A hot press plate capable of increasing the heating and cooling rate and a wafer bonding method

Abstract

The present invention relates to the technical field of wafer bonding, and discloses a hot plate capable of improving the heating and cooling rates and a wafer bonding method. The hot plate includes a pressing module, a heating module, a first cooling module, and a second cooling module that are sequentially overlapped along the axial direction. By adopting the design of a double cooling module, during the heating stage of the wafer bonding process, it is beneficial to improve the heating rate during the heating stage, effectively avoid the overheating of components such as the first cooling module and its connectors, and there is no need to overly consider the problems of water leakage or air leakage and heat resistance caused by the deformation of the welded joints of the connectors on the first cooling module due to sudden cooling and heating, which helps to reduce the complexity of designing the hot plate and can provide a stable temperature environment for the hot plate, being beneficial to improving the temperature control accuracy; during the cooling stage of the wafer bonding process, the first cooling module and the second cooling module working simultaneously can cooperate with each other to achieve double cooling, thus being beneficial to improving the cooling rate.

Description

Technical Field

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

[0002] The content of this part only provides background information related to the present invention, which may not constitute prior art.

[0003] As a key component in a wafer bonder, the hot plate can carry and heat / cool the wafer to achieve wafer bonding.

[0004] During the wafer bonding process, the heating and cooling rates of the hot plate directly affect the bonding efficiency and quality of the wafer. If the heating and cooling rates of the hot 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 heating and cooling rates will prolong the bonding time and reduce the bonding operation efficiency; 3. Too slow 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. Precise temperature control is crucial for ensuring the wafer bonding quality, and too slow heating and cooling rates may make it difficult to achieve precise temperature control.

[0005] However, the known hot plates for wafer bonding generally adopt a design in which a pressing module, a heating module, a cooling module, and a heat insulation module are sequentially arranged along the axis. For such a hot plate design, not only is it necessary to separately add a heat 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, affecting the service life of the cooling module, and only one cooling module is difficult to have a high heating and cooling rate. Summary of the Invention

[0006] In view of this, the first object of the present invention is to provide a hot plate with a dual-cooling-module design, in order to hopefully improve the heating and cooling rates of the hot plate during the wafer bonding process and extend the service life of related components. At the same time, the second object of the present invention is to provide a wafer bonding method using this hot plate, in order to hopefully improve the wafer bonding efficiency and quality.

[0007] The object of the present invention is achieved by the following technical solutions:

[0008] On the one hand, the present invention discloses a hot plate capable of improving the heating and cooling rates for wafer bonding, the hot plate includes a pressing module, a heating module, a first cooling module, and a second cooling module that are sequentially overlapped along the axis;

[0009] The heating module has a heating function; the heating module is configured to work in the heating stage during the wafer bonding process to heat the wafers to be bonded;

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

[0011] The second cooling module is configured to work continuously in the heating stage and the cooling stage during the wafer bonding process.

[0012] Furthermore, cooling channels for the coolant to flow through are provided inside both the first cooling module and the second cooling module;

[0013] Wherein, when each cooling module is in the working state, the cooling channels of each cooling module are filled with the coolant; when each cooling module is in the non-working state, the cooling channels of each cooling module are filled with air.

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

[0015] On the other hand, the present invention discloses a wafer bonding method, which uses the above-mentioned hot platen capable of improving the heating and cooling rates. The method includes the following steps:

[0016] Step S1. In the heating stage during the wafer bonding process, the heating module and the second cooling module of the hot platen work, and the first cooling module of the hot platen stops working to heat the wafers to be bonded;

[0017] Step S2. In the cooling stage during the wafer bonding process, the heating module of the hot platen stops working, and the first cooling module and the second cooling module of the hot platen work simultaneously to cool the bonded wafers.

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

[0019] The hot pressing plate disclosed in the present invention, through the design of adopting a dual cooling module, during the heating stage in the wafer bonding process, the first cooling module that stops working can act as a heat insulation member to prevent the heat provided by the heating module from being transferred to the second cooling module, thereby being beneficial 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 prevent the temperature of the first cooling module and its components such as joints from being too high, thereby effectively ensuring the service life of the first cooling module, and there is no need to overly consider the problems of water leakage or air leakage and heat resistance caused by the deformation of the welded joints of the joints on the first cooling module due to sudden cooling and heating, which helps to reduce the complexity when designing the hot pressing plate; moreover, the continuously working second cooling module can provide a stable temperature environment for the hot pressing plate, which helps to maintain the stability of the performance of related components and is beneficial to improving the temperature control accuracy. During the cooling stage in the wafer bonding process, the first cooling module and the second cooling module that work simultaneously can cooperate with each other to achieve dual cooling, thereby being beneficial to improving the cooling rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of the hot pressing plate provided by the embodiment of the present invention;

[0021] Figure 2 is Figure 1 an exploded view of the structure of the hot pressing plate shown in

[0022] Reference numerals: 10 - crimping module, 20 - heating module, 30 - first cooling module, 40 - second cooling module. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the specific embodiments. The same reference numerals in the drawings represent the same components. It should be noted that the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0024] Compared with the embodiments shown in the drawings, the feasible implementation solutions within the scope of protection of the present invention may have fewer components, have other components not shown in the drawings, different components, differently arranged components, or components with different connections, 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] Embodiments of the present invention disclose a hot press plate, in particular a hot press plate designed with a dual cooling module for wafer bonding, aiming to improve the heating and cooling rates of the hot press plate during the wafer bonding process and extend the service life of related components.

[0026] As Figure 1 and Figure 2 shown, wherein, Figure 1 shows the general structure of the exemplary hot press plate disclosed in this embodiment, Figure 2 is Figure 1 the exploded view of the structure of the hot press plate shown in Figure 1 and Figure 2 In the hot press plate shown, the hot press plate may include a crimping module 10, a heating module 20, a first cooling module 30, and a second cooling module 40 that are sequentially overlapped along the axial direction. Among them, the axial direction described in this embodiment refers to the central axis of the hot press plate.

[0027] In this embodiment, the crimping module 10, the heating module 20, the first cooling module 30, and the second cooling module 40 may all be substantially disk-shaped components. The side of the crimping module 10 facing away from the heating module 20 serves as the crimping surface, which is adapted to contact the wafer to be bonded during the wafer bonding process.

[0028] The heating module 20 has a heating function and is adapted to work during the heating stage of the wafer bonding process to heat the wafer to be bonded. Among them, the heating module 20 may have a substantially consistent structure with the heating module 20 in the known hot press plates in the prior art, and will not be elaborated here.

[0029] Furthermore, the crimping module 10 and the heating module 20 may be an integral structure as Figure 1 or Figure 2 shown. In this way, it is beneficial to reduce the volume of the entire hot press plate, thereby facilitating the optimization of the structural design of the wafer bonding machine using this hot press plate.

[0030] Both the first cooling module 30 and the second cooling module 40 have a cooling function. Specifically, cooling channels (not shown in the figure) for the circulation of the coolant are provided inside both the first cooling module 30 and the second cooling module 40. At the same time, joints (not shown in the figure) communicating with their respective cooling channels may be provided at positions such as the outer sidewalls of the first cooling module 30 and the second cooling module 40, and the joints are adapted to communicate with an external coolant source, so that the coolant provided by the external coolant source can enter the corresponding cooling channels through the joints on each cooling module, and the coolant entering the cooling channels of each cooling module can finally return to the coolant source, thereby enabling each cooling module to have a basic cooling function and realizing the recycling of the coolant.

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

[0032] Among them, the first cooling module 30 is adapted to stop working during the heating stage in the wafer bonding process, that is, no coolant is supplied 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 in 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 adapted to continuously work during the heating stage and the cooling stage in the wafer bonding process. Among them, during the heating stage in the wafer bonding process, since the first cooling module 30 stops working, at this time, the cooling channel of the first cooling module 30 is filled with air. Therefore, the first cooling module 30 will act as a heat insulation member, 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 during the heating stage. And during this process, since the stopped first cooling module 30 can play a heat insulation role, even if the second cooling module 40 continuously works, it will not overly affect the rapid heating of the wafer by the heating module 20.

[0034] Moreover, due to the second cooling module 40 continuously working during the heating stage, there is no need to separately add an insulation module in the hot plate known in the prior art, and the temperature of the environment around the hot plate (generally referring to the bonding chamber) can be effectively controlled, thereby providing a stable temperature environment for the hot plate. And compared with the insulation module, the second cooling module 40 can have a better heat insulation effect and can simplify the design of other connecting mechanisms behind the second cooling module 40. In addition, the second cooling module 40 continuously working during the heating stage can also control the temperature of the first cooling module 30 to avoid the temperature of the first cooling module 30, especially components such as the joints for introducing coolant on the first cooling module 30, from being too high, thereby effectively ensuring the service life of the first cooling module 30. And there is no need to overly consider the deformation problems of leakage or air leakage and heat resistance caused by the sudden cooling and heating of the welded joints on the first cooling module 30, which helps to reduce the complexity of designing the hot plate.

[0035] During the cooling stage in 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 mutual cooperation of the two cooling modules can perform double cooling on the bonded wafer. Compared with the design of the known hot chuck in the prior art that only has one cooling module, it is beneficial to increase the cooling rate during the cooling stage.

[0036] On the other hand, an embodiment of the present invention also provides a method for wafer bonding using the hot chuck disclosed in the present embodiment, in order to improve the wafer bonding efficiency and quality.

[0037] Among them, in the actual bonding stage, two hot chucks disclosed in the present embodiment should be used, and the two hot chucks are symmetrically arranged up and down so that the pressing modules 10 of the two hot chucks face 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 pressing modules 10 of the two hot chucks, and the upper hot chuck moves towards the lower hot chuck until the two hot chucks cooperate to tightly press and fit the bonding surfaces of the two wafers, and then the heating stage can be entered.

[0040] During the heating stage in the wafer bonding process, the first cooling module 30 of each hot chuck stops working, and the heating module 20 and the second cooling module 40 of each hot chuck work. The corresponding wafer is heated to the target temperature required for bonding through the heating module 20 of each hot chuck. And during this process, the upper hot chuck can apply the target pressure required for bonding to the two wafers until the two wafers are pressed and bonded together. Combining the foregoing, based on the fact that the first cooling module 30 stops working during the heating stage, it is possible to effectively prevent the heat provided by the heating module 20 from being transferred to the second cooling module 40, which is beneficial to increasing 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 in the wafer bonding process, the heating module 20 of each hot chuck stops working, and the first cooling module 30 and the second cooling module 40 of each hot chuck work simultaneously to perform double cooling on the bonded wafer through the mutual cooperation of the first cooling module 30 and the second cooling module 40 of each hot chuck, thereby increasing the cooling rate.

[0042] It can be seen that in the wafer bonding method disclosed in this embodiment, by using the hot chuck disclosed in this embodiment above, the temperature rising and falling rate of the wafer can be effectively increased at least during the wafer bonding process, which is beneficial to improving the wafer bonding efficiency; at the same time, since the hot chuck disclosed in this embodiment can improve the temperature control accuracy, it is beneficial to improving the wafer bonding quality.

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

Claims

1. A hot plate capable of improving the heating and cooling rate, used for wafer bonding, characterized in that, The hot pressing plate includes a crimping module, a heating module, a first cooling module, and a second cooling module that are sequentially overlapped along the axial direction; The heating module has a heating function; the heating module is configured to work in the heating stage during the wafer bonding process to heat the wafer to be bonded; Both the first cooling module and the second cooling module have a cooling function; the first cooling module is configured to work in the cooling stage during the wafer bonding process to cool the bonded wafer; The second cooling module is configured to continuously work in the heating stage and the cooling stage during the wafer bonding process; Cooling channels for the coolant to flow through are provided inside both the first cooling module and the second cooling module; Wherein, when each cooling module is in the working state, the cooling channels of each cooling module are filled with the coolant; when each cooling module is in the non-working state, the cooling channels of each cooling module are filled with air.

2. The hot pressing plate capable of increasing the heating and cooling rate according to claim 1, wherein The crimping module and the heating module are of an integral structure.

3. A wafer bonding method, characterized in that, Using the hot pressing plate capable of increasing the heating and cooling rates as described in any one of claims 1 to 2, the method includes the following steps: Step S1. In the heating stage during the wafer bonding process, the heating module and the second cooling module of the hot pressing plate work, and the first cooling module of the hot pressing plate stops working to heat the wafer to be bonded; Step S2. In the cooling stage during the wafer bonding process, the heating module of the hot pressing plate stops working, and the first cooling module and the second cooling module of the hot pressing plate work simultaneously to cool the bonded wafer.

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