OLT open-loop voltage setting method and device based on wafer feature judgment

Abstract

The invention discloses an OLT (Optical Line Terminal) open-loop voltage setting method and device based on wafer feature judgment, and aims to solve the problem that the power of a heating lamp cannot be determined due to inaccurate temperature monitoring in a low-temperature stage in a traditional wafer heating process. According to the method, the heating performance of the wafer is quantified into the characteristic value, the optimal heating power of different heating channels under different air pressures and wafer types is determined based on the characteristic value, the voltage is adjusted to set the run-through open loop stage, and finally the stability and accuracy of the wafer heating process are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of rapid thermal processing, and in particular relates to a method for setting an OLT open-loop voltage based on wafer feature judgment. Background Art

[0002] In the traditional wafer heating process, especially in the low-temperature stage, due to the limitations of existing technologies, temperature information cannot be accurately measured and monitored, so it is necessary to rely on manual setting of relevant heating parameters. This method is not only complicated to operate, but also prone to a series of production problems due to improper parameter settings, such as wafer warping or breakage. The parameter setting in this open-loop control mode not only needs to be fine-tuned according to the type and characteristics of the wafer, but also depends heavily on the experience and skills of the engineer who performs the parameter adjustment.

[0003] In response to these problems, the present invention proposes an innovative solution - an OLT (Open-Loop Tuning) open-loop voltage setting method based on wafer feature judgment. This method uses advanced sensing technology and algorithms to monitor and analyze the physical and chemical properties of the wafer in real time, thereby achieving more accurate and automated temperature control. Summary of the invention

[0004] The purpose of the present invention is to address the deficiencies of the prior art and propose an OLT open-loop voltage setting method and device based on wafer feature judgment, which solves the problem that the wafer temperature cannot be measured in a low temperature environment and thus the traditional closed-loop heating control cannot be used.

[0005] The object of the present invention is to achieve the following technical solution: a method for setting an OLT open-loop voltage based on wafer feature judgment, the method comprising the following steps:

[0006] Step 1: Obtain temperature change data of different types of wafers based on voltage experiments;

[0007] Step 2: According to the experimental data of step 1, after pre-processing, the characteristic judgment value of the wafer heating performance is determined based on the heating rate;

[0008] Step 3: For the wafer heating scenario in rapid thermal processing, the heating area and the temperature measurement area are evenly divided based on the arrangement of the halogen lamps, and a coupled system control model is constructed;

[0009] Step 4: Determine the voltage of the inner area of ​​the wafer through experimental data. It is expected that for different wafers and different gas pressures, only the voltage of the outer area of ​​the wafer can be adjusted to complete the low-temperature heating stage.

[0010] Step 5: Fix the wafer type and obtain the ideal outer ring area voltage of the wafer under different gas pressures;

[0011] Step 6: Fix the air pressure value to obtain the ideal outer ring area voltage of the wafer under different wafer types;

[0012] Step 7: Using the voltage data from steps 5 and 6, with the air pressure and wafer feature judgment value as independent variables and the heating lamp voltage as the dependent variable, fit the surface of the voltage in the outer ring area of ​​the wafer.

[0013] Furthermore, in step 1, the heating characteristics of the wafer are calculated by measuring the thermal rise rate of the wafer, and according to the heating rate of the wafer, the heating lamp voltage is selected to represent the corresponding value; so that each area can be personalized according to the thermal response characteristics of the wafer.

[0014] Furthermore, in step 2, heating characteristic data of the wafer under different voltages are collected; these data include temperature changes, heating time and voltage levels of the wafer; and the heating rate of the heating area in the 10th second of the step 1 process is selected as the wafer characteristic judgment value.

[0015] Furthermore, in step 3, the coupled system control model can simultaneously adjust the heating voltage of each area and monitor the temperature feedback of the corresponding area in real time to ensure the uniformity and accuracy of heating.

[0016] Furthermore, in step 4, the specific steps for determining the heating lamp voltage in the inner ring area of ​​the wafer are:

[0017] S1: In a laboratory environment, conduct preliminary tests on the heating area of ​​the inner circle of the wafer to collect temperature change data of different wafers under the same gas pressure; including the heating rate and temperature rise curve of the wafer under different voltage settings;

[0018] S2: Based on the data of S1, adjust the voltage of the heating lamp in the inner circle area of ​​the wafer, find the extreme value of the wafer emissivity jump, and take the middle value of the upper and lower limits as the optimal value.

[0019] Furthermore, in step 5, a systematic heating experiment is carried out on the wafer under the set air pressure conditions, and the heating effect and temperature response of the wafer under different outer ring area voltage settings of the wafer are recorded; by comparing and analyzing the data, the optimal outer ring area voltage value of the wafer under each air pressure condition is determined.

[0020] Furthermore, in step 6, by conducting a series of heating experiments under fixed gas pressure conditions, the responses of different wafer types to the voltage changes in the outer ring area of ​​the wafer, including temperature uniformity and heating rate, are recorded in detail; after analyzing the experimental data, the ideal outer ring area voltage setting of the wafer is determined for each wafer type.

[0021] Furthermore, in step 2, the hot and cold chambers have an impact on the wafer feature judgment value. The wafer feature judgment is corrected in the hot chamber case. First, the 1050 degree Celsius heating process is run 10 times continuously to ensure that the cavity is a hot cavity. Then, the basic experiment described in step 1 is performed to observe the feature judgment value of the wafer heating performance and the influence of the cold cavity.

[0022] In a second aspect, the present invention also provides an OLT open-loop voltage setting device based on wafer feature judgment, comprising a memory and one or more processors, wherein the memory stores executable code, and when the processor executes the executable code, the OLT open-loop voltage setting method based on wafer feature judgment is implemented.

[0023] In a third aspect, the present invention further provides a computer-readable storage medium having a program stored thereon, and when the program is executed by a processor, the method for setting an OLT open-loop voltage based on wafer feature judgment is implemented.

[0024] Beneficial effects of the present invention:

[0025] The present invention can reduce the influence of human factors and improve production efficiency and product quality.

[0026] The present invention has a self-learning function and can continuously optimize and adjust parameter settings according to historical data and operation results to adapt to different types of wafers and production conditions.

[0027] By implementing this feature-based open-loop voltage adjustment method, the present invention can significantly reduce the defect rate in the wafer processing process, reduce resource waste, and improve overall manufacturing efficiency. The application of this method will bring a higher level of automation and better economic benefits to the semiconductor manufacturing industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 It is a schematic diagram of the experimental flow of the 6th and 7th voltage fitting surfaces in an embodiment of the present invention.

[0030] Figure 2 Schematic diagram of the temperature rise curve of different wafer basic experimental areas 1 in the embodiment of the present invention.

[0031] Figure 3 Schematic diagram of light zone division in an embodiment of the present invention.

[0032] Figure 4 It is a schematic diagram of the sixth voltage fitting surface in an embodiment of the present invention.

[0033] Figure 5 It is a schematic diagram of the seventh voltage fitting surface in an embodiment of the present invention.

[0034] Figure 6 It is a structural diagram of an OLT open-loop voltage setting device based on wafer feature judgment provided by the present invention. DETAILED DESCRIPTION

[0035] The specific implementation of the present invention is described below to facilitate the understanding of the present invention by those skilled in the art. It should be noted that, for those skilled in the art, several improvements and modifications may be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0036] like Figure 1 As shown, the present invention provides an OLT (Open-Loop Tuning) open-loop voltage setting method based on wafer feature judgment, the method comprising the following steps:

[0037] Step 1: The OLT needs to know the heating characteristics of the wafer - the lamp power during open loop is determined based on the heating rate of each wafer. The heating characteristics of the wafer, also known as IRR (Initial Ramp Rate), is calculated by measuring the thermal rise rate of the wafer while it is heated to a constant open loop power set. Figure 2 As shown, basic voltage experiments are conducted on different types of wafers to observe the temperature changes of different wafers under the same conditions; according to the heating rate of the wafer, the lamp voltage is selected to represent the appropriate value. Based on the arrangement of halogen lamps, 420 halogen lamps are divided into zone15, 15 areas. When adjusting the voltage, it is divided into 7 areas according to zone1, zone2, zone3, zone4, zone5, zone6-9, zone10-15. The outer circle has a large area, so the lamps of several zones are merged. Figure 3 As shown, the lamp zones are divided into 7 groups: G1 = Zone 1; G2 = Zone 2; G3 = Zone 3; G4 = Zone 4; G5 = Zone 5 & Zone 6; G6 = Zone 7 to Zone 9; G7 = Zone 10 to Zone 15. This classification allows each zone to be individually adjusted according to the thermal response characteristics of the wafer. The voltage of G1 to G6 is set to 20%, and G7 is set to 5%.

[0038] Step 2: Based on the experimental data of the heating characteristics of the wafer under different voltages in step 1, these data include but are not limited to the temperature change of the wafer, heating time and voltage level. Then perform data cleaning preprocessing, and use the standard deviation method to discard data points that exceed a certain numerical standard deviation from the average value. After fully analyzing the experimental data, the heating rate of the G1 heating area around the 10th second of the step 1 process is selected as the wafer characteristic judgment value, which is used to describe the wafer heating performance; this characteristic judgment value indicates that the larger the value, the better the wafer heating performance; the smaller the value, the worse the wafer heating performance.

[0039] Step 3: For the wafer heating scenario in rapid thermal processing, in order to more finely control the heating process and accurately measure the temperature, the heating area and the temperature measurement area are divided into the same seven areas, thereby building a 7x7 coupled system control model. This model can simultaneously adjust the heating voltage of each area and monitor the temperature feedback of the corresponding area in real time to ensure the uniformity and accuracy of heating.

[0040] Step 4: After the robotic arm delivers the wafer into the cavity, the wafer will first fall on three support pillars, at which time the halogen lamp will preheat the wafer with a relatively low power; after 5 seconds, the support pillars fall and enter the support pillar ascending stage, and the wafer is placed on the edge ring. At this time, the heating lamp will increase the power to quickly heat up the wafer. In the period of time after the support pillars begin to rise, the outer ring of the wafer will be heated by the heat conduction of the edge ring and the radiation of the lamp, while the inner ring will be mainly heated by the radiation of the lamp. The outer ring consists of two areas 6 and 7, so the present invention proposes a method of adjusting the voltage of the outer ring areas 6 and 7 by keeping the middle five areas unchanged. This method conforms to the actual situation and is convenient for operation. Through experimental data, the voltage of wafer 1-5 is determined. It is expected that for different wafers and different air pressures, only the voltage of 6 and 7 needs to be adjusted to complete the low-temperature heating stage; the specific steps for determining the voltage of the heating lamps of wafer 1-5 are as follows:

[0041] S1: In a laboratory environment, preliminary tests are performed on the 1-5 heating zones of the wafer. Through these tests, temperature variation data of different wafers under the same gas pressure are collected. These data include key parameters such as the heating rate and temperature rise curve of the wafer under different voltage settings.

[0042] S2: Determine the optimal setting for the 1-5 voltage. The specific method is to adjust the 1-5 heating lamp voltage up and down based on the data of S1, find the extreme value of the wafer emissivity jump, and take the median of the upper and lower limits as the optimal value. Step 5: The wafer type is fixed to one of the experimental settings to eliminate the influence of wafer characteristics on the experimental results. Next, by adjusting the air pressure conditions, explore the ideal settings of the 6- and 7-way voltages under different air pressures. This process involves conducting a systematic heating experiment on the wafer under the set air pressure conditions, and recording the heating effect and temperature response of the wafer under different 6- and 7-way voltage settings. By comparing and analyzing these data, the optimal 6- and 7-way voltage values ​​under each air pressure condition are determined. These ideal voltage settings should ensure the uniformity and stability of wafer heating under various air pressures, thereby improving the effectiveness of the entire processing process and product quality.

[0043] Step 6: Fix the gas pressure value to a standard value in the experimental conditions to eliminate the impact of gas pressure changes on the voltage settings. Subsequently, the 6- and 7-way voltages are systematically adjusted and tested for different types of wafers to find the optimal settings for these specific wafer types. By performing a series of heating experiments under fixed gas pressure conditions, the responses of different wafer types to changes in the 6- and 7-way voltages, including temperature uniformity, heating rate, and other relevant heating characteristics, are recorded in detail. After analyzing the experimental data, the ideal 6- and 7-way voltage settings for each wafer type are determined.

[0044] Step 7: Figure 4 and Figure 5 As shown, through the experimental data of step 5 and step 6, the gas pressure and wafer feature judgment value are used as independent variables, and the heating lamp voltage is used as the dependent variable to fit the surfaces of 6 and 7 voltages.

[0045] Step 8: Set the initial condition of the cavity to a cold cavity or a hot cavity, and make corrections to the wafer feature judgment in the hot cavity case. The cold and hot cavities have a certain influence on the wafer feature judgment value. In order to explore the specific influence of the hot cavity and make corrections, first run the 1050 degrees Celsius heating process 10 times in a row to ensure that the cavity is a hot cavity, and then do the basic experiment described in step 1 to observe its judgment value and the influence of the cold cavity.

[0046] Specific implementation scenario: Basic experiments are performed on different types of wafers, where the heating lamp power in the G7 area is set to 5%, and the rest are set to 20%. The time for each basic experiment is set to run for 10 seconds after pin down.

[0047] Experimental parameter settings:

[0048] (1) Air pressure setting: 5torr, 100torr, 200torr, 480torr, 600torr, 780torr

[0049] (2) Wafer judgment value (type): 7 types

[0050] (3) Basic experiment time: 10s

[0051] Corresponding to the aforementioned embodiment of an OLT open-loop voltage setting method based on wafer feature judgment, the present invention further provides an embodiment of an OLT open-loop voltage setting device based on wafer feature judgment.

[0052] See also Figure 6 An embodiment of the present invention provides an OLT open-loop voltage setting device based on wafer feature judgment, including a memory and one or more processors, wherein the memory stores executable code, and when the processor executes the executable code, it is used to implement an OLT open-loop voltage setting method based on wafer feature judgment in the above embodiment.

[0053] An embodiment of an OLT open-loop voltage setting device based on wafer feature judgment provided by the present invention can be applied to any device with data processing capabilities, and the device with data processing capabilities can be a device or apparatus such as a computer. The device embodiment can be implemented through software, or through hardware or a combination of software and hardware. Taking software implementation as an example, as a device in a logical sense, it is formed by the processor of any device with data processing capabilities in which it is located reading the corresponding computer program instructions in the non-volatile memory into the internal memory for execution. From a hardware perspective, if Figure 6 As shown, it is a hardware structure diagram of any device with data processing capability in which an OLT open-loop voltage setting device based on wafer feature judgment provided by the present invention is located, except Figure 6 In addition to the processor, memory, network interface, and non-volatile memory shown, any device with data processing capabilities in which the apparatus in the embodiments is located may also include other hardware, generally based on the actual functions of the device with data processing capabilities, which will not be described in detail.

[0054] The implementation process of the functions and effects of each unit in the above-mentioned device is specifically described in the implementation process of the corresponding steps in the above-mentioned method, and will not be repeated here.

[0055] For the device embodiment, since it basically corresponds to the method embodiment, the relevant parts can refer to the partial description of the method embodiment. The device embodiment described above is only schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of the present invention. Ordinary technicians in this field can understand and implement it without paying creative work.

[0056] An embodiment of the present invention further provides a computer-readable storage medium having a program stored thereon. When the program is executed by a processor, an OLT open-loop voltage setting method based on wafer feature judgment in the above embodiment is implemented.

[0057] The computer-readable storage medium may be an internal storage unit of any device with data processing capability described in any of the aforementioned embodiments, such as a hard disk or a memory. The computer-readable storage medium may also be an external storage device of any device with data processing capability, such as a plug-in hard disk, a smart media card (SMC), an SD card, a flash card, etc. equipped on the device. Furthermore, the computer-readable storage medium may also include both an internal storage unit and an external storage device of any device with data processing capability. The computer-readable storage medium is used to store the computer program and other programs and data required by any device with data processing capability, and may also be used to temporarily store data that has been output or is to be output.

[0058] The present invention also provides a computer program product, including a computer program. When the computer program is executed by a processor, the method for setting an OLT open-loop voltage based on wafer feature judgment is implemented.

[0059] The above embodiments are used to illustrate the present invention rather than to limit the present invention. Any modification and change made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A method for setting an OLT open-loop voltage based on wafer feature judgment, characterized in that: The method comprises the following steps: Step 1: Obtain temperature change data of different types of wafers based on voltage experiments; Step 2: According to the experimental data of step 1, after pre-processing, the characteristic judgment value of the wafer heating performance is determined based on the heating rate; Step 3: For the wafer heating scenario in rapid thermal processing, the heating area and the temperature measurement area are evenly divided based on the arrangement of the halogen lamps, and a coupled system control model is constructed; Step 4: Determine the voltage of the inner area of ​​the wafer through experimental data. It is expected that for different wafers and different gas pressures, only the voltage of the outer area of ​​the wafer can be adjusted to complete the low-temperature heating stage. Step 5: Fix the wafer type and obtain the ideal outer ring area voltage of the wafer under different gas pressures; Step 6: Fix the air pressure value to obtain the ideal outer ring area voltage of the wafer under different wafer types; Step 7: Using the voltage data from steps 5 and 6, with the air pressure and wafer feature judgment value as independent variables and the heating lamp voltage as the dependent variable, fit the surface of the voltage in the outer ring area of ​​the wafer.

2. A method for identifying parameters of a heating control model in the field of rapid thermal processing according to claim 1, characterized in that: In step 1, the heating characteristics of the wafer are calculated by measuring the thermal rise rate of the wafer, and the heating lamp voltage is selected to represent the corresponding value according to the wafer heating rate, so that each area can be personalized according to the thermal response characteristics of the wafer.

3. A method for identifying heating control model parameters in the field of rapid thermal processing according to claim 1, characterized in that: In step 2, heating characteristic data of the wafer under different voltages are collected; these data include temperature change, heating time and voltage level of the wafer; and the heating rate of the heating area in the 10th second of the step 1 process is selected as the wafer characteristic judgment value.

4. A method for identifying parameters of a heating control model in the field of rapid thermal processing according to claim 1, characterized in that: In step 3, the coupled system control model can simultaneously adjust the heating voltage of each area and monitor the temperature feedback of the corresponding area in real time to ensure the uniformity and accuracy of heating.

5. A method for identifying parameters of a heating control model in the field of rapid thermal processing according to claim 1, characterized in that: In step 4, the specific steps for determining the heating lamp voltage in the inner ring area of ​​the wafer are: S1: In a laboratory environment, conduct preliminary tests on the heating area of ​​the inner circle of the wafer to collect temperature change data of different wafers under the same gas pressure; including the heating rate and temperature rise curve of the wafer under different voltage settings; S2: Based on the data of S1, adjust the voltage of the heating lamp in the inner circle area of ​​the wafer, find the extreme value of the wafer emissivity jump, and take the middle value of the upper and lower limits as the optimal value.

6. A method for identifying parameters of a heating control model in the field of rapid thermal processing according to claim 1, characterized in that: In step 5, a systematic heating experiment is performed on the wafer under the set air pressure conditions, and the heating effect and temperature response of the wafer under different outer ring area voltage settings of the wafer are recorded; by comparing and analyzing the data, the optimal outer ring area voltage value of the wafer under each air pressure condition is determined.

7. A method for identifying parameters of a heating control model in the field of rapid thermal processing according to claim 1, characterized in that: In step 6, a series of heating experiments are conducted under fixed gas pressure conditions to record in detail the responses of different wafer types to the voltage changes in the outer ring area of ​​the wafer, including temperature uniformity and heating rate; after analyzing the experimental data, the ideal outer ring area voltage setting of the wafer is determined for each wafer type.

8. The method for identifying parameters of a heating control model in the field of rapid thermal processing according to claim 1, characterized in that: In step 2, the hot and cold chambers have an impact on the wafer feature judgment value. The wafer feature judgment is corrected for the hot chamber. First, the 1050 degree Celsius heating process is run 10 times continuously to ensure that the cavity is a hot cavity. Then, the basic experiment described in step 1 is performed to observe the feature judgment value of the wafer heating performance and the influence of the cold chamber.

9. An OLT open-loop voltage setting device based on wafer feature judgment, comprising a memory and one or more processors, wherein the memory stores executable code, characterized in that: When the processor executes the executable code, an OLT open-loop voltage setting method based on wafer feature judgment as described in any one of claims 1 to 8 is implemented.

10. A computer-readable storage medium having a program stored thereon, characterized in that: When the program is executed by a processor, an OLT open-loop voltage setting method based on wafer feature judgment as described in any one of claims 1 to 8 is implemented.

Images