Back temperature control device and method for heating base of thin film equipment

Abstract

The present invention discloses a back temperature control device and temperature control method for a heating base of a thin film device, comprising an upper chamber, a lower chamber, a heating base and a back temperature control device, the heating base is installed in the lower chamber, the upper chamber is connected to the lower chamber, an exhaust ring is provided between the upper chamber and the lower chamber, a vacuum pump is externally connected to the exhaust ring, a spray plate is provided on the upper chamber, the spray plate is located directly above the heating base, an air intake channel is provided inside the upper chamber, the back temperature control device is installed on the back of the heating base, the back temperature control device is in contact with the heating base, a reaction vacuum chamber is formed between the upper chamber and the lower chamber, a reaction space is formed between the heating base and the upper chamber, a wafer is provided on the heating base, the present invention solves the problem of uneven thin film deposition caused by uneven heating of the wafer during heating, and the temperature of a specific area of the base can be adjusted by providing a temperature control device on the back of the base, thereby improving the overall temperature uniformity and controlling the thickness uniformity of the film.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor equipment, and in particular to a back temperature control device and a temperature control method for a heating base of a thin film device. Background Art

[0002] In the wafer thin film deposition process, especially in chemical vapor deposition, the wafer needs to be heated. The wafer needs to be heated to a certain temperature range so that the process gas can nucleate and form a film on the wafer surface. There are many forms of wafer heating. In the thin film deposition equipment for single wafers, the temperature range is between 100℃ and 650℃, and the wafer is placed on the disc heater for direct heating. In order to obtain a uniform film thickness, on the one hand, it is necessary to evenly diffuse the gas flowing in from above, and on the other hand, the temperature of the heater needs to be evenly controlled. Since the heater uses an internal buried heating wire, the heating wire heats up when it is powered on. Since the heating wire cannot be arranged completely evenly and the heat generated on the heating wire will be different, the temperature on the heating disk is not completely consistent. The temperature uniformity of the heating disk has become an important indicator for judging the performance of the heating disk and is also an important factor affecting thin film deposition.

[0003] To improve the overall temperature uniformity of the heater, existing heating plate manufacturers divide the heating plate into multiple zones and control their temperatures separately. However, this zoned temperature control method is still not precise enough, as individual temperature zones are large and can still experience significant temperature fluctuations within a zone. Therefore, the present invention proposes a locally adjustable temperature control device for the back of the heating base. Summary of the Invention

[0004] The purpose of the present invention is to provide a back temperature control device and a temperature control method for a heating base of a thin film device, so as to solve the problems raised in the above background technology.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions:

[0006] A back temperature control device for a heating base of a thin film device comprises an upper chamber, a lower chamber, a heating base and a back temperature control device, wherein the heating base is installed in the lower chamber, the upper chamber is connected to the lower chamber, and a closed cavity space is formed between the upper and lower chambers, an exhaust ring is provided between the upper and lower chambers, the exhaust ring corresponds to the outer periphery of the heating base, a vacuum pump is externally connected to the exhaust ring, a spray plate is provided on the upper chamber, the spray plate is located directly above the heating base, an air inlet channel is provided inside the upper chamber, the back temperature control device is installed on the back of the heating base, the back temperature control device is in contact with the heating base, and a reaction vacuum is formed between the upper and lower chambers. The chamber is provided with a reaction space between the heating base and the upper chamber, a wafer is arranged on the heating base, and the heat of the wafer is directly transferred through the heating base, and the back temperature control device is used to adjust the temperature of the back of the heating base; the back temperature control device (4) comprises an adjusting porous disk (41), a fixed porous disk (42), a reflecting plate (43) and a contact block (44), the adjusting porous disk (41) is in contact with the heat conducting portion (31) of the heating base (3), the fixed porous disk (42) is installed below the adjusting porous disk (41), and the reflecting plate (43) and the contact block (44) are both arranged in the adjusting porous disk (41).

[0007] Preferably, the heating base includes a disk surface and a columnar portion, the disk surface is a disk-shaped heating area, the columnar portion is arranged below the center of the disk surface, the disk surface includes a heat-conducting portion and a heating portion, the heating portion is composed of a resistance wire, the heating portion is embedded in the heat-conducting portion, and the back temperature control device is installed at the bottom of the heat-conducting portion.

[0008] Preferably, the adjusting porous disk is provided with an adjusting opening area, the shape of the adjusting opening area can be fan-shaped, connecting ribs are provided between adjacent adjusting opening areas, and adjacent adjusting opening areas are directly separated by the connecting ribs, and a stepped trough is provided at the bottom of the adjusting opening area on the adjusting porous disk, the outer contour of the stepped trough is larger than the adjusting opening area, the reflecting plate is arranged in the stepped trough, the thickness of the reflecting plate matches the depth of the stepped trough, the contact block matches the adjusting opening area, the contact block is arranged in the adjusting opening area, the upper end of the contact block contacts the bottom surface of the heating base, the contact block is located above the fixed porous disk, the fixed porous disk is provided with a contoured opening area, the size of the contoured opening area is smaller than the hole size of the upper adjusting porous disk, and the outer contour size of the stepped trough is larger than the hole size of the adjusting porous disk.

[0009] Preferably, a through hole is provided in the center of the regulating porous disk, and the diameter of the through hole is larger than the diameter of the columnar portion of the heating base. The back temperature control device can be divided into a first heat conduction area, a second heat conduction area, and a third heat conduction area according to the type of heat transfer. The first heat conduction area includes a heat transfer area and a first heat convection area, the second heat conduction area includes a radiation transfer area, a partition area and a second heat convection area, and the third heat conduction area includes a third heat convection area and a fourth heat convection area. The first heat conduction area, the second heat conduction area and the third heat conduction area are all separated by connecting ribs.

[0010] Preferably, a connecting device is further provided in the lower cavity, one end of the connecting device is installed at the bottom end of the columnar portion of the heating base, and the other end of the connecting device is connected to the back temperature control device. The connecting device fits the back temperature control device tightly to the back side of the heating base, and the connecting device fits the heating base and the back temperature control device. Point contact is adopted between the connecting device, the heating base and the back temperature control device.

[0011] Preferably, an air inlet channel is provided on the lower chamber, and one end of the air inlet channel is connected to a gas input pipeline.

[0012] A method for controlling the back temperature of a thin film device heating base is tested by the following steps:

[0013] S1. Acquisition of raw temperature data: Remove all reflectors and contact blocks, and only install the adjustable and fixed porous plates. Place a TC-Wafer on the base to detect temperature uniformity on the base. Heat the heating plate to obtain a temperature map of the base, and mark points with higher and lower temperatures.

[0014] Adjust the temperature control device on the back of S2: After cooling the base, remove it. For points with higher temperatures, increase heat dissipation by installing contact blocks at the corresponding locations; for points with lower temperatures, install reflective plates to reduce heat dissipation.

[0015] S3 Temperature Data Acquisition: After reinstalling the base, increase the temperature and measure the temperature uniformity of the base again using TC-Wafer. Adjust the temperature difference at all locations to approximately 1% of the set temperature. If it does not meet the requirements, repeat steps S2 and S3 until the temperature uniformity meets expectations.

[0016] Beneficial Effects: The present invention solves the problem of uneven thickness of thin film deposition caused by uneven heating of wafers during heating. By setting a temperature control device on the back of the base, the present invention utilizes the different thermal conductivity properties of different materials to selectively control the heat, control the speed, and control the temperature of selected areas. It can also improve the overall temperature uniformity by adjusting the local area, thereby improving the temperature uniformity of the wafer and the uniformity of thin film deposition.

[0017] The present invention can achieve local precise adjustment during the temperature adjustment process. The adjustment area is very small, which can be more precise. Each specific area has three different degrees of modes, corresponding to different heat transfer speeds, which can more accurately make the overall temperature of the base consistent. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a cross-sectional view of the cavity of the present invention;

[0019] Figure 2 This is a schematic diagram showing the structure of a back temperature control device;

[0020] Figure 3 This is an overall plan view of an embodiment for illustrating the adjustment of a porous disk;

[0021] Figure 4 This is a partial detail diagram of an embodiment for illustrating the adjustment of a porous disk;

[0022] Figure 5 This embodiment is used to illustrate an alternative solution for adjusting the shape of the openings on the porous disk;

[0023] Figure 6 This embodiment is used to demonstrate that the adjustable step sink is set on a fixed porous plate;

[0024] Figure 7 Schematic diagram of the control method of the present invention;

[0025] Figure 8 This is an embodiment used to show the temperature map before adjusting the back temperature control device;

[0026] Figure 9 This is an example used to show the temperature map after adjusting the back temperature control device.

[0027] Figure markings: 1. Upper cavity; 2. Lower cavity; 21. Air inlet channel; 3. Heating base; 31. Heat conducting part; 32. Heat generating part; 4. Back temperature control device; 41. Adjustable porous disk; 410. Through hole; 411. Adjustable opening area; 412. Connecting rib; 413. Stepped sink; 42. Fixed porous disk; 43. Reflecting plate; 44. Contact block; 100. Heat transfer area; 101. First heat convection area; 201. Radiation transfer area; 202. Partition area; 203. Second heat convection area; 300. Third heat convection area; 301. Fourth heat convection area; 6. Exhaust ring. DETAILED DESCRIPTION

[0028] The following description is merely a preferred embodiment of the present invention, and the scope of protection is not limited to this embodiment. All technical solutions based on the principles of the present invention should be within the scope of protection of the present invention. It should also be noted that improvements and modifications that do not depart from the principles of the present invention, which are within the scope of protection of the present invention, are within the scope of protection of the present invention.

[0029] like Figure 1 As shown, a single wafer thin film deposition chamber includes an upper chamber 1, a lower chamber 2, a heating base 3, and a back temperature control device 4. The heating base 3 is installed in the lower chamber 2, and the upper chamber 1 is connected to the lower chamber 2. A closed chamber space is formed between the upper chamber 1 and the lower chamber 2. An exhaust ring 6 is provided between the upper chamber 1 and the lower chamber 2. The exhaust ring 6 corresponds to the outer periphery of the heating base 3. The exhaust ring 6 is externally connected to a vacuum pump. The exhaust ring 6 is connected to the vacuum pump. The exhaust ring 6 is used to extract the by-products of the reaction out of the reaction chamber in time.

[0030] A spray plate is provided on the upper chamber 1, and the spray plate is located directly above the heating base 3. An air inlet channel 21 is provided inside the upper chamber 1. The reaction gas flows into the air inlet channel 21, is evenly distributed at the spray plate, and then flows to the heating base 3. The back temperature control device 4 is installed on the back of the heating base 3. The back temperature control device 4 is in contact with the heating base 3. A reaction vacuum chamber is formed between the upper chamber 1 and the lower chamber 2, and a reaction space is formed between the heating base 3 and the upper chamber 1. The process gas reacts here. A wafer is provided on the heating base 3, and the heat of the wafer is transferred through direct contact with the heating base 3. The back temperature control device 4 adjusts the temperature of the back of the heating base 3.

[0031] A connecting device is also provided in the lower cavity 2, one end of the connecting device is installed at the bottom end of the columnar part of the heating base 3, and the other end of the connecting device is connected to the back temperature control device 4. The connecting device fits the back temperature control device 4 tightly to the back side of the heating base 3, and the connecting device achieves fitting between the heating base 3 and the back temperature control device 4. The connecting device adopts point contact with the heating base 3 and the back temperature control device 4. The connection contact area between the connecting device and the heating base 3 is small, so that the impact of the heat brought out is reduced to a minimum. The contact area between the connecting device and the back temperature control device 4 is also small, and multiple, small-area contact methods are adopted, which does not affect the airflow disturbance on the back of the back temperature control device 4.

[0032] An air inlet channel 21 is provided on the lower cavity 2, and one end of the air inlet channel 21 is connected to a gas input pipeline. The gas can be nitrogen, helium or argon. When nitrogen is selected, the other end of the air inlet channel 21 is used to diffuse the nitrogen, and it enters the cavity in a circular shape and evenly moves upward, and blows towards the back temperature control device 4 to take away the heat.

[0033] like Figure 2As shown, the heating base 3 includes a disk surface and a columnar portion. The disk surface is a disk-shaped heating area. The columnar portion is arranged below the center of the disk surface. The columnar portion is made of a material with a good thermal insulation coefficient. The disk surface includes a heat-conducting portion 31 and a heating portion 32. The heating portion 32 is composed of a resistance wire. The heating portion 32 is embedded in the heat-conducting portion 31. The heat-conducting portion 31 is made of a high thermal conductivity material. The back temperature control device 4 is installed at the bottom of the heat-conducting portion 31. Due to the uneven arrangement gaps of the heating portion 32 and the poor contact between the heating portion 32 and the heat-conducting portion 31, the heat reflected on the disk surface of the heating base 3 is not completely uniform.

[0034] like Figure 2-4 As shown, the back temperature control device 4 includes an adjusting porous disk 41, a fixed porous disk 42, a reflecting plate 43, and a contact block 44. The adjusting porous disk 41 is in contact with the heating disk surface of the heating base 3, the fixed porous disk 42 is located below the adjusting porous disk 41, the reflecting plate 43 and the contact block 44 are arranged in the adjusting porous disk 41, and an adjusting opening area 411 is opened on the adjusting porous disk 41. The shape of the adjusting opening area 411 can be a fan shape or the like. Connecting ribs 412 are provided between adjacent adjusting opening areas 411, and adjacent adjusting opening areas 411 can be directly separated by the connecting ribs 412.

[0035] A stepped groove 413 is provided at the bottom of the adjustment opening area 411 on the adjustment porous disk 41. The outer contour of the stepped groove 413 is slightly larger than the adjustment opening area 411. The reflective plate 43 is disposed in the stepped groove 413. The thickness of the reflective plate 43 matches the depth of the stepped groove 413. The outer contour and height of the contact block 44 match the contour and height of the adjustment opening area 411. The contact block 44 is disposed in this area. The upper end of the contact block 44 contacts the bottom surface of the heating base 3. The contact block 44 is located above the fixed porous disk 42.

[0036] The fixed porous disk 42 is provided with a contoured opening area. The outer contour of the contoured opening area is similar to that of the adjustable opening area 411, but the size is different. The size (D1) of the contoured opening area is smaller than the hole size (D2) of the upper adjustable porous disk 41, so that the contact block 44 will not fall and will be fixed. The outer contour size (D3) of the stepped groove 413 is larger than the hole size (D2) of the adjustable porous disk 41.

[0037] See Figure 5 The adjustment opening area 411 on the adjustment porous disk 41 can be set to a square or hexagonal shape, and the corresponding contoured opening area on the fixed porous disk 42 also has an opening area with a similar shape. The size (D1) of the contoured opening area is smaller than the hole size (D2) of the upper adjustment porous disk 41, so that the contact block 44 will not fall and will be fixed. The outer contour size (D3) of the stepped sinking groove 413 is larger than the hole size (D2) of the adjustment porous disk 41.

[0038] See Figure 6The stepped groove 413 can also be set at the upper end of the fixed porous disk 42, and the reflective plate 43 is set in the stepped groove 413 of the fixed porous disk 42; the contact block 44 is set in the adjustment opening area 411 and the stepped groove 413, and the stepped groove 413 is opened at the upper end of the fixed porous disk 42 and the bottom of the adjustment opening area 411 on the adjustment porous disk 41. The two functions are the same, and the user can choose to open them in two positions.

[0039] A through hole 410 is provided in the center of the adjusting porous disk 41. The diameter of the through hole 410 is slightly larger than the diameter of the columnar portion of the heating base 3, so as to facilitate the installation of the adjusting porous disk 41 on the heating base 3. The back temperature control device 4 can be divided into three types according to the type of heat transfer: the first heat conduction area, the second heat conduction area, and the third heat conduction area; the first heat conduction area includes the heat transfer area 100 and the first heat convection area 101. The heat conduction area is directly in contact with the heating base 3 by the contact block 44 to quickly bring out the heat in the form of heat transfer. The first heat convection area 101 brings out the heat on the bottom surface of the contact block 44 in the form of heat convection; the second heat conduction area The domain includes a radiation transfer area 201, a partition area 202 and a second heat convection area 203; there is no airflow inside the radiation transfer area 201, so the heat can only be transferred to the reflective plate 43 on the partition area 202 by thermal radiation. This transfer method greatly reduces the heat transfer efficiency and achieves the effect of heat preservation; there is flowing gas in the second heat convection area 203, and the gas takes the heat out of this area; the third heat conduction area includes a third heat convection area 300 and a fourth heat convection area 301, and gas can flow between the third heat convection area 300 and the fourth heat convection area 301, and the gas takes the heat away from this area. The first heat conduction area, the second heat conduction area and the third heat conduction area have different heat conduction methods, so the heat loss rate of different areas can be controlled to achieve separate local regulation.

[0040] The first heat conducting area, the second heat conducting area and the third heat conducting area are separated by the connecting ribs 412 , which isolates the airflow between two adjacent areas and reduces the influence between different heat conducting areas.

[0041] like Figure 7 As shown, a method for controlling the back temperature of a thin film device heating base 3 is tested by the following steps:

[0042] S1. Acquisition of original temperature data: Remove all reflective plates 43 and contact blocks 44, and only install the adjustable porous plate 41 and the fixed porous plate 42. Place a TC-Wafer on the base to detect the temperature uniformity on the base. Heat the heating plate to obtain the temperature map of the base, and mark the points with higher and lower temperatures. Figure 8 As shown in the figure, when the set temperature is 650℃, the maximum temperature difference on the heating plate is 14.1℃.

[0043] S2 Adjustment of the back temperature control device 4: After cooling the base, remove it. For the locations with higher temperatures, it is necessary to increase heat dissipation. Contact blocks 44 are set at the corresponding locations; for the locations with lower temperatures, reflective plates 43 are set to reduce heat dissipation.

[0044] S3 Temperature data acquisition: After the base is installed, heat it up and measure the temperature uniformity of the base again with TC-Wafer. Adjust the temperature difference of all positions to about 1% of the set temperature. If it does not meet the requirements, repeat S2 and S3 until the temperature uniformity meets the expectations. Figure 9 As shown in the figure, the maximum temperature difference is reduced to 6.4°C, which improves the overall temperature uniformity.

Claims

1. A back temperature control device for a thin film device heating base, comprising an upper chamber (1), a lower chamber (2), a heating base (3) and a back temperature control device (4), characterized in that: The heating base (3) is installed in the lower chamber (2), the upper chamber (1) is connected to the lower chamber (2), and a closed cavity space is formed between the upper chamber (1) and the lower chamber (2). An air pumping ring (6) is provided between the upper chamber (1) and the lower chamber (2), and the air pumping ring (6) corresponds to the outer periphery of the heating base (3). The air pumping ring (6) is externally connected to a vacuum pump. A spray disk is provided on the upper chamber (1), and the spray disk is located directly above the heating base (3). An air inlet channel (21) is provided inside the upper chamber (1). The back temperature control device (4) is installed on the back of the heating base (3), and the back temperature control device (4) is connected to the heating base (3). The upper chamber (1) and the lower chamber (2) are in contact with each other, a reaction vacuum chamber is formed between the upper chamber (1) and the lower chamber (2), a reaction space is formed between the heating base (3) and the upper chamber (1), a wafer is arranged on the heating base (3), and the heat of the wafer is directly transferred through the heating base (3), and the back temperature control device (4) is used to adjust the temperature of the back of the heating base (3); the back temperature control device (4) includes an adjusting porous disk (41), a fixed porous disk (42), a reflecting plate (43) and a contact block (44), the adjusting porous disk (41) is in contact with the heat conducting portion (31) of the heating base (3), and the fixed porous disk (42) is installed on the adjusting porous disk (41) ), the reflecting plate (43) and the contact block (44) are both arranged in the adjusting porous disk (41); the adjusting porous disk (41) is provided with an adjusting opening area (411), the shape of the adjusting opening area (411) can be fan-shaped, connecting ribs (412) are provided between adjacent adjusting opening areas (411), and adjacent adjusting opening areas (411) are directly separated by the connecting ribs (412), the bottom of the adjusting opening area (411) on the adjusting porous disk (41) is provided with a stepped sinking groove (413), the outer contour of the stepped sinking groove (413) is larger than the adjusting opening area (411), and the reflecting plate (43) is arranged on the adjusting porous disk (41). In the stepped trough (413), the thickness of the reflecting plate (43) matches the depth of the stepped trough (413), the contact block (44) matches the adjustment opening area (411), the contact block (44) is arranged in the adjustment opening area (411), the upper end of the contact block (44) contacts the bottom surface of the heating base (3), the contact block (44) is located above the fixed porous disk (42), the fixed porous disk (42) is provided with a contoured opening area, the size of the contoured opening area is smaller than the hole size of the upper adjustment porous disk (41), and the outer contour size of the stepped trough (413) is larger than the hole size of the adjustment porous disk (41).

2. The back temperature control device of the thin film device heating base according to claim 1, characterized in that: The heating base (3) includes a disk surface and a columnar portion, wherein the disk surface is a disk-shaped heating area, and the columnar portion is arranged below the center of the disk surface. The disk surface includes a heat-conducting portion (31) and a heating portion (32), and the heating portion (32) is composed of a resistance wire. The heating portion (32) is embedded in the heat-conducting portion (31), and the back temperature control device (4) is installed at the bottom of the heat-conducting portion (31).

3. The back temperature control device of a thin film device heating base according to claim 1, characterized in that: A through hole (410) is provided in the center of the regulating porous disk (41), and the diameter of the through hole (410) is larger than the diameter of the columnar portion of the heating base (3). The back temperature control device (4) can be divided into a first heat conduction area, a second heat conduction area, and a third heat conduction area according to the type of heat transfer. The first heat conduction area includes a heat transfer area (100) and a first heat convection area (101). The second heat conduction area includes a radiation transfer area (201), a partition area (202), and a second heat convection area (203). The third heat conduction area includes a third heat convection area (300) and a fourth heat convection area (301). The first heat conduction area, the second heat conduction area, and the third heat conduction area are separated by connecting ribs (412).

4. The back temperature control device of a thin film device heating base according to claim 1, characterized in that: A connecting device is also provided in the lower chamber (2), one end of the connecting device is mounted on the bottom end of the columnar portion of the heating base (3), and the other end of the connecting device is connected to the back temperature control device (4). The connecting device tightly fits the back temperature control device (4) to the back side of the heating base (3), and the connecting device achieves fitting between the heating base (3) and the back temperature control device (4). The connecting device and the heating base (3) and the back temperature control device (4) all adopt a small area contact.

5. The back temperature control device of the thin film device heating base according to claim 4, characterized in that: An air inlet channel (21) is provided on the lower chamber (2), and one end of the air inlet channel (21) is connected to a gas input pipeline.

6. A method for controlling the back temperature of a thin film device heating base, applied to the back temperature control device according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Acquisition of original temperature data: remove all reflective plates (43) and contact blocks (44), and only install the adjustable porous plate (41) and the fixed porous plate (42). Place a TC-Wafer on the base to detect the temperature uniformity on the base. Heat the heating plate to obtain the temperature map of the base, and mark the points with higher and lower temperatures. S2 Back temperature control device adjustment: After cooling the base, remove it. For the locations with higher temperatures, it is necessary to increase heat dissipation, and set contact blocks (44) at the corresponding locations; for the locations with lower temperatures, set reflective plates (43) to reduce heat dissipation; S3 Temperature Data Acquisition: After reinstalling the base, increase the temperature and measure the temperature uniformity of the base again using TC-Wafer. Adjust the temperature difference at all locations to approximately 1% of the set temperature. If it does not meet the requirements, repeat steps S2 and S3 until the temperature uniformity meets expectations.

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