Wafer dissociation adsorption control method and semiconductor process equipment

Abstract

The invention provides a wafer dissociation adsorption control method and semiconductor process equipment, and relates to the technical field of semiconductors, and the method comprises the steps: when the processing technology of a wafer in a reaction chamber is finished, turning off the power of a radio frequency power supply, and stopping introducing reaction gas into the reaction chamber; wherein back blowing gas is continuously introduced below the wafer; performing charge neutralization control on the electrostatic chuck below the wafer, monitoring the relative distance between the wafer and the surface of the electrostatic chuck, and judging whether the wafer and the electrostatic chuck complete dissociation adsorption or not based on the relative distance; and if yes, stopping charge neutralization control on the electrostatic chuck, so that the wafer is separated from the adsorption of the electrostatic chuck. According to the invention, the wafer and the electrostatic chuck can be successfully dissociated and adsorbed before the wafer is conveyed out of the reaction chamber, so that the wafer can be completely conveyed out of the reaction chamber, the phenomenon that the wafer is deformed or broken due to the rising thrust of the ejector pin structure when the wafer is adhered due to large adsorption force between the wafer and the electrostatic chuck is avoided, and the rejection rate of finished wafer products is reduced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a wafer dissociation adsorption control method and semiconductor process equipment. Background Art

[0002] In the semiconductor material processing technology, it is usually necessary to fix the wafer to be processed on the electrostatic chuck in the reaction chamber. The electrostatic chuck fixes the wafer through the electrostatic force between the chuck and the wafer. However, after the processing is completed, due to the presence of plasma during the process, the charge on the wafer cannot be completely removed. When the wafer is taken out, the electrostatic force between the chuck and the wafer is likely to stick to the chuck.

[0003] The related wafer dissociation adsorption control technology usually introduces gas under the wafer to blow the wafer off the electrostatic chuck after the processing process is completed. If the wafer sticks to the chuck and cannot be blown off the electrostatic chuck, the three-pin structure is used to directly lift the wafer to a certain height, so that the wafer is separated from the electrostatic chuck surface, and then the robot reaches into the reaction chamber to take out the wafer. However, when there are too many residual charges on the wafer, the wafer sticks seriously, and the upward thrust of the three-pin structure can easily cause the wafer to be greatly deformed or even broken, increasing the scrap rate of finished wafers. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a wafer dissociation adsorption control method and semiconductor process equipment, which can successfully complete the dissociation adsorption of the wafer and the electrostatic chuck before the wafer is transferred out of the reaction chamber, thereby enabling the wafer to be completely transferred out of the reaction chamber, avoiding the upward thrust of the ejector structure when the adsorption force between the wafer and the electrostatic chuck is large and the wafer is stuck, causing deformation or fragmentation of the wafer, thereby reducing the scrap rate of finished wafers.

[0005] In order to achieve the above purpose, the technical solution adopted by the embodiment of the present invention is as follows:

[0006] In a first aspect, an embodiment of the present invention provides a method for controlling dissociation and adsorption of a wafer, comprising: when the processing technology of the wafer in a reaction chamber is completed, turning off the power of the RF power supply and stopping the introduction of the reaction gas into the reaction chamber; wherein, back-blowing gas is continuously introduced under the wafer; performing charge neutralization control on an electrostatic chuck under the wafer, and monitoring the relative distance between the wafer and the surface of the electrostatic chuck, and judging whether the dissociation and adsorption of the wafer and the electrostatic chuck are completed based on the relative distance; if so, stopping the charge neutralization control on the electrostatic chuck to allow the wafer to be separated from the adsorption of the electrostatic chuck.

[0007] Furthermore, an embodiment of the present invention provides a first possible implementation of the first aspect, wherein the charge neutralization control of the electrostatic chuck under the wafer includes: controlling the output voltage of the DC power supply of the electrostatic chuck to change from a positive voltage to a negative voltage at a preset decrease rate to neutralize the charge on the surface of the electrostatic chuck.

[0008] Further, an embodiment of the present invention provides a second possible implementation of the first aspect, wherein judging whether the wafer and the electrostatic chuck have completed dissociation and adsorption based on the relative distance includes:

[0009] Determine whether the relative distance is greater than a preset distance, and when the relative distance is greater than the preset distance, determine that the wafer and the electrostatic chuck have completed dissociation and adsorption

[0010] Further, the embodiment of the present invention provides a third possible implementation of the first aspect, wherein the semiconductor process equipment includes an interferometer, and the interferometer includes a signal collection module and a signal processing module;

[0011] The monitoring of the relative distance between the wafer and the surface of the electrostatic chuck and judging whether the wafer and the electrostatic chuck have completed dissociation and adsorption based on the relative distance include:

[0012] Based on the signal collection module, a laser signal is sent to the surface of the wafer, and the spectral intensity fed back by the wafer is collected, and the spectral intensity is transmitted to the signal processing module, so that the signal processing module determines whether the wafer and the electrostatic chuck have completed dissociation and adsorption based on the spectral intensity; wherein, when the spectral intensity is greater than a preset spectral intensity threshold, it is determined that the wafer and the electrostatic chuck have completed dissociation and adsorption.

[0013] Furthermore, the embodiment of the present invention provides a fourth possible implementation of the first aspect, wherein before the step of controlling the output voltage of the DC power supply of the electrostatic chuck to change from a positive voltage to a negative voltage at a preset decreasing rate, the step further includes:

[0014] When the processing of the wafer is finished, non-reactive gas is introduced into the reaction chamber, and the pressure of the back-blowing gas under the wafer is controlled to be reduced to a preset pressure.

[0015] Furthermore, an embodiment of the present invention provides a fifth possible implementation of the first aspect, wherein the preset drop rate has a value range of 100 V / s to 2000 V / s.

[0016] Furthermore, an embodiment of the present invention provides a sixth possible implementation of the first aspect, wherein the preset pressure has a value range of 1 Torr to 4 Torr.

[0017] Furthermore, an embodiment of the present invention provides a seventh possible implementation of the first aspect, wherein the value range of the preset spectral intensity threshold is initial spectral intensity*1% to initial spectral intensity*10%, and the initial spectral intensity is the spectral intensity fed back by the wafer when the signal collection module is turned on.

[0018] In a second aspect, an embodiment of the present invention further provides a semiconductor process equipment, comprising: a reaction chamber and a controller; the reaction chamber comprises an electrostatic chuck, and the surface of the electrostatic chuck is used to place a wafer;

[0019] The controller includes a processor and a memory, wherein a computer program is stored in the memory, and when the processor executes the computer program, the wafer dissociation adsorption control method as described in any one of the first aspects is performed.

[0020] Further, the embodiment of the present invention provides a first possible implementation of the second aspect, wherein the semiconductor process equipment further comprises: an interferometer, the interferometer comprising a signal collection module and a signal processing module; the signal collection module is arranged directly above the wafer;

[0021] The signal collection module is used to send a laser signal to the surface of the wafer, collect the spectral intensity fed back by the wafer, and transmit the spectral intensity to the signal processing module;

[0022] The signal processing module is used to determine whether the wafer and the electrostatic chuck have completed dissociation and adsorption based on the spectral intensity; wherein, when the spectral intensity is greater than a preset spectral intensity threshold, it is determined that the wafer and the electrostatic chuck have completed dissociation and adsorption.

[0023] The embodiment of the present invention provides a wafer dissociation adsorption control method and semiconductor process equipment, the method comprising: when the processing technology of the wafer in the reaction chamber is completed, turning off the power of the radio frequency power supply and stopping the introduction of the reaction gas into the reaction chamber; wherein, the back-blowing gas is continuously introduced under the wafer; the electrostatic chuck under the wafer is subjected to charge neutralization control, and the relative distance between the wafer and the surface of the electrostatic chuck is monitored, and whether the wafer and the electrostatic chuck have completed dissociation adsorption based on the relative distance is judged; if yes, the charge neutralization control of the electrostatic chuck is stopped to make the wafer detach from the adsorption of the electrostatic chuck. The present invention can reduce the adsorption force between the wafer and the electrostatic chuck by firstly performing dissociation adsorption control on the wafer after the wafer processing technology is completed and before the wafer is lifted by the ejector pin structure, so as to complete the dissociation adsorption between the wafer and the electrostatic chuck, and then make the wafer be able to be completely transferred out of the reaction chamber, and avoid the upward thrust of the ejector pin structure when the adsorption force between the wafer and the electrostatic chuck is large and the wafer is stuck, causing the wafer to be deformed or fragmented, thereby reducing the scrap rate of finished wafers.

[0024] Other features and advantages of the embodiments of the present invention will be described in the following description, or some features and advantages can be inferred or determined without doubt from the description, or can be learned by implementing the above-mentioned techniques of the embodiments of the present invention.

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A flow chart of a wafer dissociation adsorption control method provided by an embodiment of the present invention is shown;

[0028] Figure 2 A schematic diagram showing the change of output voltage of a DC power supply over time provided by an embodiment of the present invention is shown;

[0029] Figure 3 A schematic diagram showing the change of spectral intensity of wafer feedback over time provided by an embodiment of the present invention is shown;

[0030] Figure 4 A schematic diagram of the structure of a reaction chamber provided in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be described below in conjunction with the drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0032] At present, the processing technology of semiconductor materials usually includes process steps such as photoresist, photolithography, etching, deposition and cleaning. Taking the etching process as an example, the etching process can remove the part of the wafer that is not protected by the photoresist after the photolithography and development process, and transfer the pattern on the mask to the wafer. Common etching processes include plasma etching. Plasma is the fourth state of matter besides solid, gas and liquid, which can be generated by discharging gas at high temperature. By controlling the plasma generated above the reaction chamber to continuously bombard the wafer below, a series of physical and chemical reactions occur on the surface of the wafer, which can remove the unprotected part of the surface and achieve the etching effect. During the wafer processing process, the wafer needs to be fixed on the electrostatic chuck in the reaction chamber. The electrostatic chuck fixes the wafer through the electrostatic force between the chuck and the wafer. Compared with the mechanical chuck, the electrostatic chuck has the advantages of simple structure and less damage to the wafer. However, after the wafer processing is completed, the presence of plasma during the process will neutralize the charge on the wafer surface, resulting in the charge on the wafer cannot be completely removed when the wafer is desorbed. The electrostatic force between the chuck and the wafer sticks the wafer to the chuck, which can easily cause the wafer to deform or even break when it is removed. Therefore, a judgment method is needed to confirm that the wafer has been released from the adsorption state before the three-pin structure rises to avoid damage to the wafer caused by the needle rising.

[0033] In order to improve the above problems, an embodiment of the present invention provides a wafer dissociation adsorption control method and semiconductor process equipment, and the embodiment of the present invention is described in detail below.

[0034] This embodiment provides a wafer dissociation adsorption control method, which is applied to semiconductor process equipment, see Figure 1 The flow chart of the wafer dissociation adsorption control method shown in the figure mainly includes the following steps:

[0035] Step S102, when the processing of the wafer in the reaction chamber is finished, turning off the power of the RF power supply and stopping the introduction of the reaction gas into the reaction chamber;

[0036] The above-mentioned processing techniques may include etching processes, deposition processes, cleaning processes, and other processes that require the wafer to be adsorbed and fixed on an electrostatic chuck. When the pressure inside the reaction chamber is stable, the reaction gas is introduced into the reaction chamber and the RF power is turned on. When the wafer processing process is completed, the RF power is turned off and the reaction gas is turned off.

[0037] During the wafer processing, a back-blowing gas of a certain pressure is introduced under the wafer, and the back-blowing gas may include any one or more gases of Ar, O2, N2 and He. At the end of the wafer processing, the back-blowing gas is continuously introduced under the wafer so that the wafer can be blown away from the surface of the electrostatic chuck when the wafer and the electrostatic chuck are completely dissociated and adsorbed.

[0038] Step S104, performing charge neutralization control on the electrostatic chuck under the wafer, and monitoring the relative distance between the wafer and the surface of the electrostatic chuck, and judging whether the wafer and the electrostatic chuck have completed dissociation and adsorption based on the relative distance;

[0039] Since the charge on the wafer is not completely eliminated after the wafer processing is completed, there is an electrostatic force between the wafer and the electrostatic chuck. By controlling the power supply voltage of the electrostatic chuck or using power control to generate plasma, the charge on the electrostatic chuck is neutralized and the adsorption force between the wafer and the electrostatic chuck is reduced.

[0040] When the wafer and the electrostatic chuck complete dissociation and adsorption, there is no adsorption force between the wafer and the electrostatic chuck. Since a certain pressure of gas is continuously introduced under the wafer during the wafer processing process, when the wafer and the electrostatic chuck complete dissociation and adsorption, the wafer is blown away from the surface of the electrostatic chuck by the gas. Whether the wafer and the electrostatic chuck complete dissociation and adsorption is determined by judging whether the wafer is detached from the electrostatic chuck.

[0041] Step S106: if yes, stop the charge neutralization control on the electrostatic chuck to make the wafer separate from the adsorption of the electrostatic chuck.

[0042] When the wafer and the electrostatic chuck complete the dissociation and adsorption, there is no adsorption force between the wafer and the electrostatic chuck. At this time, the power supply controlling the electrostatic chuck can be turned off or the power control method for generating plasma can be stopped to stop the charge neutralization control of the electrostatic chuck. The wafer and the electrostatic chuck complete the dissociation and adsorption process, which makes it easier for the three-needle structure to rise and lift the wafer to a certain height to separate the wafer from the surface of the electrostatic chuck, and the robot arm reaches into the reaction chamber to take out the wafer.

[0043] The above-mentioned wafer dissociation adsorption control method provided in the present embodiment performs dissociation adsorption control on the wafer after the wafer processing process is completed and before the wafer is lifted by the ejector pin structure, thereby neutralizing the charge on the surface of the electrostatic chuck, thereby reducing the adsorption force between the wafer and the electrostatic chuck, allowing the wafer and the electrostatic chuck to complete the dissociation adsorption, and then allowing the wafer to be completely transferred out of the reaction chamber, thereby avoiding deformation or fragmentation of the wafer caused by the upward thrust of the ejector pin structure when the adsorption force between the wafer and the electrostatic chuck is large and the wafer is stuck, thereby reducing the scrap rate of finished wafers.

[0044] In one embodiment, this embodiment provides a specific implementation method for charge neutralization control of an electrostatic chuck under a wafer:

[0045] The output voltage of the DC power supply of the electrostatic chuck is controlled to change from a positive voltage to a negative voltage at a preset decreasing rate to neutralize the charge on the surface of the electrostatic chuck.

[0046] The electrostatic chuck in the reaction chamber is connected to a DC power supply (ESC power supply). By controlling the output voltage of the DC power supply to gradually decrease, the neutralization control of the surface charge of the electrostatic chuck can be achieved. The output voltage of the DC power supply of the electrostatic chuck is controlled to gradually decrease from the current positive voltage value +HV to 0V. See FIG. Figure 2 The DC power supply output voltage changes over time as shown in the figure, and then continues to decrease and turns into a reverse voltage -HV. By controlling the output voltage of the DC power supply of the electrostatic chuck to gradually decrease, the charge on the surface of the electrostatic chuck can be gradually neutralized, thereby gradually reducing the adsorption force between the wafer and the electrostatic chuck, avoiding the problem of incomplete neutralization of the charge on the surface of the electrostatic chuck caused by directly flipping the output voltage of the DC power supply from a forward voltage to a reverse voltage.

[0047] In one implementation, the preset drop rate provided in this embodiment ranges from 100 V / s to 2000 V / s. The preset drop rate of the output voltage of the DC power supply is related to the charge neutralization time required by the electrostatic chuck. For example, when the surface charge of the electrostatic chuck is large, the time required is long, and a lower preset drop rate of the output voltage needs to be set.

[0048] In one embodiment, this embodiment provides a specific implementation method for determining whether the wafer and the electrostatic chuck have completed dissociation and adsorption based on the relative distance:

[0049] It is determined whether the relative distance between the wafer and the surface of the electrostatic chuck is greater than a preset distance. When the relative distance is greater than the preset distance, it is determined that the wafer and the electrostatic chuck have completed dissociation and adsorption.

[0050] Before the electrostatic chuck is subjected to charge neutralization control, the wafer is adsorbed on the surface of the electrostatic chuck, that is, the relative distance between the wafer and the electrostatic chuck is 0. After the electrostatic chuck is subjected to charge neutralization control, the adsorption force between the wafer and the electrostatic chuck gradually decreases, and the distance between the wafer and the surface of the electrostatic chuck is detected in real time or periodically. Since back-blowing gas is introduced under the wafer, the back-blowing gas can be used to adjust the pressure on both sides of the wafer. When the adsorption force between the wafer and the electrostatic chuck becomes 0, the back-blowing gas under the wafer can blow the wafer away from the surface of the electrostatic chuck, so that the relative distance between the wafer and the electrostatic chuck gradually increases.

[0051] In a specific embodiment, a distance detection device can be set directly above the wafer in the reaction chamber to detect the distance between the detection device and the wafer. When the distance between the detection device and the wafer becomes smaller, it indicates that the wafer is detached from the electrostatic chuck, that is, the relative distance between the wafer and the electrostatic chuck becomes larger.

[0052] The preset distance can be the distance between the upper surface of the wafer and the upper surface of the electrostatic chuck when the wafer is completely separated from the electrostatic chuck. When it is detected that the relative distance between the wafer and the electrostatic chuck is greater than the preset distance, it indicates that the wafer has been blown away from the surface of the electrostatic chuck, the charge on the surface of the electrostatic chuck has been completely neutralized, and the dissociation and adsorption between the wafer and the electrostatic chuck have been completed.

[0053] In one embodiment, the semiconductor process equipment provided by this embodiment includes an interferometer, and the interferometer includes a signal collection module and a signal processing module; this embodiment provides a specific implementation method for monitoring the relative distance between the wafer and the surface of the electrostatic chuck, and judging whether the wafer and the electrostatic chuck have completed dissociation and adsorption based on the relative distance:

[0054] Based on the signal collection module, a laser signal is sent to the wafer surface, and the spectral intensity fed back by the wafer is collected, and the spectral intensity is transmitted to the signal processing module, so that the signal processing module determines whether the wafer and the electrostatic chuck have completed dissociation and adsorption based on the spectral intensity; wherein, when the spectral intensity is greater than the preset spectral intensity threshold, it is determined that the wafer and the electrostatic chuck have completed dissociation and adsorption.

[0055] An interferometer (i.e., IEP online monitoring system) is usually installed in the reaction chamber of semiconductor process equipment. The interferometer transmits a laser signal to the wafer surface through an optical fiber transmission component. The light reflected from the wafer surface and received by the signal collection module passes through the optical fiber transmission component and enters the signal processing module. The signal processing module may include a grating spectrometer. The signal processing module performs intensity resolution on the laser signal reflected by the wafer to obtain the spectral intensity of the laser signal fed back by the wafer.

[0056] The inventors have found that when the relative distance between the wafer and the electrostatic chuck changes, the spectral intensity of the laser signal fed back by the wafer will also change, see Figure 3 The schematic diagram shown is of the variation of the spectral intensity of the wafer feedback over time. When the wafer is on the surface of the electrostatic chuck during 0-12s, a laser signal with a wavelength of 450nm is emitted to the wafer, and the spectral intensity of the laser signal fed back by the wafer is about 2200. During 12-28s, the wafer is blown away from the surface of the electrostatic chuck, and the spectral intensity of the laser signal fed back by the wafer increases to about 2275. After 28s, the wafer returns to the surface of the electrostatic chuck, and the spectral intensity of the laser signal fed back by the wafer recovers to about 2200. Therefore, by detecting the spectral intensity of the wafer feedback, it is possible to accurately determine whether the wafer has detached from the electrostatic chuck and completed the dissociation and adsorption.

[0057] In one embodiment, the preset spectral intensity threshold provided in this embodiment has a value range of initial spectral intensity * 1% to initial spectral intensity * 10%, and a preferred value is initial spectral intensity * 3%. The initial spectral intensity is the spectral intensity fed back by the wafer when the signal collection module is turned on, that is, the spectral intensity fed back when the wafer is not blown off the surface of the electrostatic chuck.

[0058] At the beginning of dissociative adsorption, that is, when the charge neutralization of the electrostatic chuck begins, the wafer is adsorbed on the surface of the electrostatic chuck, and the spectral intensity of the wafer feedback remains stable (that is, it is maintained at a certain spectral intensity value). When the adsorption force between the wafer and the electrostatic chuck decreases, the gas under the wafer gradually blows the wafer away from the surface of the electrostatic chuck, and the relative distance between the wafer and the surface of the electrostatic chuck gradually increases. The spectral intensity of the wafer feedback also increases accordingly. When the spectral intensity of the wafer feedback is greater than the preset spectral intensity threshold, the spectral intensity of the wafer feedback reaches another stable state, that is, it is maintained at the preset spectral intensity threshold, determining that the wafer and the electrostatic chuck have completed dissociative adsorption, and the dissociative adsorption process ends.

[0059] In one embodiment, the method provided in this embodiment further includes: when the processing of the wafer is finished, introducing a non-reactive gas into the reaction chamber, and controlling the pressure of the back-blowing gas under the wafer to be reduced to a preset pressure;

[0060] The non-reactive gas may include any one or more gases of Ar, O2, N2 and He. The non-reactive gas introduced into the chamber may be used as a purge gas to purge the reactive gas in the reaction chamber to ensure the stability of the processed wafer.

[0061] During the wafer processing process and after the processing is completed, back-blowing gas is continuously introduced under the wafer (i.e., the back of the wafer). The back-blowing gas can blow the wafer away from the surface of the electrostatic chuck when the wafer and the electrostatic chuck complete dissociation and adsorption. By controlling the flow rate of the back-blowing gas under the wafer, the pressure of the back-blowing gas under the wafer can be reduced to below the preset pressure, thereby preventing the back-blowing gas pressure under the wafer from being too high when the adsorption force between the wafer and the electrostatic chuck decreases, which may cause lateral displacement when the wafer is blown away from the surface of the electrostatic chuck, thereby escaping from the restriction of the focusing ring.

[0062] In one implementation, the preset pressure provided in this embodiment has a value range of 1 Torr to 4 Torr. By controlling the flow range of the back-blowing gas to be 1-20 sccm, the pressure of the back-blowing gas under the wafer can be reduced to 1 Torr to 4 Torr, so as to avoid lateral displacement of the wafer due to excessive back-blowing gas pressure when the wafer is blown off the surface of the electrostatic chuck.

[0063] In one embodiment, the method provided in this embodiment further includes: when the pressure of the back-blowing gas under the wafer is reduced to a preset pressure, the interferometer is triggered to start, or the interferometer is restarted. When the pressure of the back-blowing gas under the wafer is reduced to a preset pressure, the dissociation and adsorption process starts, and the interferometer is triggered to start. If the interferometer is in use during the processing of the wafer, it is reset and turned on again, and the output voltage of the DC power supply of the electrostatic chuck is controlled to gradually decrease to the reverse voltage. The signal collection module detects the spectral intensity of the wafer feedback in real time, so that the signal processing module can judge in real time whether the wafer and the electrostatic chuck have completed the dissociation and adsorption.

[0064] In one embodiment, the method provided in this embodiment also includes: when it is determined that the wafer and the electrostatic chuck have completed dissociation and adsorption, controlling the DC power supply of the electrostatic chuck to be turned off, stopping the back-blowing gas from under the wafer, and stopping the introduction of non-reactive gas into the reaction chamber, so that the wafer can be lifted up and transferred out of the reaction chamber later.

[0065] The above-mentioned wafer dissociation adsorption control method provided in the present embodiment can gradually neutralize the charge on the surface of the electrostatic chuck by gradually reducing the output voltage of the DC power supply of the electrostatic chuck to release the charge when the wafer and the electrostatic chuck are dissociated and adsorbed; by real-time detection of the spectral intensity fed back by the wafer, it can accurately detect whether the wafer and the electrostatic chuck have completed the dissociation adsorption, and avoid the wafer sticking phenomenon during the dissociation adsorption. The dissociation adsorption detection can be completed by using the interferometer provided in the reaction chamber, and there is no need to install other equipment in the reaction chamber. It has high applicability and low cost of dissociation and adsorption.

[0066] Corresponding to the wafer dissociation adsorption control method provided in the above embodiment, an embodiment of the present invention provides a semiconductor process equipment, including: a reaction chamber and a controller; the controller is used to execute the wafer dissociation adsorption control method provided in the above embodiment;

[0067] See also Figure 4 A schematic diagram of a reaction chamber structure is shown, the reaction chamber comprises: an electrostatic chuck 41, the surface of the electrostatic chuck is used to place a wafer 42;

[0068] The controller includes a processor and a memory, wherein a computer program is stored in the memory. When the processor executes the computer program, the wafer dissociation adsorption control method provided in the above embodiment is executed.

[0069] The semiconductor process equipment provided in this embodiment further includes: an interferometer, the interferometer including a signal collection module and a signal processing module; the signal collection module is arranged directly above the wafer;

[0070] The signal collection module is used to send laser signals to the wafer surface, collect the spectral intensity fed back by the wafer, and transmit the spectral intensity to the signal processing module;

[0071] The signal processing module is used to determine whether the wafer and the electrostatic chuck have completed dissociation and adsorption based on the spectral intensity; wherein, when the spectral intensity is greater than a preset spectral intensity threshold, it is determined that the wafer and the electrostatic chuck have completed dissociation and adsorption.

[0072] like Figure 4 As shown, the reaction chamber also includes: a coil 43, a display window 44, an air intake assembly 45 and a DC power supply 46 of the electrostatic chuck 41. The air intake assembly 45 is located below the wafer 42 and is used to introduce gas to the bottom of the wafer 42. The electrostatic chuck 41 is electrically connected to the DC power supply 46.

[0073] like Figure 4 As shown, the interferometer includes a signal collection module 47, an optical fiber transmission component 48 and a signal processing module 49. The signal collection module 47 is installed at the center of the coil 43 and fixed on the display window 44, that is, the signal collection module 47 is set directly above the wafer 42. The signal collection module 47 is communicated with the signal processing module 49 through the optical fiber transmission component 48.

[0074] The semiconductor process equipment provided in this embodiment has the same implementation principle and technical effects as those of the aforementioned embodiments. For the sake of brief description, for matters not mentioned in the semiconductor process equipment embodiment, reference may be made to the corresponding contents in the aforementioned method embodiment.

[0075] Based on the above-mentioned embodiment, this embodiment provides an example of monitoring the charge release in the dissociative adsorption using the above-mentioned wafer dissociative adsorption control method, which can be specifically performed with reference to the following steps:

[0076] Step 1: After the pressure in the reaction chamber reaches the requirement, the wafer to be processed is introduced into the reaction chamber, and the output voltage of the DC power supply of the electrostatic chuck is controlled to be a high voltage of 1-10Kv, so that the wafer is adsorbed on the electrostatic chuck.

[0077] Step 2: After the wafer is adsorbed, a back-blowing gas of a certain pressure is introduced under the wafer.

[0078] The back-blowing gas is usually any one or more of He, N2, O2 and Ar, the flow rate range of the back-blowing gas is 1-20 sccm, and the gas pressure range is 1-20 Torr.

[0079] Step 3, introducing reaction gas into the reaction chamber, turning on the RF power supply until the wafer processing process is completed, turning off the RF power supply, and turning off the reaction gas.

[0080] Step 4: introduce non-reactive gas into the reaction chamber and control the pressure of the back-blowing gas under the wafer to drop to 1-4 Torr.

[0081] Step 5: Turn on the interferometer to monitor the spectral intensity of the wafer feedback.

[0082] Step 6: Control the output voltage of the DC power supply of the electrostatic chuck to gradually decrease from the forward voltage to 0V, and gradually add the reverse voltage. The voltage drop rate ranges from 100 to 2000 V / s.

[0083] Step 7: The interferometer determines whether the wafer and the electrostatic chuck have completed dissociation and adsorption based on the spectral intensity fed back by the wafer.

[0084] When the interferometer is turned on, the relative distance between the wafer and the surface of the electrostatic chuck remains unchanged, and the spectral intensity fed back by the wafer is relatively stable in the initial state (i.e., maintained around the initial spectral intensity). As the output voltage of the DC power supply of the electrostatic chuck decreases, the adsorption force between the wafer and the electrostatic chuck decreases, and the back-blowing gas introduced from under the wafer gradually blows the wafer away from the surface of the electrostatic chuck. The relative distance between the wafer and the surface of the electrostatic chuck gradually increases, and the spectral intensity fed back by the wafer also increases accordingly. When the spectral intensity is maintained around the target spectral intensity (the target spectral intensity is greater than the above-mentioned preset spectral intensity threshold), it indicates that the wafer and the electrostatic chuck have completed dissociation and adsorption.

[0085] Step 8: If the wafer and the electrostatic chuck have completed dissociation and adsorption, turn off the DC power supply of the electrostatic chuck and stop supplying back-blowing gas under the wafer.

[0086] Step 9, stop introducing non-reactive gas into the reaction chamber.

[0087] After the above steps 1 to 9, the three-needle structure rises to lift the wafer to a certain height so that the wafer is separated from the surface of the electrostatic chuck, and the robot reaches into the reaction chamber to take out the wafer, and the process is completed.

[0088] An embodiment of the present invention provides a computer-readable medium, wherein the computer-readable medium stores computer-executable instructions. When the computer-executable instructions are called and executed by a processor, the computer-executable instructions prompt the processor to implement the method described in the above embodiment.

[0089] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system described above can refer to the corresponding process in the aforementioned embodiment, and will not be repeated here.

[0090] In addition, in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0091] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0092] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, 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 therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0093] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for controlling dissociative adsorption of a wafer, characterized in that: include: When the processing of the wafer in the reaction chamber is finished, the RF power is turned off and the introduction of the reaction gas into the reaction chamber is stopped; wherein the back-blowing gas is continuously introduced under the wafer; Performing charge neutralization control on an electrostatic chuck under the wafer, and monitoring the relative distance between the wafer and the surface of the electrostatic chuck, and judging whether the wafer and the electrostatic chuck have completed dissociation and adsorption based on the relative distance; If yes, the charge neutralization control on the electrostatic chuck is stopped to release the wafer from the adsorption of the electrostatic chuck.

2. The method according to claim 1, characterized in that The charge neutralization control of the electrostatic chuck under the wafer includes: The output voltage of the DC power supply of the electrostatic chuck is controlled to change from a positive voltage to a negative voltage at a preset decreasing rate to neutralize the charge on the surface of the electrostatic chuck.

3. The method according to claim 1, characterized in that The step of judging whether the wafer and the electrostatic chuck have completed dissociation and adsorption based on the relative distance includes: It is determined whether the relative distance is greater than a preset distance, and when the relative distance is greater than the preset distance, it is determined that the wafer and the electrostatic chuck have completed dissociation and adsorption.

4. The method according to claim 1, characterized in that The semiconductor process equipment includes an interferometer, and the interferometer includes a signal collection module and a signal processing module; The monitoring of the relative distance between the wafer and the surface of the electrostatic chuck and judging whether the wafer and the electrostatic chuck have completed dissociation and adsorption based on the relative distance include: Based on the signal collection module, a laser signal is sent to the surface of the wafer, and the spectral intensity fed back by the wafer is collected, and the spectral intensity is transmitted to the signal processing module, so that the signal processing module determines whether the wafer and the electrostatic chuck have completed dissociation and adsorption based on the spectral intensity; wherein, when the spectral intensity is greater than a preset spectral intensity threshold, it is determined that the wafer and the electrostatic chuck have completed dissociation and adsorption.

5. The method according to claim 1, characterized in that Before the step of controlling the output voltage of the DC power supply of the electrostatic chuck to change from a positive voltage to a negative voltage at a preset decreasing rate, the method further includes: When the processing of the wafer is finished, non-reactive gas is introduced into the reaction chamber, and the pressure of the back-blowing gas under the wafer is controlled to be reduced to a preset pressure.

6. The method according to claim 2, characterized in that The preset drop rate ranges from 100 V / s to 2000 V / s.

7. The method according to claim 5, characterized in that The preset pressure has a value range of 1 Torr to 4 Torr.

8. The method according to claim 4, characterized in that The value range of the preset spectral intensity threshold is initial spectral intensity*1% to initial spectral intensity*10%, and the initial spectral intensity is the spectral intensity fed back by the wafer when the signal collection module is turned on.

9. A semiconductor process equipment, characterized in that: include: Reaction chamber and controller; The reaction chamber includes an electrostatic chuck, and the surface of the electrostatic chuck is used to place a wafer; The controller includes a processor and a memory, wherein a computer program is stored in the memory, and when the processor executes the computer program, the wafer dissociation adsorption control method according to any one of claims 1 to 7 is executed.

10. The semiconductor process equipment according to claim 9, characterized in that: Also includes: An interferometer, the interferometer comprising a signal collection module and a signal processing module; the signal collection module is arranged directly above the wafer; The signal collection module is used to send a laser signal to the surface of the wafer, collect the spectral intensity fed back by the wafer, and transmit the spectral intensity to the signal processing module; The signal processing module is used to determine whether the wafer and the electrostatic chuck have completed dissociation and adsorption based on the spectral intensity; wherein, when the spectral intensity is greater than a preset spectral intensity threshold, it is determined that the wafer and the electrostatic chuck have completed dissociation and adsorption.

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