Substrate processing apparatus with a connection plate, substrate processing method

Abstract

An example of a substrate processing apparatus includes an annular distribution ring, a plurality of connection plates successively to the distribution ring and having non-uniform impedances, a shower plate electrically connected to the plurality of connection plates, and a stage disposed below the shower plate to face the shower plate.

Description

Technical Field

[0001] Examples involving substrate processing apparatus and substrate processing methods are described. Background Technology

[0002] By supplying high-frequency power to the spray plate at multiple points, it is sometimes possible to plasmaize the gas supplied between the spray plate and the platform. Deviations or inhomogeneities may occur in the plasma generated in this way; that is, the plasma density may be higher at some locations and lower at others. Summary of the Invention

[0003] Some examples described herein can solve the above problems. These examples can also provide apparatus and methods for controlling the distribution of plasma density in a simple manner.

[0004] In some examples, a substrate processing apparatus includes: an annular distribution ring; a plurality of connecting plates continuous to the distribution ring and having non-uniform impedance; a spray plate electrically connected to the plurality of connecting plates; and a platform disposed below the spray plate to face the spray plate. Attached Figure Description

[0005] Figure 1 This is a cross-sectional perspective view of the substrate processing apparatus;

[0006] Figure 2 This is a perspective view of the distribution ring and connecting plate;

[0007] Figure 3 This is a cross-sectional view of a substrate processing apparatus according to another example;

[0008] Figure 4 A connecting plate with coils is shown;

[0009] Figure 5 A connecting plate with coils is shown;

[0010] Figure 6 A connecting plate with coils is shown;

[0011] Figure 7 This illustrates the relationship between the number of coil turns and inductance;

[0012] Figure 8 The apparatus used for the experiment is shown;

[0013] Figure 9 The test results are shown;

[0014] Figure 10 A scalable impedance regulator is shown;

[0015] Figure 11 Another example of a scalable impedance regulator is shown;

[0016] Figure 12 This is a cross-sectional view of a substrate processing apparatus according to another example;

[0017] Figure 13 yes Figure 12 A partial plan view of the substrate processing apparatus; and

[0018] Figure 14 The change in plasma distribution relative to the capacitance change of the capacitor element is shown. Detailed Implementation

[0019] The substrate processing apparatus and substrate processing method will be described with reference to the accompanying drawings. Identical or corresponding components may be indicated by the same reference numerals, and repeated descriptions may be omitted.

[0020] Figure 1 This is a cross-sectional perspective view illustrating an example of the structure of a substrate processing apparatus. The substrate processing apparatus has a parallel plate structure including a stand 10 and spray plates. The spray plates include a lower spray plate 14 facing the stand 10 and an upper spray plate 16 disposed on the lower spray plate 14. The lower spray plate 14 is provided with slits such that gas supplied to the space between the lower spray plate 14 and the upper spray plate 16 is supplied between the lower spray plate 14 and the stand 10. For example, the lower spray plate 14 is mounted on a discharge pipe 12 via, for example, an O-ring. According to another example, the lower spray plate 14 and the upper spray plate 16 can be integrated into a single component.

[0021] A relay ring 18 is placed on the upper spray plate 16 and the lower spray plate 14. The relay ring 18 and the spray plates can be made of metal. The discharge pipe 12 can be made of ceramic. A specific example of ceramic is, for example, alumina. Figure 1 Distribution ring 20 and connecting plates 22, 24 are shown, which are used to supply high-frequency power to the downward spray plate 14 at multiple points.

[0022] Figure 2 This is a perspective view showing the distribution ring 20 and the connecting plates 22, 24, 26, and 28. The distribution ring 20 is made of a ring-shaped conductive material. Multiple connecting plates 22, 24, 26, and 28 are formed of a conductive material continuously connected to the distribution ring 20. The material of the distribution ring 20 and the connecting plates 22, 24, 26, and 28 is, for example, aluminum. The number of connecting plates can be any number, two or more. A protrusion 20a is disposed on the upper surface of the distribution ring 20. High-frequency power can be supplied to the protrusion 20a. According to one example, the high-frequency power supplied from the high-frequency power application device 20b to the protrusion 20a has a frequency of 27.12 MHz or higher.

[0023] Connecting plates 22, 24, and 28 are each folded plate in shape. Connecting plate 26 includes a coil 26A and plate-shaped ends 26B and 26C disposed at both ends of the coil 26A. A portion of connecting plate 26 is provided with the coil 26A to provide inductance to the high-frequency power path. As a result, the multiple connecting plates 22, 24, 26, and 28 have non-uniform impedance. The number of connecting plates with coils can be any number, two or more. At least one of the multiple connecting plates has a coil, one end of which is electrically connected to the distribution ring 20 and the other end of which is electrically connected to the lower spray plate 14.

[0024] Figure 1 The diagram shows a portion of the connecting plates 22, 24 electrically connected to the lower spray plate 14 via a relay ring 18. In this example, all connecting plates 22, 24, 26, 28 are in contact with the lower spray plate via the relay ring 18. For example, it is possible to configure the connection plates to form through-holes extending through the respective connecting plates, the relay ring 18, and the lower spray plate 14, and then use these through-holes to screw them together.

[0025] Figure 3 This is a cross-sectional view of a substrate processing apparatus based on another example. Figure 3 The image shows a chamber 30 covering the lower spray plate 14 and the platform 10. In this example, the connecting plate and the lower spray plate 14 are in direct or indirect contact with each other. The means for securing the connecting plate to the lower spray plate 14 are tightened, for example, similar to those described above. Figure 1 Examples and Figure 3 In both examples, the high-frequency power application device 20b is connected to the protrusion 20a that contacts the distribution ring 20.

[0026] Figures 4 to 6 This is a view showing an example of the construction of the connecting plate 26. Figures 4 to 6 The coil 26A with different numbers of turns is shown. Figure 4 The equations for calculating the inductance provided by connecting plate 26 are shown. Different inductance values ​​can be provided to the high-frequency power path by changing the shape of the coil. Figures 4 to 6 In the middle, the ends 26B and 26C may need to be shaped to achieve the necessary connection. Figure 7 This is a graph showing the relationship between the number of turns in a coil and its inductance. As the number of turns in the coil increases, the inductance increases.

[0027] Next, an example of a substrate processing method using the above-described substrate processing apparatus will be described. First, the substrate to be processed by plasma is placed on the stand 10. Then, while supplying gas from the spray plate to the space between the spray plate and the stand 10, high-frequency power is applied to the lower spray plate 14. The high-frequency power is supplied from the high-frequency power application device 20b to the lower spray plate 14 through the distribution ring 20 and a plurality of connecting plates 22, 24, 26, 28 having non-uniform impedance. As a result, plasma is generated between the lower spray plate 14 and the stand 10. Since coils are provided to at least one of the plurality of connecting plates 22, 24, 26, 28 to give the connecting plates non-uniform impedance, the in-plane distribution of the plasma density can be controlled.

[0028] Plasma processing on a substrate can include, for example, film formation, etching, or film modification. According to one example, the aforementioned non-uniform impedance causes the plasma density in the plasma generation space to become uniform. Therefore, in one example, the film can be made to have a substantially uniform thickness.

[0029] Figure 8 , 9 It is a diagram showing the structure of the apparatus used for the experiment and the experimental results. Figure 8 A through-hole 30A formed in chamber 30 is shown. Through-hole 30A is a hole for inserting or removing a substrate into or from chamber 30. For example, when a connecting plate with uniform impedance is used, the plasma density tends to be higher near through-hole 30A and lower away from through-hole 30A. Figure 9 The “POR” column shows the test results when using a connection plate with uniform impedance. “Range” indicates the difference between the maximum and minimum film thicknesses in the substrate of interest. “1 sigma” represents the standard deviation. From the graph in the “POR” column, it can be understood that the plasma density is higher near the penetration 30A located in the upper left of the graph, and lower further away from the penetration 30A.

[0030] Figure 9 The "3.5 coil" column indicates the use of... Figure 5 The test results are as follows when the coil is used as coil 26A. Figure 9 The "5.5 coil" column indicates the use of... Figure 6The test results are as follows, with the coil serving as coil 26A. In both tests, the penetration 30A was located on the upper left side, and coil 26A was placed in the connecting plate furthest from the penetration 30A. These results indicate that providing a coil to connecting plate 26 (which is the connecting plate furthest from the penetration 30A among multiple connecting plates) improves plasma uniformity. For example, by using a coil, the plasma density on the test bench 10 near the penetration 30A can be equal to or lower than the plasma density on the test bench 10 furthest from the penetration 30A. In some examples, the connecting plate has at least one coil positioned furthest from the penetration 30A.

[0031] Figure 10 This is a perspective view illustrating an example of the construction of a connection plate according to another example. In this example, a retractable impedance adjuster 50 is provided. The retractable impedance adjuster 50 includes a magnetic rod 51, a support block 52, and a micrometer 54. By rotating the micrometer 54, the insertion amount of the magnetic rod 51 into the coil 26A can be adjusted. Specifically, the magnetic rod 51 can be adjusted along... Figure 10 The arrow in the diagram moves in the direction of the movement. Since the insertion amount is displayed on the micrometer 54, the operator can easily achieve the required insertion amount to obtain the desired impedance. In this way, the retractable impedance adjuster 50 is configured to insert or remove the magnetic rod 51 from the coil 26A.

[0032] Figure 11 This diagram illustrates a modified example of a retractable impedance regulator. The retractable impedance regulator 55 includes a magnetic rod 51, a receiving portion 56 for accommodating a part of the magnetic rod 51, and a set screw 57. The set screw 57 is inserted into a screw hole in the receiving portion 56, thereby pressing and securing the magnetic rod 51 to the receiving portion 56. Besides... Figure 10 , 11 In addition to the examples provided, various types of scalable impedance regulators can be used, which can adjust the insertion amount of the magnetic rod 51 into the coil 26A. Adjusting the insertion amount causes a change in magnetic flux, thereby adjusting the inductance. The inductance L is given by Nφ / I. “N” represents the number of turns of the coil, φ represents the magnetic flux [wb], and I represents the current [A].

[0033] According to another example, each of the multiple connection plates may be equipped with a coil, and the aforementioned retractable impedance regulator can be provided to all connection plates. This configuration facilitates precise adjustment of impedance non-uniformity. According to yet another example, providing coils and retractable impedance regulators to at least two connection plates allows for adjustment of impedance non-uniformity.

[0034] Figure 12This is a cross-sectional view of a substrate processing apparatus according to another example. Connecting plate 60 is shown as one of a plurality of connecting plates continuous to distributing ring 20. In this example, screw holes are formed in distributing ring 20 and connecting plate 60, and screws 61 are fastened into the screw holes to secure both. According to one example, connecting plate 60 includes a metal portion 60a, a capacitor element 60b, a first heat insulation member 60c, and a metal portion 60d. For example, the various components (metal portion 60a, capacitor element 60b, first heat insulation member 60c, and metal portion 60d) can be secured by conductive adhesive, solder, or screws. One electrode of capacitor element 60b contacts metal portion 60a, and its other electrode contacts first heat insulation member 60c. Capacitor element 60b is, for example, a ceramic capacitor.

[0035] The aforementioned screw holes are formed in the metal portion 60a. The material of the metal portions 60a and 60d is, for example, aluminum. The material of the first heat insulation member 60c can be any material with a lower thermal conductivity than that of the lower spray plate 14. According to one example, the lower spray plate 14 is formed of aluminum, and the first heat insulation member 60c includes at least one of Ni, Co, and Ti. This first heat insulation member 60c can be disposed between the capacitor element 60b and the lower spray plate 14 in the high-frequency power path.

[0036] The upper surface of the lower spray plate 14 is provided with an annular groove. A second heat insulation member 70 is disposed in the groove. In the plan view, the second heat insulation member 70 has an annular shape that fits into the groove and is formed of a material with a lower thermal conductivity than that of the lower spray plate 14. According to one example, the lower spray plate 14 is formed of aluminum, and the second heat insulation member 70 includes at least one of Ni, Co, and Ti.

[0037] Figure 13 yes Figure 12A partial plan view of the substrate processing apparatus. The second heat insulation member 70 is arranged in a ring shape along the portion near the outer edge of the lower spray plate 14. All connecting plates 22, 24, 28, and 60 are in contact with the second heat insulation member 70. In other words, all connecting plates 22, 24, 28, and 60 are electrically connected to the lower spray plate 14 via the second heat insulation member 70. Therefore, one end of the capacitor element 60b is electrically connected to the distribution ring 20 and its other end is electrically connected to the lower spray plate 14. By rotating the member having the distribution ring 20 and connecting plates 22, 24, 28, and 60 relative to the second heat insulation member 70, the contact position between the connecting plates 22, 24, 28, and 60 and the second heat insulation member 70 can be easily changed. This change alters the feed position to the lower spray plate 14, thus enabling adjustment of the plasma distribution. The connecting plates can be securely connected to the second heat insulation member 70 using screws 62. When using screws 62, a number of screw holes, for example multiples of 4, should be drilled in the second insulation member 70 to allow the connecting plate to rotate relative to the second insulation member 70.

[0038] Figure 12 A spray plate heater 14A is shown. The spray plate heater 14A is provided to heat the lower spray plate 14. Figure 12 In the example, the spray plate heater 14A is disposed on the outer edge portion of the lower spray plate 14. Figure 13 The illustration shows a configuration with two spray plate heaters 14A. A first heat insulation member 60c and a second heat insulation member 70 prevent the capacitor element 60b from reaching excessively high temperatures due to the lower spray plate 14 heated by the spray plate heaters 14A. Therefore, the capacitor element 60b is maintained, for example, at a temperature below 125°C.

[0039] In this example, a first heat-insulating member 60c and a second heat-insulating member 70 are provided to prevent the capacitor element 60b from being damaged due to high temperatures. According to another example, either the first heat-insulating member 60c or the second heat-insulating member 70 may be omitted. According to yet another example, any cooling device, such as a blower or a coolant supply device, can be used to cool the capacitor element 60b.

[0040] In this way, Figure 12 , 13 In the illustrated substrate processing apparatus, at least one of the plurality of connecting plates is provided with a capacitor element 60b. The provision of the capacitor element results in impedance non-uniformity among the plurality of connecting plates. For example, supplying high-frequency power to the downward spray plate 14 through the non-uniform impedance allows correction of plasma uniformity caused by the apparatus construction.

[0041] Figure 14 This is a graph showing the change in plasma distribution relative to the change in capacitance of the capacitor element supplied to the connecting plate. Figure 14The results obtained through simulation are shown, in which 27.12 MHz of high-frequency power is supplied to multiple points. Figure 14 In the eight plasma density distributions shown, the through-hole 30A for inserting and removing the wafer is located in the upper left. In the eight examples disclosed herein, each substrate processing apparatus is provided with four connecting plates. A capacitor element is provided on the connecting plate furthest from the through-hole 30A. In this case, the sheath capacitance of the inner wall of the through-hole 30A increases, causing the plasma density to tend to increase near the through-hole 30A. Therefore, in actual film deposition, the film thickness on the through-hole side tends to increase, making it difficult to improve in-plane uniformity. For example, it should be understood that when the capacitance of the capacitor element is 213 pF, 425 pF, or 637 pF, a high plasma density may be generated near the through-hole 30A. However, in the range of 1062 to 2125 pF, the plasma density furthest from the through-hole 30A can be increased. Figure 14 In the example, a roughly uniform distribution of plasma density can be obtained with a capacitance of 2125pF or higher.

[0042] At least one of a plurality of connecting plates can be configured as connecting plate 60. According to another example, the configuration of connecting plate 60 is applied to all connecting plates to create non-uniform capacitance of the capacitor elements, which helps to regulate plasma density. According to another example, the configuration of connecting plate 60 is applied to at least two connecting plates to create non-uniform capacitance of the capacitor elements, which also helps to regulate plasma density.

Claims

1. A substrate processing apparatus, comprising: Circular distribution ring; Multiple connecting plates, which are continuous to the distribution ring and have non-uniform impedance; The spray plate is electrically connected to multiple connecting plates; as well as The platform is positioned below the spray plate and faces the spray plate.

2. The substrate processing apparatus according to claim 1, wherein, At least one of the plurality of connecting plates has a coil, one end of which is electrically connected to the distribution ring and the other end of which is electrically connected to the spray plate.

3. The substrate processing apparatus according to claim 2, further comprising a chamber surrounding the spray plate and the stand, the chamber having a through-hole to allow a substrate to be inserted or removed therethrough, wherein, The plurality of connecting plates include at least one coil containing the coil, the at least one coil being positioned away from the through portion.

4. The substrate processing apparatus according to claim 2 or 3 further includes a retractable impedance adjuster configured to insert or remove a magnetic rod into or from the coil.

5. The substrate processing apparatus according to claim 4, wherein, All of the multiple connecting plates have the coil, and the retractable impedance regulator is provided for each coil.

6. The substrate processing apparatus according to claim 4, wherein, The retractable impedance regulator has a micrometer configured to indicate the amount of insertion of the magnetic rod into the coil.

7. The substrate processing apparatus according to claim 4, wherein, The retractable impedance adjuster includes a receiving portion for accommodating a part of a magnetic rod; and A set screw is inserted into the screw hole of the receiving part to press and fix the magnetic rod to the receiving part.

8. The substrate processing apparatus according to claim 1, wherein, At least one of the plurality of connecting plates has a capacitor element, one end of which is electrically connected to the distribution ring and the other end of which is electrically connected to the spray plate.

9. The substrate processing apparatus according to claim 8, wherein, The capacitor element is a ceramic capacitor.

10. The substrate processing apparatus according to claim 8 or 9, wherein, The connecting plate with the capacitor element includes a first heat insulation member between the capacitor element and the spray plate, the first heat insulation member having a lower thermal conductivity than the spray plate.

11. The substrate processing apparatus according to claim 10, wherein, The first thermal insulation component contains at least one of Ni, Co, and Ti.

12. The substrate processing apparatus according to claim 8 or 9, further comprising a second heat-insulating member having an annular shape, which is fitted in an annular groove on the upper surface of the spray plate and is formed of a material with a lower thermal conductivity than the spray plate, wherein, The connecting plate with the capacitor element contacts the spray plate via the second heat insulation member.

13. The substrate processing apparatus according to claim 12, wherein, The second thermal insulation component includes at least one of Ni, Co, and Ti.

14. The substrate processing apparatus according to any one of claims 1-3, 8, and 9, further comprising a high-frequency power application device connected to the distribution ring.

15. The substrate processing apparatus according to any one of claims 1-3, 8, and 9 further includes a spray plate heater configured to heat the spray plate.

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