Low-temperature bonding equipment

Abstract

The utility model belongs to the technical field of wafer bonding, and discloses low-temperature bonding equipment. The low-temperature bonding equipment comprises a cavity, two supporting frames and an ion source assembly, the supporting frames are installed in the cavity and include the first supporting frame and the second supporting frame opposite to the first supporting frame, the first supporting frame is used for clamping a first sample, and the second supporting frame is used for clamping a second sample; the first supporting frame and the second supporting frame are each internally provided with a first gas circulation channel, and the first gas circulation channels are used for circulating low-temperature gas. The temperature of the support frame is selectively configured between-300 DEG C and 0 DEG C; the ion source assembly is used for irradiating the first sample and the second sample. The low-temperature bonding equipment provided by the utility model can realize low-temperature bonding.

Description

Technical Field

[0001] The utility model relates to the technical field of wafer bonding, in particular to a low-temperature bonding device. Background Technique

[0002] The direct bonding technology can make wafers or chips of different materials form covalent bonds through atomic-level contact and then be combined together. The direct bonding technology can enable the bonded body to achieve structural properties that are difficult to achieve with single-material wafers or traditional processing methods, so it has high application value in the fields of microelectronics, microelectromechanics, or multi-functional chip integration.

[0003] If one wants to perform direct bonding on materials with relatively low melting points or materials with a large mismatch in thermal expansion coefficients, the traditional high-temperature bonding method is no longer applicable. The existing technology has developed a plasma-activated bonding process, that is, in a high-vacuum environment, before room-temperature bonding, the bonding materials are surface-treated with plasma to produce a clean surface and dangling chemical bonds on the material surface. However, the bonded body prepared by this bonding method has the problem of warping due to the mismatch in thermal expansion coefficients.

[0004] Therefore, there is an urgent need for a low-temperature bonding device to solve the above technical problems. Content of the Utility Model

[0005] The purpose of the utility model is to provide a low-temperature bonding device, aiming to solve the problem that when using the existing bonding device to bond a bonded sample, the formed bonded body is prone to warping due to the mismatch in thermal expansion coefficients. The low-temperature bonding device can achieve low-temperature bonding and can effectively alleviate the warping of the bonded body caused by the mismatch in thermal expansion coefficients.

[0006] To achieve this purpose, the utility model adopts the following technical solutions:

[0007] A low-temperature bonding device, comprising:

[0008] A cavity;

[0009] A support frame, installed in the cavity. There are two support frames, namely a first support frame and a second support frame opposite to the first support frame. The first support frame is used to clamp a first sample, and the second support frame is used to clamp a second sample. The first sample and the second sample are arranged opposite to each other. A first gas circulation channel is provided in both the first support frame and the second support frame, and the first gas circulation channel is used to circulate low-temperature gas;

[0010] An ion source assembly, which is used to irradiate the first sample and the second sample.

[0011] Optionally, the ion source assembly includes an ion source and a housing. The housing is provided with a receiving cavity for mounting the ion source, and the orientation of the opening of the receiving cavity is set at an angle with respect to the surface of the first sample or the second sample.

[0012] Optionally, a second gas circulation channel is provided in the housing. The second gas circulation channel surrounds the periphery of the ion source and is used for circulating cryogenic gas.

[0013] Optionally, the cryogenic bonding device further includes an atmosphere preparation component, which is used for evacuating the cavity.

[0014] Optionally, the cryogenic bonding device further includes temperature measuring elements. The temperature measuring elements include a first temperature measuring element and a second temperature measuring element. The first temperature measuring element is disposed between the first support frame and the first sample, and the second temperature measuring element is disposed between the second support frame and the second sample.

[0015] Optionally, the two support frames form a support frame group, and at least two support frame groups are provided in the cavity.

[0016] Optionally, the cryogenic bonding device further includes a manipulator, which is used for transporting the bonded body formed after bonding the first sample and the second sample.

[0017] Optionally, the cryogenic bonding device further includes a bonded body placement area, which is used for placing the bonded body.

[0018] Optionally, the first support frame clamps the first sample through an electrostatic chuck; the second support frame clamps the second sample through an electrostatic chuck.

[0019] Optionally, the cryogenic gas is helium or nitrogen.

[0020] Advantages of the present utility model: The low-temperature bonding device provided by the present utility model is provided with a first gas circulation channel in both the first support frame and the second support frame. The first gas circulation channel is used to circulate low-temperature gas. When bonding the first sample and the second sample, the circulated low-temperature gas is fed into the first support frame and the second support frame, and the temperatures of the first support frame and the second support frame are selectively configured between -300°C and 0°C. The temperature of the first sample is reduced to the same as that of the first support frame through thermal contact between the first support frame and the first sample, and the temperature of the second sample is reduced to the same as that of the second support frame through thermal contact between the second support frame and the second sample, so that the first sample and the second sample reach a low-temperature state, and thus low-temperature bonding is achieved. It can effectively alleviate the warping caused by the mismatch of the thermal expansion coefficients of the bonded body, and low-temperature bonding can pre-apply internal stress inside the bonded body. The pre-applied internal stress will change the lattice spacing inside the material, correspondingly change the electronic energy band structure and density, and thus change the mobility of carriers, improving the performance of the devices prepared later. Brief Description of the Drawings

[0021] Figure 1 is a schematic structural diagram of the low-temperature bonding device provided by an embodiment of the present utility model;

[0022] Figure 2 is a schematic structural diagram when the low-temperature bonding device provided by an embodiment of the present utility model performs bonding treatment on a sample.

[0023] In the figure:

[0024] 100, cavity;

[0025] 210, first support frame; 220, second support frame; 230, first gas circulation channel;

[0026] 300, first sample;

[0027] 400, second sample;

[0028] 510, ion source; 520, housing; 521, second gas circulation channel; 530, ion beam. Detailed Embodiments

[0029] The present utility model will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present utility model, rather than limiting the present utility model. Additionally, it should be noted that for the sake of description, only parts related to the present utility model are shown in the drawings, rather than all the structures.

[0030] In the description of the present utility model, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0031] In the present utility model, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "over", and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath", and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0032] In the description of this embodiment, the orientation or positional relationships such as "up", "down", "right", etc. are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present utility model. In addition, the terms "first" and "second" are only used for distinction in description and do not have special meanings.

[0033] This embodiment provides a low-temperature bonding device, aiming to solve the problem that when using the existing bonding device to bond a bonded sample, the bonded body is prone to warping due to the mismatch of the thermal expansion coefficients. This low-temperature bonding device can achieve low-temperature bonding and can effectively alleviate the warping of the bonded body caused by the mismatch of the thermal expansion coefficients. Among them, low-temperature bonding means that the bonding temperature is lower than 0 °C.

[0034] As Figure 1 and Figure 2 shown, this low-temperature bonding device includes a cavity 100, a support frame, and an ion source assembly. The support frame is installed inside the cavity 100. There are two support frames, namely a first support frame 210 and a second support frame 220 arranged opposite to the first support frame 210. The first support frame 210 is used to clamp a first sample 300, and the second support frame 220 is used to clamp a second sample 400. The first sample 300 and the second sample 400 are arranged opposite to each other. First gas circulation channels 230 are provided inside both the first support frame 210 and the second support frame 220, and the first gas circulation channels 230 are used to circulate low-temperature gas. Among them,Figure 1 and Figure 2 Both indicate the flow direction of the cryogenic gas. The temperature of the support frame is selectively configured between -300°C and 0°C, and the ion source assembly is used to irradiate the first sample 300 and the second sample 400.

[0035] In the cryogenic bonding device provided in this embodiment, by providing a first gas circulation channel 230 in both the first support frame 210 and the second support frame 220, the first gas circulation channel 230 is used to circulate the cryogenic gas. When the first sample 300 and the second sample 400 are bonded, the circulated cryogenic gas is fed into the first support frame 210 and the second support frame 220, and the temperatures of both the first support frame 210 and the second support frame 210 are selectively configured between -300°C and 0°C. The temperature of the first sample 300 is reduced to the same as that of the first support frame 210 through thermal contact between the first support frame 210 and the first sample 300, and the temperature of the second sample 400 is reduced to the same as that of the second support frame 220 through thermal contact between the second support frame 220 and the second sample 400. Thus, the first sample 300 and the second sample 400 reach a cryogenic state, and cryogenic bonding is realized. This can effectively relieve the warping caused by the mismatch of the thermal expansion coefficients of the bonded body, and cryogenic bonding can pre-apply internal stress inside the bonded body. The pre-applied internal stress will change the lattice spacing inside the material, correspondingly change the electronic energy band structure and density, and thus change the mobility of carriers, improving the performance of the device prepared later.

[0036] Optionally, the ion source assembly includes an ion source 510 and a housing 520. The housing 520 is provided with a receiving cavity for installing the ion source 510, and the orientation of the opening of the receiving cavity forms an angle with the surface of the first sample 300 or the second sample 400. During irradiation, the high-speed ion beam 530 generated by the ion source 510 is neutralized and then irradiated on the surface of the first sample 300 or the second sample 400 through the opening of the receiving cavity to clean the surface of the first sample 300 or the second sample 400 and generate dangling chemical bonds on the surface of the first sample 300 or the second sample 400; the orientation of the opening of the receiving cavity forms an angle with the surface of the first sample 300 or the second sample 400 to avoid interfering with the bonding process of the first sample 300 and the second sample 400. In this embodiment, two ion source assemblies are provided, one ion source assembly is used to irradiate the first sample 300, and the other ion source assembly is used to irradiate the second sample 400. In other embodiments, the ion source assembly can also be set to one or more. For example, if there is one ion source assembly, two ion sources 510 are provided in one ion source assembly, one ion source 510 is used to irradiate the first sample 300, and the other ion source 510 is used to irradiate the second sample 400. Those skilled in the art can set it according to needs.

[0037] Further, a second gas circulation channel 521 is provided inside the housing 520. The second gas circulation channel 521 surrounds the ion source 510 and is used to circulate cryogenic gas. By circulating cryogenic gas in the second gas circulation channel 521, the cryogenic gas can cool the housing 520, effectively avoiding the heat radiation of the ion source 510.

[0038] Preferably, the two support frames form a support frame group, and at least two support frame groups can be provided in the cavity 100. By providing at least two support frame groups, the at least two support frame groups can be cooled separately, facilitating multiple bonding processes. For example, two support frame groups are provided in the cavity 100. The temperatures of the two support frames of one support frame group are both reduced to -100°C, and the temperatures of the two support frames of the other support frame group are both reduced to -200°C. The first sample 300 and the second sample 400 are first bonded on the support frame group at -100°C to form a first bonded body. Subsequently, the first bonded body and other samples are bonded on the support frame group at -200°C to form a second bonded body.

[0039] In this embodiment, the cryogenic bonding device further includes an atmosphere preparation component, which is used to evacuate the cavity 100. Optionally, the atmosphere preparation component is set as a vacuum pump.

[0040] Preferably, the cryogenic bonding device further includes temperature measuring elements, which include a first temperature measuring element and a second temperature measuring element. The first temperature measuring element is arranged between the first support frame 210 and the first sample 300, and the second temperature measuring element is arranged between the second support frame 220 and the second sample 400. By arranging the first temperature measuring element between the first support frame 210 and the first sample 300, and the second temperature measuring element between the second support frame 220 and the second sample 400, the separate temperature control of the first sample 300 and the second sample 400 can be realized according to the temperature representation of the first temperature measuring element and the second temperature measuring element.

[0041] Optionally, the cryogenic bonding device further includes a manipulator, which is used to transfer the bonded body formed after the bonding of the first sample 300 and the second sample 400.

[0042] The low-temperature bonding device further includes a bond body placement area for placing the bond body. During operation, a manipulator can be used to transfer the bond body to the bond body placement area. Exemplarily, the temperature of the bond body placement area is set to 0°C - 50°C to raise the temperature of the bond body at negative temperature to the ambient temperature. When the temperature of the bond body rises to the working ambient temperature, an expected internal stress distribution can be formed in the bond body due to the temperature change. This expected stress distribution will change the lattice spacing inside the material, correspondingly change the electronic band structure, thereby changing the mobility of carriers and reducing the generation of cracks or defects. During the actual bonding process, different bonding temperatures can be set according to the material differences of the bond bodies. When the bond body rises from the bonding temperature to the working ambient temperature, an expected internal stress distribution can be formed in the bond body, thereby creating a high electron mobility, optical nonlinear effect or unusual piezoelectric effect on the bonding surface. By setting the bond body placement area, the bond body is prevented from directly rising / falling in temperature on the support frame, thereby reducing the frequency of temperature rise and fall of the support frame and improving the bonding rate. Alternatively, when the temperature of the bond body placement area is also -300°C - 0°C, it is used to lower the temperature of the bond body to the target temperature and then bond it with other samples.

[0043] Optionally, the first support frame 210 clamps the first sample 300 through an electrostatic chuck; the second support frame 220 clamps the second sample 400 through an electrostatic chuck. The electrostatic chuck has strong adaptability and can precisely fix the sample on the tabletop of the support frame. Optionally, the low-temperature gas is helium or nitrogen.

[0044] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention and are not intended to limit the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. Low temperature bonding equipment, characterized in that: include: Cavity (100); A support frame installed in the cavity (100), wherein two support frames are provided, namely a first support frame (210) and a second support frame (220) arranged opposite to the first support frame (210), wherein the first support frame (210) is used to clamp a first sample (300), and the second support frame (220) is used to clamp a second sample (400), and the first sample (300) and the second sample (400) are arranged opposite to each other, and a first gas circulation channel (230) is provided in each of the first support frame (210) and the second support frame (220), and the first gas circulation channel (230) is used to circulate low-temperature gas; The temperature of the support frame is selectively configured between -300°C and 0°C; An ion source assembly is provided, the ion source assembly being used to irradiate the first sample (300) and the second sample (400).

2. The low temperature bonding equipment according to claim 1, characterized in that: The ion source assembly comprises an ion source (510) and a shell (520), wherein the shell (520) is provided with a housing cavity for installing the ion source (510), and the cavity opening of the housing cavity is oriented at an angle to the surface of the first sample (300) or the second sample (400).

3. The low temperature bonding equipment according to claim 2, characterized in that: A second gas circulation channel (521) is provided in the housing (520). The second gas circulation channel (521) is arranged around the ion source (510) and is used for circulating low-temperature gas.

4. The low temperature bonding equipment according to claim 1, characterized in that: The low-temperature bonding equipment further comprises an atmosphere preparation component, wherein the atmosphere preparation component is used to perform a vacuum process on the cavity (100).

5. The low temperature bonding equipment according to claim 1, characterized in that: The low-temperature bonding device also includes a temperature measuring element, which includes a first temperature measuring element and a second temperature measuring element, wherein the first temperature measuring element is arranged between the first support frame (210) and the first sample (300), and the second temperature measuring element is arranged between the second support frame (220) and the second sample (400).

6. The low temperature bonding equipment according to claim 1, characterized in that: The two support frames form a support frame group, and at least two support frame groups are arranged in the cavity (100).

7. The low temperature bonding equipment according to claim 1, characterized in that: The low-temperature bonding equipment also includes a robot arm, which is used to transport a bonded body formed after the first sample (300) and the second sample (400) are bonded.

8. The low temperature bonding equipment according to claim 1, characterized in that: The low-temperature bonding equipment further comprises a bonding body placement area, and the bonding body placement area is used to place the bonding body.

9. The low temperature bonding equipment according to claim 1, characterized in that: The first support frame (210) clamps the first sample (300) through an electrostatic chuck; and the second support frame (220) clamps the second sample (400) through an electrostatic chuck.

10. The low temperature bonding equipment according to claim 1, characterized in that: The cryogenic gas is helium or nitrogen.

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