Method and equipment for de-bonding ultrathin wafer

Abstract

The invention discloses a de-bonding method and equipment for an ultrathin wafer, and belongs to the technical field of semiconductor processing. Before a wafer is fed into a cleaning chamber, the cleaning chamber is communicated with a feeding chamber and a de-bonding chamber, so that the air pressure of the three chambers is normal pressure; after the debonded wafer is conveyed into the cleaning chamber, the cleaning chamber is separated from the feeding chamber and the debonding chamber, so that the wafer is cleaned in an environment without pressure difference, the wafer is more stable and does not drift when being rotated and cleaned, and meanwhile, a cleaning solution is also prevented from splashing; and when the cleaning of the wafer is completed, the cleaning chamber is subjected to air exhaust, so that when the cleaning chamber is communicated with the feeding chamber again, pressure differences are formed between the feeding chamber and the cleaning chamber as well as between the debonding chamber and the cleaning chamber, so that residual cleaning liquid in the cleaning chamber is prevented from splashing when the wafer is taken out, and air exhaust is stopped until the wafer is taken out. According to the invention, the problem of wafer drifting in a cleaning link in a wafer de-bonding process can be effectively solved.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor processing, and in particular relates to a debonding method and equipment for ultra-thin wafers. Background Art

[0002] Silicon carbide (SiC) is a wide bandgap semiconductor with a bandgap energy of approximately 2.36 to 3.3 electron volts (eV), which is much higher than silicon's 1.12 eV. The high bandgap energy enables devices made from SiC wafer substrates to operate at higher temperatures and voltages without failure, and has higher thermal stability and breakdown voltage. In addition, SiC's thermal conductivity is approximately 3-4.9W / cm·K, much higher than silicon's 1.5W / cm·K, which enables SiC semiconductor chips to more effectively diffuse the heat generated inside when current flows through, maintaining stable operation of the chip. These characteristics of silicon carbide wafers enable them to withstand greater pressure and wear during the manufacturing process, making it easier to achieve thinner thicknesses.

[0003] Thinner silicon carbide wafers have brought great benefits to the processing cost and yield of semiconductor devices. Taking the processing of SiC diodes as an example, as the thickness of the SiC wafer is thinned, a lower threshold voltage VF and higher surge parameters can be obtained. Therefore, SiC ultra-thin wafers with the same threshold voltage and surge parameters can make more single dies, greatly reducing the cost of a single die. However, as the thickness of ultra-thin wafers (thickness <70um) becomes thinner during the thinning process, it brings challenges to the subsequent debonding process, as explained below:

[0004] See also Figure 1 As shown in FIG. 1 , the existing debonding process includes: wafer feeding, debonding, cleaning and wafer taking. Figure 2 As shown, the existing debonding process equipment includes a feed chamber and a debonding chamber and a cleaning chamber respectively arranged on both sides of the feed chamber. Among them, the wafer feeding link refers to the mechanical arm in the feed chamber transferring the wafer in the wafer clamp to the debonding chamber; the debonding link refers to the debonding component in the debonding chamber separating the companion wafer of the wafer on the debonding station from the wafer by melting the bonding wax; the cleaning link refers to the mechanical arm transferring the debonded wafer to the cleaning chamber, and the cleaning component cleans the debonded wafer on the cleaning station; the wafer taking link refers to the mechanical arm taking the cleaned wafer out of the cleaning chamber.

[0005] At present, the feed chamber, debonding chamber and cleaning chamber are conventionally connected; during the debonding process, the feed chamber and the debonding chamber maintain standard atmospheric pressure, and in order to prevent the cleaning materials in the cleaning chamber from splashing back or diffusing outward during cleaning and corroding the spare parts material, during the cleaning process, the cleaning chamber is always controlled to be at a negative pressure relative to the feed chamber and the debonding chamber, that is, a pressure difference distribution of A=B>C is formed; wherein A is the debonding chamber air pressure, B is the feed chamber air pressure, and C is the cleaning chamber air pressure.

[0006] However, during the cleaning process, the wafer is adsorbed on a cleaning carrier and rotates with it. Although the cleaning carrier has a certain adsorption force on the wafer, due to the internal and external pressure difference shown above (i.e. A=B>C) exists throughout the entire cleaning process, the wafer adsorbed on the cleaning carrier will still drift during the cleaning process and cannot be cleaned normally; this problem is particularly serious for ultra-thin wafers (thickness <70um), and in severe cases the wafer will be thrown off. Summary of the invention

[0007] The purpose of the present invention is to provide a method and device for debonding ultra-thin wafers, aiming to solve the problem of wafer drift in the cleaning process during the wafer debonding process. The present invention is achieved through the following scheme:

[0008] A first aspect of the present invention provides a debonding method for ultra-thin wafers, comprising: sequentially performing a wafer feeding step, a debonding step, a cleaning step and a wafer taking step on a debonding process device having a feeding chamber, a debonding chamber and a cleaning chamber; wherein the cleaning step specifically comprises:

[0009] S310, connecting the cleaning chamber with the feeding chamber and the debonding chamber so that the air pressures of the three chambers are all at normal pressure;

[0010] S320, transferring the wafer after debonding in the debonding chamber to a cleaning chamber, and isolating the cleaning chamber from the feeding chamber and the debonding chamber;

[0011] S330, controlling the cleaning component of the cleaning chamber to adsorb the wafer onto the cleaning station, and controlling the cleaning component to clean the wafer under the normal pressure;

[0012] S340, when the cleaning component completes cleaning of the wafer, evacuating the cleaning chamber;

[0013] S350, connecting the cleaning chamber with the feeding chamber and the debonding chamber, so that a pressure difference is formed between the feeding chamber, the debonding chamber and the cleaning chamber;

[0014] S360, controlling the cleaning component of the cleaning chamber to cancel the adsorption of the wafer, and stopping the pumping of the cleaning chamber after the wafer is taken out.

[0015] As a preferred technical solution, before step S310, a clamp for storing wafers to be debonded and wafers after cleaning is pre-configured in the feed chamber, and a transfer component for transferring wafers between the feed chamber, the debonding chamber and the cleaning chamber is pre-configured in the feed chamber.

[0016] As a preferred technical solution, the material port of the debonding chamber is configured to be always connected to the feeding chamber; a pressure regulating plate is arranged at the material port of the cleaning chamber, and the cleaning chamber is connected to the feeding chamber and the debonding chamber by controlling the pressure regulating plate to be opened; and the cleaning chamber is separated from the feeding chamber and the debonding chamber by controlling the pressure regulating plate to be closed.

[0017] As a preferred technical solution, an exhaust port is arranged on the cleaning chamber, and an exhaust component connected to the exhaust port is arranged outside the cleaning chamber, and the exhaust component is controlled to exhaust or stop exhausting the cleaning chamber.

[0018] As a preferred technical solution, the debonding step specifically includes:

[0019] S211, heating the wafer to 170-200° C. and maintaining the temperature for 5-25 min to fully melt the bonding wax;

[0020] S212, controlling the adsorption heat sliding speed to 50-100 mm / min to separate the wafer and the companion wafer.

[0021] As a preferred technical solution, in the debonding step, N2 gas is introduced from the bottom of the debonding chamber.

[0022] As a preferred technical solution, in step S330, controlling the cleaning component to clean the wafer under the normal pressure specifically includes:

[0023] S331, spray acetone for 60-90s;

[0024] S332, spray isopropyl alcohol for 5 to 30 seconds;

[0025] S333, spin dry at a speed of 1000-3000RPM.

[0026] A second aspect of the present invention provides a debonding device for ultra-thin wafers, comprising:

[0027] A feeding chamber, in which a clamp for storing wafers and a conveying assembly for conveying wafers are arranged;

[0028] a debonding chamber, in which a debonding assembly is disposed;

[0029] a cleaning chamber in which a cleaning component is disposed;

[0030] It is characterized in that it also includes an air pressure regulating system, which cooperates with the conveying component and the cleaning component to perform the cleaning process described above.

[0031] As a preferred technical solution, the air pressure regulating system includes:

[0032] An air pressure sensor is disposed in the cleaning chamber to monitor the real-time air pressure information of the cleaning chamber and send the information to the main control module;

[0033] A wafer detection sensor is arranged in the cleaning chamber to monitor the wafer presence information on the cleaning component and send the information to the main control module;

[0034] A pressure regulating plate, which opens or blocks the material port of the cleaning chamber under control;

[0035] An exhaust component, which is controlled to exhaust or stop exhausting air from an exhaust port arranged on the cleaning chamber;

[0036] The main control module receives the real-time air pressure information and wafer in-place information and controls the actions of the conveying component, the cleaning component, the pressure regulating plate and the exhaust component.

[0037] As a preferred technical solution, the exhaust assembly includes a common negative pressure unit in the factory, an electric control valve and a negative pressure branch, one end of the negative pressure branch is connected to the common negative pressure unit in the factory, and the other end is connected to the exhaust port; the electric control valve is arranged on the negative pressure branch and is controlled by the main control module.

[0038] As a preferred technical solution, the vacuum assembly includes a dedicated vacuum pump and a vacuum pipeline, one end of the vacuum pipeline is connected to the dedicated vacuum pump, and the other end is connected to the vacuum port; the dedicated vacuum pump is controlled by the main control module.

[0039] The debonding method and device of ultra-thin wafers provided by the present invention, before the wafer is sent into the cleaning chamber, the cleaning chamber is first connected with the feeding chamber and the debonding chamber, so that the air pressure of the three chambers is normal pressure; after the wafer after debonding is transferred to the cleaning chamber, the cleaning chamber is isolated from the feeding chamber and the debonding chamber, so that the wafer is cleaned in an environment without pressure difference, and the wafer is more stable when rotating for cleaning, and no drift occurs, and the cleaning liquid is also avoided from splashing out; when the cleaning of the wafer is completed, the cleaning chamber is evacuated, so that when the cleaning chamber and the feeding chamber are connected again, the feeding chamber and the debonding chamber form a pressure difference with the cleaning chamber, so that when the wafer is taken out, the cleaning liquid remaining in the cleaning chamber is avoided from splashing out, until the exhaust is stopped after the wafer is taken out. In addition, during debonding, N2 atmosphere is introduced, so that the wafer is in N2 gas atmosphere during debonding, which can fully protect the Ag on the back of the wafer to prevent oxidation. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The figure is a flow chart of the debonding process in the prior art.

[0041] Figure 2 The figure is a schematic diagram of the structure of the existing debonding process equipment in the prior art.

[0042] Figure 3 A schematic diagram of introducing nitrogen gas during the debonding step in the ultra-thin wafer debonding method provided in an embodiment of the present invention.

[0043] Figure 4 A flow chart of the cleaning step in the debonding method for ultra-thin wafers provided in an embodiment of the present invention.

[0044] Figure 5 A schematic diagram of the open state of the voltage regulating plate in the debonding method of the ultra-thin wafer provided in an embodiment of the present invention.

[0045] Figure 6 A schematic diagram of the open state of the voltage regulating plate in the debonding method of the ultra-thin wafer provided in an embodiment of the present invention.

[0046] Figure 7 A block diagram of the gas pressure regulating system in the ultra-thin wafer debonding equipment provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0047] The technical solutions of the embodiments of the present invention are explained and described below in conjunction with the drawings of the embodiments of the present invention, but the following embodiments are only preferred embodiments of the present invention, not all of them. In the description of the present invention, the terms "first" and "second" are only used for the purpose of distinction in the description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more, unless otherwise clearly defined.

[0048] The specific implementation modes of the present invention are described in detail below with reference to the accompanying drawings. Under the premise that there is no conflict between them, the technical features of each specific implementation mode can be inherited and used interchangeably.

[0049] This embodiment provides a method for debonding an ultra-thin wafer, which sequentially performs the following steps based on a debonding process device:

[0050] S100, film feeding stage;

[0051] S200, debonding step;

[0052] S300, cleaning step;

[0053] S400, film retrieval step.

[0054] In this embodiment, the debonding process equipment includes a feed chamber and a debonding chamber and a cleaning chamber respectively arranged on both sides of the feed chamber. The feed chamber is equipped with a clamp for storing wafers to be debonded and wafers after cleaning, and is also equipped with a conveying component for conveying wafers between the feed chamber, the debonding chamber and the cleaning chamber; in addition, a debonding component is arranged in the debonding chamber, and a cleaning component is arranged in the cleaning chamber.

[0055] Among them, the purpose of the debonding process is to separate the thinned thin wafer and the companion wafer. The companion wafer is usually made of SIC material with a diameter 0.6mm-1mm larger than the thinned material and a thickness of 505um. During debonding, the wafer to be debonded is first placed in a predetermined clamp, and under the action of a conveying component (such as a robotic arm), the wafer is taken to the debonding station of the debonding chamber, and then the debonding component performs the debonding operation.

[0056] As a specific implementation method, the debonding process in this embodiment specifically includes: firstly, heating the wafer to 170-200°C for 5-25 minutes to fully melt the bonding wax; then, separating the thin wafer and the companion wafer by controlling the adsorption heat sliding speed to 50-100 mm / min. Figure 3As shown, during the heating and debonding process, N2 gas is introduced from the bottom of the debonding chamber, and the wafer is placed in an N2 gas atmosphere, which fully protects the back side Ag to prevent oxidation.

[0057] Combination Figure 4 As shown, the cleaning step is to clean the debonded wafer. During cleaning, the wafer needs to be adsorbed on the wafer carrier and cleaned and dried under high-speed rotation. The cleaning step specifically includes steps S310 to S360, which are described in detail below:

[0058] S310, connect the cleaning chamber with the feeding chamber and the debonding chamber so that the air pressures in the three chambers are all at normal pressure, that is, A=B=C, where A is the air pressure in the debonding chamber, B is the air pressure in the feeding chamber, and C is the air pressure in the cleaning chamber.

[0059] Specifically, the material port of the debonding chamber is always connected to the feeding chamber, and the feeding chamber is connected to the outside, that is, the air pressure of the debonding chamber and the feeding chamber is the ambient air pressure during the entire cleaning process; in this embodiment, a pressure regulating plate is configured at the material port of the cleaning chamber, and the material port of the cleaning chamber is opened by controlling the pressure regulating plate, so that the cleaning chamber is connected to the feeding chamber and the debonding chamber, see Figure 5 shown.

[0060] S320, transferring the wafers after debonding in the debonding chamber to the cleaning chamber, and isolating the cleaning chamber from the feeding chamber and the debonding chamber. Specifically, the material port of the cleaning chamber is closed by controlling the pressure regulating plate, and the cleaning chamber is isolated from the feeding chamber and the debonding chamber. Figure 6 shown.

[0061] S330, controlling the cleaning component of the cleaning chamber to adsorb the wafer onto the cleaning station, and controlling the cleaning component to clean the wafer under the normal pressure; wherein controlling the cleaning component to clean the wafer under the normal pressure specifically includes:

[0062] S331, spray acetone for 60-90s;

[0063] S332, spray isopropyl alcohol for 5 to 30 seconds;

[0064] S333, spin dry at a speed of 1000-3000RPM.

[0065] S340, when the cleaning component completes cleaning of the wafer, the cleaning chamber is evacuated.

[0066] Specifically, combined Figure 5 and Figure 6 As shown, a vacuum port is arranged on the cleaning chamber, and a vacuum assembly connected to the vacuum port is arranged outside the cleaning chamber, and the vacuum assembly is controlled to vacuum or stop vacuuming the cleaning chamber.

[0067] S350, connecting the cleaning chamber with the feeding chamber and the debonding chamber, specifically, opening the tiaoya plate to form a pressure difference between the feeding chamber, the debonding chamber and the cleaning chamber, that is, A=B>C.

[0068] S360, controlling the cleaning component of the cleaning chamber to cancel the adsorption of the wafer, and stopping the pumping of the cleaning chamber after the wafer is taken out.

[0069] This embodiment also provides a debonding device for ultra-thin wafers, including the feed chamber, debonding chamber and cleaning chamber mentioned above: it also includes an air pressure regulating system, which cooperates with the conveying component and the cleaning component to perform the cleaning step described above.

[0070] like Figure 7 As shown, the air pressure regulating system comprises:

[0071] An air pressure sensor is arranged in the cleaning chamber to monitor the real-time air pressure information of the cleaning chamber and send it to the main control module;

[0072] The wafer detection sensor is arranged in the cleaning chamber to monitor the wafer in-place information on the cleaning component and send it to the main control module; for example, in step S310,

[0073] A pressure regulating plate, which opens or blocks the material port of the cleaning chamber under control;

[0074] An exhaust component, which is controlled to exhaust or stop exhausting air from an exhaust port arranged on the cleaning chamber;

[0075] The main control module receives the real-time air pressure information and wafer in-place information and controls the actions of the conveying component, the cleaning component, the pressure regulating plate and the exhaust component.

[0076] Specifically, in step S310, the real-time air pressure of the cleaning chamber is monitored by the air pressure sensor. When the main control module confirms that the air pressures in the cleaning chamber, the feed chamber and the debonding chamber are consistent, a control instruction is sent to the robotic arm to transfer the wafer into the wafer carrier plate of the cleaning chamber and be adsorbed, and then the robotic arm quickly moves out and closes the pressure regulating plate; at this time, the wafer detection sensor senses the wafer, and the main control module controls the cleaning component to start the cleaning operation; after the cleaning is completed, the main control module controls the vacuum component to perform a vacuum operation for 5-10 seconds, and at the same time opens the pressure regulating plate to control the robotic arm to quickly take out the wafer.

[0077] As an optional implementation, the exhaust assembly includes a common negative pressure unit in the factory, an electric control valve and a negative pressure branch, one end of the negative pressure branch is connected to the common negative pressure unit in the factory, and the other end is connected to the exhaust port; the electric control valve is arranged on the negative pressure branch and is controlled by the main control module.

[0078] As another optional implementation, the vacuum assembly includes a dedicated vacuum pump and a vacuum pipeline, one end of the vacuum pipeline is connected to the dedicated vacuum pump, and the other end is connected to the vacuum port; the dedicated vacuum pump is controlled by the main control module.

[0079] The debonding method and device of ultra-thin wafers provided by the present invention, before the wafer is sent into the cleaning chamber, the cleaning chamber is first connected with the feeding chamber and the debonding chamber, so that the air pressure of the three chambers is normal pressure; after the wafer after debonding is transferred to the cleaning chamber, the cleaning chamber is isolated from the feeding chamber and the debonding chamber, so that the wafer is cleaned in an environment without pressure difference, and the wafer is more stable when rotating for cleaning, and no drift occurs, and the cleaning liquid is also avoided from splashing out; when the cleaning of the wafer is completed, the cleaning chamber is evacuated, so that when the cleaning chamber and the feeding chamber are connected again, the feeding chamber and the debonding chamber form a pressure difference with the cleaning chamber, so that when the wafer is taken out, the cleaning liquid remaining in the cleaning chamber is avoided from splashing out, until the exhaust is stopped after the wafer is taken out. In addition, during debonding, N2 atmosphere is introduced, so that the wafer is in N2 gas atmosphere during debonding, which can fully protect the Ag on the back of the wafer to prevent oxidation.

[0080] The above disclosure is only the preferred embodiment of the present application, which certainly cannot be used to limit the scope of rights of the present application. Therefore, equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A method for debonding an ultra-thin wafer, comprising: On a debonding process device having a feeding chamber, a debonding chamber and a cleaning chamber, a wafer feeding link, a debonding link, a cleaning link and a wafer taking link are sequentially performed; characterized in that the cleaning link specifically includes: S310, connecting the cleaning chamber with the feeding chamber and the debonding chamber so that the air pressures of the three chambers are all at normal pressure; S320, transferring the wafer after debonding in the debonding chamber to a cleaning chamber, and isolating the cleaning chamber from the feeding chamber and the debonding chamber; S330, controlling the cleaning component of the cleaning chamber to adsorb the wafer onto the cleaning station, and controlling the cleaning component to clean the wafer under the normal pressure; S340, when the cleaning component completes cleaning of the wafer, evacuating the cleaning chamber; S350, connecting the cleaning chamber with the feeding chamber and the debonding chamber, so that a pressure difference is formed between the feeding chamber, the debonding chamber and the cleaning chamber; S360, controlling the cleaning component of the cleaning chamber to cancel the adsorption of the wafer, and stopping the pumping of the cleaning chamber after the wafer is taken out.

2. The method for debonding an ultra-thin wafer according to claim 1, characterized in that: The material port of the debonding chamber is configured to be always connected with the feeding chamber; a pressure regulating plate is configured at the material port of the cleaning chamber, and the cleaning chamber is connected with the feeding chamber and the debonding chamber by controlling the pressure regulating plate to be opened; the cleaning chamber is isolated from the feeding chamber and the debonding chamber by controlling the pressure regulating plate to be closed.

3. The debonding method of an ultra-thin wafer according to claim 1 or 2, characterized in that: An air suction port is arranged on the cleaning chamber, and an air suction component connected to the air suction port is arranged outside the cleaning chamber, and the air suction component is controlled to evacuate or stop evacuating the cleaning chamber.

4. The method for debonding an ultra-thin wafer according to claim 1, characterized in that: The debonding step specifically includes: S211, heating the wafer to 170-200° C. and maintaining the temperature for 5-25 min to fully melt the bonding wax; S212, controlling the adsorption heat sliding speed to 50-100 mm / min to separate the wafer and the companion wafer.

5. The debonding method of an ultra-thin wafer according to claim 1 or 4, characterized in that: In the debonding step, N2 gas is introduced from the bottom of the debonding chamber.

6. The method for debonding an ultra-thin wafer according to claim 1, characterized in that: In step S330, the cleaning component is controlled to clean the wafer under the normal pressure, specifically including: S331, spray acetone for 60-90s; S332, spray isopropyl alcohol for 5 to 30 seconds; S333, spin dry at a speed of 1000-3000RPM.

7. A debonding device for ultra-thin wafers, comprising: A feeding chamber, in which a clamp for storing wafers and a conveying assembly for conveying wafers are arranged; a debonding chamber, in which a debonding assembly is disposed; a cleaning chamber in which a cleaning component is disposed; It is characterized in that it also includes an air pressure regulating system, which cooperates with the conveying component and the cleaning component to perform the cleaning process described in any one of claims 1-6.

8. The ultra-thin wafer debonding device according to claim 7, characterized in that: The air pressure regulating system comprises: An air pressure sensor is disposed in the cleaning chamber to monitor the real-time air pressure information of the cleaning chamber and send the information to the main control module; A wafer detection sensor is arranged in the cleaning chamber to monitor the wafer presence information on the cleaning component and send the information to the main control module; A pressure regulating plate, which opens or blocks the material port of the cleaning chamber under control; An exhaust component, which is controlled to exhaust or stop exhausting air from an exhaust port arranged on the cleaning chamber; The main control module receives the real-time air pressure information and wafer in-place information and controls the actions of the conveying component, the cleaning component, the pressure regulating plate and the exhaust component.

9. The ultra-thin wafer debonding device according to claim 8, characterized in that: The exhaust assembly includes a common negative pressure unit in the factory, an electric control valve and a negative pressure branch. One end of the negative pressure branch is connected to the common negative pressure unit in the factory, and the other end is connected to the exhaust port. The electric control valve is arranged on the negative pressure branch and is controlled by the main control module.

10. The ultra-thin wafer debonding device according to claim 8, characterized in that: The vacuum assembly includes a dedicated vacuum pump and a vacuum pipeline, one end of the vacuum pipeline is connected to the dedicated vacuum pump, and the other end is connected to the vacuum port; the dedicated vacuum pump is controlled by the main control module.

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