Hot-pressing disc capable of improving temperature rising and falling rate and wafer bonding method

Abstract

The invention relates to the technical field of wafer bonding, and discloses a hot-pressing disc capable of increasing the temperature increasing and decreasing rate and a wafer bonding method, and the hot-pressing disc comprises a crimping module, a heating module, a first cooling module and a second cooling module which are sequentially overlapped in the axial direction. By adopting the design of the double cooling modules, in the heating stage in the wafer bonding process, the heating rate in the heating stage is improved, and the situation that the temperature of the first cooling module and the joint and other components on the first cooling module is too high can be effectively avoided; the water leakage or gas leakage problem and the heat resistance problem caused by shock cooling and shock heating deformation of the welding position of the connector on the first cooling module do not need to be considered too much, the complexity of designing the hot-pressing disc can be reduced, a stable temperature environment can be provided for the hot-pressing disc, and the temperature control precision can be improved; in the cooling stage in the wafer bonding process, the first cooling module and the second cooling module which work at the same time can be matched with each other to achieve dual cooling, and therefore the cooling rate can be increased.

Description

Technical Field

[0001] The present invention relates to the technical field of wafer bonding, and in particular to a hot pressing plate and a wafer bonding method capable of improving the heating and cooling rates. Background Art

[0002] The contents in this section merely provide background information related to the present invention and may not constitute prior art.

[0003] As a key component in the wafer bonding machine, the hot press plate can support, heat and cool the wafer to achieve wafer bonding.

[0004] During the wafer bonding process, the heating and cooling rates of the hot press plate will directly affect the bonding efficiency and quality of the wafers. If the heating and cooling rates of the hot press plate are not fast enough, at least the following problems may occur: 1. Slow cooling may cause uneven distribution of thermal stress between the two bonded wafers, thus affecting the bonding quality; 2. Too slow a heating and cooling rate will extend the bonding time and reduce the efficiency of the bonding operation; 3. Too slow a cooling rate will cause related components to be in a high temperature environment for a long time, affecting the service life of the components; 4. Accurate temperature control is crucial to ensure the quality of wafer bonding, and too slow a heating and cooling rate may make it difficult to achieve accurate temperature control.

[0005] However, known hot pressing plates for wafer bonding generally adopt a design in which a crimping module, a heating module, a cooling module and a thermal insulation module are sequentially arranged along the axial direction. For a hot pressing plate of this design, not only is it necessary to separately add a thermal insulation module to isolate the heat generated by the heating module during the heating stage, but also during the heating stage, the temperature of the cooling module will be too high to affect the service life of the cooling module, and it is difficult to have a high heating and cooling rate by only setting up one cooling module. Summary of the invention

[0006] In view of this, the first object of the present invention is to provide a hot press platen with a dual cooling module design, in the hope of increasing the heating and cooling rate of the hot press platen during wafer bonding and increasing the service life of related components. At the same time, the second object of the present invention is to provide a method for wafer bonding using the hot press platen, in the hope of improving the wafer bonding efficiency and quality.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] On the one hand, the present invention discloses a hot pressing plate capable of improving the heating and cooling rate, which is used for wafer bonding, and the hot pressing plate comprises a pressing module, a heating module, a first cooling module and a second cooling module which are sequentially overlapped and arranged along the axial direction;

[0009] The heating module has a heating function; the heating module is configured to operate in a heating phase during wafer bonding to heat the wafer to be bonded;

[0010] The first cooling module and the second cooling module both have a cooling function; the first cooling module is configured to operate in a cooling stage during a wafer bonding process to cool the bonded wafers;

[0011] The second cooling module is configured to operate continuously during a heating phase and a cooling phase of a wafer bonding process.

[0012] Furthermore, the first cooling module and the second cooling module are both provided with cooling channels for the circulation of coolant;

[0013] When each cooling module is in working state, the cooling channel of each cooling module itself is filled with the cooling liquid; when each cooling module is in non-working state, the cooling channel of each cooling module itself is filled with air.

[0014] Furthermore, the crimping module and the heating module are an integrated structure.

[0015] On the other hand, the present invention discloses a wafer bonding method, using the above-mentioned hot pressing platen capable of improving the heating and cooling rate, the method comprising the following steps:

[0016] Step S1. During the heating stage of the wafer bonding process, the heating module and the second cooling module of the hot pressing plate are operated, and the first cooling module of the hot pressing plate is stopped to heat the wafer to be bonded;

[0017] Step S2. During the cooling stage of the wafer bonding process, the heating module of the hot press plate stops working, and the first cooling module and the second cooling module of the hot press plate work simultaneously to cool the bonded wafer.

[0018] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects:

[0019] The hot press plate disclosed in the present invention adopts a dual cooling module design. During the heating stage of the wafer bonding process, the first cooling module that stops working can act as a heat insulating member to prevent the heat provided by the heating module from being transferred to the second cooling module, which is conducive to improving the heating rate during the heating stage; at the same time, since the second cooling module continues to work during the heating stage, it can effectively avoid the first cooling module and its joints and other components from being too high, thereby effectively ensuring the service life of the first cooling module, and there is no need to excessively consider the water leakage or air leakage problems and heat resistance problems caused by the sudden cooling and heating deformation of the welding part of the joint on the first cooling module, which helps to reduce the complexity of designing the hot press plate; and the continuously working second cooling module can provide a stable temperature environment for the hot press plate, which helps to maintain the stability of the performance of related components and helps to improve the temperature control accuracy. During the cooling stage of the wafer bonding process, the first cooling module and the second cooling module that work at the same time can cooperate with each other to achieve double cooling, which is conducive to improving the cooling rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of a hot pressing plate provided in an embodiment of the present invention;

[0021] Figure 2 for Figure 1 An exploded view of the structure of the heat press plate is shown in FIG.

[0022] Icon: 10-crimping module, 20-heating module, 30-first cooling module, 40-second cooling module. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described in conjunction with specific implementation methods below. The same figure marks in the accompanying drawings represent the same components. It should be noted that the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Compared to the embodiments shown in the drawings, feasible embodiments within the scope of the present invention may have fewer components, other components not shown in the drawings, different components, differently arranged components, or differently connected components, etc. In addition, two or more components in the drawings may be implemented in a single component, or a single component shown in the drawings may be implemented as multiple separate components.

[0025] An embodiment of the present invention discloses a hot press plate, in particular a hot press plate with a dual cooling module design, which is used for wafer bonding, in the hope of improving the heating and cooling rates of the hot press plate during the wafer bonding process and improving the service life of related components.

[0026] like Figure 1 and Figure 2 As shown, Figure 1 shows the general structure of an exemplary hot press plate disclosed in this embodiment, Figure 2 for Figure 1 The structural exploded view of the heat press plate is shown in FIG. Figure 1 and Figure 2 In the hot pressing plate shown, the hot pressing plate may include a crimping module 10, a heating module 20, a first cooling module 30 and a second cooling module 40 which are sequentially overlapped along the axial direction. The axial direction in this embodiment refers to the central axis of the hot pressing plate.

[0027] In this embodiment, the crimping module 10, the heating module 20, the first cooling module 30 and the second cooling module 40 can all be roughly disc-shaped components. The side of the crimping module 10 facing away from the heating module 20 serves as a crimping surface, which is suitable for contacting the wafer to be bonded during the wafer bonding process.

[0028] The heating module 20 has a heating function, and is suitable for working in the heating stage of the wafer bonding process to heat the wafer to be bonded. The heating module 20 may have a substantially identical structure to the heating module 20 in the hot pressing plate known in the prior art, and will not be described in detail herein.

[0029] Furthermore, the crimping module 10 and the heating module 20 may be as follows Figure 1 or Figure 2 The integrated structure shown is helpful in reducing the volume of the entire heat pressing plate, thereby facilitating optimization of the structural design of a wafer bonding machine using the heat pressing plate.

[0030] The first cooling module 30 and the second cooling module 40 both have cooling functions. Specifically, the first cooling module 30 and the second cooling module 40 are both provided with cooling channels (not shown in the figure) for the circulation of coolant inside, and at the same time, joints (not shown in the figure) connected to their own cooling channels can be provided at parts such as the outer wall of the first cooling module 30 and the second cooling module 40, and the joints are suitable for connecting with an external coolant source, so that the coolant provided by the external coolant source can enter the corresponding cooling channel through the joints on each cooling module, and the coolant entering the cooling channel of each cooling module can eventually return to the coolant source, so that each cooling module has a basic cooling function and realizes the recycling of the coolant.

[0031] Among them, when each cooling module is in working state, the cooling channel of each cooling module itself is filled with coolant, and when each cooling module is in non-working state, the cooling channel of each cooling module itself is filled with air. That is, when the first cooling module 30 is in working state, the cooling channel of the first cooling module 30 is filled with coolant, and when the first cooling module 30 is in non-working state, the cooling channel of the first cooling module 30 is filled with air; correspondingly, when the second cooling module 40 is in working state, the cooling channel of the second cooling module 40 is filled with coolant, and when the second cooling module 40 is in non-working state, the cooling channel of the second cooling module 40 is filled with air. The coolant described in this embodiment can be, but is not limited to, cooling water.

[0032] Among them, the first cooling module 30 is suitable for stopping working during the heating stage of the wafer bonding process, that is, no coolant is provided to the cooling channel of the first cooling module 30, so that the heating module 20 can quickly heat the wafer to be bonded. During the cooling stage of the wafer bonding process, the heating module 20 stops working and the first cooling module 30 works to cool the bonded wafer.

[0033] The second cooling module 40 is suitable for continuous operation during the heating and cooling stages of the wafer bonding process. In the heating stage of the wafer bonding process, since the first cooling module 30 stops working, the cooling channel of the first cooling module 30 is filled with air, so the first cooling module 30 will act as a heat insulation component, which can effectively prevent the heat provided by the heating module 20 from being transferred to the second cooling module 40, thereby helping to increase the heating rate in the heating stage. In this process, since the stopped first cooling module 30 can play a heat insulation role, even if the second cooling module 40 continues to work, it will not affect the rapid heating of the wafer by the heating module 20 too much.

[0034] Furthermore, since the second cooling module 40 works continuously during the heating stage, there is no need to separately add the heat insulation module in the hot press plate known in the prior art, and the temperature of the surrounding environment of the hot press plate (generally referring to the bonding cavity) can be effectively controlled, thereby providing a stable temperature environment for the hot press plate. Compared with the heat insulation module, the second cooling module 40 can have a better heat insulation effect, and can simplify the design of other connection mechanisms behind the second cooling module 40. Furthermore, the second cooling module 40 that works continuously during the heating stage can also control the temperature of the first cooling module 30 to avoid the first cooling module 30, especially the temperature of the joints for passing the coolant on the first cooling module 30, being too high, thereby effectively ensuring the service life of the first cooling module 30, and there is no need to excessively consider the water leakage or air leakage caused by the deformation of the joints on the first cooling module 30 due to sudden cooling and heating, as well as the heat resistance problem, which helps to reduce the complexity of designing the hot press plate.

[0035] During the cooling stage of the wafer bonding process, the heating module 20 stops working, and the first cooling module 30 and the second cooling module 40 work simultaneously. At this time, the cooperation of the two cooling modules can perform doubly cooling on the bonded wafers, which is beneficial to improving the cooling rate during the cooling stage compared to the design of only one cooling module on the hot pressing plate known in the prior art.

[0036] On the other hand, an embodiment of the present invention further provides a method for wafer bonding using the hot pressing plate disclosed in the above embodiment, in the hope of improving the wafer bonding efficiency and quality.

[0037] In the actual bonding stage, two heat pressing plates disclosed in the above embodiment should be used, and the two heat pressing plates are symmetrically arranged up and down so that the compression modules 10 of the two heat pressing plates are opposite to each other.

[0038] Specifically, the wafer bonding method may include the following steps:

[0039] Step S1. When performing wafer bonding, the two wafers to be bonded are placed between the crimping modules 10 of the two hot pressing plates, and the upper hot pressing plate moves toward the lower hot pressing plate until the two hot pressing plates cooperate to press the bonding surfaces of the two wafers tightly together, then the heating stage can be entered.

[0040] During the heating stage of the wafer bonding process, the first cooling module 30 of each heat press plate stops working, and the heating module 20 and the second cooling module 40 of each heat press plate work to heat the corresponding wafer to the target temperature required for bonding through the heating module 20 of each heat press plate, and in this process, the heat press plate located above can apply the target pressure required for bonding to the two wafers until the two wafers are pressed and bonded together. Combined with the above, based on the fact that the first cooling module 30 stops working during the heating stage, it can effectively prevent the heat provided by the heating module 20 from being transferred to the second cooling module 40, which is conducive to improving the heating rate during the heating stage.

[0041] Step S2. After the two wafers are pressed and bonded together, the cooling stage can be entered. During the cooling stage of the wafer bonding process, the heating modules 20 of each hot pressing plate stop working, and the first cooling module 30 and the second cooling module 40 of each hot pressing plate work simultaneously, so that the first cooling module 30 and the second cooling module 40 of each hot pressing plate cooperate with each other to perform double cooling on the bonded wafers, thereby increasing the cooling rate.

[0042] It can be seen that the wafer bonding method disclosed in this embodiment, by adopting the hot pressing plate disclosed in the above-mentioned embodiment, can at least effectively improve the heating and cooling rate of the wafer during the wafer bonding process, thereby helping to improve the wafer bonding efficiency; at the same time, since the hot pressing plate disclosed in this embodiment can improve the temperature control accuracy, it is helpful to improve the wafer bonding quality.

[0043] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A hot pressing plate capable of increasing the heating and cooling rate, used for wafer bonding, characterized in that: The hot pressing plate comprises a pressing module, a heating module, a first cooling module and a second cooling module which are sequentially overlapped along the axial direction; The heating module has a heating function; the heating module is configured to operate in a heating phase during wafer bonding to heat the wafer to be bonded; The first cooling module and the second cooling module both have a cooling function; the first cooling module is configured to operate in a cooling stage during a wafer bonding process to cool the bonded wafers; The second cooling module is configured to operate continuously during a heating phase and a cooling phase of a wafer bonding process.

2. The hot pressing plate capable of improving the heating and cooling rate according to claim 1, characterized in that: The first cooling module and the second cooling module are both provided with cooling channels for circulating coolant; When each cooling module is in working state, the cooling channel of each cooling module itself is filled with the cooling liquid; when each cooling module is in non-working state, the cooling channel of each cooling module itself is filled with air.

3. The hot pressing plate capable of improving the heating and cooling rate according to claim 1, characterized in that: The crimping module and the heating module are an integrated structure.

4. A wafer bonding method, characterized in that: Using the hot pressing plate capable of improving the heating and cooling rate as claimed in any one of claims 1 to 3, the method comprises the following steps: Step S1. During the heating stage of the wafer bonding process, the heating module and the second cooling module of the hot pressing plate are operated, and the first cooling module of the hot pressing plate is stopped to heat the wafer to be bonded; Step S2. During the cooling stage of the wafer bonding process, the heating module of the hot press plate stops working, and the first cooling module and the second cooling module of the hot press plate work simultaneously to cool the bonded wafer.

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