A method for determining temperature of a rapid heat treatment machine

Abstract

The present application provides a method for determining the temperature of a rapid thermal processing machine, comprising: obtaining an initial detection substrate obtained by generating a silicon nitride layer on a silicon substrate; determining a relationship expression for describing the machine temperature of the rapid thermal processing machine and the etching rate of the silicon nitride layer; transporting the initial detection substrate to a rapid thermal processing machine to be tested whose display temperature is a preset machine temperature, performing rapid thermal processing on the initial detection substrate according to preset thermal processing conditions, and measuring a first detection thickness value of the first detection substrate obtained after the rapid thermal processing; performing hydrofluoric acid etching on the first detection substrate for a preset time period, and measuring a second detection thickness value of a second detection substrate obtained after the etching; determining an actual etching rate of the silicon nitride layer for the initial detection substrate based on the first detection thickness value, the second detection thickness value and the preset time period; and determining an actual machine temperature corresponding to the actual etching rate based on the actual etching rate and the relationship expression.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a temperature determination method for a rapid thermal processing machine. Background Art

[0002] The nickel silicide (Ni Sicilide) process is used in the chip manufacturing process of 65nm~28nm specifications to reduce the contact resistance between the contact hole Contact of the transistor generated on the wafer and the polysilicon Poly on the gate Gate. The specific steps of the nickel silicide process include native oxide removal, metal deposition, the first silicidation reaction, unreacted metal removal, and the second silicidation reaction. Among them, the silicidation reaction has the greatest impact on the resistance of the final metal silicide. The temperature of the silicidation reaction determines the reaction degree of the silicidation reaction. However, there is a difference between the actual temperature provided by the rapid thermal processing machine that performs the silicidation reaction and the target temperature it displays, which affects the execution efficiency of the silicidation reaction. Summary of the invention

[0003] In view of this, the purpose of the present application is to at least provide a method for determining the temperature of a rapid thermal processing machine, by generating an initial test substrate on a silicon substrate to obtain a silicon nitride layer, and determining a relationship expression describing the relationship between the machine temperature and the etching rate of the silicon nitride layer, thereby transporting the initial test substrate to a rapid thermal processing machine and performing rapid thermal processing according to preset thermal processing conditions, and then performing hydrofluoric acid etching on the first test substrate obtained by performing the rapid thermal processing, and measuring the thickness difference before and after etching, and determining the etching rate by the thickness difference and the etching time, thereby determining the machine temperature corresponding to the etching rate according to the relationship expression, thereby obtaining the machine temperature of the rapid thermal processing machine, solving the technical problem in the prior art that the rapid thermal processing machine may cause the displayed temperature to be different from the actual temperature as the usage time gradually increases, and achieving the technical effect of improving the accuracy of the machine temperature of the rapid thermal processing machine.

[0004] This application mainly includes the following aspects:

[0005] In a first aspect, an embodiment of the present application provides a temperature determination method for a rapid thermal processing machine, the method comprising: obtaining an initial detection substrate obtained by generating a silicon nitride layer on a silicon substrate; determining a relationship expression for describing a machine temperature of the rapid thermal processing machine and an etching rate of the silicon nitride layer, the rapid thermal processing machine being used to perform rapid thermal processing during the generation of nickel silicide; transporting the initial detection substrate to a rapid thermal processing machine to be tested whose display temperature is a preset machine temperature, performing rapid thermal processing on the initial detection substrate according to preset thermal processing conditions, and measuring a first detection thickness value of the first detection substrate obtained after the rapid thermal processing; performing hydrofluoric acid etching on the first detection substrate for a preset time period, and measuring a second detection thickness value of a second detection substrate obtained after etching; determining an actual etching rate of the silicon nitride layer for the initial detection substrate based on the first detection thickness value, the second detection thickness value and the preset time period; determining an actual machine temperature corresponding to the actual etching rate based on the actual etching rate and the relationship expression.

[0006] Optionally, the relationship expression is determined in the following manner: by performing multiple calibration processes to obtain the machine temperature and etching rate corresponding to each calibration process, wherein, for each calibration process, the calibration process includes sequentially generating a silicon nitride layer on a preset silicon substrate, performing the rapid thermal treatment and the hydrofluoric acid etching at the machine temperature corresponding to the calibration process to obtain the etching rate of the calibration process; the relationship expression is obtained based on the etching rates corresponding to each machine temperature.

[0007] Optionally, multiple calibration processes are performed in the following manner: the following calibration processes are performed on a preset silicon substrate: an initial processing substrate is obtained by generating a silicon nitride layer on the preset silicon substrate, the initial processing substrate is transported to a standard rapid thermal processing machine whose display temperature is the machine temperature corresponding to this calibration process, the initial processing substrate is rapidly thermally processed according to preset thermal processing conditions, and a first calibration thickness value of a first calibration substrate obtained after the rapid thermal processing is measured, the machine temperature corresponding to each calibration process is different, and the difference between the machine temperature displayed by the standard rapid thermal processing machine and the actual temperature meets the process requirements for executing the nickel silicide generation process, the first calibration substrate is etched with hydrofluoric acid for a preset time period, and a second calibration thickness value of a second calibration substrate obtained after etching is measured, the etching rate at the machine temperature corresponding to this calibration process is determined based on the first calibration thickness value, the second calibration thickness value and the preset time period, the remaining silicon nitride layer on the second calibration substrate is etched with hydrofluoric acid to obtain a preset silicon substrate, and the calibration process is re-executed to perform multiple calibration processes.

[0008] Optionally, the machine temperature corresponding to each calibration process belongs to a preset temperature range, and the preset temperature range is a temperature range for performing rapid thermal processing during the nickel silicide generation process.

[0009] Optionally, the method further comprises: removing the silicon nitride layer on the second detection substrate to obtain the silicon substrate, so as to reuse the silicon substrate.

[0010] Optionally, the preset heat treatment conditions are used to control the conversion relationship between the machine temperature of the rapid thermal processing machine and the etching rate obtained by performing the hydrofluoric acid etching, wherein the preset heat treatment conditions include annealing time and a first input gas and flow rate of the rapid thermal processing machine, the annealing time is less than or equal to a preset time threshold for performing rapid thermal processing during the nickel silicide generation process, and the first input gas includes oxygen, which is used to react with the silicon nitride layer during rapid thermal processing to increase the possibility of a conversion relationship between the machine temperature and the etching rate.

[0011] Optionally, the method further comprises: taking the difference between the actual machine temperature and the preset machine temperature as the compensation temperature of the rapid thermal processing machine to be tested, so as to compensate the display temperature of the rapid thermal processing machine to be tested.

[0012] Optionally, the method also includes: generating the silicon nitride layer on the silicon substrate through a furnace tube process according to preset generation conditions, wherein the preset generation conditions are used to generate the silicon nitride layer and limit the thickness of the silicon nitride layer to meet the thickness requirement of hydrofluoric acid etching within a preset time period, and the preset generation conditions include temperature parameters, pressure parameters, multiple second input gases of the furnace tube, and the flow rate corresponding to each second input gas.

[0013] Optionally, the plurality of second incoming gases include ammonia and hexachlorodisilane.

[0014] Optionally, the actual etching rate of the silicon nitride layer of the initial detection substrate is determined by: calculating the first difference between the first detection thickness value and the second detection thickness value, and taking the ratio of the first difference to the preset time period as the actual etching rate; and / or, the etching rate at the machine temperature corresponding to each calibration treatment is determined by: calculating the second difference between the first calibrated thickness value and the second calibrated thickness value, and taking the ratio of the second difference to the preset time period as the etching rate at the machine temperature corresponding to each calibration treatment.

[0015] An embodiment of the present application provides a temperature determination method for a rapid thermal processing machine, the method comprising: obtaining an initial detection substrate obtained by generating a silicon nitride layer on a silicon substrate; determining a relationship expression for describing a machine temperature of the rapid thermal processing machine and an etching rate of the silicon nitride layer, the rapid thermal processing machine being used to perform rapid thermal processing in a nickel silicide generation process; transporting the initial detection substrate to a rapid thermal processing machine to be tested whose display temperature is a preset machine temperature, performing rapid thermal processing on the initial detection substrate according to preset thermal processing conditions, and measuring a first detection thickness value of a first detection substrate obtained after the rapid thermal processing; performing hydrofluoric acid etching on the first detection substrate for a preset time period, and measuring a second detection thickness value of a second detection substrate obtained after etching; determining an actual etching rate of the silicon nitride layer for the initial detection substrate based on the first detection thickness value, the second detection thickness value and the preset time period; and determining an actual machine temperature corresponding to the actual etching rate based on the actual etching rate and the relationship expression. An initial test substrate is obtained by generating a silicon nitride layer on a silicon substrate, and a relationship expression describing the machine temperature and the etching rate of the silicon nitride layer is determined, so that the initial test substrate is transported to a rapid thermal processing machine and subjected to rapid thermal processing according to preset thermal processing conditions, and then the first test substrate obtained by the rapid thermal processing is etched with hydrofluoric acid, and the thickness difference before and after etching is measured, and the etching rate is determined by the thickness difference and the etching time, so that the machine temperature corresponding to the etching rate is determined according to the relationship expression, thereby obtaining the machine temperature of the rapid thermal processing machine, solving the technical problem in the prior art that the rapid thermal processing machine may cause the displayed temperature to be different from the actual temperature as the use time gradually increases, and achieving the technical effect of improving the accuracy of the machine temperature of the rapid thermal processing machine.

[0016] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A schematic diagram showing a relationship curve between sheet resistance and temperature provided in an embodiment of the present application is shown.

[0019] Figure 2A flow chart of a method for determining the temperature of a rapid thermal processing machine provided in an embodiment of the present application is shown.

[0020] Figure 3 A schematic diagram of a curve corresponding to an expression for describing the relationship between the machine temperature and the etching rate provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0021] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the drawings in the present application only serve the purpose of explanation and description and are not used to limit the scope of protection of the present application. In addition, it should be understood that the schematic drawings are not drawn in real proportion. The flowchart used in this application shows the operations implemented according to some embodiments of the present application. It should be understood that the operations of the flowchart can be implemented out of sequence, and the steps without logical context can be reversed in order or implemented simultaneously. In addition, those skilled in the art, under the guidance of the content of the present application, can add one or more other operations to the flowchart, or remove one or more operations from the flowchart.

[0022] In addition, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0023] In the prior art, in the process of manufacturing transistors on a wafer, after forming the source and drain, a metal layer of at least nickel Ni or titanium nitride TiN is deposited on the source, drain and gate, and then an annealing treatment (i.e., silicidation reaction) is performed to react the metal layer with the silicon in the gate, source and drain to form a nickel silicide with low resistivity, thereby reducing the contact resistance. In addition, after the nickel silicide is formed, a wet cleaning process is required to remove metals such as titanium or nickel that have not reacted with the silicon in the substrate. After removing the unreacted metal, a second silicidation reaction is required to control the conversion of all silicon-nickel compounds into a low-resistance phase. Furthermore, it is necessary to accurately control the temperature of the rapid thermal processing machine used to perform the annealing treatment to improve the execution effect of the silicidation reaction, thereby ensuring that the generation of nickel silicide meets the resistance requirements.

[0024] In the prior art, a certain thickness of nickel is deposited on a silicon substrate, and the upper and lower surfaces of the deposited silicon substrate are connected to a resistance detection device to determine whether the nickel layer is normally deposited by detecting the resistance of the deposited silicon substrate. After determining that the nickel layer is deposited on the silicon substrate, the deposited silicon substrate is moved to a rapid thermal processing machine to perform a silicidation reaction. Then, nickel and silicon react to generate a mixture containing at least one nickel-silicon compound (generally including Ni2Si and NiSi). At this time, the upper and lower surfaces of the silicon substrate that generates the mixture are again connected to a resistance detection device to determine the sheet resistance RS of the silicon substrate at this time, and within a certain temperature range, there is a linear relationship between the sheet resistance and the temperature. Therefore, the actual temperature of the rapid thermal processing machine that performs the silicidation reaction can be determined by detecting the resistance value of the sheet resistance, so as to achieve temperature correction of the rapid thermal processing machine. The rapid thermal processing machine after temperature correction can perform the annealing process in the production of nickel silicide on the substrate containing the transistor structure, so as to optimize the annealing process. However, temperature correction performed in this manner will generate a mixture on the silicon substrate. After the mixture is generated, the silicon substrate cannot be subjected to nickel deposition again and the temperature correction cannot be repeated, so the silicon substrate has to be scrapped, which in turn increases costs.

[0025] See also Figure 1 , Figure 1 Schematic diagram of the relationship between sheet resistance and temperature provided in the embodiment of the present application. Figure 1 As shown, the horizontal axis refers to the actual temperature of the rapid thermal processing machine that performs the silicidation reaction, and the vertical axis refers to the resistance value of the thin layer resistor. The relationship curve between the thin layer resistance and the temperature is used to indicate the corresponding thin layer resistance at each actual temperature. In the temperature range of 290°C to 305°C, there is a good linear relationship between the thin layer resistance and the temperature. Furthermore, the silicon substrate covered with a certain thickness of nickel is transported to a rapid thermal processing machine with a pre-calibrated temperature accuracy and the temperature of the rapid thermal processing machine is set. After the rapid thermal processing of the preset processing time is performed in the machine, the silicon substrate is taken out and the thin layer resistance is detected. The aforementioned rapid thermal processing is performed multiple times by repeatedly changing the machine temperature to obtain the relationship curves between each temperature and the thin layer resistance of the pre-calibrated rapid thermal processing machine. Therefore, when temperature calibration is performed on other rapid thermal processing machines, the first temperature can be set for other rapid thermal processing machines, and a silicon substrate can be placed in the machine to perform rapid thermal processing for a preset processing time, and then the silicon substrate can be taken out and the sheet resistance of the silicon substrate can be detected, so as to determine the actual second temperature of the machine through the detected sheet resistance and the relationship curve, thereby realizing temperature calibration of the rapid thermal processing machine during the application process.

[0026] Based on this, the embodiment of the present application provides a method for determining the temperature of a rapid thermal processing machine, wherein an initial detection substrate is obtained by generating a silicon nitride layer on a silicon substrate, and a relationship expression describing the machine temperature and the etching rate of the silicon nitride layer is determined, thereby transporting the initial detection substrate to a rapid thermal processing machine and performing rapid thermal processing according to preset thermal processing conditions, and then performing hydrofluoric acid etching on the first detection substrate obtained by performing the rapid thermal processing, and measuring the thickness difference before and after etching, and determining the etching rate by the thickness difference and the etching time, thereby determining the machine temperature corresponding to the etching rate according to the relationship expression, thereby obtaining the machine temperature of the rapid thermal processing machine, solving the technical problem in the prior art that the rapid thermal processing machine may cause the displayed temperature to be different from the actual temperature as the use time gradually increases, and achieving the technical effect of improving the accuracy of the machine temperature of the rapid thermal processing machine, which is specifically as follows:

[0027] See also Figure 2 , Figure 2 This is a flow chart of a method for determining the temperature of a rapid thermal processing machine provided in an embodiment of the present application. Figure 2 As shown, the temperature determination method of a rapid thermal processing machine provided in an embodiment of the present application includes the following steps:

[0028] S101: Acquire an initial test substrate obtained by growing a silicon nitride layer on a silicon substrate.

[0029] The silicon substrate includes silicon material to facilitate deposition of a silicon nitride layer in a furnace tube process.

[0030] Specifically, the method further includes: generating the silicon nitride layer on the silicon substrate through a furnace tube process according to preset generating conditions. That is, the silicon substrate is transported into a furnace tube, and the furnace tube process is performed according to preset generating conditions, so that the silicon substrate is covered with the silicon nitride layer on its surface, so as to facilitate subsequent hydrofluoric acid etching of the silicon nitride layer.

[0031] The preset generation conditions are used to generate a silicon nitride layer and limit the thickness of the silicon nitride layer to meet the thickness requirement of hydrofluoric acid etching within a preset time period. That is, the thickness of the silicon nitride layer generated by the furnace tube process executed according to the preset generation conditions is at least greater than the thickness of the silicon nitride layer consumed by hydrofluoric acid etching within the preset time period, so as to prevent the accuracy of etching rate calculation from being affected due to failure to fully perform hydrofluoric acid etching within the preset time period.

[0032] Specifically, since hydrofluoric acid etching will not etch the silicon substrate, if the thickness of the silicon nitride layer is small, the silicon nitride layer on the silicon substrate will be etched away before the preset time period is reached. As a result, the etched thickness measured before and after the preset time period is less than the thickness required for full etching, resulting in a smaller calculated result of the etching rate, affecting the accuracy of the calculation.

[0033] The preset generation conditions include temperature parameters, pressure parameters, multiple second incoming gases of the furnace tube and the flow rate corresponding to each second incoming gas. The multiple second incoming gases include ammonia and hexachlorodisilane.

[0034] Exemplarily, the preset generation conditions include: the temperature parameter is set at 565°C to 595°C, the pressure parameter is set at 0.2torr to 0.3torr, the flow rate of ammonia is 1600 ml / min to 1900 ml / min, and the flow rate of hexachlorodisilane (HCD) is 35 ml / min to 45 ml / min. Then, the furnace tube process is performed according to the preset generation conditions to generate HCD silicon nitride on the silicon substrate.

[0035] S102: Determine an expression for describing the relationship between the temperature of a rapid thermal processing machine and the etching rate of the silicon nitride layer.

[0036] The rapid thermal processing machine is used to perform rapid thermal processing in the process of forming nickel silicide. That is, a relational expression reflecting the relationship between the machine temperature of the rapid thermal processing machine and the etching rate of the silicon nitride layer is predetermined.

[0037] Specifically, the relational expression is determined in the following manner: multiple calibration processes are performed to obtain the machine temperature and etching rate corresponding to each calibration process, wherein, for each calibration process, the calibration process includes sequentially generating a silicon nitride layer on a preset silicon substrate, performing the rapid thermal treatment and the hydrofluoric acid etching at the machine temperature corresponding to the calibration process to obtain the etching rate of the calibration process; the relational expression is obtained based on the etching rates corresponding to each machine temperature.

[0038] The actual temperature of the standard rapid thermal processing machine used to perform multiple calibration processes in the present application is consistent with the machine temperature displayed, so that a relationship expression that accurately reflects the relationship between the machine temperature and the etching rate can be obtained. Exemplarily, the standard rapid thermal processing machine can be a new rapid thermal processing machine that has not been used yet or a rapid thermal processing machine that has been temperature calibrated using the relationship curve between sheet resistance and temperature in the prior art.

[0039] Among them, for each calibration process, the display temperature of the rapid thermal processing machine is adjusted to the machine temperature corresponding to the calibration process, so that the preset silicon substrate covering the silicon nitride layer is moved to the rapid thermal processing machine for rapid thermal processing, and after the rapid thermal processing is completed, the silicon nitride layer is etched with hydrofluoric acid, and the etching rate of the calibration process is determined by measuring the thickness difference before and after etching and the etching time. Furthermore, the machine temperature displayed by the rapid thermal processing machine is controlled to be different during each calibration process, and the furnace tube process executed according to the preset generation conditions, the rapid thermal processing performed according to the preset thermal processing conditions, and the hydrofluoric acid concentration and the preset time period for hydrofluoric acid etching are set to be the same for each calibration process, so that only the machine temperature is different for each calibration process, thereby improving the accuracy of the expression for determining the relationship between the machine temperature and the etching rate.

[0040] Exemplarily, the machine temperature and etching rate corresponding to each calibration process are fitted to obtain a relational expression. The data fitting can be fitted into a linear function. In order to increase the accuracy of calculating the machine temperature by the etching rate after data fitting, the present application fits the relational expression into a quadratic function. The specific method of data fitting and the specific form of the fitted relational expression are not limited in this application.

[0041] For example, see Figure 3 , Figure 3 This is a schematic diagram of a curve corresponding to the relationship expression between the machine temperature and the etching rate provided in the embodiment of the present application. Figure 3 As shown, the horizontal axis refers to the corresponding machine temperature under each calibration process, and the vertical axis refers to the corresponding etching rate under each calibration process. By fitting the data of the machine temperature and etching rate corresponding to multiple calibration processes, the fitting function y=-0.00078x 2 +4.4214x-584.66, where x is used to represent the machine temperature, y is used to represent the etching rate, and the determination coefficient R of the fitting function is 2 =0.9998, which shows that the fitting effect of the fitting function is good, and the fitting function can be used as a relational expression to describe the relationship between the machine temperature and the etching rate.

[0042] Specifically, multiple calibration processes are performed in the following manner: the following calibration processes are performed on a preset silicon substrate: an initial processing substrate is obtained by generating a silicon nitride layer on the preset silicon substrate, the initial processing substrate is transported to a standard rapid thermal processing machine whose display temperature is the machine temperature corresponding to this calibration process, the initial processing substrate is rapidly thermally processed according to preset thermal processing conditions, and a first calibration thickness value of a first calibration substrate obtained after the rapid thermal processing is measured, the machine temperature corresponding to each calibration process is different, and the difference between the machine temperature displayed by the standard rapid thermal processing machine and the actual temperature meets the process requirements for performing the nickel silicide generation process, the first calibration substrate is etched with hydrofluoric acid for a preset time period, and a second calibration thickness value of a second calibration substrate obtained after etching is measured, the etching rate at the machine temperature corresponding to this calibration process is determined based on the first calibration thickness value, the second calibration thickness value and the preset time period, the remaining silicon nitride layer on the second calibration substrate is etched with hydrofluoric acid to obtain a preset silicon substrate, and the calibration process is re-executed to perform multiple calibration processes.

[0043] The etching rate at the machine temperature corresponding to each calibration process is determined in the following manner: a second difference between the first calibrated thickness value and the second calibrated thickness value is calculated, and a ratio of the second difference to the preset time period is used as the etching rate at the machine temperature corresponding to each calibration process.

[0044] Among them, the machine temperature displayed by the standard rapid thermal processing machine can be the same as the actual temperature. The difference between the machine temperature displayed by the standard rapid thermal processing machine and the actual temperature should not have a significant impact on the execution of the annealing process. Furthermore, the difference needs to meet the machine temperature difference standard when the annealing process is actually performed. The relationship expression obtained in this way will not affect the certainty of determining the actual machine temperature, thereby avoiding affecting the execution effect of the annealing process.

[0045] The preset silicon substrate is used for performing the calibration process, and thus, does not need to have a semiconductor structure. The preset silicon substrate includes silicon material to facilitate the generation of a silicon nitride layer in the furnace tube process. During the initial calibration process, the silicon nitride layer is directly generated on the preset silicon substrate according to the preset generation conditions to obtain an initial processing substrate. Furthermore, the initial processing substrate is transported to a standard rapid thermal processing machine, and the standard rapid thermal processing machine is adjusted to correspond to different machine temperatures during each calibration process, the initial processing substrate is rapidly thermally processed according to the same preset thermal processing conditions, and a first calibration thickness value of the first calibration substrate obtained after the rapid thermal processing is measured, and the first calibration substrate is subjected to hydrofluoric acid etching for a preset time period and a second calibration thickness value of the second calibration substrate obtained after etching is measured, so that the difference between the first calibration thickness value and the second calibration thickness value is used as the thickness etched within the preset time period, and the ratio of the difference to the preset time period is used as the etching rate at the machine temperature corresponding to each calibration process, and further, after each measurement of the second calibration thickness value, the second calibration substrate is subjected to hydrofluoric acid etching to remove silicon nitride, so as to obtain the preset silicon substrate again, and the silicon nitride layer is produced again through the furnace tube process, so as to realize the reuse of the preset silicon substrate.

[0046] Specifically, the machine temperature corresponding to each calibration process belongs to a preset temperature range, and the preset temperature range is the temperature range for rapid thermal processing during the nickel silicide generation process. In other words, the machine temperature covered by the control relationship expression belongs to the temperature range for rapid thermal processing during the actual nickel silicide generation process, so that the etching rate through the relationship expression can correspond to the temperature required for nickel silicide production, so that the etching rate obtained during subsequent calibration belongs to the etching rate range covered by the relationship expression, and then the actual temperature can be inferred by combining the relationship expression and the etching rate.

[0047] For example, the temperature range of the rapid thermal processing during the actual nickel silicide formation process is 290° C. to 310° C., that is, the temperature of the standard rapid thermal processing machine needs to be controlled between 290° C. and 310° C. for each calibration process.

[0048] Among them, the preset heat treatment conditions are used to control the conversion relationship between the machine temperature of the rapid thermal processing machine and the etching rate obtained by performing the hydrofluoric acid etching, wherein the preset heat treatment conditions include annealing time and the first input gas and flow rate of the rapid thermal processing machine, the annealing time is less than or equal to the preset time threshold for performing rapid thermal processing during the nickel silicide generation process, and the first input gas includes oxygen, which is used to react with the silicon nitride layer during rapid thermal processing to increase the possibility of a conversion relationship between the machine temperature and the etching rate.

[0049] Exemplarily, the preset heat treatment conditions include: annealing time of 10 seconds to 60 seconds, oxygen flow rate of 50 sccm to 100 sccm. Thus, by performing annealing under the conditions of annealing time and oxygen flow rate filled with oxygen, a fitting curve reflecting the correlation between the machine temperature and the etching rate can be obtained after subsequent hydrofluoric acid etching. That is, by setting the preset heat treatment conditions, it is possible to increase the possibility of a corresponding relationship between the machine temperature and the etching rate, so as to obtain a relationship expression.

[0050] S103: transporting the initial inspection substrate to a rapid thermal processing machine to be inspected whose display temperature is a preset machine temperature, performing rapid thermal processing on the initial inspection substrate according to preset thermal processing conditions, and measuring a first inspection thickness value of the first inspection substrate obtained after the rapid thermal processing.

[0051] That is, the rapid thermal processing machine to be tested refers to a rapid thermal processing machine that needs to be temperature calibrated again after the machine has been working for a period of time, and the preset machine temperature can be understood as the machine temperature displayed by the rapid thermal processing machine to be tested. Then, after the initial test substrate is transported to the rapid thermal processing machine to be tested whose displayed temperature is the preset machine temperature, the initial test substrate is rapidly thermally processed according to the same preset thermal processing conditions as the calibration process, and the first test thickness value of the first test substrate obtained after the rapid thermal processing is measured.

[0052] S104: performing hydrofluoric acid etching on the first detection substrate for a preset period of time, and measuring a second detection thickness value of the second detection substrate obtained after etching.

[0053] That is, the first detection substrate is etched with hydrofluoric acid for a preset period of time under the same conditions as the hydrofluoric acid etching performed in the calibration process, and the second detection thickness value of the second detection substrate is measured after the preset period of time.

[0054] Furthermore, when it is necessary to determine the temperature of other rapid thermal processing machines to be tested, the furnace tube process can be performed on the second test substrate again according to the preset generation conditions to generate a silicon nitride layer, and then rapid thermal treatment can be performed in other rapid thermal processing machines to be tested according to the preset thermal treatment conditions, and finally hydrofluoric acid etching is performed for a preset time period, and the etching rate is determined by detecting the thickness of the substrate before and after hydrofluoric acid etching, so as to achieve temperature determination for other rapid thermal processing machines to be tested, and then the substrate can be reused.

[0055] Specifically, the method further includes: removing the silicon nitride layer on the second detection substrate to obtain the silicon substrate, so as to reuse the silicon substrate.

[0056] Exemplarily, hydrofluoric acid will not corrode the silicon substrate, and then the silicon nitride layer on the second detection substrate is cleaned by hydrofluoric acid to obtain the silicon substrate again.

[0057] S105: Determine an actual etching rate of the silicon nitride layer of the initial inspection substrate according to the first inspection thickness value, the second inspection thickness value and the preset time period.

[0058] Determining the actual etching rate of the silicon nitride layer of the initial detection substrate by: calculating a first difference between the first detection thickness value and the second detection thickness value, and taking the ratio of the first difference to the preset time period as the actual etching rate;

[0059] S106: Determine the actual machine temperature corresponding to the actual etching rate according to the actual etching rate and the relationship expression.

[0060] The method further includes: using the difference between the actual machine temperature and the preset machine temperature as the compensation temperature of the rapid thermal processing machine to be tested, so as to compensate the display temperature of the rapid thermal processing machine to be tested.

[0061] That is to say, the actual machine temperature corresponding to the actual etching rate is determined by the relational expression characterizing the relationship between the machine temperature and the etching rate and the actual etching rate, and then the temperature of the rapid thermal processing machine to be tested is calibrated by the actual machine temperature. Then, when the rapid thermal processing machine to be tested is used in the subsequent use, the machine temperature and the compensation temperature displayed by the rapid thermal processing machine to be tested can be used to determine the actual machine temperature of the rapid thermal processing machine to be tested, so as to accurately determine the machine temperature of the rapid thermal processing machine to be tested, thereby increasing the thermal processing efficiency of the rapid thermal processing machine to be tested and reducing the contact resistance of transistors produced in the semiconductor manufacturing process.

[0062] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0063] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0064] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present application, 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, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, and other media that can store program codes.

[0065] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for determining the temperature of a rapid thermal processing machine, characterized in that: The method comprises: obtaining an initial test substrate obtained by growing a silicon nitride layer on a silicon substrate; Determine an expression for describing the relationship between the temperature of a rapid thermal processing machine and the etching rate of the silicon nitride layer, wherein the rapid thermal processing machine is used to perform rapid thermal processing in the nickel silicide formation process; The initial detection substrate is transported to a rapid thermal processing machine to be detected whose display temperature is a preset machine temperature, the initial detection substrate is subjected to rapid thermal processing according to preset thermal processing conditions, and a first detection thickness value of the first detection substrate obtained after the rapid thermal processing is measured; Performing hydrofluoric acid etching on the first detection substrate for a preset time period, and measuring a second detection thickness value of the second detection substrate obtained after etching; Determining an actual etching rate of the silicon nitride layer of the initial detection substrate according to the first detection thickness value, the second detection thickness value and the preset time period; According to the actual etching rate and the relationship expression, an actual machine temperature corresponding to the actual etching rate is determined.

2. The method according to claim 1, characterized in that The relational expression is determined in the following manner: The machine temperature and etching rate corresponding to each calibration process are obtained by performing multiple calibration processes, wherein for each calibration process, the calibration process includes sequentially generating a silicon nitride layer on a preset silicon substrate, performing the rapid thermal process and the hydrofluoric acid etching at the machine temperature corresponding to the calibration process to obtain the etching rate of the calibration process; The relationship expression is obtained according to the corresponding etching rates at various machine temperatures.

3. The method according to claim 2, characterized in that Perform multiple calibrations in the following ways: The following calibration process is performed on a preset silicon substrate: an initial processing substrate is obtained by generating a silicon nitride layer on the preset silicon substrate, The initial processing substrate is transported to a standard rapid thermal processing machine whose displayed temperature is the machine temperature corresponding to the current calibration processing, and the initial processing substrate is rapidly thermally processed according to preset thermal processing conditions, and a first calibration thickness value of the first calibration substrate obtained after the rapid thermal processing is measured. The machine temperature corresponding to each calibration processing is different, and the difference between the machine temperature displayed by the standard rapid thermal processing machine and the actual temperature meets the process requirements for executing the nickel silicide formation process. The first calibration substrate is etched with hydrofluoric acid for a preset time period, and a second calibration thickness value of the second calibration substrate obtained after etching is measured, According to the first calibrated thickness value, the second calibrated thickness value and the preset time period, the etching rate at the machine temperature corresponding to the current calibration process is determined, The remaining silicon nitride layer on the second calibration substrate is etched with hydrofluoric acid to obtain a preset silicon substrate, and the calibration process is re-performed to perform multiple calibration processes.

4. The method according to claim 3, characterized in that The machine temperature corresponding to each calibration process belongs to a preset temperature range, and the preset temperature range is a temperature range for performing rapid thermal processing during the nickel silicide generation process.

5. The method according to claim 1, characterized in that: The method further comprises: The silicon nitride layer on the second detection substrate is removed to obtain the silicon substrate, so as to reuse the silicon substrate.

6. The method according to any one of claims 1 to 3, characterized in that: The preset heat treatment condition is used to control the temperature of the rapid thermal processing machine and there is a conversion relationship between the etching rate obtained by performing the hydrofluoric acid etching. Among them, the preset heat treatment conditions include annealing time and the first input gas and flow rate of the rapid thermal processing machine, the annealing time is less than or equal to the preset time threshold for performing rapid thermal processing during the nickel silicide generation process, and the first input gas includes oxygen, which is used to react with the silicon nitride layer during the rapid thermal processing to increase the possibility of a conversion relationship between the machine temperature and the etching rate.

7. The method according to claim 1, characterized in that The method further comprises: The difference between the actual machine temperature and the preset machine temperature is used as the compensation temperature of the rapid thermal processing machine to be tested, so as to compensate the display temperature of the rapid thermal processing machine to be tested.

8. The method according to claim 3, characterized in that The method further comprises: generating the silicon nitride layer on the silicon substrate through a furnace process according to preset generating conditions, The preset generation condition is used to generate a silicon nitride layer and limit the thickness of the silicon nitride layer to meet the thickness requirement of hydrofluoric acid etching within a preset time period. The preset generation conditions include temperature parameters, pressure parameters, multiple second incoming gases of the furnace tube, and the flow rate corresponding to each second incoming gas.

9. The method according to claim 8, characterized in that The plurality of second incoming gases include ammonia and hexachlorodisilane.

10. The method according to claim 3, characterized in that: The actual etching rate of the silicon nitride layer of the initial test substrate is determined by: Calculating a first difference between the first detected thickness value and the second detected thickness value, and taking a ratio of the first difference to the preset time period as the actual etching rate; and / or, The etching rate at the machine temperature corresponding to each calibration process is determined by the following method: A second difference between the first calibrated thickness value and the second calibrated thickness value is calculated, and a ratio of the second difference to the preset time period is used as an etching rate at the machine temperature corresponding to each calibration process.

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