Substrate processing apparatus and method of improving signal-to-noise ratio of a lower pyrometer

Abstract

The application provides a substrate processing device, which comprises a reaction cavity, a susceptor, a susceptor supporting device, a lower heating device, a lower reflecting plate and a lower pyrometer, the susceptor supporting device comprises a shaft and a plurality of arms, one end of the arm is connected with the shaft, and the other end of the arm is connected with the susceptor; the lower heating device is arranged below the reaction cavity; the lower pyrometer is arranged below the lower reflecting plate, a detection signal emitted by the lower pyrometer reaches a detection point on the back surface of the susceptor, and the detection signal is used for measuring the temperature below the susceptor; the detection signal emitted by the lower pyrometer forms an included angle with a vertical axis on a plane in which the susceptor is located in a radial direction, and the included angle is [‑15°, 30°]. The substrate processing device provided by the application reduces the influence of the rotation of the arm on the pyrometer and improves the signal-to-noise ratio.

Description

Technical Field

[0001] This invention relates to the field of semiconductor equipment technology, and in particular to a substrate processing device and a method for improving the signal-to-noise ratio of a thermometer. Background Technology

[0002] Existing semiconductor thin-film equipment, such as epitaxial growth equipment and CVD equipment, requires high temperatures for processing. During processing, a thermometer (e.g., a pyrometer) is needed to monitor the temperature of the substrate (or wafer) in real time and provide feedback to the temperature control system. The temperature control system then outputs the corresponding temperature to heat the substrate and pedestal to the required processing temperature. The thermometer must have extremely high measurement accuracy and repeatability, and during measurement, it needs a high signal-to-noise ratio to ensure the effectiveness and real-time performance of the pyrometer's measurements.

[0003] In addition, the uniformity of existing thin film deposition is greatly related to temperature and process gas flow field distribution. In order to ensure the uniformity of thin film deposition, existing technologies often use a rotating substrate.

[0004] However, as Figure 1 As shown, the rotation of the base 108 is driven by the base support device 104, which has multiple arms. The rotation of these multiple arms will block the thermometer 105, reducing the signal-to-noise ratio of the thermometer 105. Summary of the Invention

[0005] The purpose of this invention is to provide a substrate processing device and a method for improving the signal-to-noise ratio of a lower thermometer, in order to solve the problem of low signal-to-noise ratio of the lower thermometer.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] A substrate processing apparatus, comprising:

[0008] The reaction chamber is used for substrate processing.

[0009] A base, placed inside the reaction chamber, is used to support the substrate;

[0010] A base support device for supporting the base, the base support device including a shaft and a plurality of arms, one end of the arm being connected to the shaft and the other end of the arm being connected to the base;

[0011] A lower heating device is placed below the reaction chamber to provide thermal radiation to the reaction chamber during the process.

[0012] The lower reflector is used to reflect the thermal radiation from the lower heating device into the reaction chamber;

[0013] The lower thermometer is placed below the lower reflector. The detection signal emitted by the lower thermometer reaches the detection point on the back of the base and is used to measure the temperature below the base. The detection signal emitted by the lower thermometer forms an angle with the vertical axis on the radial plane of the base, and the angle is [-15°, 30°].

[0014] Optionally, the lower reflector includes an annular plate having an opening through which the detection signal passes to the back of the base.

[0015] Optionally, the lower reflector further includes an annular sidewall, one end of which is connected to one end of the annular plate, and the annular sidewall is a complete ring.

[0016] Optionally, the included angle is [-10°, 20°].

[0017] Optionally, the included angle is 0°.

[0018] Optionally, the distance from the detection point to the center of the base is [50mm, 150mm].

[0019] Optionally, the distance is [70mm, 135mm].

[0020] Optionally, the distance is [80mm, 125mm].

[0021] Optionally, the lower heating device includes a plurality of heating lamps.

[0022] Optionally, the lower heating device includes a lower outer ring heating lamp group and a lower inner ring heating lamp group, both of which are arranged in a ring. The lower outer ring heating lamp group is used to heat the outer ring of the base, and the lower inner ring heating lamp group is used to heat the inner ring of the base.

[0023] Optionally, the lower reflector includes a lower inner ring reflector and a lower outer ring reflector. The lower inner ring reflector is used to reflect the heat radiation of the lower inner ring heating lamp assembly, and the lower outer ring reflector is used to reflect the heat radiation of the lower outer ring heating lamp assembly.

[0024] Optionally, the lower thermometer is positioned below the lower inner ring reflector.

[0025] Optionally, the lower inner ring reflector includes an annular plate and an annular sidewall. The annular plate has an opening, and one end of the annular sidewall is connected to one end of the annular plate. The annular sidewall is a complete ring.

[0026] Optionally, the opening is circular.

[0027] Optionally, the lower thermometer is a pyrometer.

[0028] This invention also discloses a method for improving the signal-to-noise ratio of a lower thermometer, the method comprising:

[0029] Step 1: Provide the substrate processing apparatus as described above;

[0030] Step 2: Make the detection signal emitted by the lower thermometer form an angle with the vertical axis on the radial plane of the base, wherein the angle is [-15°, 30°].

[0031] Optionally, the method further includes: step three, making the distance from the detection point on the back of the base to the center of the base [50mm, 150mm]; step three is performed before step two, or simultaneously with step two, or after step two.

[0032] Optionally, the included angle is [-10°, 20°].

[0033] Optionally, the included angle is 0°.

[0034] Optionally, the distance is [80mm, 125mm].

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] By setting a special included angle θ and distance S, unlike the existing technology that centers the detection point, this method moves the detection point away from the center, reducing the impact of arm rotation on the pyrometer and improving the signal-to-noise ratio. In particular, it eliminates the need for a notch on the lower reflector, avoiding uneven heating caused by heat radiation leakage. At the same time, the accuracy of temperature measurement is greatly increased when the included angle θ is in the range of -5° to 5°, and the advantage is even more obvious when the included angle θ is at 0°. Attached Figure Description

[0037] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the drawings described below are one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort:

[0038] Figure 1 This is a schematic diagram of the structure of a substrate processing device in the prior art;

[0039] Figure 2 This is a schematic diagram of the detection signal path in the prior art;

[0040] Figure 3 This is a graph showing test data from a thermometer in the existing technology.

[0041] Figure 4 This is a schematic diagram of the structure of the lower reflector in the prior art;

[0042] Figure 5 This is a schematic diagram of the substrate processing equipment of the present invention;

[0043] Figure 6 This is a schematic diagram showing the relationship between the thermometer and the included angle θ.

[0044] Figure 7 This is a schematic diagram of the structure of the lower reflector of the present invention;

[0045] Figure 8 This is a graph showing the test data of the thermometer of the present invention. Detailed Implementation

[0046] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, further illustrates the solution proposed by the present invention. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, used only to facilitate and clearly illustrate the embodiments of the present invention. Please refer to the drawings to make the objectives, features, and advantages of the present invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation conditions of the present invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by the present invention, should still fall within the scope of the technical content disclosed in the present invention.

[0047] Figure 1 This is a schematic diagram of the structure of a substrate processing device in the prior art. For example... Figure 1As shown, the substrate processing equipment includes a reaction chamber, a base 108, a base support device 104, a heating device 102, a reflector 106, and a thermometer. The reaction chamber includes an upper dome 103, a lower dome 107, and a flange that seals and fixes the upper and lower domes. The reaction chamber is used for processing the substrate. The base 108 is placed inside the reaction chamber to support the substrate. The base support device 104 supports the base 108 and includes a shaft and multiple arms. One end of each arm is connected to the shaft, and the other end of each arm is connected to the base. Rotation of the shaft drives the multiple arms to rotate, thereby driving the base 108 to rotate. The heating device... A heating element 102 is used to provide thermal radiation to the reaction chamber during the process. It includes an upper heating element positioned above the reaction chamber and a lower heating element positioned below it. A reflector 106 is used to reflect the thermal radiation from the heating elements into the reaction chamber. The reflector 106 includes an upper reflector and a lower reflector. The upper reflector reflects the thermal radiation from the upper heating element into the reaction chamber, and the lower reflector reflects the thermal radiation from the lower heating element into the reaction chamber. Optionally, depending on the configuration of the lower heating element, the lower reflector may consist only of a lower reflector, or it may include a lower inner ring reflector and a lower outer ring reflector. The reaction chamber has an inlet on one side and an outlet on the other side. Process gas enters the reaction chamber through the inlet and, under the thermal radiation of the heating elements, decomposes and reacts to grow a thin film on the substrate. The upper thermometer 101, positioned at the center above the reaction chamber, monitors the temperature at the center of the substrate's upper surface. The lower thermometer 105 monitors the temperature approximately 20 mm from the center of the lower surface of the base 108. The upper thermometer 101 is primarily used during temperature calibration because the substrate's upper surface is a smooth sheet with constant emissivity during calibration, resulting in a stable reading for the upper thermometer 101. However, the shape of the substrate's upper surface varies depending on the process and product, causing variations in emissivity and affecting the upper thermometer 101's reading. The lower thermometer 105 measures the emissivity of a silicon carbide coating on the lower surface of the base, and therefore, its data is typically used as temperature feedback for the process. Figure 2 However, the base support device 104 has several arms on its upper part. When the base support device 104 rotates, and the arms reach the detection signal P of the pyrometer, they will periodically have a significant impact on the measured value of the lower thermometer 105. For details of the impact, please refer to the appendix. Figure 3 , Figure 3The figure shows data from a prior art test using a lower thermometer 105. The readings of the thermometer 105 after one rotation are shown. Horizontal values ​​represent valid signals, while triangular values ​​represent interference signals. The valid signal accounts for approximately 38%, resulting in a low signal-to-noise ratio. Signals acquired during process handling require processing, specifically filtering interference signals. When the base 108 temperature is stable, filtering interference signals has little impact on temperature control. However, during the heating or cooling process of the base 108, the interference signal accounts for a significant proportion. If this interference signal is filtered out, the temperature feedback received by the temperature control system will be distorted and delayed, preventing the temperature control system from outputting the appropriate power in a timely and accurate manner to heat the base 108 to the required temperature.

[0048] Not only that, such as Figure 1 As shown, in the prior art, the lower thermometer 105 forms an angle θ with the vertical axis yy' on the radial plane of the base. This angle θ is large enough to ensure that the detection signal P reaches the detection point on the back of the base 108 near the center of the base, a distance of approximately 10-20 mm. Because the detection point is near the center of the base 108, the detection signal P is also very close to the center (i.e., the axis) of the base support device 104. Therefore, the detection signal P is blocked by the arm for a longer time, resulting in a low signal-to-noise ratio. Furthermore, due to the large angle, the lower reflector needs a separate notch 1065 to avoid obstructing the detection signal P. Figure 4 It can be seen that the lower reflector includes an annular plate 1061 and an annular sidewall 1063. One end of the annular sidewall is connected to one end of the annular plate. Both the annular plate 1061 and the annular sidewall 1063 are provided with notches 1065 to avoid the detection signal P. Such notches cause the heat radiation of the lower heating device to leak from the notches, resulting in uneven heat distribution and ultimately uneven film deposition.

[0049] like Figure 5 The diagram shows a schematic of a substrate processing device provided by the present invention. A lower thermometer 105 is placed below the lower reflector. The detection signal P emitted by the lower thermometer reaches the detection point O2 on the back of the base 108, used to measure the temperature below the base 108. The detection signal emitted by the lower thermometer forms an angle θ with the vertical axis yy' on the radial plane of the base 108. When the detection signal P is parallel to the vertical axis yy', the angle θ is 0° (e.g., ...). Figure 5 As shown in the diagram, when the detection signal P deflects from 0° toward the center O1 of the base 108, the included angle θ is negative (as shown in the diagram). Figure 1As shown in the figure, when the detection signal P deflects from 0° toward the edge of the base 108, the included angle θ is positive (not shown in the figure). The included angle θ of the present invention deflects very little toward the center O1, or even not toward the center O1 (i.e., θ is 0°), or even deflects toward the edge of the base 108. Optionally, the included angle θ is [-15°, 30°]. Such an included angle θ can make the detection signal P reach the detection point O2 on the back of the base 108 away from the center O1 of the base. Then the distance between the detection signal P and the center (i.e., the axis) of the base support device 104 also becomes farther. Therefore, compared with the prior art, at the same rotation speed of the base support device 104, the time when the detection signal P is blocked by the arm is shorter, which ultimately improves the signal-to-noise ratio. Optionally, the included angle is [-10°, 20°]. This can make the detection signal P further away from the center (i.e., the axis) of the base support device 104, and improve the signal-to-noise ratio.

[0050] Based on the above principle, when the detection signal P reaches the detection point O2 on the back of the base 108 at the edge of the base 108, the detection signal P is blocked by the arm for the shortest time, resulting in the highest signal-to-noise ratio. However, experiments have shown that... Figure 6 As shown, when the thermometer is placed vertically to measure the temperature of a horizontal plate, the detection signal is parallel to the vertical axis yy' (i.e., the included angle θ is 0°, as shown in the figure). Figure 6 The temperature measurement accuracy is highest when the angle is less than or equal to 5° (at position S1), followed by when the angle θ is between 5° and 30° (e.g., at position S1). Figure 6 At position S2, the temperature measurement accuracy of the detection signal is also relatively high, but when the included angle θ is greater than 30° (e.g., ... Figure 6 In the case of the S3 position, the accuracy of the temperature measurement by the detection signal cannot be guaranteed. Therefore, it is further preferred that the included angle θ is [-5°, 20°]. When further considering the temperature accuracy, it is preferred that the included angle θ is [-5°, 5°]. More preferably, the included angle θ is [0°, 20°]. When further considering the temperature accuracy, it is preferred that the included angle θ is [0°, 5°]. Preferably, the included angle θ is 0°, which has the highest temperature accuracy.

[0051] like Figure 5 As shown, the setting of the included angle θ ensures that the detection point O2 is far away from the base center O1. The distance S from the detection point O2 to the base center O1 is [50mm, 150mm]. In order to improve the signal-to-noise ratio, the detection signal P needs to be further away from the center O1 of the base support device 104. Optionally, the distance S is [70mm, 135mm]. However, due to the obstruction of the lower outer ring reflector, the detection signal P is difficult to reach the vicinity of the base edge. Therefore, preferably, the distance S is [80mm, 125mm].

[0052] This invention avoids creating a notch on the annular sidewall of the lower reflector, such as... Figure 7 As shown, the lower reflector of the present invention includes an annular plate 1061 and an annular sidewall 1063. The annular plate has an opening 1067 through which the detection signal reaches the back of the base. One end of the annular sidewall is connected to one end of the annular plate, and the annular sidewall is a complete ring. It can be seen that the lower reflector of the present invention has an opening only on the annular plate, minimizing the impact on heat radiation leakage and non-uniform temperature distribution.

[0053] Specifically, both the upper and lower heating devices include several heating lamps, optionally halogen lamps. The lower heating device includes a lower outer ring heating lamp group and a lower inner ring heating lamp group, both arranged in a ring. The lower outer ring heating lamp group heats the outer ring of the base, and the lower inner ring heating lamp group heats the inner ring of the base. The lower inner ring reflector reflects the heat radiation from the lower inner ring heating lamp group, and the lower outer ring reflector reflects the heat radiation from the lower outer ring heating lamp group. Specifically, both the lower inner ring reflector and the lower outer ring reflector include an annular plate and an annular sidewall, with one end of the annular sidewall connected to one end of the annular plate. Optionally, the lower thermometer is placed below the lower inner ring reflector. The annular plate of the lower inner ring reflector has an opening, and the annular sidewall of the lower inner ring reflector is a complete ring; optionally, the opening is circular. Optionally, the lower thermometer is a pyrometer.

[0054] Methods to improve the signal-to-noise ratio of a thermometer include:

[0055] Step 1: Provide the substrate processing equipment described above;

[0056] Step 2: Make the detection signal emitted by the lower thermometer form an angle with the vertical axis on the radial plane of the base, wherein the angle is [-15°, 30°].

[0057] The method further includes: Step three, making the distance from the detection point on the back of the base to the center of the base [50mm, 150mm]; Optionally, Step three is performed before Step two, simultaneously with Step two, or after Step two. Specifically, in Step three, the distance S can be adjusted simultaneously by adjusting the included angle θ; or the included angle θ is fixed, and the distance S is adjusted by moving the lower thermometer radially along the base; Optionally, both the included angle and the distance in the method can be within the range described above.

[0058] Figure 8The graph shows the test data of the lower thermometer of this invention. The experiment was conducted with an included angle θ of 0° and a distance S of 98mm. As can be seen, the effective signal ratio increased from 38% to 71%. When the base is heating or cooling, the effective signal fed back by the lower thermometer 105 is greatly improved, which in turn improves the timeliness and accuracy of the output power of the temperature control system. It can accurately and efficiently heat the base 108 to the required temperature, thereby improving the stability of related epitaxial process products.

[0059] In summary, the substrate processing device and method for improving the signal-to-noise ratio of a lower thermometer provided by this invention, through the setting of a special included angle θ and distance S, differs from the prior art in that the detection point is brought towards the center. By moving the detection point away from the center, the influence of arm rotation on the pyrometer is reduced, thus improving the signal-to-noise ratio. In particular, it eliminates the need for a notch on the lower reflector, avoiding uneven heating caused by heat radiation leakage. At the same time, the accuracy of temperature measurement is greatly increased when the included angle θ is in the range of [-5°, 5°], and the advantage is even more obvious when the included angle θ is at 0°.

[0060] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0061] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A substrate processing apparatus, characterized in that, include: The reaction chamber is used for substrate processing. A base, placed inside the reaction chamber, is used to support the substrate; A base support device for supporting the base, the base support device including a shaft and a plurality of arms, one end of the arm being connected to the shaft and the other end of the arm being connected to the base; A lower heating device is placed below the reaction chamber to provide thermal radiation to the reaction chamber during the process. The lower reflector is used to reflect the thermal radiation from the lower heating device into the reaction chamber; The lower thermometer is placed below the lower reflector. The detection signal emitted by the lower thermometer reaches the detection point on the back of the base and is used to measure the temperature below the base. The detection signal emitted by the lower thermometer forms an angle with the vertical axis on the radial plane of the base, and the angle is [-15°, 30°]. in, The lower heating device includes several heating lamps; The lower heating device includes a lower outer ring heating lamp group and a lower inner ring heating lamp group. Both the lower outer ring heating lamp group and the lower inner ring heating lamp group are arranged in a ring. The lower outer ring heating lamp group is used to heat the outer ring of the base, and the lower inner ring heating lamp group is used to heat the inner ring of the base. The lower reflector includes a lower inner ring reflector and a lower outer ring reflector. The lower inner ring reflector is used to reflect the heat radiation of the lower inner ring heating lamp assembly, and the lower outer ring reflector is used to reflect the heat radiation of the lower outer ring heating lamp assembly. The lower thermometer is positioned below the lower inner ring reflector. The lower inner ring reflector includes an annular plate and an annular sidewall. The annular plate has an opening, and one end of the annular sidewall is connected to one end of the annular plate. The annular sidewall is a complete ring.

2. The substrate processing apparatus as described in claim 1, characterized in that, The lower reflector includes an annular plate with an opening through which the detection signal passes to the back of the base.

3. The substrate processing apparatus as described in claim 2, characterized in that, The lower reflector also includes an annular sidewall, one end of which is connected to one end of the annular plate, and the annular sidewall is a complete annulus.

4. The substrate processing apparatus as described in claim 1, characterized in that, The included angle is [-10°, 20°].

5. The substrate processing apparatus as described in claim 1, characterized in that, The included angle is 0°.

6. The substrate processing apparatus as claimed in claim 1, characterized in that, The distance from the detection point to the center of the base is [50mm, 150mm].

7. The substrate processing apparatus as described in claim 6, characterized in that, The distance is [70mm, 135mm].

8. The substrate processing apparatus as described in claim 6, characterized in that, The distance is [80mm, 125mm].

9. The substrate processing apparatus as described in claim 1 or 2, characterized in that, The opening is circular.

10. The substrate processing apparatus according to any one of claims 1-8, characterized in that, The lower thermometer is a pyrometer.

11. A method for improving the signal-to-noise ratio of a thermometer, characterized in that, The method includes: Step 1: Provide a substrate processing apparatus as described in any one of claims 1-10; Step 2: Make the detection signal emitted by the lower thermometer form an angle with the vertical axis on the radial plane of the base, wherein the angle is [-15°, 30°].

12. The method as described in claim 11, characterized in that, The method further includes: step three, making the distance from the detection point on the back of the base to the center of the base [50mm, 150mm]; step three is performed before step two, or simultaneously with step two, or after step two.

13. The method as described in claim 11, characterized in that, The included angle is [-10°, 20°].

14. The method as described in claim 11, characterized in that, The included angle is 0°.

15. The method as described in claim 12, characterized in that, The distance is [80mm, 125mm].

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