Plasma processing apparatus and method of using the plasma processing apparatus

Abstract

To improve optical measurement accuracy of an object to be processed.SOLUTION: A plasma processing apparatus 10 disclosed includes: a stage 11 on which an object to be processed is placed; a chamber 12 which houses the stage 11 therein and has a first opening 12a at a top thereof; a first dielectric member 13 which forms a first space Si in the chamber 12 by closing the first opening 12a, and has a second opening 13a; a first induction coil 16 which generates a plasma for processing the object to be processed, the first induction coil extending, above the first dielectric member 13, from a central side toward an outer peripheral side of the first dielectric member 13; and a protrusion 15 which forms a second space S2 and has a dielectric window 15 for optical measurement at a top part of the protrusion, the second space communicating with the first space S1 via the second opening 13a and extending more upward than the first dielectric member 13.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a plasma processing apparatus and a method of using the plasma processing apparatus. [Background technology]

[0002] Conventionally, plasma processing apparatuses for plasma processing of workpieces are known (for example, Patent Document 1). The plasma processing apparatus of Patent Document 1 includes a stage on which the workpiece is placed, a chamber that houses the stage and has an opening at the top, a dielectric window that closes the opening to form a predetermined space within the chamber, and an induction coil that is disposed above the dielectric window and generates plasma for processing the workpiece. The dielectric window is translucent and has a recess formed on its underside. In the plasma processing apparatus of Patent Document 1, gas is ejected from inside the recess to prevent reaction products generated during plasma processing from adhering to the dielectric window. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-086748 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the plasma processing apparatus of Patent Document 1, there is still a risk that reaction products may adhere to the dielectric window. If reaction products adhere to the dielectric window, the accuracy of optical measurement of the workpiece through the dielectric window decreases. In this situation, one of the objects of the present disclosure is to improve the accuracy of optical measurement of the workpiece. [Means for solving the problem]

[0005] One aspect of the present disclosure relates to a plasma processing apparatus including: a stage on which a workpiece is placed; a chamber that accommodates the stage and has a first opening at an upper portion; a first dielectric member that closes the first opening to form a first space within the chamber and has a second opening; a first induction coil that extends above the first dielectric member from a center to an outer periphery of the first dielectric member and generates plasma for processing the workpiece; and a protrusion that communicates with the first space via the second opening and forms a second space that extends above the first dielectric member and has a dielectric window at its top for optical measurement.

[0006] Another aspect of the present disclosure relates to a method for using a plasma processing apparatus including: a stage on which a workpiece is placed; a chamber that accommodates the stage and has a first opening at an upper portion; a first dielectric member that closes the first opening to form a first space in the chamber and has a second opening; a first induction coil that extends above the first dielectric member from a center to an outer periphery of the first dielectric member and generates plasma for processing the workpiece; and a protrusion that forms a second space that communicates with the first space via the second opening and extends above the first dielectric member and has a dielectric window at its top, wherein information about the workpiece is detected from above the dielectric window through the second space by an optical sensor. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to improve the accuracy of optical measurement of a workpiece. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view schematically showing a plasma processing apparatus according to a first embodiment. [Figure 2] FIG. 2 is a plan view schematically showing the cover of the first embodiment. [Figure 3] FIG. 10 is a cross-sectional view schematically showing a plasma processing apparatus according to a second embodiment. [Figure 4] FIG. 10 is a plan view schematically showing a cover of the second embodiment. [Figure 5] FIG. 10 is a cross-sectional view schematically showing a plasma processing apparatus according to a third embodiment. [Figure 6] FIG. 10 is a plan view schematically showing a cover of a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes an example of a plasma processing apparatus and a method of using the plasma processing apparatus according to the present disclosure. However, the present disclosure is not limited to the example described below. While the following description may use specific numerical values ​​and materials, other numerical values ​​and materials may be used as long as the effects of the present disclosure are obtained.

[0010] (Plasma processing equipment) The plasma processing apparatus according to the present disclosure is an apparatus for plasma processing of a workpiece. The plasma processing apparatus may be, for example, a plasma etching apparatus, a plasma dicer, a plasma ashing apparatus, or a plasma CVD apparatus. The plasma processing apparatus includes a stage, a chamber, a first dielectric member, a first induction coil, and a protrusion.

[0011] The stage is an element on which the workpiece is placed. The stage may have a horizontal mounting surface on which the workpiece is placed. The stage may have a flow path through which a coolant flows to cool the workpiece during plasma processing. The stage may have an electrostatic adsorption mechanism for adsorbing the workpiece. The stage may have a lower electrode to which high-frequency power is applied. The workpiece may be, for example, a semiconductor substrate to be singulated by plasma etching. The semiconductor substrate has a plurality of element regions and division regions that define the element regions. The element regions have, for example, a semiconductor layer and a wiring layer. By etching the division regions, element chips having the semiconductor layer and the wiring layer are obtained. The workpiece may be placed on the stage while supported by a carrier. The carrier may be, for example, a resin sheet held at its outer periphery by a frame.

[0012] The chamber may house the stage and have a first opening at the top. The chamber may be formed in a hollow cylindrical shape. The first opening may be open upward.

[0013] The first dielectric member forms a first space in the chamber by closing the first opening, and also has a second opening. The first dielectric member may be formed in a plate shape having a horizontally extending region. The first space may be a space in which a stage is disposed. The second opening may penetrate the first dielectric member from top to bottom. The second opening may be disposed in a central portion of the first dielectric member. The first dielectric member may be made of ceramics such as quartz, alumina, or aluminum nitride.

[0014] The first induction coil extends from the center to the outer periphery of the first dielectric member above the first dielectric member (outside the first space) and generates plasma for processing the workpiece. The first induction coil is disposed, for example, in an annular region excluding the central region above the first dielectric member so as to face the first space. The magnetic field generated by the first induction coil acts mainly on the source gas in the first space via the first dielectric member.

[0015] The protrusion forms a second space that communicates with the first space via the second opening and extends above the first dielectric member. The second space facilitates control of the distribution of plasma generated in the first space. The protrusion may fit into the second opening. The protrusion may be formed in a cylindrical shape extending vertically. The wall thickness of the protrusion may be smaller than the thickness of the first dielectric member. The protrusion may be made of a dielectric material or other materials. The protrusion has a dielectric window at its top for optical measurement. The dielectric window is translucent and may be made of, for example, quartz. The dielectric window is located above the first dielectric member. In other words, the dielectric window is located away from the first space where plasma processing is performed. This makes it difficult for reaction products generated during plasma processing in the first space to adhere to the dielectric window. This allows optical measurement of the workpiece through the dielectric window to be performed with high accuracy.

[0016] The thickness Tw of the dielectric window may be smaller than the thickness T1 of the first dielectric member. Because the area of ​​the dielectric window is small, even a thin dielectric window can be prevented from being damaged by atmospheric pressure. This configuration allows optical measurement of the workpiece through the dielectric window to be performed with even higher accuracy. T2 may be, for example, 20% or more and 50% or less of T1.

[0017] The height of the protrusion may be greater than the diameter of the protrusion. With this configuration, since the second space is long in the vertical direction, reaction products generated in the first space are less likely to reach the dielectric window. Therefore, the dielectric window is less likely to become dirty, further improving the accuracy of optical measurement of the workpiece. The dielectric window may also be located higher than the top of the first induction coil and the second induction coil. For example, the dielectric window may be located in a position that is not shielded by the lid that covers the first induction coil and the second induction coil. This allows optical measurement to be performed more easily without space limitations.

[0018] The plasma processing apparatus may further include an optical sensor disposed above the dielectric window for detecting information about the workpiece. The optical sensor may be, but is not limited to, an infrared sensor. The information about the workpiece may be, for example, the thickness of at least a portion of the workpiece and / or the temperature of the workpiece.

[0019] The plasma processing apparatus may further include a second induction coil surrounding the protrusion and generating plasma for processing the workpiece. The second induction coil may be positioned so as not to overlap the first induction coil in the vertical direction. This configuration increases the degree of freedom in controlling the plasma distribution on the stage by adjusting the power supplied to the first and second induction coils. This makes it easier to uniformly irradiate the workpiece with plasma. For example, when dividing a semiconductor substrate into individual pieces by plasma etching, the etching rate of the divided regions (the rate at which the workpiece is plasma etched) can be controlled to be uniform.

[0020] The plasma processing apparatus may further include a first gas inlet passage for supplying a first source gas to a region facing the first induction coil in the first space, and a second gas inlet passage for supplying a second source gas to a region facing the second induction coil in the first space or the second space. With this configuration, the first source gas is supplied near the first induction coil, and the second source gas is supplied near the second induction coil. Therefore, plasma containing each source gas is generated with high efficiency by each induction coil. The first source gas and the second source gas may be the same or different.

[0021] (Method of using plasma processing device) A method of using the plasma processing apparatus according to the present disclosure is a method of using the above-described plasma processing apparatus, and includes a step of detecting information about the workpiece using an optical sensor from above the dielectric window through the second space. The information about the workpiece may be, for example, the thickness of at least a portion of the workpiece and / or the temperature of the workpiece. This method allows for highly accurate optical measurement of the workpiece through the dielectric window.

[0022] As described above, according to the present disclosure, the accuracy of optical measurement of the workpiece can be improved by preventing the dielectric window from becoming dirty.

[0023] An example of a plasma processing apparatus and a method for using the plasma processing apparatus according to the present disclosure will be described in detail below with reference to the drawings. The above-described components and steps can be applied to the components and steps of the example plasma processing apparatus and the method for using the plasma processing apparatus described below. The components and steps of the example plasma processing apparatus and the method for using the plasma processing apparatus described below can be modified based on the above description. Furthermore, the matters described below may be applied to the above-described embodiment. Among the components and steps of the example plasma processing apparatus and the method for using the plasma processing apparatus described below, components and steps that are not essential to the plasma processing apparatus and the method for using the plasma processing apparatus according to the present disclosure may be omitted. Note that the diagrams shown below are schematic and do not accurately reflect the shapes and numbers of actual components.

[0024] First Embodiment A first embodiment of the present disclosure will be described. A plasma processing apparatus 10 of this embodiment is an apparatus for plasma processing an object to be processed (e.g., a semiconductor substrate). The plasma processing apparatus 10 of this embodiment is a plasma dicer, but is not limited to this. As shown in FIGS. 1 and 2, the plasma processing apparatus 10 includes a stage 11, a chamber 12, a first dielectric member 13, a cover 14, a second dielectric member 15, a first induction coil 16, a second induction coil 17, a first high-frequency power supply 18, a second high-frequency power supply 19, and an optical sensor 23.

[0025] The stage 11 is an element on which the workpiece is placed. The stage 11 has a horizontal placement surface 11a on which the workpiece is placed. The stage 11 has a flow path (not shown) through which a coolant flows to cool the workpiece during plasma processing. The stage 11 has an electrostatic adsorption mechanism (not shown) for adsorbing the workpiece. The stage 11 has a lower electrode (not shown) to which high-frequency power is applied.

[0026] The chamber 12 accommodates the stage 11 and has a first opening 12a at the top. The chamber 12 is formed in a hollow cylindrical shape, but is not limited to this. The first opening 12a opens upward. The chamber 12 is disposed on the outer periphery side of the stage 11 and has an exhaust port 12b for exhausting the source gases (first and / or second source gases) used in the plasma processing. An exhaust device (not shown) is connected to this exhaust port 12b. The chamber 12 is made of a conductive material (e.g., metal).

[0027] The first dielectric member 13 closes the first opening 12a to form a first space S1 inside the chamber 12, and also has a second opening 13a. The first dielectric member 13 is formed in the shape of a horizontally extending plate. The first space S1 is a space in which the stage 11 is disposed. The second opening 13a passes through the first dielectric member 13 from top to bottom. The second space S2 is disposed in the center of the first dielectric member 13. The first dielectric member 13 has a recess 13b on its upper surface. The first dielectric member 13 is made of quartz, but is not limited to this.

[0028] The cover 14 is provided to cover the lower surface of the first dielectric member 13. The cover 14 has a first gas inlet passage 14b that supplies a first source gas to a region of the first space S1 facing the first induction coil 16. The first gas inlet passage 14b is formed by a groove or recess formed in the upper surface of the cover 14. The first gas inlet passage 14b communicates with the outside of the chamber 12 and with the first space S1 via a first gas hole 14d. A plurality of the first gas holes 14d are arranged at intervals in the circumferential direction (see FIG. 2). A plurality of the first gas holes 14d are arranged at intervals in the radial direction (the left-right direction in FIG. 1). The first gas inlet passage 14b is formed between the cover 14 and the first dielectric member 13. The first source gas is supplied to the first gas inlet passage 14b from a gas source (not shown). The cover 14 has a third opening 14a that overlaps with the second opening 13a. The third opening 14a is located in the center of the cover 14. The cover 14 is made of aluminum nitride, but is not limited to this.

[0029] The second dielectric member 15 forms a second space S2 that communicates with the first space S1 via the second opening 13a and the third opening 14a and extends upward beyond the first dielectric member 13. The second dielectric member 15 fits into the second opening 13a and the third opening 14a. The second dielectric member 15 is formed in a cylindrical shape that extends vertically. The wall thickness of the second dielectric member 15 is smaller than the thickness of the first dielectric member 13. The height (vertical dimension) of the second dielectric member 15 is larger than the diameter of the second dielectric member 15. The second dielectric member 15 is made of aluminum nitride, but is not limited to this. The second dielectric member 15 is an example of a protrusion.

[0030] A gas pipe 25 is connected to the second space S2 formed by the second dielectric member 15, for supplying a second source gas to a region in the second space S2 facing the second induction coil 17. The second source gas is supplied to the gas pipe 25 from a gas source (not shown). The gas pipe 25 is an example of a second gas introduction path.

[0031] The second dielectric member 15 has a dielectric window 15a for optical measurement at its top. The dielectric window 15a transmits light emitted by the optical sensor 23, the workpiece placed on the stage 11, or the plasma. The thickness (vertical dimension) of the dielectric window 15a is smaller than the thickness (vertical dimension) of the first dielectric member 13. The maximum thickness of the dielectric window 15a may be smaller than the minimum thickness of the first dielectric member 13. The dielectric window 15a may be integral with or separate from the cylindrical portion of the second dielectric member 15.

[0032] The first induction coil 16 extends from the center to the outer periphery of the first dielectric member 13 above the first dielectric member 13 and generates plasma for treating the workpiece. Each first induction coil 16 is composed of one or more conductors extending spirally in the circumferential direction. A portion of the outer periphery of the first induction coil 16 is disposed inside a recess 13b formed in the first dielectric member 13. The first induction coil 16 receives high-frequency power from the first high-frequency power supply 18 and generates a magnetic field. This magnetic field acts on the source gas (first and / or second source gas) in the first space S1 via the first dielectric member 13, generating plasma.

[0033] The second induction coil 17 is disposed to surround the second dielectric member 15 and generates plasma for treating the workpiece. The second induction coil 17 is spirally wound around the second dielectric member 15 and extends vertically along the second dielectric member 15. The second induction coil 17 is disposed more inward than the first induction coil 16. The second induction coil 17 receives high-frequency power from the second high-frequency power supply 19 and generates a magnetic field. This magnetic field acts on the source gas (first and / or second source gas) in the first space S1 and / or the second space S2 via the second dielectric member 15, thereby generating plasma.

[0034] First high frequency power supply 18 supplies high frequency power (e.g., AC power of 3 to 30 MHz) to first induction coil 16. First high frequency power supply 18 is connected to one end of first induction coil 16 via first matching box 21 such as a variable capacitor. The other end of first induction coil 16 is grounded via conductive chamber 12.

[0035] Second high frequency power supply 19 supplies high frequency power (e.g., AC power of 3 to 30 MHz) to second induction coil 17. Second high frequency power supply 19 is connected to one end of second induction coil 17 via second matching box 22 such as a variable capacitor. The other end of second induction coil 17 is grounded via conductive chamber 12.

[0036] The frequency of the power from first high frequency power supply 18 (power applied to first induction coil 16) and the frequency of the power from second high frequency power supply 19 (power applied to second induction coil 17) are different from each other. However, both frequencies may be the same.

[0037] The optical sensor 23 is disposed above the dielectric window 15a and detects information about the workpiece. The optical sensor 23 irradiates the workpiece with light through the dielectric window 15a, the second space S2, and the first space S1, and detects information about the workpiece by receiving the reflected light. Alternatively, the optical sensor 23 detects information about the workpiece by receiving light emitted from the workpiece through the dielectric window 15a, the second space S2, and the first space S1. Alternatively, the optical sensor 23 detects information about the workpiece and the plasma by receiving light emitted from the plasma through the dielectric window 15a, the second space S2, and the first space S1. The optical sensor 23 may be, for example, an infrared sensor, but is not limited thereto. The information about the workpiece may be, for example, the thickness of at least a portion of the workpiece and / or the temperature of the workpiece. The information about the plasma may be, for example, the composition of the plasma.

[0038] Note that light reflected from the workpiece, light emitted by the workpiece, or light emitted by the plasma reaches the optical sensor 23 via the first space S1, the second space S2, and the dielectric window 15a. In this case, by increasing the height of the second space S2, i.e., by increasing the height of the dielectric member 15, it is possible to reduce the proportion of the optical path through the atmosphere (specifically, the optical path between the dielectric window 15a and the optical sensor 23) in the total optical path for the light to reach the optical sensor 23. This improves the measurement accuracy of the optical sensor 23. In particular, this improves the measurement accuracy when measuring the temperature of the workpiece using an infrared sensor.

[0039] -How to use the plasma processing equipment- A method of using the plasma processing apparatus of this embodiment will be described. This method uses the above-described plasma processing apparatus 10. By supplying source gases (first and second source gases) to the chamber 12 and applying power to the first and second induction coils 16 and 17, plasma for processing the workpiece is generated, and the workpiece is processed. Furthermore, in this method, information about the workpiece is detected by the optical sensor 23 from above the dielectric window 15a. This makes it possible to appropriately adjust the power applied to the first and second induction coils 16 and 17 based on the information about the workpiece. For example, the power applied to the first and second induction coils 16 and 17 can be adjusted based on the thickness of at least a portion of the workpiece. When a semiconductor substrate is singulated by plasma etching, the etching rate of the division regions can be controlled to be as uniform as possible across the entire surface of the semiconductor substrate.

[0040] Second Embodiment A second embodiment of the present disclosure will be described. The plasma processing apparatus 10 of this embodiment differs from the first embodiment in the configuration of the cover 14. The following mainly describes the differences from the first embodiment.

[0041] As shown in FIGS. 3 and 4, in addition to the first gas inlet passage 14b, the cover 14 has a second gas inlet passage 14c that supplies the second source gas to a region of the first space S1 facing the second induction coil 17. The second gas inlet passage 14c is configured as a groove or a recess formed in the upper surface of the cover 14. The second gas inlet passage 14c is formed, for example, so as to be surrounded by the annular first gas inlet passage 14b. The second gas inlet passage 14c communicates with the outside of the chamber 12 and with the first space S1 via the second gas holes 14e. The second gas holes 14e are arranged at intervals in the circumferential direction (see FIG. 4). The second gas holes 14e are arranged at intervals in the radial direction (the left-right direction in FIG. 3). The second gas inlet passage 14c is formed between the cover 14 and the first dielectric member 13. The second source gas is supplied to the second gas inlet passage 14c from a gas source (not shown).

[0042] The second induction coil 17 has a portion that extends vertically along the second dielectric member 15 and a portion that extends horizontally along the first dielectric member 13. The former is configured in a spiral shape that extends vertically, and the latter is configured in a whorl (spiral) shape that extends horizontally.

[0043] Third Embodiment A third embodiment of the present disclosure will be described. The plasma processing apparatus 10 of this embodiment differs from the second embodiment in that it includes a cylindrical member 24. The following mainly describes the differences from the second embodiment.

[0044] As shown in FIGS. 5 and 6 , the plasma processing apparatus 10 includes a cylindrical member 24 disposed inside the second dielectric member 15. The cylindrical member 24 divides the second space S2 into an outer space S21 and an inner space S22. The outer space S21 is connected to the second gas inlet passage 14c of the cover 14. A second source gas is supplied to the outer space S21 from a gas source (not shown) via a gas pipe 25. To prevent the gas pipe 25 from being affected by the second induction coil 17, the gas pipe 25 may supply the second source gas to the outer space S21 from a position higher than the tops of the first and second induction coils 16 and 17. The inner space S22 is connected to the first space S1. The inner space S22 can be used to generate plasma. The inner space S22 can also be used to detect information about the workpiece using an optical sensor 23 from above the dielectric window 15a. The cylindrical member 24 is fitted into the third opening 14a of the cover 14. The cylindrical member 24 is made of, but is not limited to, aluminum nitride. The second dielectric member 15 of this embodiment is made of quartz. The first gas inlet path 14b and the second gas inlet path 14c are separated from each other by an O-ring 26. By separating the first gas inlet path 14b and the second gas inlet path 14c, the supply amounts of the first source gas and the second source gas can be controlled more accurately. [Industrial Applicability]

[0045] The present disclosure can be used for a plasma processing apparatus and a method of using the plasma processing apparatus. [Explanation of symbols]

[0046] 10: Plasma processing equipment 11: Stage 11a: Placement surface 12: Chamber 12a: 1st opening 12b: Exhaust port 13: First dielectric member 13a: 2nd opening 13b: Recess 14: Cover 14a: Third opening 14b: First gas inlet 14c: Second gas inlet 14d: First gas hole 14e: Second gas hole 15: Second dielectric member (protrusion) 15a: Dielectric window 16: First induction coil 17: Second induction coil 18: 1st high frequency power supply 19:Second high frequency power supply 21: 1st matching box 22:Second matching box 23: Optical sensor 24: Cylindrical member 25: Gas piping (second gas inlet) 26: O-ring S1: 1st space S2:Second space S21: Outside space S22: Inner space

Claims

1. a stage on which the object to be processed is placed; a chamber containing the stage and having a first opening at an upper portion; a first dielectric member that closes the first opening to form a first space in the chamber and has a second opening; a first induction coil extending from the center to the outer periphery of the first dielectric member above the first dielectric member and generating plasma for treating the workpiece; a protrusion that forms a second space that communicates with the first space via the second opening and extends above the first dielectric member, and that has a dielectric window for optical measurement at its top; a second induction coil provided to surround the protrusion and configured to generate plasma for treating the object to be treated; a first gas inlet passage for supplying a first source gas to a region of the first space facing the first induction coil; a second gas inlet passage for supplying a second source gas to a region of the first space or the second space facing the second induction coil; A plasma processing apparatus comprising:

2. The plasma processing apparatus of claim 1 , wherein the thickness of the dielectric window is smaller than the thickness of the first dielectric member.

3. The plasma processing apparatus according to claim 1 , wherein the height of the protrusion is greater than the diameter of the protrusion.

4. 4. The plasma processing apparatus according to claim 1, further comprising an optical sensor provided above said dielectric window for detecting information relating to said object to be processed.

5. a stage on which the object to be processed is placed; a chamber containing the stage and having a first opening at an upper portion; a first dielectric member that closes the first opening to form a first space in the chamber and has a second opening; a first induction coil extending from the center to the outer periphery of the first dielectric member above the first dielectric member and generating plasma for treating the workpiece; a protrusion having a dielectric window at its top, the protrusion defining a second space that communicates with the first space via the second opening and extends above the first dielectric member; a second induction coil provided to surround the protrusion and configured to generate plasma for treating the object to be treated; a first gas inlet passage for supplying a first source gas to a region of the first space facing the first induction coil; a second gas inlet passage for supplying a second source gas to a region of the first space or the second space facing the second induction coil; A method of using a plasma processing apparatus comprising: A method of using a plasma processing apparatus, comprising detecting information about the workpiece from above the dielectric window through the second space with an optical sensor.

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