A method of monitoring a silicon wafer for slip lines

Abstract

The application provides a method for monitoring slip lines of silicon wafers, performing PM on a machine cavity; depositing intrinsic films on a first silicon wafer in the machine cavity; providing a second silicon wafer, depositing films on the second silicon wafer in the machine cavity to obtain temperature changes of different positions of the second silicon wafer; obtaining a slip window according to the temperature changes; using the slip window to perform a conventional run, and correcting the slip window of the product in real time. According to the characteristics of the heating lamp tube of the ASM cavity, the application summarizes the relationship between the internal and external differences of the doped silicon wafer and the slip line window, so as to achieve the real-time monitoring of the state of the slip lines generated by the machine.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a method for monitoring the generation of slip lines on a silicon wafer. Background Technology

[0002] Epitaxy involves growing a layer of doped single-crystal silicon on a silicon wafer to obtain ideal high-quality silicon material. In the bipolar process, it is mainly used to improve the reverse breakdown voltage. In the MOS process, it destroys the thyristor SCR structure formed between the substrate and the device, thereby preventing the latch-up effect of CMOS (a low-impedance path generated by the interaction of parasitic PNP and NPN bipolar BJTs).

[0003] BCD / BCM buried layer epitaxy: Currently, a normal pressure and high temperature process is used to reduce pattern drift and distortion during epitaxy. At the same time, most of the silicon wafers used are low-doped boron. These silicon wafers have low thermal conductivity and uneven heating in different parts of the silicon wafer in the cavity. The resulting temperature gradient will introduce thermal stress, which will cause dislocation slip movement, especially vertical upward climbing movement, producing slip lines. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method for monitoring the generation of slip lines on silicon wafers, in order to solve the problem that the prior art cannot monitor the occurrence of slip lines on silicon wafers in real time during the PM cycle.

[0005] To achieve the above and other related objectives, the present invention provides a method for monitoring the formation of slip lines on a silicon wafer, comprising at least:

[0006] Step 1: Perform PM on the machine cavity;

[0007] Step 2: Deposit an intrinsic film on the first silicon wafer in the machine cavity;

[0008] Step 3: Provide a second silicon wafer, and perform film deposition on the second silicon wafer in the machine cavity to obtain the temperature changes at different locations of the second silicon wafer;

[0009] Step 4: Obtain the slip window based on the temperature change;

[0010] Step 5: Use the slip window to perform regular inventory checks and adjust the product slip window in real time.

[0011] Preferably, the machine cavity in step one is a machine cavity used for deposition processes on silicon wafers.

[0012] Preferably, the intrinsic film in step two is an undoped film.

[0013] Preferably, the substrate doping type of the second silicon wafer in step three is different from that of the first silicon wafer.

[0014] Preferably, the substrate type of the second silicon wafer in step three is P-type ion lightly doped.

[0015] Preferably, in step three, a film is deposited on the second silicon wafer to obtain the resistance changes at different locations of the second silicon wafer affected by temperature, and then the temperature changes at the corresponding locations are obtained from the resistance changes at the different locations.

[0016] Preferably, the slip window in step four represents the safe temperature range of the machine cavity to exclude the occurrence of slip lines.

[0017] Preferably, during the routine delivery process in step five, the substrate type of the product is the same as the substrate type of the second silicon wafer.

[0018] As described above, the method for monitoring the generation of slip lines on silicon wafers according to the present invention has the following beneficial effects: Based on the characteristics of the heating lamp tube in the ASM cavity, the present invention summarizes the relationship between the internal and external differences of the doped silicon wafer and the slip line window, thereby achieving real-time monitoring of the state of slip line generation on the machine. Attached Figure Description

[0019] Figure 1 The diagram shows a flowchart of the method for monitoring the generation of slip lines on a silicon wafer in this invention.

[0020] Figure 2 The data are displayed as temperature ratios, RS differences, ANN morphology, and slip line graphs for different SCRs in this invention. Detailed Implementation

[0021] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0022] Please see Figures 1 to 2 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0023] This invention provides a method for monitoring the formation of slip lines on a silicon wafer, such as... Figure 1 As shown, Figure 1 The flowchart shown is a method for monitoring the generation of slip lines on a silicon wafer according to the present invention, which includes at least the following steps:

[0024] Step 1: Perform PM on the machine cavity; PM refers to the periodic maintenance of the machine cavity. The machine is a machine used for deposition processes.

[0025] Furthermore, in this embodiment, the machine cavity mentioned in step one is a machine cavity for performing a deposition process on silicon wafers.

[0026] Step 2: Deposit an intrinsic film on the first silicon wafer in the machine cavity;

[0027] Furthermore, in this embodiment, the intrinsic film in step two is an undoped film. This serves as a reference for subsequent steps of the method.

[0028] Step 3: Provide a second silicon wafer, and perform film deposition on the second silicon wafer in the machine cavity to obtain the temperature changes at different locations of the second silicon wafer;

[0029] Furthermore, in step three of this embodiment, the substrate doping type of the second silicon wafer is different from that of the first silicon wafer.

[0030] Furthermore, in step three of this embodiment, the substrate type of the second silicon wafer is P-type ion lightly doped.

[0031] Furthermore, in step three of this embodiment, a film is deposited on the second silicon wafer to obtain the resistance changes at different locations of the second silicon wafer affected by temperature, and then the temperature changes at the corresponding locations are obtained from the resistance changes at the different locations.

[0032] Step 4: Obtain the slip window based on the temperature change;

[0033] Furthermore, in step four of this embodiment, the slip window represents the safe temperature range for excluding machine cavity where slip lines may occur. The slip window is also known as the slip line window.

[0034] Step 5: Use the slip window to perform regular inventory checks and adjust the product slip window in real time.

[0035] Furthermore, in step five of this embodiment, the substrate type of the product during routine delivery is the same as the substrate type of the second silicon wafer.

[0036] Furthermore, in step five of this embodiment, the slip window of the real-time correction product is updated once a week.

[0037] During epitaxy, when silicon wafers are deposited at high temperatures, when the temperature difference between the center and the edge reaches 25°C, stress greater than 1000 PSI will be generated, forming a slip line.

[0038] Based on the characteristics of ASM (Xianjing) chamber heating lamps, the relationship between the internal and external differences of implant wafers and slip line windows is summarized, enabling real-time monitoring of the slip line status of the machine.

[0039] In BCD / BCM buried layer epitaxy: For the slip line method of monitoring equipment, the temperature difference between the inside and outside of the implant wafer (monitor wafer) in ASM (Xianjing) is used to reflect the temperature field changes of the equipment, thereby realizing real-time monitoring of the slip line and improving the safety of the epitaxy process of BCD / BCM products.

[0040] like Figure 2 As shown, Figure 2 The data are displayed as temperature ratios, RS differences, ANN morphology, and slip line graphs for different SCRs in this invention.

[0041] Therefore, as verified by DOE experiments, the temp power (SCR) ratio is linearly correlated with the internal and external temperature difference of RS. Increasing the SCR ratio by 1 increases the internal and external temperature difference of RS by approximately 0.72. The internal and external temperature difference of RS during temperature calibration is -0.7 to 5.1, and the slip line is within the safe range. Slip line monitoring can be performed using a routine temperature calibration monitor.

[0042] In this embodiment, during BCD / BCM buried layer epitaxy on the epitaxial machine, an implant wafer is used to monitor the silicon wafer slip line. The epitaxial machine is an ASM (Xianchuang) model. The epitaxial temperature is 1100-1150℃.

[0043] In summary, based on the characteristics of the ASM cavity heating lamp, this invention summarizes the relationship between the internal and external differences of doped silicon wafers and the slip line window, achieving real-time monitoring of the slip line generation status of the machine. Therefore, this invention effectively overcomes various shortcomings of the prior art and has high industrial application value.

[0044] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for monitoring the formation of slip lines on a silicon wafer, characterized in that, At least including: Step 1: Perform PM on the machine cavity; Step 2: Deposit an intrinsic film on the first silicon wafer in the machine cavity; Step 3: Provide a second silicon wafer. The substrate doping type of the second silicon wafer is different from that of the first silicon wafer. Perform film deposition on the second silicon wafer in the machine cavity to obtain the resistance change of different positions of the second silicon wafer affected by temperature. Then, obtain the temperature change of different positions of the second silicon wafer from the resistance change of different positions. Step 4: Obtain the slip window based on the temperature change; Step 5: Use the slip window to perform regular inventory checks and adjust the product slip window in real time.

2. The method for monitoring the generation of slip lines on a silicon wafer according to claim 1, characterized in that: The machine cavity mentioned in step one is the machine cavity used for the deposition process on silicon wafers.

3. The method for monitoring the generation of slip lines on a silicon wafer according to claim 1, characterized in that: The intrinsic film mentioned in step two is an undoped film.

4. The method for monitoring the generation of slip lines on a silicon wafer according to claim 1, characterized in that: The substrate type of the second silicon wafer in step three is P-type ion lightly doped.

5. The method for monitoring the generation of slip lines on a silicon wafer according to claim 1, characterized in that: The slip window mentioned in step four is for excluding the safe temperature range of the machine cavity where slip lines may appear.

6. The method for monitoring the generation of slip lines on a silicon wafer according to claim 1, characterized in that: In step five, during the routine delivery process, the substrate type of the product is the same as the substrate type of the second silicon wafer.

Images