Semiconductor manufacturing apparatus and temperature control method

Abstract

The application provides a semiconductor manufacturing equipment and a temperature control method. The current surface temperature of each substrate is synchronously obtained during the epitaxial growth process, and the current temperature difference of each substrate is obtained according to the current surface temperature of each substrate and the target setting temperature. The target substrate of temperature abnormality, the target interval change amount corresponding to the target substrate and the predetermined adjustment direction are determined according to each current temperature difference and the first calibration relationship. The target lifting mechanism which needs to be controlled is determined according to the number and position of the target substrate and the distance between each projection mark. The target lifting mechanism is controlled to run the target interval change amount in the predetermined adjustment direction or the opposite direction of the predetermined adjustment direction. The application can correct the surface temperature field uniformity of the substrate in real time, and does not interfere with the normal process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor manufacturing, and in particular to a semiconductor manufacturing device and a temperature control method. BACKGROUND

[0002] In a semiconductor manufacturing device, a susceptor is used to carry a substrate, and a heating device is usually arranged below the susceptor to heat the susceptor and transfer heat from the susceptor to the substrate to meet the process temperature requirement. In order to obtain the temperature of the susceptor or wafer in real time, an optical probe is usually arranged above the susceptor, for example, a spray hole of a gas injection device is used as an optical channel, or an optical window is arranged on a top plate of a chamber above the susceptor, and a blackbody radiation principle is used to perform optical temperature measurement on the area where the susceptor or substrate is located.

[0003] In some semiconductor manufacturing devices, for example, a MOCVD (metal organic chemical vapor deposition) device used for large-scale manufacturing of GaN (gallium nitride) or GaAs (gallium arsenide) thin film growth, a plurality of grooves are usually uniformly arranged on a susceptor in a circumferential direction to respectively carry and limit a substrate (such as a wafer), and the uniformity of the wavelength and thickness of the semiconductor material layer grown on the surface of the substrate in each groove is increasingly required, and the uniformity of the temperature field is an important influencing factor of the performance uniformity.

[0004] The distance between the susceptor and the heating device has an important influence on the uniformity of the temperature field of each substrate surface. In the prior art, in order to achieve the temperature uniformity of the substrate surface, a specific structural region on the susceptor is usually designed or selected in terms of material, and the distance between the susceptor and the heating device is adapted, so that different specific regions on the susceptor have different heat transfer characteristics. However, the implementation of the temperature uniformity of this scheme puts high requirements on the initial installation and positioning of the heating device, and increases the cost of process installation and debugging.

[0005] Moreover, different process controls will make the process gas flow field above the substrate have different influences on the wafer temperature, and even if different heat transfer characteristics are designed for different specific regions on the susceptor to adapt to the distance between the susceptor and the heating device, the influence of the process gas flow field on the temperature of the substrate surface cannot be solved.

[0006] In addition, due to process requirements or automatic substrate transfer requirements, the susceptor is frequently controlled to rotate or lift. In the lifting process controlled by the lifting device, a servo motor drives a lead screw, and the lead screw drives a lifting bottom plate and a rotating device to move, so that the susceptor moves towards or away from the upper cover of the chamber. If the lifting device deviates from the horizontal level due to lead screw slip, part damage, etc., the temperature uniformity will also be affected. In this application scenario, if the temperature uniformity of the substrate is monitored during the process, real-time intervention and adjustment cannot be achieved under the premise of not stopping the machine. SUMMARY

[0007] In order to solve the problem that the existing semiconductor manufacturing equipment cannot realize real-time temperature field correction in the process, the present application provides a semiconductor manufacturing equipment and a temperature control method.

[0008] In order to achieve the above-mentioned purpose, the present application provides a temperature control method of a semiconductor manufacturing equipment, wherein the semiconductor manufacturing equipment comprises a chamber, a susceptor with a plurality of grooves, a heating device arranged below the susceptor, a rotating device penetrating the chamber and connected to the susceptor, a lifting bottom plate arranged on the rotating device, a plurality of lifting mechanisms arranged on the lifting bottom plate and connected to the chamber bottom plate to drive the susceptor to lift, and a projection mark formed by the connection between the lifting mechanism and the chamber bottom plate towards the projection plane of the bearing top surface of the susceptor.

[0009] The temperature control method comprises:

[0010] S0: obtaining a first calibration relationship between the temperature difference of the susceptor and the variation amount of the distance between the heating device and the susceptor under different set temperatures;

[0011] S1: placing each wafer in the corresponding groove, controlling the rotating device to drive the susceptor to rotate, and performing an epitaxial process flow;

[0012] During the execution of the epitaxial process flow in step S1, the following steps are further included:

[0013] S11: obtaining the current temperature difference of each wafer according to the current surface temperature and the target set temperature of each wafer, determining the target wafer with temperature abnormality, the target distance variation amount corresponding to the target wafer and the predetermined adjustment direction according to the current temperature difference and the first calibration relationship;

[0014] S12: determining the target lifting mechanism that needs to be controlled according to the number, position and proximity of the target wafer and each projection mark;

[0015] S13: controlling the target lifting mechanism to run the target distance variation amount in the predetermined adjustment direction or the opposite direction of the predetermined adjustment direction.

[0016] Further, the number of lifting mechanisms is at least 3, each projection mark is uniformly distributed along the same circumferential direction on the bearing top surface, and at least one lifting mechanism exists in each half area of the bearing top surface.

[0017] Further, in step S11, the number of target wafers is 1, and in step S12, the lifting mechanism corresponding to the projection mark closest to the target wafer is obtained as the target lifting mechanism.

[0018] Further, in step S12, the number of the target substrates is at least two, and the absolute values of the current temperature differences of the at least two target substrates are different, the target substrate with the largest absolute value of the current temperature difference is selected as a priority target substrate, in step S12, the lifting mechanism corresponding to the projection mark closest to the priority target substrate is selected as the target lifting mechanism, and in step S13, the target lifting mechanism is controlled to run in the predetermined adjustment direction.

[0019] Further, in step S11, the number of the target substrates is at least two, and the absolute values of the current temperature differences of the at least two target substrates are different, the target substrate with the largest absolute value of the current temperature difference is selected as a priority target substrate, in step S12, the lifting mechanism corresponding to the projection mark closest to the priority target substrate is selected as the target lifting mechanism, and in step S13, the target lifting mechanism is controlled to run in the predetermined adjustment direction.

[0020] Further, the number of the priority target substrates is at least two, and the absolute values of the current temperature differences of the priority target substrates are the same, in step S12, the lifting mechanism corresponding to the projection mark closest to each of the priority target substrates is selected as the target lifting mechanism, and in step S13, the target lifting mechanism is controlled to run in the predetermined adjustment direction.

[0021] Further, the number of the target substrates is at least two, and the current temperature differences of the target substrates are the same, in step S12, after it is determined that the distances between each of the target substrates and the corresponding closest projection mark are consistent, the closest projection mark corresponding to each of the target substrates is obtained, the lifting mechanism corresponding to the obtained projection mark is selected as the target lifting mechanism, and in step S13, the target lifting mechanism is controlled to run in the predetermined adjustment direction.

[0022] Further, the number of the target substrates is at least two, and the current temperature differences of the target substrates are the same, in step S12, after it is determined that the distances between each of the target substrates and the corresponding closest projection mark are consistent, and each of the target substrates is located in the same half region of the plane on which the bearing top surface is located, the lifting mechanism corresponding to at least one projection mark in the other half region of the plane on which the bearing top surface is located is selected as the target lifting mechanism, and in step S13, the target lifting mechanism is controlled to run in the opposite direction of the predetermined adjustment direction.

[0023] Further, each of the target substrates is located in the same sector, the sector has a center at the center of the bearing top surface, and the radius lines are respectively tangent to the two target substrates, the other half region of the plane on which the bearing top surface is located includes a symmetric sector which is axially symmetric to the sector, in step S12:

[0024] when the symmetric sector has at least one projection mark, the lifting mechanism corresponding to the at least one projection mark in the symmetric sector is selected as the target lifting mechanism;

[0025] When the symmetric sector does not have the projection mark, the lifting mechanism corresponding to the projection mark closest to the symmetric sector is taken as the target lifting mechanism.

[0026] Further, the central angle of the sector is not more than 60 degrees.

[0027] Further, in step S11:

[0028] When the temperature difference between the current surface temperature of the substrate and the target set temperature is positive, the predetermined adjustment direction is away from the area where the heating device is located;

[0029] When the temperature difference between the current surface temperature of the substrate and the target set temperature is negative, the predetermined adjustment direction is close to the area where the heating device is located.

[0030] Further, the substrate and the heating device have a process distance, and in step S0, the step of obtaining the first calibration relationship comprises:

[0031] S01: control the heating device to heat the substrate according to the heating power corresponding to the set temperature until the substrate reaches temperature steady state, and obtain the initial steady state temperature of the substrate;

[0032] S02: maintain the heating power of the heating device unchanged, and control each lifting mechanism to rise or fall by a certain distance synchronously;

[0033] S03: obtain the current steady state temperature of the substrate, and obtain the calibration temperature difference according to the current steady state temperature of the substrate and the initial steady state temperature, and obtain the distance change amount according to the displacement change amount of each lifting mechanism and the process distance;

[0034] S04: control each lifting mechanism to continue to rise or fall by a certain distance synchronously;

[0035] S05: repeat steps S03 to S04 until the substrate is controlled to rise or fall to the corresponding position threshold, so as to obtain the corresponding relationship between the calibration temperature difference and the distance change amount of the substrate at the set temperature;

[0036] Further, in the step of obtaining the first calibration relationship, the distance between the substrate and the heating device is controlled to be not less than the minimum process distance, so as to avoid the motion interference between the substrate and the heating device, and the process distance is greater than the minimum process distance.

[0037] Further, before the epitaxial process flow of step S1 is performed, the susceptor has an initial horizontal position, and a process spacing between the susceptor and the heating device, and during any of the processes of steps S1, S11, S12 and S13, it is determined whether a vertical distance of a side surface of the susceptor relative to the initial horizontal position exceeds a preset distance threshold value, and / or whether a minimum value of the process spacing is lower than a minimum process spacing, and if so, the target lifting mechanism is controlled to stop running.

[0038] Further, the preset distance threshold value is not more than 0.5 mm.

[0039] Further, the minimum process spacing is not less than 4 mm.

[0040] Further, the temperature control method further comprises obtaining a second calibration relationship, the second calibration relationship being a corresponding relationship between an axial run-out difference threshold value and an upper limit of a running speed of the lifting mechanism at different rotation speeds of the susceptor lower than the first rotation speed threshold value, the axial run-out difference threshold value being a maximum axial run-out value of the susceptor allowed by the epitaxial process flow at different rotation speeds, and the first rotation speed threshold value being not more than 400 rpm.

[0041] In step S1, the rotating device is controlled to drive the susceptor to rotate at a rotation speed lower than the first rotation speed threshold value.

[0042] Step S13 further comprises obtaining a current rotation speed of the susceptor and obtaining the upper limit of the running speed of the target lifting mechanism in the second calibration relationship according to the current rotation speed of the susceptor.

[0043] Further, the method of the present application further comprises obtaining an axial run-out difference threshold value and a radial run-out difference threshold value, and in step S0, the step of obtaining the second calibration relationship is performed at room temperature, comprising:

[0044] P01: control the chamber to maintain a process pressure required by the epitaxial growth process;

[0045] P02: control the rotating device to drive the susceptor to rotate at a fixed rotation speed, control each lifting mechanism to synchronously ascend or descend at different motion speeds in sequence, and monitor axial run-out difference and radial run-out difference of the susceptor at each running speed by optical distance measurement method;

[0046] P03: select a running speed corresponding to a run-out difference reaching or closest to a minimum value of the axial run-out difference threshold value and the radial run-out difference threshold value as an upper limit of the corresponding running speed at the fixed rotation speed;

[0047] P04: control the rotating device to drive the susceptor to rotate at a speed increased to another fixed rotation speed;

[0048] Steps P02 to P04 are repeatedly performed.

[0049] The second aspect of the present application provides a semiconductor manufacturing equipment, comprising:

[0050] a chamber, a susceptor arranged in the chamber, and a heating device arranged between the susceptor and a chamber bottom plate of the chamber;

[0051] a rotating device penetrating the chamber and connected to the susceptor;

[0052] a lifting bottom plate arranged below the chamber and surrounding the rotating device;

[0053] a plurality of lifting mechanisms arranged on the lifting bottom plate, arranged circumferentially around the chamber and connected to the chamber bottom plate, so as to drive the susceptor to perform lifting movement through the rotating device, and a projection mark of a connection position between each lifting mechanism and the chamber bottom plate is directed to a plane of a bearing top surface of the susceptor;

[0054] an optical temperature measuring device arranged above the chamber and used for measuring a current surface temperature of each substrate;

[0055] a master control device pre-stored with a first calibration relationship and in communication connection with the rotating device, the optical temperature measuring device, the heating device and each lifting mechanism, the first calibration relationship being a corresponding relationship between a calibration temperature difference of the susceptor and a distance change amount between the heating device and the susceptor at different set temperatures.

[0056] By adopting the above technical solution, the semiconductor manufacturing equipment and the temperature control method have the following beneficial effects:

[0057] In the process of performing semiconductor processes, the target substrate with temperature anomaly is positioned based on the real-time surface temperature of each substrate, the target lifting mechanism that needs to be controlled is determined according to the distance between the target substrate and each lifting mechanism, the target displacement deviation of the target lifting mechanism is obtained according to the first calibration relationship, and the target lifting mechanism is dynamically adjusted to the desired position by controlling the target lifting mechanism according to the target displacement deviation without interrupting the process, so as to realize real-time correction of the distance between the susceptor and the heating device, improve the surface temperature field uniformity of the substrate, and not interfere with the normal process. BRIEF DESCRIPTION OF DRAWINGS

[0058] Figure 1 FIG. 1 is a structural schematic diagram of the semiconductor manufacturing equipment of the present application;

[0059] Figure 2 Flow chart for performing temperature control in step S11 of the present application;

[0060] Figure 3 Schematic diagram of the measuring track of each optical probe in the present application;

[0061] Figure 4 Flow chart for acquiring the first calibration relation in step S0 of the present application;

[0062] Figure 5 Principle diagram for positioning the measuring point in the present application;

[0063] Figure 6 Principle diagram for acquiring the target substrate in the present application;

[0064] Figure 7A Principle diagram for determining the target lifting mechanism in one embodiment of the present application;

[0065] Figure 7B Principle diagram for determining the target lifting mechanism in another embodiment of the present application;

[0066] Figure 7C Principle diagram for determining the target lifting mechanism in yet another embodiment of the present application;

[0067] Figure 8 Flow chart for acquiring the second calibration relation in step S0 of the present application. DETAILED DESCRIPTION

[0068] The present application is described in detail below with specific reference to particular embodiments. Those skilled in the art will easily understand other advantages and effects of the present application from the content disclosed in the specification. The present application can also be implemented or applied in other different embodiments, and the details in the specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present application.

[0069] It should be noted that the diagrams provided in the present embodiment only schematically illustrate the basic concept of the present application, and although the diagrams only show the components related to the present application, they are not drawn according to the number, shape and size of the components in actual implementation. The shape, number, positional relationship and proportion of the components in actual implementation can be changed at will under the premise of realizing the technical solution of the present application, and the component layout form can also be more complex.

[0070] As mentioned above, even if the non-uniformity of the substrate temperature is monitored during the process, real-time intervention and adjustment cannot be made under the premise of not stopping the machine.

[0071] Therefore, the present application provides a semiconductor manufacturing equipment and a temperature control method, which can adjust the uniformity of the surface temperature field of the substrate in real time without stopping the equipment, thereby improving the yield of epitaxial growth and not interfering with the normal process.

[0072] The semiconductor manufacturing equipment provided by the present application can be a chemical vapor deposition (CVD) equipment, further can be a plasma-enhanced chemical vapor deposition (PECVD) equipment, a metal-organic chemical vapor deposition (MOCVD) equipment, etc. The semiconductor manufacturing equipment provided by the embodiments of the present application implements an epitaxial growth process. It should be understood that the equipment is only exemplary.

[0073] As shown in Figure 1 The semiconductor manufacturing equipment provided by the present application comprises a chamber 1, a susceptor 2 and a heating device 7 arranged in the chamber 1, a rotating device 3 penetrating the bottom of the chamber 1 and rotatingly connecting the susceptor 2, a lifting base plate 4 arranged outside the chamber 1 and surrounding the rotating device 3, and a plurality of lifting mechanisms 5 arranged on the lifting base plate 4 and connecting a chamber bottom plate 12 of the chamber 1. The loading top surface of the susceptor 2 is provided with a plurality of grooves 20 distributed in the circumferential direction and used for accommodating and limiting the substrates, respectively. The projection of the connection between the lifting mechanism 5 and the chamber bottom plate 12 of the chamber 1 towards the plane of the loading top surface of the susceptor 2 is a projection mark. The heating device 7 is arranged between the susceptor 2 and the chamber bottom plate 12.

[0074] The temperature control method provided by the present application comprises:

[0075] S0: obtaining a first calibration relationship, which is a corresponding relationship between a calibration temperature difference of the susceptor and a variation amount of the distance between the heating device and the susceptor at different set temperatures;

[0076] S1: placing each substrate in the corresponding groove, controlling the semiconductor manufacturing equipment to execute an epitaxial process flow at a target set temperature and a set pressure, and controlling the rotating device to drive the susceptor to rotate in the epitaxial process flow;

[0077] In the process of executing the epitaxial process flow in step S1, the temperature control method further comprises synchronously executing Figure 2 the temperature control steps shown in

[0078] S11: obtaining the current surface temperature of each substrate, obtaining the current temperature difference of each substrate according to the current surface temperature of each substrate and the target set temperature, determining the target substrate with temperature abnormality, the target variation amount of the distance corresponding to the target substrate and the predetermined adjustment direction according to the current temperature difference of each substrate and the first calibration relationship;

[0079] S12: Determine the target lifting mechanism that needs to be lifted and lowered based on the number and position of the target substrate and its distance from each projection mark;

[0080] S13: Controls the target lifting mechanism to change the target spacing by moving in the predetermined adjustment direction or the opposite direction.

[0081] The technical solution of this application will be described in detail below through specific embodiments.

[0082] Example 1

[0083] This embodiment provides a semiconductor manufacturing apparatus for performing epitaxial growth processes on a substrate. For example... Figure 1 The semiconductor manufacturing equipment shown (taking an MOCVD equipment as an example) includes a chamber 1 with a base 2 and a heating device 7 inside, an upper cover 13 located above the chamber 1 and having a gas injection device, a rotating device 3 with a dynamic seal passing through the bottom of the chamber 1 and rotatably connected to the base 2, a lifting base plate 4 located outside the chamber 1 and surrounding the rotating device 3, several lifting mechanisms 5 located on the lifting base plate 4 and connected to the chamber base plate 12 of the chamber 1, and an optical temperature measuring device 6 located above the upper cover 13; it also includes a main control device (not shown) that is communicatively connected to the rotating device 3, the optical temperature measuring device 6 and each lifting mechanism 5.

[0084] In some embodiments, the substrate is a wafer.

[0085] In some embodiments, the number of lifting mechanisms 5 is at least 3.

[0086] In some embodiments, each lifting mechanism 5 is evenly arranged along the same circumference on the chamber floor 12 to ensure the smooth lifting and lowering operation of the rotating device 3.

[0087] The base 2 is preferably disc-shaped, with its top surface facing the top of the chamber 1. The top surface is provided with a plurality of grooves 20 evenly distributed along the circumference. Each groove 20 is used to support a substrate and to accommodate and limit it, so that the substrate can rotate with the base 2.

[0088] In some embodiments, the base 2 is preferably made of graphite and has a disc-shaped structure. In some embodiments, the surface of the graphite base 2 is covered with a silicon carbide layer.

[0089] During epitaxial growth, the rotating device 3 is controlled to rotate the base 2 that carries the substrate to be coated, thereby improving the uniformity of film formation. For example... Figure 1As shown, the base 2 is supported in the chamber 1 by a base support device 9, and the rotary device 3 is connected to the base support device 9 after penetrating the chamber bottom plate 12. The rotary device 3 is used to drive the rotation of the base 2, so that the substrate on the base 2 rotates with the base 2. The specific implementation is a conventional technical means in the art, which will not be described here.

[0090] In some embodiments, the base support device 9 is arranged at the middle of the bottom surface of the base 2, extends towards the rotary device 3 and is connected thereto, so as to drive the rotation of the base 2 in a central manner. The specific implementation is a conventional technical means in the art.

[0091] The lifting mechanism 5 is used to control the lifting or lowering of the base. The lifting mechanism 5 is arranged outside the chamber 1 and is fixedly connected to the rotary device 3. Specifically, the lifting mechanism 5 surrounds the rotary device 3. One end of the lifting mechanism 5 is fixed on the chamber bottom plate 12 and extends towards the lifting bottom plate 4 and is fixedly arranged on the lifting bottom plate 4. Since the rotary device 3 is arranged in the chamber 1 in a dynamic sealing manner, the lifting movement of the lifting bottom plate 4 can also synchronously drive the synchronous movement of the rotary device 3, thereby driving the lifting of the base 2.

[0092] In some embodiments, referring to Figure 1 , the lifting mechanism 5 includes a lead screw 51 and a driving mechanism 52. The driving mechanism 52 is arranged on the lead screw 51, the lead screw 51 is fixedly arranged on the lifting bottom plate 4, extends towards the chamber bottom plate 12 and is fixedly arranged on the chamber bottom plate 12. In some specific embodiments, the top end of the lead screw 51 is fixed to the chamber bottom plate 12 through a fixing seat (the fixing seat allows the lead screw to rotate, but restricts the axial movement thereof), the lead screw 51 is fixed to the lifting bottom plate 4 through a nut and a flange or a connecting block, and the bottom end of the lead screw 51 is connected to the driving mechanism 52 (such as a servo motor or a stepping motor) through a shaft coupling. When the driving mechanism 52 is started, the lead screw 51 is driven to rotate, the nut of the lead screw 51 is driven to move linearly along the lead screw 51 because it cannot rotate, and the lifting bottom plate 4 is lifted to move towards or away from the chamber bottom plate 12, thereby driving the rotary device 3 to synchronously move towards or away from the upper cover 13, so as to drive the base 2 to lift or lower through the rotary device 3. The specific adaptation of the fixing seat on the chamber bottom plate and the lead screw, and the specific adaptation of the lead screw, the nut and the flange or the connecting block are conventional technical means in the art, which will not be described here.

[0093] In some embodiments, the lead screw 51 extends axially along the chamber 1, and the load-carrying top surface of the base 2 and the chamber bottom plate 12 are both perpendicular to the axial direction of the chamber 1.

[0094] In Figure 1In the shown example, three lifting mechanisms 5 are provided on the lifting base 4, each of which is driven by a separate driving mechanism 52, but it should be understood that the present embodiment is not limited thereto. Each of the lifting mechanisms 5 can also be driven independently by the same driving mechanism 52.

[0095] As in the background art, the distance between the susceptor 2 and the heating device 7 has a significant influence on the uniformity of the temperature field on the surface of each wafer.

[0096] In particular for epitaxial growth processes, it is well known in the art that epitaxial growth requires a high precision in the control of the temperature of the wafer. For example, in the case of growing a GaN layer on a silicon substrate using a MOCVD device to produce a Light Emitting Diode (LED), a deviation of 1 °C in the control of the temperature of the wafer will cause a deviation of more than 1 nm in the central wavelength of the LED from the central wavelength that is intended to be achieved by the process design, which can cause a fundamental change in the light emission performance of the LED, for example, a blue LED that is intended to be produced cannot be produced.

[0097] In order to achieve a precise control of the temperature of the wafer, a heating device is provided below the susceptor to heat the susceptor, which transmits heat to the wafer to achieve temperature control. There is a certain distance between the heating device and the susceptor to avoid interference with the movement of the susceptor (e.g. lifting or rotation). According to the requirements of the process on the temperature and the precision control, a precise control of the temperature of the wafer is achieved by reasonably designing the distance between the heating device and the susceptor, the heating power, in combination with the size characteristics of the susceptor and related theories such as heat conduction, so as to be conducive to the uniformity of the temperature field near the top surface of the susceptor.

[0098] In addition, the interaction between the gas flow field formed by the process gas provided by the gas injection device above the top surface of the susceptor and the temperature field near the top surface of the susceptor is complementary. In the process of installing the susceptor, in order to facilitate process adjustment and smooth rotation, the distance between the heating device 7 and the susceptor 2 is designed under the premise that the susceptor has good levelness. However, for epitaxial growth processes with very strict requirements on temperature control precision, for example, indium phosphide (InP) based devices, which are extremely sensitive to temperature, the control precision is usually required to be within ±0.5 °C, otherwise the quantum well thickness and composition are easily not up to the requirements and the light emission wavelength cannot be accurately locked. Even if the distance between the heating device 7 and the susceptor 2 is reasonably adjusted, due to the influence of the gas flow field above the top surface of the susceptor 2, the complexity of the environment in the chamber, and the inevitable jumping of the rotation of the susceptor 2, the temperature of the wafer carried by each groove cannot be completely consistent, which affects the quality control of each film forming wafer in the same batch and easily causes yield loss.

[0099] In the prior art, even if the significant non-uniformity of the surface temperature of each substrate is obtained in real time during the process by the optical temperature measurement method, the real-time adjustment method is limited. For the case where the surface temperature of each substrate is low or high, the problem can be alleviated by adjusting the heating power. However, for the case where only part of the substrate temperature is high or low, or some are high and some are low, the effect of adjusting the heating power is very limited. Because even if the temperature abnormal substrate problem is solved, other normal temperature substrates will also appear abnormal.

[0100] Therefore, the present application relies on the optical temperature measurement device 6 to obtain the surface temperature of the substrate or the susceptor, uses the temperature change of each substrate to determine the target substrate with temperature abnormality, and adjusts the corresponding target lifting mechanism, so that the temperature abnormal substrate can be corrected while reducing or even avoiding the influence on other normal temperature substrates.

[0101] The optical temperature measurement device 6 of the embodiment includes at least one optical probe 61 arranged above the chamber, and a signal processing unit 62 connected with the optical probe through an optical fiber. The optical probe 61 collects the thermal radiation signal of the substrate or the susceptor 2 through the optical window of the upper cover 13 or the spray hole of the gas injection device. The signal processing unit 62 is used to convert the collected signal of the corresponding optical probe into the corresponding temperature value. The specific implementation is a conventional technical means in the art, which is not described here.

[0102] In some embodiments, the signal processing unit 62 is a photodetector.

[0103] In some embodiments, when there are multiple optical probes 61, the distances from different optical probes 61 to the central axis of the susceptor 2 are different, and preferably distributed along the radial direction of the susceptor 2, so that as shown in Figure 3 , the measurement trajectories of different optical probes 61 have different radii when the susceptor 2 rotates, but the measurement trajectories of all optical probes 61 pass through the grooves 20 (i.e. pass through the substrates), so as to realize real-time collection of the substrate temperature.

[0104] In some embodiments, as shown in Figure 3 , the measurement trajectory of each optical probe 61 does not exceed the inner scanning boundary L1 and the outer scanning boundary L2. The inner scanning boundary L1 is a circular boundary with the central axis of the susceptor 2 as the center and tangent to each groove 20, and the outer scanning boundary L2 is a circular boundary with the central axis of the susceptor 2 as the center and tangent to each groove 20.

[0105] In the example shown in Figure 1 , the heating device 7 of the embodiment is supported by a heating support device 71 supporting the heating device 7. The heating support device 71 is arranged in the rotating device 3 through the chamber bottom plate 12, but does not rotate with the rotating device 3. The specific implementation is a conventional technical means in the art.

[0106] In some embodiments, the rotating device 3 is arranged in a central driving manner on the base 2, and the heating device 7 is supported by a heating support device 71 and arranged around the support device below the base 2, and the bottom of the heating support device is arranged on the inner bottom surface of the cavity. The specific implementation is a conventional technical means in the art.

[0107] In the embodiment, an elastic sealing member 8 is further arranged between the cavity bottom plate 12 and the lifting bottom plate 4, and the elastic sealing member 8 forms a sealed space with the cavity bottom plate 12 and the lifting bottom plate 4, thereby realizing the sealing of the cavity 1. Specifically, the two ends of the elastic sealing member 8 are respectively arranged on the cavity bottom plate 12 and the lifting bottom plate 4 in a sealing manner around the rotating device 3. The elastic sealing member 8 is hollow inside to allow the rotating device 3 to penetrate through.

[0108] In some embodiments, the elastic sealing member 8 is a bellows.

[0109] In the embodiment, the lifting control, the rotation control and the temperature control of the base 2 are all controlled by the main control device.

[0110] In some embodiments, the main control device pre-stores the first calibration relationship.

[0111] In some embodiments, the main control device pre-stores the first calibration relationship and the second calibration relationship.

[0112] Specifically, the first calibration relationship is a corresponding relationship between a calibrated temperature difference of the base 2 and a change amount of the distance between the heating device 7 and the base 2 at different set temperatures.

[0113] Specifically, the second calibration relationship is a corresponding relationship between an axial run-out difference threshold value and an upper limit of the running rate of the lifting mechanism at different rotation speeds of the base below a first rotation speed threshold value, the axial run-out difference threshold value is a maximum axial run-out value of the base allowed by the epitaxial process at different rotation speeds, and the first rotation speed threshold value is not more than 400 rpm.

[0114] In some embodiments, the main control device further monitors and controls the process of epitaxial growth.

[0115] After the substrate is placed on the base 2, the main control device controls the semiconductor manufacturing equipment to perform epitaxial growth on the substrate. During the epitaxial growth process, the rotating device 3 drives the base 2 to rotate, and at the same time performs the following steps: obtain the current surface temperature of each substrate, and obtain the current temperature difference of each substrate based on the current surface temperature of each substrate and the target set temperature; determine the target substrate with abnormal temperature, its corresponding target spacing change, and the predetermined adjustment direction based on the current temperature difference and the first calibration relationship; determine the target lifting mechanism that needs to be lifted and lowered based on the number of target substrates, their positions, and their distance from each projection mark; and control the target lifting mechanism to move along the predetermined adjustment direction or the opposite direction of the predetermined adjustment direction to determine the target spacing change.

[0116] Example 2

[0117] This embodiment provides specific implementation steps for obtaining the aforementioned first calibration relationship. As mentioned earlier, the first calibration relationship is the correspondence between the calibration temperature difference of the base 2 and the change in the distance between the heating device 7 and the base 2 under different set temperatures.

[0118] It should be understood that when calibrating the first calibration relationship, the working distance is used as the reference benchmark for the change in distance between the base 2 and the heating device 7. The process distance refers to the distance between the base 2 and the heating device 7 during process execution.

[0119] To facilitate understanding of the working spacing, the control process of the epitaxial growth process is first introduced. The main control device has pre-stored process program information, which includes steps for performing pre-transfer preparation, removing the substrate to be coated, transferring the substrate to be coated to the base 2, performing pre-epitaxy growth preparation, and performing the epitaxial growth process. Specifically, during the epitaxial growth process, the base 2 and the heating device 7 should be separated by the process spacing. After one round of epitaxial growth, the main control device controls the gas injection device to provide chemically inert purging gas into the chamber 1, controls the rotating device 3 to stop rotating so that the base 2 is stationary, and controls the heating device 7 to stop working to cool down to the transfer temperature. After the pressure inside and outside the chamber 1 is equal, the transfer port of the chamber 1 is opened, the base 2 is raised to the transfer position opposite to the transfer port, the substrate to be coated is transferred out of the base 2, the substrate to be coated is transferred from the transfer port to the base 2, and then the base 2 is lowered to the process position. After the main control device controls the wafer transfer port to the closed state, it controls the gas injection device and the exhaust device to make the pressure in the chamber 1 reach the process pressure. After controlling the heating device 7 to meet the process temperature requirements, it drives the base 2 to rotate. Then, it controls the gas injection device to provide process gas for epitaxial growth into the chamber 1 to carry out the epitaxial growth process.

[0120] like Figure 4 As shown, the steps for obtaining the first calibration relationship in this embodiment specifically include:

[0121] S01: controlling the heating device 7 to heat the susceptor 2 at a heating power corresponding to a set temperature until the susceptor 2 reaches a temperature steady state, and obtaining an initial steady state temperature of the susceptor 2;

[0122] S02: maintaining the heating power of the heating device 7 unchanged, and controlling each lifting mechanism 5 to synchronously rise or fall by a certain distance;

[0123] S03: obtaining a current steady state temperature of the susceptor 2, and obtaining a calibration temperature difference according to the current steady state temperature and the initial steady state temperature of the susceptor 2, obtaining a displacement change amount of each lifting mechanism 5, and obtaining a spacing change amount according to the displacement change amount of each lifting mechanism 5 and the process spacing;

[0124] S04: controlling each lifting mechanism 5 to continue to synchronously rise or fall by a certain distance;

[0125] The steps S03 to S04 are repeatedly executed until the susceptor 2 is controlled to rise or fall to a corresponding position threshold, so as to obtain a corresponding relationship between the calibration temperature difference (ΔT1, ΔT1,…, ΔTm) and the spacing change amount (Δh1, Δh1,…, Δhm) of the susceptor at the set temperature.

[0126] It should be understood that the set temperature in the calibration process should be consistent with the set temperature in the process. In some embodiments, it is preferred to control the susceptor 2 to rise for calibration, so as to avoid the situation that the susceptor 2 is continuously lowered and is likely to interfere with the movement of the heating device 7.

[0127] In some embodiments, for an epitaxial growth process with very high temperature control accuracy, in order to ensure the effectiveness and rapid controllability of heat transfer from the heating device 7 to the susceptor 2, the spacing between the heating device 7 and the susceptor 2 is generally 4-6 mm. In this case, in order to avoid the calibration of the susceptor 2 being limited by the spacing between the susceptor 2 and the heating device 7 and being unable to obtain complete data, the calibration of the susceptor 2 being controlled to fall can be performed after the susceptor 2 is first raised to an upper limit position.

[0128] In some embodiments, in the step of obtaining the first calibration relationship, the spacing between the susceptor 2 and the heating device 7 is controlled to be not less than a minimum process spacing, so as to avoid the movement interference between the susceptor 2 and the heating device 7, thereby protecting the safety of the two. Wherein, the process spacing is greater than the minimum process spacing.

[0129] Embodiment 3

[0130] This embodiment provides that the following temperature control steps are synchronously performed during the epitaxial process in step S1:

[0131] S11: obtaining a current surface temperature of each substrate, and obtaining a current temperature difference of each substrate according to the current surface temperature of each substrate and a target set temperature, and determining a target substrate with temperature abnormality, a target interval change amount corresponding to the target substrate and a predetermined adjustment direction according to the current temperature difference and a first calibration relationship;

[0132] S12: determining a target lifting mechanism that needs to be controlled in lifting according to the number, position and distance of each projection mark of the target substrate;

[0133] S13: controlling the target lifting mechanism to run the target interval change amount in the predetermined adjustment direction or the opposite direction of the predetermined adjustment direction.

[0134] The embodiment solves the problem of partial high / low of the substrates by real-time temperature compensation of local micro-lifting of the susceptor in the process, improves the consistency of the thickness, composition and light-emitting wavelength of the epitaxial layer, and improves the batch yield without stopping and breaking the vacuum.

[0135] Specifically, the step S11 of obtaining the current surface temperature of each substrate includes: calculating an average temperature value of the corresponding substrate region measured by the optical temperature measuring device, and taking the average temperature value as the current surface temperature of the corresponding substrate.

[0136] The susceptor carries a plurality of substrates, and the substrates are arranged in a circumferential direction of the susceptor. Figure 3 In the example shown, there are 12 substrates uniformly distributed in the circumferential direction. In order to accurately identify the current measurement position of the optical probe, the embodiment is provided with an angle origin mark 10 on the susceptor or the rotating device, which marks the beginning of each scanning period, i.e., the angle origin. The measurement position of the optical probe can be defined according to the included angle between the line connecting the measurement point on the measurement track and the center of the susceptor and the line connecting the angle origin mark 10 and the center of the susceptor (see the included angle formed by the two green lines in Figure 5 ).

[0137] In some embodiments, the angle origin mark 10 can be a notch, a protrusion or any other form, and the embodiment does not make any specific limitation thereto.

[0138] The optical probe 61 will continuously scan the surface of the substrate during the rotation of the susceptor, forming a scanning track as shown in Figure 5The scanning trajectory is shown, and a series of temperature data points are acquired. Each temperature data point is timestamped and includes the current angular position of the base. Since the circumferential position of each substrate on the base is pre-set and known, the main control device can map the scanned temperature data points onto the corresponding substrate after establishing an absolute angular coordinate system through the angular origin mark. For example, if the center of one substrate is known to be located at 30 degrees from the angular origin mark (i.e., the angle between the line connecting the center of the substrate and the base origin and the angular origin mark and the base center is 30 degrees), then all temperature data collected within the range of 30 degrees ± Δθ can be attributed to the substrate region of that substrate, where Δθ is a preset offset angle threshold.

[0139] In other embodiments, it is not necessary to create an angle origin mark on the base. The drive motor of the rotating device (such as a servo motor) is typically equipped with an encoder that generates a Z-phase pulse signal (or Home signal) to indicate the absolute position of the motor rotor, thereby locating the measurement position of the optical probe. The specific implementation method is conventional in the art.

[0140] In step S11, the target substrate with temperature anomalies, the corresponding change in target spacing, and the predetermined adjustment direction are determined based on the current temperature differences and the first calibration relationship, including:

[0141] First, determine whether the current temperature difference of each substrate is within the preset temperature difference range. If not, the substrate with the current temperature difference exceeding the preset temperature difference range is taken as the target substrate with temperature abnormality so that targeted correction can be carried out in the future.

[0142] like Figure 6 As shown, each black dot represents a substrate, "Test" represents the target set temperature, and the preset temperature difference range includes the range between the upper and lower limits of error. Figure 6 Two substrates have current temperature differences exceeding the preset temperature difference range, therefore there are two target substrates, with the substrate highlighted in red having a larger absolute value of current temperature difference.

[0143] In some embodiments, the upper limit error and the lower limit error are no more than 0.5 degrees Celsius.

[0144] Then, the target spacing change corresponding to the target substrate is determined based on the current temperature difference of the target substrate and the first calibration relationship. Specifically, this includes matching the current temperature difference of the target substrate with the calibration temperature difference of the base in the first calibration relationship, and using the spacing change corresponding to the matched calibration temperature difference as the target spacing change corresponding to the target substrate.

[0145] Finally, determine the sign of the temperature difference between the current surface temperature of the target substrate and the target set temperature. If the temperature difference is positive, it indicates that the temperature of the target substrate is too high, and the predetermined adjustment direction is to move away from the area where the heating device is located. If the temperature difference is negative, it indicates that the temperature of the target substrate is too low, and the predetermined adjustment direction is to move closer to the area where the heating device is located.

[0146] In this embodiment, as Figure 7A As shown, the number of lifting mechanisms is at least 3, ensuring that the base can rotate smoothly even when in a controllable tilt state, avoiding resonance between the flying plates and the machinery, and providing a mechanical basis for real-time fine-tuning. An example of 12 base plates is shown, labeled A to L.

[0147] The orthographic projection of the connection between the lifting mechanism 5 and the chamber floor 12 of the chamber 1 toward the bearing top surface of the base 2 is marked by projection marks (denoted as 5A, 5B, and 5C respectively). Each projection mark is evenly distributed along the same circumference on the bearing top surface plane. There is at least one lifting mechanism in each of the two halves of the bearing top surface plane.

[0148] In some embodiments, in step S11, the number of target substrates is 1, and in step S12, the lifting mechanism corresponding to the projection mark closest to the target substrate is obtained as the target lifting mechanism.

[0149] by Figure 7A For example, assuming substrate A is the target substrate and its closest projection mark 5A is the lifting mechanism corresponding to projection mark 5A, then the lifting mechanism is determined to be the target lifting mechanism. That is, when only one substrate has an abnormal temperature, the nearest lifting mechanism is directly selected for single-point compensation. The algorithm is simple, has the fastest response, and avoids excessive linkage that could cause temperature drift in other substrates.

[0150] In some embodiments, in step S12, if the number of projection marks closest to the target substrate is at least two, then at least one lifting mechanism corresponding to the closest projection mark is selected as the target lifting mechanism. For example, a predetermined priority algorithm can be used to select one or both.

[0151] In some embodiments, the number of target substrates is at least 2, and the absolute values ​​of the current temperature difference of at least two target substrates are different. The target substrate with the largest absolute value of temperature difference is selected as the priority target substrate. In step S12, the lifting mechanism corresponding to the projection mark closest to the priority target substrate is selected as the target lifting mechanism. In step S13, the target lifting mechanism is controlled to run along a predetermined adjustment direction.

[0152] like Figure 6As shown, the substrate with the largest absolute error value is identified by the red box, and this substrate is determined as the priority target substrate. The lifting mechanism corresponding to the projection mark closest to this substrate is then used as the target lifting mechanism.

[0153] That is, in scenarios where multiple substrates are abnormal and the absolute values ​​of temperature differences are inconsistent, the substrate with the largest temperature difference is compensated first, so that the system can correct the most abnormal substrate with the fewest number of actions and the fastest speed, thus shortening the closed-loop convergence time.

[0154] In some embodiments, the number of priority target substrates is at least 2, and the absolute value of their current temperature difference is the same. In step S12, the lifting mechanism corresponding to the projection mark with the smallest distance between each priority target substrate is selected as the target lifting mechanism. In step S13, the target lifting mechanism is controlled to run along a predetermined adjustment direction.

[0155] by Figure 7B For example, substrates A and C are both priority target substrates, and the absolute value of their current temperature difference is the same. The projection mark closest to substrate A is projection mark 5A, and the projection mark closest to substrate C is projection mark 5B. The distance between substrate A and projection mark 5A is less than the distance between substrate C and projection mark 5B. Therefore, for substrates A and C, substrate A is adjusted with more priority. Thus, the lifting mechanism corresponding to projection mark 5A, which is closest to substrate A, is selected as the target lifting mechanism to avoid mechanical lag and over-adjustment caused by choosing the farthest one, and to maintain adjustment accuracy.

[0156] In some embodiments, the number of target substrates is at least 2 and their current temperature difference is the same. In step S12, after determining that the distance between each target substrate and the corresponding closest projection mark is consistent, the closest projection mark corresponding to each target substrate is obtained, and the lifting mechanism corresponding to each obtained projection mark is used as the target lifting mechanism. In step S13, the target lifting mechanism is controlled to run along the predetermined adjustment direction.

[0157] In some embodiments, the number of target substrates is at least 2 and their current temperature difference is the same. In step S12, it is determined that the distance between each target substrate and the corresponding closest projection mark is consistent and they are located in the same half of the plane where the top surface is located. Then, the lifting mechanism corresponding to at least one projection mark in the other half of the plane where the top surface is located is used as the target lifting mechanism. In step S13, the target lifting mechanism is controlled to run in the opposite direction of the predetermined adjustment direction.

[0158] Therefore, by utilizing the symmetrical half-zone reverse compensation strategy, the temperature deviation of the symmetrical area can be balanced by a remote lifting mechanism without adding hardware.

[0159] In some embodiments, each target substrate is located in a same sector, the sector has a center of a circle with a center of a top surface of the carrier as the center of the circle, and a radius of the circle is tangent to each of the two target substrates, the other half of the plane where the top surface of the carrier is located comprises a symmetric sector which is axially symmetric to the sector, and in step S12:

[0160] When there is at least one projection mark in the symmetric sector, the lifting mechanism corresponding to the at least one projection mark in the symmetric sector is taken as the target lifting mechanism.

[0161] For example, the substrate B and the substrate C are located in the same sector, the symmetric sector of the sector has a projection mark 5C, and the lifting mechanism corresponding to the at least one projection mark 5C in the symmetric sector is taken as the target lifting mechanism, so that the temperature correction of the two substrates can be realized by adjusting one lifting mechanism through reverse compensation. Figure 7C

[0162] When there is no projection mark in the symmetric sector, the lifting mechanism closest to the at least one projection mark in the symmetric sector is taken as the target lifting mechanism.

[0163] In some embodiments, the central angle of the sector is not more than 60 degrees.

[0164] Before the epitaxial process flow of step S1 is performed, the susceptor has an initial horizontal position, and a process distance between the susceptor and the heating device, in any of the processes of steps S1, S11, S12 and S13, it is determined whether the vertical distance of one side surface of the susceptor relative to the initial horizontal position exceeds a preset distance threshold value, and / or whether the minimum value of the process distance is lower than a minimum process distance, if so, the target lifting mechanism is controlled to stop running.

[0165] Therefore, through the minimum distance limitation, it is ensured that there is no mechanical interference during real-time fine adjustment, the service life of the heating device and the susceptor is prolonged, and the maintenance downtime is reduced.

[0166] In some embodiments, the preset distance threshold value is not more than 0.5 millimeter.

[0167] In some embodiments, the minimum process distance is not less than 4 millimeters.

[0168] Embodiment 4

[0169] The embodiment provides a temperature control method, which is different from the embodiment 3 in that it further comprises obtaining a second calibration relationship, the second calibration relationship is a corresponding relationship between an axial runout difference threshold value and an upper limit of a running rate of the lifting mechanism at different rotation speeds of the susceptor below a first rotation speed threshold value, the axial runout difference threshold value is a maximum axial runout value of the susceptor allowed by the epitaxial process flow at different rotation speeds, and the first rotation speed threshold value is not more than 400 rpm.

[0170] ​In step S1, the rotating device drives the susceptor to rotate at a speed lower than a first rotation speed threshold value;

[0171] In step S13, the current rotation speed of the susceptor is obtained, and a corresponding upper limit of the operation speed of the lifting mechanism is obtained in the second calibration relationship according to the current rotation speed of the susceptor.

[0172] Since the provided second calibration relationship is a corresponding relationship between the axial jump difference threshold value and the upper limit of the operation speed of the lifting mechanism at different rotation speeds of the susceptor lower than the first rotation speed threshold value, the axial jump difference threshold value is the maximum axial jump value of the susceptor allowed by the epitaxial process at different rotation speeds. According to the current rotation speed of the susceptor, the corresponding upper limit of the operation speed of the lifting mechanism is obtained in the second calibration relationship, and the operation of the lifting mechanism required to be controlled is controlled at the upper limit of the operation speed, which can further ensure that the fine adjustment of the lifting mechanism can be safely and quickly completed at high speed without interfering with the normal process, and the productivity and stability are considered.

[0173] In obtaining the second calibration relationship, the optical distance measuring method is used to test the jump difference of the susceptor jump. Since the optical distance measuring method has a non-negligible measurement error for distance measurement in a high-temperature chamber, the susceptor is driven to rotate at room temperature for calibration.

[0174] The second calibration relationship is obtained at room temperature, as shown in Figure 8 The specific steps are as follows:

[0175] P01: control the chamber 1 to maintain the process pressure required for epitaxial growth process;

[0176] P02: control the rotating device 3 to drive the susceptor 2 to rotate at a fixed rotation speed, control each lifting mechanism 5 to synchronously ascend or descend at different motion speeds in sequence, and use the optical distance measuring method to monitor the axial jump difference and the radial jump difference of the susceptor at each operation speed;

[0177] P03: select the operation speed corresponding to the jump difference reaching or closest to the minimum value of the axial jump difference threshold value and the radial jump difference threshold value as the corresponding upper limit of the operation speed at the fixed rotation speed;

[0178] P04: control the rotating device 3 to drive the susceptor 2 to rotate at another fixed rotation speed;

[0179] Repeat steps P02 to P04 until a preset stopping condition is reached, and obtain the second calibration relationship.

[0180] Since the rotation device drives the susceptor to rotate in the process, not only the gravity of the susceptor itself needs to be overcome, but also the influence of the pressure in the cavity on the rotation of the susceptor. Compared with the same lifting adjustment of the susceptor while rotating the susceptor under the process pressure, the susceptor jumping conditions are different. Therefore, in step P01, the control maintains the process pressure required for epitaxial growth in the chamber 1. The calibration of the second calibration relationship of P02 to P04 is carried out under this pressure atmosphere.

[0181] In step P02, specifically, the rotation device 3 drives the susceptor 2 to rotate at a fixed rotation speed, first controls each lifting mechanism 5 to rise to the first position (for example, 1 millimeter) at a speed of V1, and monitors the axial jump difference and the radial jump difference of the susceptor in this test process; then control each lifting mechanism 5 to rise to the second position (for example, 1 millimeter) again at a speed of V2 higher than V1, and monitor the axial jump difference and the radial jump difference of the susceptor in this process, repeat the above process, increase the speed each time. More specifically, since the axial jump difference threshold and the radial jump difference threshold are empirical values obtained according to the requirements of the epitaxial growth process, this step is tested until the monitored axial jump difference and the radial jump difference of the susceptor are higher than the corresponding axial jump difference threshold and the radial jump difference threshold.

[0182] After the step of calibrating the corresponding relationship between the running speed of different lifting mechanisms 5 and the jump difference at a fixed rotation speed, the control of the rotation device driving the susceptor to rotate is increased to another fixed rotation speed, and the above calibration process is repeated.

[0183] In some embodiments, after the step of calibrating the corresponding relationship between the running speed of different lifting mechanisms 5 and the jump difference at a fixed rotation speed (P02 and P03), the distance between each cavity is obtained by the distance measuring device, and it is judged that the range (i.e. the difference between the maximum and minimum values in the group of data) of the distance between each cavity does not exceed the predetermined range threshold, which proves that the levelness of the susceptor meets the requirements, and then the control of the rotation device driving the susceptor to rotate is increased to another fixed rotation speed (P04), so as to avoid the problem that the deviation of the levelness of the susceptor caused by the previous calibration process affects the accuracy of the subsequent calibration.

[0184] In some embodiments, after the steps (P02 and P03) of calibrating the relationship between the operating speed of the different lifting mechanisms 5 and the runout difference at a fixed rotating speed are completed, the control is performed to synchronize the operation of each lifting mechanism to the initial position of the base, and then the outer distance of each cavity is obtained and it is determined whether the range is not more than the preset range threshold, and then step P04 is performed. For the case where the initial distance between the base and the reference surface of the cavity is small, the position of the base lifting is not limited and cannot be debugged to complete the data (there may be no lifting space when the runout threshold is not exceeded).

[0185] In some embodiments, the base is preferably controlled to rise for calibration to avoid the situation that the base is continuously lowered and easily interferes with the movement of the heating device.

[0186] In some embodiments, for epitaxial growth processes with very high temperature control accuracy requirements, in order to ensure the effectiveness and rapid controllability of the heat transfer from the heating device to the base, the distance between the heating device and the base cannot be large, generally 4-6 mm. In this case, in order to avoid the calibration of the base lowering being limited by the distance between the base and the heating device and being unable to obtain complete data, the base can be first raised to the upper limit position and then the calibration of the base lowering is controlled.

[0187] In the above calibration process, in the case of the base 2 being empty, an optical distance measuring device is used to emit a distance measuring light beam to the rotating base 2, and distance measuring information in the test time is obtained, so as to calculate the runout difference of the base based on the distance measuring information. When the axial runout difference needs to be obtained, the distance measuring light beam is incident to the top surface of the base 2 along the upper side of the base 2; when the radial runout difference needs to be obtained, the distance measuring light beam is incident to the side wall of the base 2 along the radial direction of the base 2.

[0188] More specifically, the optical ranging device emits detection light vertically through the spray hole to the top surface of the base via the optical window on the gas injection device. The optical ranging device receives feedback light information, and the information of the detection light and the feedback light is converted into corresponding voltage signals. Through corresponding data processing, a voltage jump column chart with time variation can be obtained, and the height values of each base can be obtained. The specific data processing method and the implementation method of the optical ranging device are conventional technical means in the art. For example, the optical ranging device can use a laser range finder or a blue light range finder. According to the change of the height values of each base within the test time, the jump difference values (the absolute value of the difference between the test height value and the initial height value, the initial height value being the height value of the base measured at a base speed of 0) can be obtained. The average of each jump difference value is the jump difference value under the corresponding axial jump condition at the speed. Similarly, the optical ranging device emits detection light vertically to the side wall of the base via the optical window on the side wall of the chamber 1. According to the received feedback light information and the information of the emitted detection light, data processing can be performed to obtain the radial distance of the side wall of the base from the light outlet. According to the change of each radial distance within the test time, the jump difference value under the corresponding radial jump at the speed can be obtained. As shown in FIG. 8, with the increase of the speed, the jump difference value of the axial jump tends to decrease and the change trend tends to be stable; while the jump difference value of the radial jump tends to increase and the change trend tends to increase. At high speed, the radial jump is dominant (possibly due to high centrifugal force), while at low speed, the axial jump is dominant (possibly due to the high gravity of the base relative to the centrifugal force). Figure 3

[0189] ​It is well known to those skilled in the art that structural factors such as the degree of gear backlash of the speed reducer of the rotating machine, the stability of the connection between the support shaft and the bearing device, etc. make it impossible to avoid the radial runout and axial runout of the susceptor. For epitaxial growth processes, the rotation of the susceptor also has the effect of dragging the gas flow field to mix homogeneously, which is conducive to the film quality. The rotation, runout of the susceptor, combined with factors such as temperature and pressure, all play a role in the final film quality on the substrate. In the design of epitaxial growth processes, there are requirements for the radial runout threshold and the axial runout threshold. Generally, the relevant runout threshold requirements are proposed according to the specific epitaxial growth process and product performance requirements. For example, in the case of a silicon carbide homoepitaxial growth process on a 6-inch silicon carbide substrate, the product requires that the number of basal plane dislocations and stacking fault dislocations of the silicon carbide epitaxial layer be below 20. In the process design, the process speed is 900 rpm, the process pressure is 100 mbar, the process gas provided by the gas injection device is controlled to have a silane flow rate of 200 sccm~ 400 sccm, a propane flow rate of 70 sccm ~ 150 sccm, and a hydrogen chloride flow rate of 2000 sccm~5000 sccm. The control requirement for the axial runout is higher than that for the radial runout, the axial runout difference is controlled to be below 0.5 mm, and the radial runout difference is controlled to be below 0.8 mm. For the acquisition of the second calibration relationship corresponding to this epitaxial growth process, in step P02, under the condition that the susceptor rotates at 900 rpm and the pressure in the chamber 1 is 100 mbar, the lifting mechanisms are controlled to run upward at a rate of 0.1 mm / s for 1 mm. During this process, the axial runout and radial runout of the susceptor are obtained respectively, and the runout difference is compared with the process requirement control difference. If it is judged that the process requirement is not exceeded, the lifting mechanisms are controlled to run upward at a rate of 0.2 mm / s for 1 mm after confirming that the susceptor runs stably. During this process, the runout of the susceptor is continuously obtained and judged whether it meets the process requirement. This is repeated until the axial runout difference and the radial runout difference obtained by testing under the control of the lifting mechanisms at a rate of 0.4 mm / s approach the process requirement, and the axial runout difference and the radial runout difference obtained by testing under the control of the lifting mechanisms at a rate of 0.5 mm / s exceed the process requirement difference, i.e. 0.4 mm / s is used as the upper limit of the running rate of each lifting mechanism used for real-time leveling of the susceptor under the current rotation speed (900 rpm) of the susceptor.

[0190] In addition, in the process of monitoring the axial runout difference and the radial runout difference, if the monitored axial runout difference exceeds the corresponding runout difference threshold required by the process, while the radial runout difference has not yet exceeded the corresponding runout difference threshold required by the process, the corresponding lifting mechanism control rate at which the axial runout difference exceeds the limit required by the process is used as the test endpoint. Conversely, the same applies.

[0191] Furthermore, considering that the present application needs to level the susceptor in real time during the epitaxial growth process, i.e. when the susceptor is in a rotating state, the jumping of the susceptor in this case is obviously more significant than the jumping of the susceptor in a rotating state only. If the lifting speed of each lifting mechanism is not effectively controlled, the film forming quality will be affected due to the significant interference of the susceptor jumping with the process gas flow field. Based on the above reasons, in order to achieve the premise of controlling the rotation of the rotating device to drive the susceptor to rotate, and to control the movement of the lifting mechanism to realize the real-time leveling of the susceptor inside the chamber without interfering with the normal process, it is necessary to determine the corresponding relationship between the jumping threshold of the susceptor at different rotating speeds and the upper limit of the running speed of the lifting mechanism, and to rotate the appropriate upper limit of the running speed of the lifting mechanism.

[0192] However, the conventional technology in the art stops the rotation of the susceptor before controlling the lifting movement, which obviously affects the stability of the gas flow field above the top surface of the susceptor (a suitable rotating speed of the susceptor forms a drag mixing of the gas flow field above the top surface of the susceptor, which is beneficial to the uniformity of film forming). The reason for selecting the appropriate upper limit of the running speed is to balance the influence of the susceptor jumping and the lifting efficiency, to realize the rapid leveling of the susceptor without interrupting the normal process, and to minimize or even avoid the adverse effects of the leveling of the susceptor 2 on the semiconductor material layer being grown during the process.

[0193] Although the specific embodiments of the present application are described above, those skilled in the art should understand that this is only an example, and the protection scope of the present application is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present application, and such changes and modifications fall within the protection scope of the present application.

Claims

1. A temperature control method of a semiconductor manufacturing apparatus, characterized by, The semiconductor manufacturing equipment comprises a chamber, a susceptor with a plurality of grooves, a heating device arranged below the susceptor, a rotating device penetrating the chamber and connected to the susceptor, a lifting base arranged on the rotating device, a plurality of lifting mechanisms arranged on the lifting base and connected to the chamber bottom plate to drive the susceptor to lift, and the projection of the connection between the lifting mechanism and the chamber bottom plate to the plane of the bearing top surface of the susceptor is a projection mark; The temperature control method comprises: S0: obtaining a first calibration relationship between the temperature difference of the susceptor and the interval change amount between the heating device and the susceptor under different set temperatures; S1: placing each wafer in the corresponding groove, controlling the rotating device to drive the susceptor to rotate, and performing an epitaxial process; In the process of step S1 performing the epitaxial process, the following steps are further included: S11: obtaining and determining the current temperature difference of each wafer according to the current surface temperature and the target set temperature of each wafer, and determining the target wafer with temperature abnormality, the target interval change amount corresponding to the target wafer, and the predetermined adjustment direction according to the first calibration relationship and the current temperature difference; S12: determining the target lifting mechanism that needs to be controlled according to the number, position and distance of the target wafer from each projection mark; S13: controlling the target lifting mechanism to run the target interval change amount in the predetermined adjustment direction or the opposite direction of the predetermined adjustment direction.

2. The temperature control method of claim 1, wherein, The number of lifting mechanisms is at least 3, each projection mark is uniformly distributed along the same circumference on the plane of the bearing top surface, and at least one lifting mechanism exists in each half area of the plane of the bearing top surface.

3. The temperature control method of claim 1, wherein, In step S11, the number of target wafers is 1, and in step S12, the lifting mechanism corresponding to the projection mark closest to the target wafer is obtained as the target lifting mechanism.

4. The temperature control method of claim 3, wherein, In step S12, the number of projection marks closest to the target wafer is at least 2, and at least one of the lifting mechanisms corresponding to the closest projection marks is selected as the target lifting mechanism.

5. The temperature control method of claim 1, wherein In step S11, the number of target wafers is at least 2, and the absolute values of the current temperature differences of the at least two target wafers are different. The target wafer with the largest absolute value of temperature difference is selected as the priority target wafer, and in step S12, the lifting mechanism corresponding to the projection mark closest to the priority target wafer is selected as the target lifting mechanism. In step S13, the target lifting mechanism is controlled to run in the predetermined adjustment direction.

6. The temperature control method of claim 5, wherein, The number of priority target wafers is at least 2, and the absolute values of the current temperature differences of each priority target wafer are the same. In step S12, the lifting mechanism corresponding to the projection mark closest to each priority target wafer is selected as the target lifting mechanism, and in step S13, the target lifting mechanism is controlled to run in the predetermined adjustment direction.

7. The temperature control method of claim 1, wherein, The number of the target substrates is at least two and the current temperature differences of each target substrate are the same. In step S12, after judging that the distances between each target substrate and the closest corresponding projection mark are consistent, the closest corresponding projection mark of each target substrate is obtained. The lifting mechanism corresponding to the obtained projection mark is taken as the target lifting mechanism. In step S13, the target lifting mechanism is controlled to run in the predetermined adjustment direction.

8. The temperature control method of claim 1, wherein, The number of the target substrates is at least two and the current temperature differences of each target substrate are the same. In step S12, after judging that the distances between each target substrate and the closest corresponding projection mark are consistent and located in the same half area of the plane where the bearing top surface is located, the lifting mechanism corresponding to at least one projection mark in the other half area of the plane where the bearing top surface is located is taken as the target lifting mechanism. In step S13, the target lifting mechanism is controlled to run in the opposite direction of the predetermined adjustment direction.

9. The temperature control method of claim 8, wherein, Each target substrate is located in the same sector, the sector has a center and a radius, the center is the center of the bearing top surface, and the radius is respectively tangent to two target substrates. The other half area of the plane where the bearing top surface is located includes a symmetric sector which is axially symmetric to the sector. In step S12: When there is at least one projection mark in the symmetric sector, the lifting mechanism corresponding to at least one projection mark in the symmetric sector is taken as the target lifting mechanism; When there is no projection mark in the symmetric sector, the lifting mechanism corresponding to at least one projection mark closest to the symmetric sector is taken as the target lifting mechanism.

10. The temperature control method of claim 9, wherein, The central angle of the sector is not more than 60 degrees.

11. The temperature control method of claim 1, wherein, In step S11: When the temperature difference between the current surface temperature of the substrate and the target set temperature is positive, the predetermined adjustment direction is away from the area where the heating device is located; When the temperature difference between the current surface temperature of the substrate and the target set temperature is negative, the predetermined adjustment direction is close to the area where the heating device is located.

12. The temperature control method of claim 1, wherein, The base and the heating device have a process distance. In step S0, the step of obtaining the first calibration relationship includes: S01: controlling the heating device to heat the base according to the heating power corresponding to the set temperature until the base reaches a temperature steady state, and obtaining the initial steady state temperature of the base; S02: maintaining the heating power of the heating device unchanged, and controlling each lifting mechanism to rise or fall by a certain distance synchronously; S03: obtaining the current steady state temperature of the base, and obtaining the calibration temperature difference according to the current steady state temperature of the base and the initial steady state temperature, and obtaining the distance change amount according to the displacement change amount of each lifting mechanism and the process distance; S04: controlling each lifting mechanism to continue to rise or fall by a certain distance synchronously; S05: repeating steps S03 to S04 until the base is controlled to rise or fall to the corresponding position threshold, so as to obtain the corresponding relationship between the calibration temperature difference and the distance change amount of the base at the set temperature.

13. The temperature control method of claim 12, wherein, In the step of obtaining the first calibration relationship, a distance between the susceptor and the heating device is controlled to be not less than a minimum process distance to avoid motion interference between the susceptor and the heating device, the process distance being greater than the minimum process distance.

14. The temperature control method of claim 1, wherein, Before the epitaxial process flow of step S1 is performed, the susceptor has an initial horizontal position, and a process distance between the susceptor and the heating device is provided, in any of the processes of steps S1, S11, S12 and S13, it is determined whether a vertical distance of a side surface of the susceptor relative to the initial horizontal position exceeds a preset distance threshold value, and / or whether a minimum value of the process distance is less than a minimum process distance, if so, the target lifting mechanism is controlled to stop running.

15. The temperature control method of claim 14, wherein, The preset distance threshold value is not more than 0.5 mm.

16. The temperature control method of any one of claims 13 or 14, wherein, The minimum process distance is not less than 4 mm.

17. The temperature control method of claim 1, wherein, Further comprising obtaining a second calibration relationship, the second calibration relationship being a corresponding relationship between an axial run-out difference threshold value at different rotation speeds lower than a first rotation speed threshold value and an upper limit of a running speed of the lifting mechanism, the axial run-out difference threshold value being a maximum axial run-out value of the susceptor allowed by the epitaxial process flow at different rotation speeds, the first rotation speed threshold value being not more than 400 rpm; In step S1, the rotating device is controlled to rotate the susceptor at a rotation speed lower than the first rotation speed threshold value; Step S13 further comprises obtaining a current rotation speed of the susceptor and obtaining the upper limit of the running speed of the target lifting mechanism in the second calibration relationship according to the current rotation speed of the susceptor.

18. The control method according to claim 17, characterized by, Further comprising obtaining an axial run-out difference threshold value and an axial run-out difference threshold value, in step S0, the step of obtaining the second calibration relationship is performed at room temperature, comprising: P01: control the chamber to maintain a process pressure required by the epitaxial process flow; P02: control the rotating device to rotate the susceptor at a fixed rotation speed, control each lifting mechanism to synchronously ascend or descend at different motion speeds in sequence, and monitor axial run-out difference values and axial run-out difference values of the susceptor at each running speed by optical distance measurement method; P03: select a running speed corresponding to a run-out difference value reaching or closest to a minimum value of the axial run-out difference threshold value and the axial run-out difference threshold value as the corresponding upper limit of the running speed at the fixed rotation speed; P04: control the rotating device to increase the rotation speed of the susceptor to another fixed rotation speed; Repeat steps P02 to P04.

19. A semiconductor manufacturing apparatus, characterized by comprising: Comprise: a chamber, a susceptor and a heating device, the susceptor being arranged in the chamber, and a plurality of grooves for accommodating and limiting substrates being arranged on the susceptor in a circumferential direction, and the heating device being arranged between the susceptor and a chamber bottom plate of the chamber; a rotating device, a dynamic seal penetrating the chamber and connected to the susceptor; a lifting bottom plate located below the chamber and surrounding the rotating device; A plurality of lifting mechanisms are arranged on the lifting base and are arranged circumferentially around the chamber and are connected to the chamber bottom plate, so as to drive the base to perform lifting movement through the rotating device, and the connection between the lifting mechanism and the chamber bottom plate is a projection mark projected towards the plane of the load top surface of the base; An optical temperature measuring device is arranged above the chamber and is used for measuring the current surface temperature of each substrate; A main control device pre-stores a first calibration relationship and is in communication connection with the rotating device, the optical temperature measuring device, the heating device and each lifting mechanism, and the first calibration relationship is a corresponding relationship between the calibration temperature difference of the base and the distance change amount between the heating device and the base under different set temperatures; The main control device controls the semiconductor manufacturing equipment to perform epitaxial growth process on the substrate, and in the process of epitaxial growth, the rotating device drives the base to rotate, and the following steps are performed at the same time: obtaining the current temperature difference of each substrate according to the current surface temperature and the target set temperature of each substrate, determining the target substrate with temperature anomaly, the target distance change amount corresponding to the target substrate and the predetermined adjustment direction according to each current temperature difference and the first calibration relationship; According to the number, position and distance of each projection mark, the target lifting mechanism which needs to be controlled is determined; The target lifting mechanism is controlled to run the target distance change amount in the predetermined adjustment direction or the opposite direction of the predetermined adjustment direction.

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