Semiconductor manufacturing apparatus and temperature control method

Abstract

The invention provides semiconductor manufacturing equipment and a temperature control method, and the method comprises the steps: synchronously obtaining the current surface temperature of each substrate in a process of executing an epitaxial growth technology, and obtaining the current temperature difference of each substrate according to the current surface temperature of each substrate and a target set temperature; according to each current temperature difference and the first calibration relationship, determining a target substrate with abnormal temperature, a corresponding target spacing variation and a preset adjustment direction; determining a target lifting mechanism which needs to be subjected to lifting control according to the number and the positions of the target substrates and the distance between the target substrates and the projection marks; and the target lifting mechanism is controlled to move by the target distance variation in the preset adjusting direction or the reverse direction of the preset adjusting direction. According to the invention, the uniformity of the substrate surface temperature field can be corrected in real time, and the normal process is not interfered.

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 substrate surface temperature 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 slippage, part damage, etc., the temperature uniformity will also be affected. In this application scenario, if the substrate temperature is not uniform 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 projection of the connection between the lifting mechanism and the chamber bottom plate towards the plane of the bearing top surface of the susceptor. The temperature control method comprises: S0: obtaining a first calibration relationship between the temperature difference of the susceptor and the variation of the distance 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; During the execution of the epitaxial process in step S1, the following steps are further included: 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 corresponding to the target wafer, and the predetermined adjustment direction according to the current temperature difference and the first calibration relationship; 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; S13: controlling the target lifting mechanism to run the target distance variation in the predetermined adjustment direction or the opposite direction of the predetermined adjustment direction.

[0009] Further, 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 of the two half-areas of the plane of the bearing top surface.

[0010] 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.

[0011] Further, in step S12, the number of projection marks closest to the target wafer is at least 2, and at least one lifting mechanism corresponding to the closest projection mark is selected as the target lifting mechanism.

[0012] Further, in step S11, the number of the target substrates is at least two, 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.

[0013] 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.

[0014] 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 closest projection mark are the same, the closest projection mark corresponding to each of the target substrates is obtained, the lifting mechanism corresponding to each of the obtained closest projection marks is selected as the target lifting mechanism, and in step S13, the target lifting mechanism is controlled to run in the predetermined adjustment direction.

[0015] 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 closest projection mark are the same, 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.

[0016] Further, each of the target substrates 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 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: 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 selected 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 selected as the target lifting mechanism.

[0017] Further, the central angle of the sector is not more than 60 degrees.

[0018] Further, 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 region 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 region where the heating device is located.

[0019] Further, the substrate and the heating device have a process distance therebetween, and in step S0, the step of obtaining the first calibration relationship comprises: S01: controlling the heating device to heat the substrate according to the heating power corresponding to the set temperature until the substrate reaches a temperature steady state, and obtaining an initial steady state temperature of the substrate; S02: maintaining the heating power of the heating device unchanged, and controlling each lifting mechanism to synchronously rise or fall by a certain distance; S03: obtaining a current steady state temperature of the substrate, and obtaining the calibration temperature difference according to the current steady state temperature of the substrate 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 synchronously rise or fall by a certain distance; S05: repeating steps S03 to S04 until the substrate is controlled to rise or fall to a 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; 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 a minimum process distance, so as to avoid motion interference between the substrate and the heating device, and the process distance is greater than the minimum process distance.

[0020] Further, before performing the epitaxial process flow of step S1, the substrate has an initial horizontal position, and the substrate and the heating device have a process distance therebetween, and in any process of performing steps S1, S11, S12 and S13, it is judged whether the vertical distance of one side surface of the substrate relative to the initial horizontal position exceeds a preset distance threshold and / or whether the minimum value of the process distance is lower than a minimum process distance, and if so, the target lifting mechanism is controlled to stop running.

[0021] Further, the preset distance threshold is not more than 0.5 millimeter.

[0022] Further, the minimum process distance is not less than 4 millimeters.

[0023] 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 and an upper limit of an operation speed of the lifting mechanism at different rotation speeds of the susceptor below the first rotation speed threshold, the axial run-out difference threshold being a maximum axial run-out of the susceptor allowed by the epitaxial process at different rotation speeds, and the first rotation speed threshold being less than or equal to 400 rpm. In step S1, the rotating device is controlled to rotate the susceptor at a rotation speed below the first rotation speed threshold. Step S13 further comprises obtaining a current rotation speed of the susceptor and obtaining the upper limit of the operation speed of the target lifting mechanism in the second calibration relationship according to the current rotation speed of the susceptor.

[0024] Further, the method of the present application further comprises obtaining an axial run-out difference threshold and a radial run-out difference threshold, and in step S0, the step of obtaining the second calibration relationship at room temperature comprises: P01: maintaining a process pressure required by the epitaxial growth process in the chamber; P02: controlling the rotating device to rotate the susceptor at a fixed rotation speed, controlling the lifting mechanisms to synchronously ascend or descend at different motion speeds in sequence, and monitoring axial run-out differences and radial run-out differences of the susceptor at different operation speeds by optical distance measurement; P03: selecting an operation speed corresponding to a run-out difference reaching or closest to a minimum value of the axial run-out difference threshold and the radial run-out difference threshold as an upper limit of the corresponding operation speed at the fixed rotation speed; P04: controlling the rotating device to increase the rotation speed of the susceptor to another fixed rotation speed; Steps P02 to P04 are repeatedly performed.

[0025] The second aspect of the present application provides a semiconductor manufacturing equipment, comprising: a chamber, a susceptor and a heating device, the susceptor being arranged in the chamber, and the susceptor being provided with a plurality of grooves distributed circumferentially and used for accommodating and limiting substrates, 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 connecting the susceptor; a lifting bottom plate, located below the chamber and surrounding the rotating device; a plurality of lifting mechanisms, arranged on the lifting bottom plate, arranged circumferentially around the chamber and connected to the chamber bottom plate of the chamber, so as to drive the susceptor to move up and down by the rotating device, and a projection mark being formed by projecting the connection between the lifting mechanism and the chamber bottom plate towards a plane on which a load-bearing top surface of the susceptor is located. An optical temperature measuring device is arranged above the chamber and used to measure the current surface temperature of each substrate; A master 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 a calibration temperature difference of the susceptor and a variation of the distance between the heating device and the susceptor at different set temperatures.

[0026] By adopting the above technical solution, the semiconductor manufacturing equipment and the temperature control method have the following beneficial effects: In the process of performing the semiconductor process, the target substrate with temperature anomaly is located 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 then the target lifting mechanism is dynamically adjusted to the desired position by controlling the target lifting mechanism to run according to the target displacement deviation, so that the real-time correction of the distance between the susceptor and the heating device is realized, the surface temperature field uniformity of the substrate is improved, and the normal process is not disturbed. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 FIG. 1 is a structural schematic diagram of the semiconductor manufacturing equipment of the present application; Figure 2 FIG. 2 is a flowchart of the temperature control in step S11 in the present application; Figure 3 FIG. 3 is a schematic diagram of the measurement track of each optical probe in the present application; Figure 4 FIG. 4 is a flowchart of the step of obtaining the first calibration relationship in step S0 in the present application; Figure 5 FIG. 5 is a principle diagram of locating the measurement point in the present application; Figure 6 FIG. 6 is a principle diagram of obtaining the target substrate in the present application; Figure 7A FIG. 7 is a principle diagram of determining the target lifting mechanism in one embodiment of the present application; Figure 7B FIG. 8 is a principle diagram of determining the target lifting mechanism in another embodiment of the present application; Figure 7C FIG. 9 is a principle diagram of determining the target lifting mechanism in another embodiment of the present application; Figure 8 FIG. 10 is a flowchart of the step of obtaining the second calibration relationship in step S0 in the present application. DETAILED DESCRIPTION

[0028] Following, the advantages and effects of the present application can be easily understood by those skilled in the art from the description. The present application can also be implemented or applied by different specific embodiments, and various modifications or changes can be made to the details in the description without departing from the spirit of the present application.

[0029] It should be noted that the diagrams provided in the embodiments only schematically illustrate the basic concepts of the present application, and the diagrams only show the components related to the present application, not 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 solutions of the present application, and the component layout form can also be more complex.

[0030] 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.

[0031] Therefore, the present application provides a semiconductor manufacturing equipment and a temperature control method to real-time adjust the uniformity of the substrate surface temperature field under the premise of not stopping the machine, so as to improve the yield of epitaxial growth without interfering with the normal process.

[0032] 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 realizes epitaxial growth process. It should be understood that the equipment is only exemplary.

[0033] As shown in Figure 1 The semiconductor manufacturing equipment provided by the present application comprises a chamber 1 internally provided with a susceptor 2 and a heating device 7, a rotating device 3 penetrating through the bottom of the chamber 1 and rotationally connected to the susceptor 2, a lifting bottom plate 4 located outside the chamber 1 and surrounding the rotating device 3, and a plurality of lifting mechanisms 5 provided on the lifting bottom plate 4 and connected to the chamber bottom plate 12 of the chamber 1. The load-bearing top surface of the susceptor 2 is provided with a plurality of grooves 20 distributed in the circumferential direction and respectively used for accommodating and limiting the substrate. The projection of the connection between the lifting mechanism 5 and the chamber bottom plate 12 of the chamber 1 towards the plane where the load-bearing top surface of the susceptor 2 is located is a projection mark. The heating device 7 is provided between the susceptor 2 and the chamber bottom plate 12.

[0034] The temperature control method provided by the present application comprises: S0: Obtaining a first calibration relationship, where the first calibration relationship is a correspondence between a calibration temperature difference of the base and a change in the distance between the heating device and the base at different set temperatures; S1: placing each substrate in a corresponding groove, controlling the semiconductor manufacturing equipment to perform an epitaxial process at a target set temperature and set pressure, and controlling the rotating device to drive the base to rotate during the epitaxial process; During the process of executing the epitaxial process in step S1, the process also includes synchronously executing Figure 2 Temperature control steps shown: S11: Acquire 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, and determine the target substrate with abnormal temperature, the corresponding target spacing change, and the predetermined adjustment direction based on each current temperature difference and the first calibration relationship; S12: determining the target lifting mechanism that needs to be lifted and lowered according to the number and position of the target substrates and the distance between the target substrates and the projection marks; S13: Control the target lifting mechanism to run the target distance change amount along the predetermined adjustment direction or the opposite direction of the predetermined adjustment direction.

[0035] The technical solution of this application is described in detail below through specific embodiments.

[0036] Example 1 This embodiment provides a semiconductor manufacturing device for performing an epitaxial growth process on a substrate. Figure 1 The semiconductor manufacturing equipment shown (taking MOCVD equipment as an example) includes a chamber 1 with a base 2 and a heating device 7 installed therein, an upper cover 13 provided 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, a plurality of lifting mechanisms 5 provided on the lifting base plate 4 and connected to the chamber bottom plate 12 of the chamber 1, and an optical temperature measuring device 6 provided above the upper cover 13; and 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.

[0037] In some embodiments, the substrate is a wafer.

[0038] In some embodiments, the number of the lifting mechanisms 5 is at least three.

[0039] In some embodiments, the lifting mechanisms 5 are evenly arranged along the same circumferential direction on the chamber bottom plate 12 to ensure smooth lifting and lowering of the rotating device 3 .

[0040] The base 2 is preferably in a disc shape, and its top surface faces the top of the chamber 1. The top surface is provided with a plurality of grooves 20 evenly distributed in the circumferential direction, each of which is used to carry a substrate and achieve the functions of containing and limiting the substrate, so that the substrate can rotate with the base 2.

[0041] In some embodiments, the base 2 is preferably made of graphite and has a disc shape. In some embodiments, the surface of the graphite base 2 is covered with a silicon carbide layer.

[0042] During epitaxial growth, the rotating device 3 is used to drive the base 2 carrying the substrate to be plated to rotate, thereby facilitating the uniformity of film formation. Figure 1 As shown in FIG. 1, the base 2 is supported in the chamber 1 by a base support device 9, and the rotating device 3 is connected to the base support device 9 after penetrating the bottom plate 12 of the chamber 1. The rotating device 3 is used to drive the base 2 to rotate, 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 is not described here.

[0043] In some embodiments, the base support device 9 is arranged at the middle of the bottom surface of the base 2, extends towards the rotating 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.

[0044] 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 rotating device 3. Specifically, the lifting mechanism 5 surrounds the rotating device 3. One end of the lifting mechanism 5 is fixed on the bottom plate 12 of the chamber 1 and extends towards the lifting bottom plate 4 and is fixedly arranged on the lifting bottom plate 4. Since the rotating device 3 is arranged in the chamber 1 in a dynamic sealing manner, the lifting mechanism 5 can drive the lifting bottom plate 4 to move up and down, and at the same time, can also drive the rotating device 3 to move synchronously, thereby driving the base 2 to move up and down.

[0045] In some embodiments, with reference to Figure 1The lifting mechanism 5 comprises a screw rod 51 and a driving mechanism 52. The driving mechanism 52 is arranged on the screw rod 51, the screw rod 51 is fixedly arranged on the lifting base plate 4, extends towards the chamber base plate 12 and is fixedly arranged on the chamber base plate 12. In some specific embodiments, the top end of the screw rod 51 is fixed to the chamber base plate 12 through a fixing seat (the fixing seat allows the screw rod to rotate but restricts its axial movement), the screw rod 51 is fixed to the lifting base plate 4 through a nut and a flange or a connecting block, and the bottom end of the screw rod 51 is connected to the driving mechanism 52 (such as a servo motor or a stepper motor) through a shaft coupling. When the driving mechanism 52 is started, the screw rod 51 is driven to rotate, the nut of the screw rod 51 is driven to move linearly along the screw rod 51 because it cannot rotate, and the lifting base plate 4 is driven to lift to move towards or away from the chamber base plate 12, so that the rotary device 3 is synchronously driven to move towards or away from the upper cover 13, and the base 2 is driven to lift by the rotary device 3. The specific adaptation mode of the fixing seat on the chamber base plate and the screw rod, and the specific adaptation mode of the screw rod and the nut and the flange or the connecting block are conventional technical means in the art, which will not be described here.

[0046] In some embodiments, the screw rod 51 extends axially along the chamber 1, and the load-bearing top surface of the base 2 and the chamber base plate 12 are both perpendicular to the axial direction of the chamber 1.

[0047] In Figure 1 In the example shown, three lifting mechanisms 5 are arranged on the lifting base plate 4, and each lifting mechanism 5 is driven by an independent driving mechanism 52, but it should be understood that the present embodiment is not limited thereto. Each lifting mechanism 5 can also be driven and controlled independently by the same driving mechanism 52.

[0048] As in the background art, the distance between the base 2 and the heating device 7 has an important influence on the uniformity of the temperature field of each wafer surface.

[0049] Especially for epitaxial growth processes, it is well known in the art that epitaxial growth has a high requirement for the precision of wafer temperature control. Taking the use of a MOCVD device to grow a GaN layer on a silicon substrate to prepare a light emitting diode (LED) as an example, if the wafer temperature deviation is controlled to be 1 degree Celsius, the central wavelength of the LED will deviate by more than 1 nm from the central wavelength required to be achieved by the process design, which will seriously change the light-emitting performance of the prepared LED, for example, the blue LED originally required to be obtained cannot be obtained due to the deviation of the central wavelength of the LED.

[0050] The semiconductor manufacturing equipment, taking the MOCVD equipment as an example, in order to realize the accurate control of the temperature of the substrate, a heating device is arranged below the susceptor to heat the susceptor, and the susceptor transmits heat to the substrate to realize the temperature control. There is a certain spacing between the heating device and the susceptor to not interfere with the movement (such as lifting or rotating) of the susceptor. According to the requirements of the process on the temperature and the accuracy control, the accurate control of the temperature of the substrate is realized by reasonably designing the spacing between the heating device and the susceptor, the heating power, combining the size characteristics of the susceptor and the related theory of heat conduction, so as to benefit the uniformity of the temperature field near the top surface of the susceptor.

[0051] In addition, the interaction between the gas flow field formed by the process gas provided by the gas injection device above the bearing 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, considering the smooth rotation and the convenience of process adjustment, the spacing between the heating device 7 and the susceptor 2 is usually designed under the premise of controlling the susceptor to have good levelness. However, for epitaxial growth processes with very strict temperature control accuracy requirements, for example, indium phosphide (InP) based devices, such devices are extremely sensitive to temperature, and usually require control accuracy within ±0.5°C, otherwise the quantum well thickness and composition are easy to not meet the requirements and cannot accurately lock the light-emitting wavelength. Even if the spacing between the heating device 7 and the susceptor 2 is reasonably adjusted, due to the influence of the gas flow field above the bearing top surface of the susceptor 2, the complexity of the environment in the cavity, and the inevitable jumping of the susceptor rotation, the temperature of the substrate carried by each groove cannot be completely consistent, which affects the product control of each film forming substrate in the same batch and easily causes yield reduction.

[0052] In the prior art, even if the significant non-uniformity of the surface temperature of each substrate is obtained in real time through the optical temperature measurement method during the process, the real-time adjustment method for this is also limited. For the case that the surface temperature of each substrate is low or high, the problem can be alleviated by adjusting the heating power. However, for the case that 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.

[0053] 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 as to correct the substrate with temperature abnormality under the premise of reducing or even avoiding the influence on other normal temperature substrates.

[0054] The optical temperature measuring 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 susceptor 2 through the optical window of the upper cover 13 or the spray hole on the gas injection device. The signal processing unit 62 is used to convert the collected signal of the corresponding optical probe into a corresponding temperature value. The specific implementation is a conventional technical means in the art, which is not described here.

[0055] In some embodiments, the signal processing unit 62 is a photodetector.

[0056] 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, 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 substrate), so as to realize real-time collection of the temperature of the substrate.

[0057] 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.

[0058] 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.

[0059] In some embodiments, the rotating device 3 is arranged in the susceptor 2 in a central driving manner, the heating device 7 is arranged around the support device below the susceptor 2 and is supported by the heating support device 71, and the bottom of the heating support device is arranged on the inner bottom surface of the chamber. The specific implementation is a conventional technical means in the art.

[0060] In the embodiment, a resilient sealing member 8 is further arranged between the chamber bottom plate 12 and the lifting bottom plate 4, and the resilient sealing member 8 forms a sealed space with the chamber bottom plate 12 and the lifting bottom plate 4, so as to realize sealing of the chamber 1. Specifically, the two ends of the resilient sealing member 8 are respectively arranged on the chamber bottom plate 12 and the lifting bottom plate 4 around the rotating device 3. The inside of the resilient sealing member 8 is hollow to allow the rotating device 3 to penetrate through.

[0061] In some embodiments, the resilient sealing member 8 is a bellows.

[0062] In the embodiment, the lifting control, the rotation control and the temperature control of the susceptor 2 are all controlled by the master control device.

[0063] In some embodiments, the master control device pre-stores the first calibration relationship.

[0064] In some embodiments, the master control device pre-stores the first calibration relationship and the second calibration relationship.

[0065] Specifically, the first calibration relationship is a corresponding relationship between a calibration temperature difference of the susceptor 2 and a variation amount of the distance between the heating device 7 and the susceptor 2 at different set temperatures.

[0066] Specifically, the second calibration relationship is a corresponding relationship between an axial run-out difference threshold value and an upper limit of the running speed of the lifting mechanism at different rotation speeds of the susceptor below a 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 at different rotation speeds, and the first rotation speed threshold value being not more than 400 rpm.

[0067] In some embodiments, the master control device also monitors and controls the process of epitaxial growth.

[0068] After the substrates are placed on the susceptor 2, the master control device controls the semiconductor manufacturing equipment to perform the epitaxial growth process on the substrates. During the epitaxial growth process, the rotation device 3 drives the susceptor 2 to rotate, and the following steps are performed simultaneously: obtaining the current surface temperature of each substrate, and 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 distance variation amount corresponding to the target substrate, and the predetermined adjustment direction according to the first calibration relationship and the current temperature difference of each substrate; determining the target lifting mechanism that needs to be controlled in lifting according to the number, position and distance of each target substrate from each projection mark; and 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.

[0069] Embodiment 2 The embodiment provides specific implementation steps for obtaining the first calibration relationship. As described above, the first calibration relationship is a corresponding relationship between a calibration temperature difference of the susceptor 2 and a variation amount of the distance between the heating device 7 and the susceptor 2 at different set temperatures.

[0070] It should be understood that, when calibrating the first calibration relationship, the working distance is taken as a reference for the variation amount of the distance between the susceptor 2 and the heating device 7, and the process distance refers to the distance between the susceptor 2 and the heating device 7 during process execution.

[0071] To facilitate understanding of the working distance, first introduce the control process of epitaxial growth process. The main control device pre-stores process program information, which includes steps for performing wafer transfer preparation, moving the coated substrate out and transferring the to-be-coated substrate onto the susceptor 2, performing epitaxial growth process preparation steps, and performing epitaxial growth process. Specifically, during the epitaxial growth process, the susceptor 2 and the heating device 7 should be separated by a process distance. After one round of epitaxial growth process, the main control device controls the gas injection device to provide a chemically inert purge gas into the chamber 1, controls the rotation device 3 to stop rotating so that the susceptor 2 is in a stationary state, and controls the heating device 7 to stop working to cool down to the wafer transfer temperature. After the pressure in the chamber 1 is equalized, the main control device controls the wafer transfer port of the chamber 1 to be in an open state, controls the susceptor 2 to rise to a wafer transfer position opposite the wafer transfer port, transfers the coated substrate out of the susceptor 2, transfers the to-be-coated substrate into the susceptor 2 from the wafer transfer port, and then controls the susceptor 2 to descend to the process position. After the main control device controls the wafer transfer port to be in a closed state, the gas injection device and the exhaust device are controlled to make the pressure in the chamber 1 reach the process pressure, the heating device 7 is controlled to meet the process temperature requirement, the susceptor 2 is driven to rotate, and then the gas injection device provides process gas for epitaxial growth into the chamber 1 to perform epitaxial growth process.

[0072] As shown in Figure 4 , the step of obtaining the first calibration relationship specifically includes: S01: control the heating device 7 to heat the susceptor 2 according to the heating power corresponding to the set temperature until the susceptor 2 reaches a temperature steady state, and obtain the initial steady state temperature of the susceptor 2; S02: maintain the heating power of the heating device 7 unchanged, and control each lifting mechanism 5 to synchronously rise or descend by a certain distance; S03: obtain the current steady state temperature of the susceptor 2, and obtain the calibration temperature difference according to the current steady state temperature and the initial steady state temperature of the susceptor 2, obtain the displacement change of each lifting mechanism 5, and obtain the distance change according to the displacement change of each lifting mechanism 5 and the process distance; S04: control each lifting mechanism 5 to continue to synchronously rise or descend by a certain distance; Repeat steps S03 to S04 until the susceptor 2 is controlled to rise or descend to a corresponding position threshold, so as to obtain the corresponding relationship between the calibration temperature difference (ΔT1, ΔT1,…, ΔTm) and the distance change (Δh1, Δh1,…, Δhm) of the susceptor at the set temperature.

[0073] 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 easily interferes with the movement of the heating device 7.

[0074] In some embodiments, for epitaxial growth processes with very high temperature control precision requirements, in order to ensure the effectiveness and rapid controllability of the heat transfer from the heating device 7 to the susceptor 2, the distance between the heating device 7 and the susceptor 2 is generally not large, usually 4-6 mm. In this case, in order to avoid the calibration of the lowering of the susceptor 2 being limited by the distance between the susceptor 2 and the heating device 7 and being unable to obtain complete data, the calibration of the lowering of the susceptor 2 can be performed after the susceptor 2 is first raised to the upper limit position.

[0075] In some embodiments, in the step of obtaining the first calibration relationship, the distance between the susceptor 2 and the heating device 7 is controlled to be not less than a minimum process distance, so as to avoid interference between the movement of the susceptor 2 and the heating device 7, thereby protecting the safety of the two. The process distance is greater than the minimum process distance.

[0076] Embodiment 3 The present embodiment provides the following temperature control steps, which are synchronously performed during the epitaxial process in step S1: S11: obtaining the current surface temperature of each wafer, and obtaining the current temperature difference of each wafer according to the current surface temperature of each wafer and the target set temperature, and determining the target wafer with temperature abnormality, the target distance change amount corresponding to the target wafer, and the predetermined adjustment direction according to each current temperature difference and the first calibration relationship; S12: determining the target lifting mechanism that needs to be controlled in lifting according to the number, position, and distance of each projection mark of the target wafer; S13: controlling the target lifting mechanism to run in the predetermined adjustment direction or the opposite direction of the predetermined adjustment direction by the target distance change amount.

[0077] The present embodiment solves the problem of partial wafers being too high or too low by performing real-time temperature compensation on the local micro-lifting of the susceptor during the process, improves the consistency of the thickness, composition, and light-emitting wavelength of the epitaxial layer, and improves the yield of batches without stopping the machine and breaking the vacuum.

[0078] Specifically, the step S11 of obtaining the current surface temperature of each wafer includes: calculating the average temperature value of the corresponding wafer region currently measured by the optical temperature measuring device, and taking the average temperature value as the current surface temperature of the corresponding wafer.

[0079] The susceptor carries a plurality of wafers, and the susceptor is provided with a plurality of lifting mechanisms. Figure 3 In the example shown, 12 wafers are uniformly distributed in the circumferential direction. In order to accurately identify the current measurement position of the optical probe, the present embodiment is provided with an angle origin mark 10 on the susceptor or the rotating device, which marks the beginning of each scanning cycle, i.e., the angle origin. The measurement position of the optical probe can be determined 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 FIG. 2). Figure 5is defined by the angle formed by the two green lines in the figure.

[0080] In some embodiments, the angle origin mark 10 may be a notch, a protrusion, or any other form, and this embodiment does not impose any specific limitation on this.

[0081] During the rotation of the base, the optical probe 61 continuously scans the surface of the substrate to form Figure 5 The scanning trajectory shown in the figure is used to obtain a series of temperature data points. Each temperature data point is timestamped and the angular position information of the base at that time. Since the circumferential position of each substrate on the base is pre-set and known, the main control device can map the temperature data points obtained by scanning to the corresponding substrate after establishing an absolute angular coordinate system through the angle origin mark. For example, it is known that the center of one of the substrates is located at 30 degrees from the angle origin mark (that is, the angle between the line connecting the center of the substrate and the origin of the base and the angle origin mark and the center of the base is 30 degrees), then all temperature data collected within the range of 30 degrees ± Δθ can be attributed to the substrate area of ​​the substrate, where Δθ is the preset offset angle threshold.

[0082] In other embodiments, the base does not need to be marked with an angle origin. The rotating device's drive motor (such as a servo motor) is typically equipped with an encoder that generates a Z-phase pulse signal (or Home signal) indicating the absolute position of the motor rotor, thereby determining the measurement position of the optical probe. The specific implementation method is conventional in the art.

[0083] In step S11, the target substrate with abnormal temperature, the corresponding target spacing change, and the predetermined adjustment direction are determined according to each current temperature difference and the first calibration relationship, including: First, determine whether the current temperature difference corresponding to each substrate is within the preset temperature difference range. If not, the substrate whose current temperature difference exceeds the preset temperature difference range is regarded as the target substrate with temperature abnormality, so as to realize targeted correction later.

[0084] like Figure 6 As shown in the figure, each black dot represents a substrate, Test represents the target set temperature, and the preset temperature difference range includes the range between the upper limit error and the lower limit error. Figure 6 The current temperature difference of two substrates exceeds the preset temperature difference range, so there are two target substrates, among which the current temperature difference of the substrate framed by the red frame is larger in absolute value.

[0085] In some embodiments, the upper limit error and the lower limit error are no greater than 0.5 degrees Celsius.

[0086] Then, a 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, the target spacing change includes matching the current temperature difference of the target substrate with the calibrated temperature difference of the base in the first calibration relationship, and using the spacing change corresponding to the matched calibrated temperature difference as the target spacing change corresponding to the target substrate.

[0087] Finally, the positive or negative temperature difference between the current surface temperature of the target substrate and the target set temperature is determined. When the temperature difference between the current surface temperature of the target substrate and the target set temperature is positive, it indicates that the target substrate temperature is too high, and 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, it indicates that the target substrate temperature is too low, and the predetermined adjustment direction is close to the area where the heating device is located.

[0088] In this embodiment, if Figure 7A As shown, the number of lifting mechanisms is at least three, ensuring that the base can rotate smoothly even when it is in a controllable tilt state, avoiding flying plates and mechanical resonance, and providing a mechanical basis for real-time fine-tuning. The number of substrates is shown as 12, labeled A through L.

[0089] The orthographic projections of the connection between the lifting mechanism 5 and the chamber bottom plate 12 of the chamber 1 toward the plane where the bearing top surface of the base 2 is located are projection marks (represented as 5A, 5B, and 5C respectively). The projection marks are evenly distributed along the same circumferential direction on the plane where the bearing top surface is located. There is at least one lifting mechanism in the two half areas of the plane where the bearing top surface is located.

[0090] In some embodiments, in step S11 , the number of target substrates is 1, and in step S12 , a lifting mechanism corresponding to a projection mark closest to the target substrate is obtained as a target lifting mechanism.

[0091] by Figure 7A For example, assuming substrate A is the target substrate and is closest to projection mark 5A, the lift mechanism corresponding to projection mark 5A is determined to be the target lift mechanism. In other words, when only one substrate with an abnormal temperature is present, the closest lift mechanism is directly selected for single-point compensation. This algorithm is simple, provides the fastest response, and avoids excessive linkage that could cause temperature drift on other substrates.

[0092] In some embodiments, in step S12, if the number of projection marks closest to the target substrate is at least two, then the lifting mechanism corresponding to at least one of the closest projection marks is selected as the target lifting mechanism. For example, one selection can be made according to a predetermined priority algorithm or one can be selected at random.

[0093] In some embodiments, the number of target substrates is at least two, 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 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 a target lifting mechanism, and in step S13, the target lifting mechanism is controlled to run in the predetermined adjustment direction.

[0094] As shown in FIG. 6, the error absolute value of the substrate in the red box is the largest, and thus the substrate is determined as a priority target substrate. The lifting mechanism corresponding to the projection mark closest to the substrate is selected as a target lifting mechanism. Figure 6

[0095] That is, in the case of multiple-substrate abnormality and inconsistent absolute values of temperature differences, the substrate with the largest temperature difference is preferentially compensated, so that the system can correct the most abnormal substrate in the smallest number of actions and at the fastest speed, and the closed-loop convergence time is shortened.

[0096] In some embodiments, the number of 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 priority target substrate is selected as a target lifting mechanism, and in step S13, the target lifting mechanism is controlled to run in the predetermined adjustment direction.

[0097] For example, as shown in FIG. 7, the substrate A and the substrate C are both priority target substrates, and the absolute values of the current temperature differences of the two are the same. The projection mark closest to the substrate A is the projection mark 5A, and the projection mark closest to the substrate C is the projection mark 5B. The distance between the substrate A and the projection mark 5A is smaller than the distance between the substrate C and the projection mark 5B. Therefore, the substrate A is more preferentially adjusted than the substrate C, and thus the lifting mechanism corresponding to the projection mark 5A closest to the substrate A is selected as a target lifting mechanism, so as to avoid mechanical hysteresis and over-adjustment caused by seeking the farthest, and the adjustment accuracy is maintained. Figure 7B

[0098] In some embodiments, the number of 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 the target substrates and the corresponding closest projection marks are consistent, the closest projection marks corresponding to the target substrates are obtained, the lifting mechanisms corresponding to the obtained projection marks are selected as target lifting mechanisms, and in step S13, the target lifting mechanisms are controlled to run in the predetermined adjustment direction.

[0099] ​​In some embodiments, the number of target substrates is at least 2 and the current temperature difference of each is the same. In step S12, it is determined that the distances between each target substrate and the corresponding closest projection mark are consistent and are located in the same half of the plane where the carrier top surface is located. Then, the lifting mechanism corresponding to at least one projection mark in the other half of the plane where the carrier top surface is located is used as the target lifting mechanism. In step S13, the target lifting mechanism is controlled to operate in the opposite direction of the predetermined adjustment direction.

[0100] Therefore, by utilizing the symmetrical half-area reverse compensation strategy, the temperature deviation in the symmetrical area can be balanced by the remote lifting mechanism without adding hardware.

[0101] In some embodiments, each target substrate is located in the same sector, the sector is centered on the center of the carrier top surface, the radius line is circumscribed to the two target substrates respectively, and the other half of the plane where the carrier top surface is located includes a symmetrical sector symmetrical to the sector axis. In step S12: When there is at least one projection mark in the symmetrical sector, the lifting mechanism corresponding to the at least one projection mark in the symmetrical sector is used as the target lifting mechanism.

[0102] by Figure 7C For example, substrate B and substrate C are located in the same sector, and there is a projection mark 5C in the symmetrical sector of the sector. The lifting mechanism corresponding to at least one projection mark 5C in the symmetrical sector is used as the target lifting mechanism, so that a lifting mechanism can be adjusted through reverse compensation to achieve temperature correction of the two substrates.

[0103] When there is no projection mark in the symmetrical sector, the lifting mechanism corresponding to at least one projection mark closest to the symmetrical sector is used as the target lifting mechanism.

[0104] In some embodiments, the central angle of the sector does not exceed 60 degrees.

[0105] Before executing the epitaxial process flow of step S1, the base has an initial horizontal position, and there is a process spacing between the base and the heating device. During any process of executing step S1, step S11, step S12 and step S13, it is determined whether the vertical distance of one side of the base relative to the initial horizontal position exceeds a preset distance threshold, and / or whether the minimum value of the process spacing is lower than the minimum process spacing. If so, the target lifting mechanism is controlled to stop running.

[0106] Therefore, by limiting the minimum spacing, it is ensured that there will be no mechanical interference during real-time fine-tuning, extending the life of the heating device and the base and reducing maintenance downtime.

[0107] In some embodiments, the preset distance threshold does not exceed 0.5 mm.

[0108] In some embodiments, the minimum process pitch is no less than 4 mm.

[0109] Embodiment 4 The embodiment provides a temperature control method, which is different from that in Embodiment 3 in that the method further comprises obtaining a second calibration relationship, the second calibration relationship being a corresponding relationship between an axial jump difference threshold value and an upper limit of a running speed of the lifting mechanism at different rotation speeds of the susceptor below a first rotation speed threshold value, the axial jump difference threshold value being a maximum axial jump value of the susceptor allowed by an epitaxial process at the different rotation speeds, and the first rotation speed threshold value being less than or equal to 400 rpm.

[0110] In step S1, the rotation device is controlled to drive the susceptor to rotate at a rotation speed below 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.

[0111] Since the provided second calibration relationship is a corresponding relationship between an axial jump difference threshold value and an upper limit of a running speed of the lifting mechanism at different rotation speeds of the susceptor below a first rotation speed threshold value, the axial jump difference threshold value being a maximum axial jump value of the susceptor allowed by an epitaxial process at the different rotation speeds, and the first rotation speed threshold value being less than or equal to 400 rpm, the upper limit of the running speed of the lifting mechanism corresponding to the current rotation speed of the susceptor is obtained in the second calibration relationship, and the movement of the lifting mechanism required to be controlled is controlled at the upper limit of the running 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 taken into account.

[0112] In obtaining the second calibration relationship, the embodiment uses an optical distance measuring method to test the jump difference of the susceptor jump. Since the optical distance measuring method has an unignorable measurement error in measuring the distance of the high-temperature chamber, the present application drives the susceptor to rotate at room temperature for calibration.

[0113] The embodiment obtains the second calibration relationship at room temperature, as shown in FIG. 2, and the specific steps are as follows: Figure 8 P01: control the chamber 1 to maintain the process pressure required by the epitaxial growth process; P02: control the rotation device 3 to drive the susceptor 2 to rotate at a fixed rotation speed, control the lifting mechanisms 5 to synchronously ascend or descend at different movement 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 running speed; P03: select the running 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 running speed at the fixed rotation speed; P04: control the rotation device 3 to increase the rotation speed of the susceptor 2 to another fixed rotation speed; P05: repeat steps P02 and P03 until the rotation speed of the susceptor 2 reaches the first rotation speed threshold value. The steps P02 to P04 are repeated until a preset stop condition is reached, and a second calibration relationship is obtained.

[0114] Since the rotating 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 rotation of the susceptor under the process pressure while the susceptor is adjusted in the same way, the jumping of the susceptor is different. Therefore, in step P01, the chamber 1 is controlled to maintain the process pressure required for epitaxial growth. The calibration of the second calibration relationship of P02 to P04 is carried out under this pressure atmosphere.

[0115] In step P02, specifically, the rotating device 3 drives the susceptor 2 to rotate at a fixed speed, first controls each lifting mechanism 5 to rise to the first position (for example, 1 mm) at a speed of V1, and monitors the axial jump difference and the radial jump difference of the susceptor in this test process; then controls each lifting mechanism 5 to rise to the second position (for example, 1 mm) again at a speed of V2 higher than V1, and monitors the axial jump difference and the radial jump difference of the susceptor in this process, and repeats the above process each time the speed is increased. 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, the 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.

[0116] After the step of calibrating the corresponding relationship between the running speed of different lifting mechanisms 5 and the jump difference at a fixed rotating speed is completed, the rotating speed of the rotating device driving the susceptor is increased to another fixed rotating speed, and the above calibration process is repeated.

[0117] 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 rotating speed (P02 and P03) is completed, 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 value and the minimum value in the group of data) of the numerical value of each cavity is not more than the predetermined range threshold, which proves that the levelness of the susceptor meets the requirements, and then the rotating speed of the rotating device driving the susceptor is increased to another fixed rotating 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.

[0118] In some embodiments, after the steps (P02 and P03) of calibrating the relationship between the running speed of the different lifting mechanisms 5 and the runout difference at a fixed rotating speed are completed, the control is performed to run the lifting mechanisms synchronously 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 is no lifting space when the runout threshold is not exceeded).

[0119] In some embodiments, the base is preferably controlled to rise for calibration to avoid the case where the base is continuously lowered and easily interferes with the movement of the heating device.

[0120] In some embodiments, for the epitaxial growth process with very high temperature control accuracy, 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 is 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.

[0121] 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.

[0122] More specifically, an optical ranging device emits probe light vertically toward the top surface of the susceptor through an optical window on the gas injection device and the spray channel. The optical ranging device receives feedback light information and converts the probe light and feedback light information into corresponding voltage signals. Through appropriate data processing, a histogram of the voltage change over time and the height values ​​of each susceptor can be obtained. The specific data processing methods and implementation of the optical ranging device are conventional in the art. For example, the optical ranging device can be a laser rangefinder or a blue light ranging instrument. Based on the change in each susceptor height value over the test time, the individual runout differences (the absolute value of the difference between the test height value and the initial height value, where the initial height value is the susceptor height value measured at a susceptor rotation speed of 0) can be obtained. The average of the individual runout differences is the runout difference value for the corresponding axial runout at that rotation speed. Similarly, an optical ranging device emits probe light vertically toward the susceptor sidewall through an optical window on the sidewall of chamber 1. Data processing based on the received feedback light information and the emitted probe light information can be performed to determine the radial distances of the susceptor sidewall from the light outlet. According to the change of each radial distance during the test time, the runout difference under the corresponding radial runout at the speed can be obtained. Figure 3 As shown, as the speed increases, the axial runout difference decreases and becomes more stable, while the radial runout difference increases and becomes more pronounced. At high speeds, radial runout dominates (possibly due to high centrifugal force), while at low speeds, axial runout dominates (possibly due to the base weight, which is higher relative to the centrifugal force).

[0123] It is well known to those skilled in the art that the radial and axial runouts of the base are unavoidable due to structural factors such as the degree of tooth clearance matching of the reducer of the rotating motor and the stability of the connection between the support shaft and the bearing device. For the epitaxial growth process, the rotation of the base also has the function of dragging the gas flow field to mix it, which is beneficial to the quality of the film. The rotation and runout of the base, combined with factors such as temperature and pressure, play a role in the quality of the final film formed on the substrate. In terms of epitaxial growth process design, there are requirements for radial runout thresholds and axial runout thresholds. Generally, relevant runout threshold requirements are proposed based on the specific epitaxial growth process and product performance requirements. For example, taking the silicon carbide homoepitaxial growth process on a 6-inch silicon carbide substrate as an example, the product requires that the number of basal plane dislocations and stacking faults of the silicon carbide epitaxial layer obtained is less than 20. In terms of process design, the process speed is 900 rpm, the process pressure is 100 mbar, and the process gas flow rate of monosilane provided by the gas injection device is controlled to be 200 sccm to 400 sccm, the propane flow rate is 70 sccm to 150 sccm, and the hydrogen chloride flow rate is 2000 sccm to 5000 sccm. The control requirements for axial runout are higher than those for radial runout. The runout difference of axial runout is controlled below 0.5mm, and the runout difference of radial runout is controlled below 0.8mm. For obtaining the second calibration relationship corresponding to this epitaxial growth process, in step P02, when the base rotates at 900 rpm and the pressure in chamber 1 is 100 mbar, each lifting mechanism is controlled to run upward by 1 mm at a rate of 0.1 mm / s. During this process, the runout difference corresponding to the axial runout and radial runout of the base is obtained and compared with the control difference required by the process. If it is determined that it does not exceed the process requirements and the base is running smoothly, each lifting mechanism is controlled to run upward by 1 mm at a rate of 0.2 mm / s. During this process, the runout of the base is continued to be obtained and determined to see whether it meets the process requirements. Repeat this process until the axial runout difference and radial runout difference tested when the lifting mechanism is controlled to move at a speed of 0.4 mm / s are close to the process requirements, and the axial runout difference and radial runout difference tested when the lifting mechanism is controlled to move at 0.5 mm / s both exceed the process requirements. That is, 0.4 mm / s is used as the upper limit of the operating speed of each lifting mechanism used for real-time leveling of the base at the current rotation speed of the base (900 rpm).

[0124] In addition, during the monitoring of 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 monitored axial runout difference exceeds the limit required by the process is used as the test endpoint, and vice versa.

[0125] 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 rotate the appropriate upper limit of the lifting mechanism operation speed according to the corresponding relationship between the jumping threshold of the susceptor at different rotating speeds and the upper limit of the lifting mechanism operation speed.

[0126] 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 rotation 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 operation speed to move the lifting mechanism 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.

[0127] 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 for semiconductor manufacturing equipment, characterized in that: The semiconductor manufacturing equipment includes: a chamber, a base having a plurality of grooves, a heating device provided below the base, a dynamic seal penetrating the chamber and connected to a rotating device of the base, a lifting base provided on the rotating device, and a plurality of lifting mechanisms provided on the lifting base and connected to the chamber bottom plate to drive the base to move up and down, wherein the orthographic projection of the connection between the lifting mechanism and the chamber bottom plate toward the plane where the bearing top surface of the base is located is a projection mark; The temperature control method comprises: S0: Obtaining a first calibration relationship between the temperature difference of the base and the change in the distance between the heating device and the base at different set temperatures; S1: placing each substrate in the corresponding groove, controlling the rotating device to drive the base to rotate, and performing the epitaxial process; During the process of executing the epitaxial process in step S1, the following steps are also included: S11: obtaining a current temperature difference of each substrate based on a current surface temperature of each substrate and a target set temperature, and determining a target substrate with abnormal temperature, a corresponding target spacing change, and a predetermined adjustment direction based on each current temperature difference and the first calibration relationship; S12: determining a target lifting mechanism that needs to be lifted and lowered according to the number and position of the target substrates and the distance between the target substrates and the projection marks; S13: Control the target lifting mechanism to move the target distance change amount along the predetermined adjustment direction or the opposite direction of the predetermined adjustment direction.

2. The temperature control method according to claim 1, wherein: The number of the lifting mechanisms is at least 3, the projection marks are evenly distributed along the same circumferential direction on the plane where the bearing top surface is located, and there is at least one lifting mechanism in the two half areas of the plane where the bearing top surface is located.

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

4. The temperature control method according to claim 3, wherein: In step S12, if the number of projection marks closest to the target substrate is at least 2, then a lifting mechanism corresponding to at least one of the closest projection marks is selected as the target lifting mechanism.

5. The temperature control method according to claim 1, wherein: In step S11, the number of the target substrates is at least 2, and the absolute values ​​of the current temperature differences of at least two of the target substrates are different. The target substrate with the largest absolute value of the 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 used as the target lifting mechanism. In step S13, the target lifting mechanism is controlled to operate along the predetermined adjustment direction.

6. The temperature control method according to claim 5, wherein: The number of the priority target substrates is at least 2, and the absolute value of the current temperature difference of each 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 operate along the predetermined adjustment direction.

7. The temperature control method according to claim 1, wherein: The number of the target substrates is at least 2 and the current temperature difference of each 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 operate along the predetermined adjustment direction.

8. The temperature control method according to claim 1, wherein: The number of the target substrates is at least 2 and the current temperature difference of each is the same. In step S12, it is determined that the distances between each target substrate and the corresponding closest projection mark are consistent and are located in the same half of the plane where the carrier top surface is located. Then, the lifting mechanism corresponding to at least one projection mark in the other half of the plane where the carrier top surface is located is used as the target lifting mechanism. In step S13, the target lifting mechanism is controlled to operate in the opposite direction of the predetermined adjustment direction.

9. The temperature control method according to claim 8, wherein: Each of the target substrates is located in the same sector, the sector is centered on the center of the carrier top surface, and the radius line is circumscribed to the two target substrates respectively. The other half of the plane where the carrier top surface is located includes a symmetrical sector that is symmetrical to the sector axis. In step S12: When there is at least one projection mark in the symmetrical sector, the lifting mechanism corresponding to the at least one projection mark in the symmetrical sector is used as the target lifting mechanism; When the symmetrical sector does not have the projection mark, the lifting mechanism corresponding to at least one projection mark closest to the symmetrical sector is used as the target lifting mechanism.

10. The temperature control method according to claim 9, wherein: The central angle of the sector does not exceed 60 degrees.

11. The temperature control method according to 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 moves 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 a negative value, the predetermined adjustment direction approaches the area where the heating device is located.

12. The temperature control method according to claim 1, wherein: There is a process distance between the base and the heating device. 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 of the lifting mechanisms to synchronously rise or fall a certain distance; S03: obtaining the current steady-state temperature of the susceptor, and obtaining a calibration temperature difference based on the current steady-state temperature of the susceptor and the initial steady-state temperature, and obtaining and obtaining the spacing variation based on the displacement variation of each lifting mechanism and the process spacing; S04: Controlling each of the lifting mechanisms to continue to rise or fall synchronously by a certain distance; S05: Repeat steps S03 to S04 until the base is controlled to rise or fall to a corresponding position threshold, thereby obtaining a corresponding relationship between the calibrated temperature difference of the base and the distance change at the set temperature.

13. The temperature control method according to claim 12, wherein: In the step of obtaining the first calibration relationship, the distance between the base and the heating device is controlled to be no less than the minimum process distance to avoid motion interference between the base and the heating device, and the process distance is greater than the minimum process distance.

14. The temperature control method according to claim 1, wherein: Before executing the epitaxial process flow of step S1, the base has an initial horizontal position, and there is a process spacing between the base and the heating device. During any process of executing step S1, step S11, step S12 and step S13, it is determined whether the vertical distance of one side of the base relative to the initial horizontal position exceeds a preset distance threshold, and / or whether the minimum value of the process spacing is lower than the minimum process spacing. If so, the target lifting mechanism is controlled to stop running.

15. The temperature control method according to claim 14, wherein: The preset distance threshold does not exceed 0.5 mm.

16. The temperature control method according to any one of claims 13 or 14, characterized in that: The minimum process spacing is not less than 4 mm.

17. The temperature control method according to claim 1, wherein: The method further includes obtaining a second calibration relationship, the second calibration relationship being a correspondence between an axial runout difference threshold of the susceptor and an upper limit of an operating speed of the lifting mechanism at different speeds lower than the first speed threshold, the axial runout difference threshold being a maximum axial runout of the susceptor allowed by the epitaxial growth process at different speeds, and the first speed threshold not exceeding 400 rpm; In step S1, the rotating device is controlled to drive the base to rotate at a speed lower than the first speed threshold; Step S13 further includes obtaining a current rotation speed of the base and obtaining an upper limit of the operating speed of the target lifting mechanism in the second calibration relationship according to the current rotation speed of the base.

18. The control method according to claim 17, wherein: The method further includes obtaining an axial runout difference threshold and an axial runout difference threshold. In step S0, the step of obtaining the second calibration relationship is performed at room temperature, including: P01: controlling the process pressure in the chamber to maintain the process pressure required by the epitaxial process; P02: Controlling the rotating device to drive the base to rotate at a fixed speed, controlling each of the lifting mechanisms to synchronously ascend or descend at different movement speeds that increase in sequence, and using optical ranging to monitor the axial runout difference and axial runout difference of the base at each operating speed; P03: selecting the operating speed corresponding to the runout difference that reaches or is closest to the minimum of the axial runout difference threshold and the axial runout difference threshold as the corresponding operating speed upper limit at the fixed speed; P04: Control the rotation device to increase the rotation speed of the base to another fixed rotation speed; Repeat steps P02 to P04.

19. A semiconductor manufacturing device, characterized in that: include: A chamber, a base and a heating device, wherein the base is arranged in the chamber and has a plurality of grooves distributed along the circumference and respectively used to accommodate and limit the substrate, and the heating device is arranged between the base and the chamber bottom plate of the chamber; a rotating device with a dynamic seal extending through the chamber and connected to the base; a lifting base plate, located below the chamber and surrounding the rotating device; A plurality of lifting mechanisms are provided on the lifting bottom plate, are arranged along the circumference of the chamber and are connected to the chamber bottom plate of the chamber, so as to drive the base to perform lifting motion through the rotating device, and the orthographic projection of the connection between the lifting mechanism and the chamber bottom plate toward the plane where the bearing top surface of the base is located is a projection mark; an optical temperature measuring device, disposed above the chamber and used to measure the current surface temperature of each substrate; The main control device pre-stores a first calibration relationship and is communicatively connected to the rotating device, the optical temperature measuring device, the heating device, and each of the lifting mechanisms. The first calibration relationship is the correspondence between the calibrated temperature difference of the base and the change in the distance between the heating device and the base at different set temperatures.

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