and the accuracy of the focusing, only the centers of the aluminum wire 105 and the germanium wire 104 can be heated, so that the regions of heating and melting can be controlled. Thus, even if the aluminum germanium diffusion region melts, aluminum germanium does not diffuse out of the boundary because the gap between wafers 101, 102 is kept constant by the unmelted portions of aluminum line 105 and germanium line 106. Therefore, as shown in fig. 7b, when the central portions of aluminum line 105 and germanium line 106 melt and bond, they do not diffuse to nearby functional device 127.

First embodiment of a Room temperature wafer eutectic bonding Module

Fig. 8 shows a cross-sectional view of a first embodiment of a room temperature wafer eutectic bonding module of the present application. As shown in fig. 8, it is necessary to apply a bonding force at the edge position of the quartz plate 106 described above, and therefore, the thickness thereof must be sufficient to withstand the bonding force. Typically, the thickness of the quartz plate may be in the range of 10 millimeters (mm) to 20 millimeters (mm). Fig. 8 also shows a schematic view of a bonding chamber in which two aligned wafers are placed on the bonding station 107. It should be noted that the bonding station 107 does not contain an embedded heater because there is no need to heat the lower wafer 102. The bonding force is applied by a cylindrical metal ring 108 having an inner diameter larger than the diameter of the wafer. Within the cavity of the cylindrical metal ring 108, an Infrared (IR) generator and an Infrared (IR) scanner 109 are placed. Generally, an Infrared (IR) generator is large in volume, and thus is disposed outside the bonding chamber, and then reaches the infrared scanner 109 through a through hole of the cylindrical metal ring 108.

An infrared camera is also provided inside the infrared scanner 109 to detect the metal wire at the bonding interface. When the metal lines are detected, an infrared beam 110 passes through the quartz plate 106, the upper wafer 101, and the germanium (Ge) line 104, is irradiated onto the surface of the aluminum (Al) line 105, and is scanned along the aluminum line 105. The quartz material of the quartz plate 106, the silicon (Si) material of the upper wafer 101, and the germanium (Ge) material of the germanium line 104 are all transparent to an Infrared (IR) beam 110; therefore, germanium (Ge) lines (104) have to be deposited on the top wafer 101 in order to enable better performance by the bonding techniques in this application.

If an aluminum (Al) wire 105 is deposited on the upper wafer 101, the aluminum (Al) wire 105 is heated by an Infrared (IR) beam 110, and then heat is transferred to an aluminum germanium (AlGe) bonding interface through the aluminum (Al) wire 105, and a bonding process is performed. The disadvantage of this bonding method is that the aluminum (Al) line 105 heats up at the aluminum/silicon (Al/Si) interface and then transfers to the aluminum/germanium (Al/Ge) interface, and the germanium (Ge) line 104 diffuses into the aluminum/silicon (Al/Si) interface. Therefore, the molten aluminum germanium (AlGe) may be sputtered and diffuse out of the bonding wire, thereby damaging the device. Thus, the results produced using aluminum (Al) lines 105 at upper wafer 101 are not the same as the results produced using germanium (Ge) lines 104 at upper wafer 101.

During semiconductor or micro-electromechanical systems (MEMS) fabrication, it is desirable to deposit various thin films on a wafer (e.g., the surface of upper wafer 101. however, only certain thin films may be deposited on upper wafer 101 that are transparent to Infrared (IR) beam 110, such as silicon dioxide (SiO2) or silicon nitride (Si3N 4).

The thickness of the germanium (Ge) line 104 and the aluminum (Al) line 105 is not particularly required, and only needs to be in the range of 100 nanometers (nm) to 1 micrometer (um). If the bond height needs to be higher than about 2 micrometers (μm), a dummy material, such as copper (Cu), may be used under the aluminum (Al) line 105. The prosthetic material is much easier to deposit and pattern than aluminum (Al). There are no special requirements for the width of the germanium (Ge) lines 104 and the aluminum (Al) lines 105, and the minimum width is determined by the width of the ir beam 110 and the accuracy requirements.

The invention further discloses a bonding method by using the room-temperature wafer eutectic bonding module in the first embodiment. First, the two wafers 101 and 102 are aligned using the quartz plate 106 and clamped to the bond chuck 103. The alignment may also be accomplished using an aligner. Preferably, the alignment operation described above is performed at room temperature, thereby allowing a higher degree of alignment, typically controllable in the range of plus/minus (+/-)0.5 to 2 microns. The aligned wafer stack is then placed in the bonding chamber. A vacuum system 112 is then used to evacuate the bonding chamber to a predetermined pressure and lower the top piston 111 until the cylindrical metal ring 108 contacts the quartz plate 106. Germanium aluminum (AlGe) bonding belongs to eutectic bonding, so that high bonding force does not need to be applied by the top piston 111, and only good physical contact between the aluminum (Al) wire 105 and the germanium (Ge) wire 104 is required by the bonding force. Typically, only 20 kilo-newtons (KN) to 50 kilo-newtons (KN) of bonding force is required to bond two 300 millimeter (mm) wafers.

After the top piston 111 applies the bonding force, an Infrared (IR) camera in the Infrared (IR) scanner 109 starts detecting the bonding wires 104, 105 around the individual die (die), then emits an Infrared (IR) beam 110 onto the bonding wires 104, 105 and scans the respective bonding wires 104, 105. The infrared beam 110 heats the aluminum (Al) wire 105 by passing through quartz, silicon (Si), and germanium (Ge) materials to the surface of the aluminum (Al) wire 105. The heated aluminum (Al) wire 105 will further heat the germanium (Ge) wire 104 as long as there is good physical contact between the germanium (Ge) wire 104 and the aluminum (Al) wire 105. Once the germanium (Ge) line 104 is heated, it rapidly diffuses, forming an intermetallic aluminum germanium (AlGe) alloy.

It should be noted that the portion heated by the Infrared (IR) beam 110 is only a few micrometers in the area of the surface of the aluminum (Al) wire 105 irradiated by the infrared beam 110. The depth to which the aluminum (Al) wire 105 is heated can be controlled by the irradiation time of the infrared beam 110. Thus, by employing aluminum (Al) lines 105 and germanium (Ge) lines 104 that are several microns thick, e.g., 2 to 5 microns (μm), heat flow from the bonding interface to the wafers 101, 102 may be significantly reduced. This eliminates any stress that may be generated between the bond wires 104, 105 and the wafers 101, 102.

Alternatively, the aluminum (Al) line 105 and the germanium (Ge) line 104 may be identified with an Infrared (IR) camera within the scanner 109 described above. It first identifies global alignment marks on wafers 101, 102; the software of the scanner 109 may then direct an optical system to scan an Infrared (IR) beam 110 over the bonding wires 104, 105 by inputting the die layout of the wafers 101, 102.

The Infrared (IR) scanner 109 also includes a mobile unit. After bonding is completed for one die, the Infrared (IR) scanner 109 can move to the next die by the movable unit and perform the same bonding operation. This process continues until all of the dies on wafers 101, 102 have been bonded. The bonding force is then released and the pressure in the bonding chamber is returned to atmospheric pressure, and the bonded wafer stack 101, 102 is unloaded together with the bond chuck 103. Finally, the bonded stack of wafers 101, 102 may be removed from the bond chuck 103 using a robotic system or manually.

In the present application, the temperature of the bonding interface can be controlled by varying the energy and irradiation time of the Infrared (IR) beam 110. Preferably, the Infrared (IR) source is a suitable infrared laser source. It will be appreciated that other Infrared (IR) sources may be suitable. The width of the Infrared (IR) beam 110 may also be adjusted to accommodate the width of the aluminum germanium (GeAl) line used by using the optical system described above in the infrared scanner 109 described above. An Infrared (IR) beam 110 is controlled by an electromechanical system on an infrared scanner 109 to bond each of the bonding wires 104, 105.

Second embodiment of Room temperature wafer eutectic bonding Module

Fig. 9 illustrates a second embodiment of a room temperature wafer eutectic bonding module of the present application. The hardware configuration shown in figure 9 includes a piston plate 113 that applies a compressive force to the stack of wafers 101, 102. The other hardware configuration in the second embodiment is substantially the same as that of the first embodiment.

Preferably, the piston plate 113 is made of stainless steel, and may have a thickness ranging from 10 millimeters (mm) to 20 mm. The hardware configuration also includes a linear groove 114 that passes through the center of the piston plate 113. The width 115 of the linear groove 114 should be kept to a minimum, preferably less than 10 millimeters (mm). The length of the linear groove 114 must be at least 5 millimeters (mm) greater than the diameter of the wafers 101, 102. For example, the linear groove 114 has a length of 305 millimeters (mm) for bonding a 300 millimeter (mm) wafer.

The piston plate 113 is connected to an apply piston 118 by two bent rods 116a, 116 b. At the junction of the force application piston 118 and the two bent rods 116a, 116b there is an electromechanical unit 117 for rotating the piston plate 113 about the axis of the force application piston 118.

The Infrared (IR) scanner 109 is located above the linear groove 114. Preferably, the Infrared (IR) scanner 109 is fixed to the piston plate 113 and is relatively movable with respect to the linear groove 114.

In use, a bonding force is first applied to the stack of wafers 101, 102 by the piston plate 113. The infrared scanner 109 then scans the bonding wires 104, 105 around the die within the linear recess 114. After all the dies located in the linear groove 114 have been bonded, the bonding force is released and the piston plate 113 is slightly rotated using the electromechanical unit 117, so that new dies present in the linear groove 114 are bonded.

Eutectic bonding system for wafers at room temperature

Fig. 10 illustrates a system 140 for room temperature wafer eutectic bonding according to the present application. Fig. 10 illustrates a system for automated wafer bonding. The system includes a wafer pre-cleaning module 119, a wafer alignment and clamping module 120, a wafer bonding module 121 as previously described, a wafer de-clamping module 122, a wafer handling front end module 123, and a wafer transfer module 126. The wafer pre-cleaning module 119 is used to perform surface cleaning, particularly metal oxide removal, on the upper wafer 101 and the lower wafer 102. The wafer alignment and clamping module 120 is used to align and hold the upper wafer 101 and the lower wafer 102 prior to bonding. The wafer de-chucking module 122 is used to remove the wafer stack formed by the upper wafer 101 and the lower wafer 102 from the fixture after bonding. The front end module 123 further includes a wafer cassette 124, a first wafer stage 129, a second wafer stage 130, and a wafer transfer module 126. The wafer 125 may be automatically removed from the pod 124, automatically transferred to the wafer tables 129, 130, and automatically transferred to the system 140 via the wafer transfer module 126 by the wafer automated processing front end module 123.

In particular, the wafer pre-clean module 119 typically uses a plasma assisted wafer cleaning method, i.e., a radio frequency power (RF power) is applied to the wafer table (not shown) to generate a plasma.

The wafer bonding module 121 has the same or similar hardware configuration as that of the first and second embodiments.

By using the system, the wafer bonding of a full-automatic wafer level can be carried out.

To sum up, the hardware configuration, module and system of room temperature wafer eutectic bonding in this application have following advantage:

only the aluminum germanium (AlGe) bonding interface is heated. I.e. the heating zone may be limited to the aluminium germanium (AlGe) bonding interface. Therefore, the silicon (Si) wafer located behind the germanium (Ge) line and the aluminum (Al) line is not heated.

The molten aluminum germanium (AlGe) can be prevented from splashing, thereby increasing the yield of the device.

Since the upper and lower wafers are not heated, the wafers are not thermally expanded to cause misalignment. While also helping to reduce the width of the bond wire.

The wafer table is not provided with a heater for heating the wafer, thereby reducing the equipment cost and the manufacturing cost.

The hardware configurations, modules, and systems of the present application may also be applied to other eutectic metals. However, when other metal alloys are used, the top metal layer may be heated, which may heat a local area of the silicon (Si) wafer.

It is finally necessary to point out here: the above description is only for the preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention should be covered by the protection scope of the present invention.

Claims (10)

1. A hardware configuration for room temperature wafer eutectic bonding, comprising:

an upper wafer having a first semi-metal film on a lower surface thereof;

a lower wafer having a second metal film on an upper surface thereof; and

a platen disposed above the upper surface of the upper wafer;

the method is characterized in that:

the first semi-metal film and the pressing plate are transparent to infrared light; and

the first half metal film and the second metal film form a eutectic metal by eutectic bonding.

2. The room temperature wafer eutectic bonding hardware configuration of claim 1, wherein:

the first semi-metal film is a germanium (Ge) film;

the second metal film is an aluminum (Al) film.

3. The room temperature wafer eutectic bonding hardware configuration of claim 1, wherein:

the pressing plate is a quartz plate.

4. The room temperature wafer eutectic bonding hardware configuration of claim 1, wherein: the bonding chuck is used for clamping the upper wafer and the lower wafer.

5. The room temperature wafer eutectic bonding hardware configuration of claim 1, wherein: the pressure applying device further comprises a force applying piston for applying pressure to the pressure plate.

6. A module for room temperature wafer eutectic bonding, comprising:

the hardware configuration for room temperature wafer eutectic bonding of any one of claims 1 to 5;

an infrared generator for generating an infrared beam; and

an infrared scanner for detecting the first half-metal film and the second metal film in the hardware configuration.

7. The room temperature wafer eutectic bonded module of claim 6, wherein:

the infrared scanner further includes an infrared camera for recognizing the first half metal film and the second metal film.

8. The room temperature wafer eutectic bonded module of claim 6, wherein:

the infrared scanner also includes an optical module for directing and conditioning the infrared beam.

9. The room temperature wafer eutectic bonded module of claim 6, further comprising:

a piston plate connected to the force applying piston in the hardware configuration for transmitting the bonding force generated by the force applying piston to the pressure plate in the hardware configuration; and

an electromechanical unit for rotating said piston plate;

wherein the piston plate further comprises a linear groove for passing the infrared beam.

10. A system for room temperature wafer eutectic bonding, comprising:

the room temperature wafer eutectic bonded module of claim 6;

a wafer pre-cleaning module for cleaning the surfaces of the upper and lower wafers;

a wafer alignment and clamping module for aligning and securing the upper wafer and the lower wafer together;

a wafer de-chucking module for removing a wafer stack formed by the upper wafer and the lower wafer from the holding apparatus; and

a wafer automated processing front end module for automatically transferring the upper and lower wafers.

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