Substrate heating apparatus and substrate heating method

Abstract

To suppress a substrate from decreasing in heating efficiency owing to LED light.SOLUTION: A substrate heating apparatus comprises: a storage chamber which stores a substrate; a transparent window which is provided in a wall part of the storage chamber to face the stored substrate; a heating light source which irradiates the substrate with irradiation light through the transparent window to heat the substrate; and a light-transmissive mask member which is interposed between the transparent window and the stored substrate.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a substrate heating apparatus and a substrate heating method. [Background technology]

[0002] As the temperature of semiconductor device manufacturing processes has become lower in recent years, impurities such as unreacted by-products and residual gases may remain inside various films formed on the surface of a substrate, such as a wafer, on which a semiconductor device is formed. If these impurities vaporize and are released from the films when the wafer is subjected to various processes, this can affect the quality of the semiconductor device manufactured. Therefore, techniques for heating the wafer have been developed to vaporize and release impurities remaining inside various films before the wafer is subjected to various processes. For example, a technique has been proposed in which the wafer is heated by irradiating it with LED light from a light irradiation unit (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-117618 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology according to the present disclosure suppresses a decrease in the efficiency of heating a substrate by LED light. [Means for solving the problem]

[0005] One aspect of the technology disclosed herein is a substrate heating device comprising: a storage chamber for storing a substrate; a transparent window provided in a wall of the storage chamber facing the stored substrate; a heating light source that irradiates the substrate with light through the transparent window to heat the substrate; and a light-transmitting mask member interposed between the transparent window and the stored substrate. [Effects of the Invention]

[0006] According to the technology of the present disclosure, it is possible to suppress a decrease in the efficiency of heating the substrate by LED light. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a plan view schematically illustrating a configuration of a substrate processing system including a substrate heating device according to an embodiment of the technology disclosed herein. [Figure 2] FIG. 2 is a cross-sectional view schematically showing the configuration of a load lock chamber in FIG. [Figure 3] 3 is a diagram showing the LED light source in FIG. 2 as viewed from below. FIG. [Figure 4] FIG. 3 is a cross-sectional view schematically showing the configuration of the mounting table in FIG. 2. [Figure 5] FIG. 3 is a diagram for explaining the configuration of a mask member in FIG. 2. [Figure 6] FIG. 2 is a cross-sectional view schematically illustrating the configuration of a mask member having a lens function. DETAILED DESCRIPTION OF THE INVENTION

[0008] In the technology described in Patent Document 1, wafers are heated in a load-lock chamber whose interior can be switched between vacuum and atmospheric pressure. Specifically, a wafer is placed inside the load-lock chamber, and after the pressure inside the load-lock chamber is reduced, LED light is irradiated onto the wafer from an LED light source installed outside the load-lock chamber through a transparent window installed facing the wafer. Impurities vaporized and released from the heated wafer are then expelled outside the load-lock chamber by the exhaust system of the load-lock chamber.

[0009] However, impurities vaporized and released from the wafer may reach the transparent window before being released outside the load lock chamber, causing the impurities to adhere to the transparent window. When impurities adhere to the transparent window, the transmittance of the transparent window decreases, reducing the efficiency of heating the wafer with LED light from the LED light source. In response to this problem, the technology disclosed herein interposes a translucent mask member between the transparent window and the wafer.

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the technology according to the present disclosure will now be described with reference to the accompanying drawings. Fig. 1 is a plan view schematically showing the configuration of a substrate processing system 10 including a substrate heating device according to this embodiment.

[0011] 1, a substrate processing system 10 includes four load ports 11 to which are attached FOUPs (not shown), which are containers that house a plurality of wafers W (substrates) each having a diameter of, for example, 300 mm. These load ports 11 are connected to a loader chamber 12, which is an atmospheric transfer chamber. The loader chamber 12 has a substantially rectangular parallelepiped shape, and the interior of the loader chamber 12 is maintained at atmospheric pressure. A transfer robot 13 (substrate transfer mechanism) for transferring the wafers W is disposed inside the loader chamber 12.

[0012] The transfer robot 13 has a base 14 that is movable in the longitudinal direction of the loader chamber 12, an arm 15 that is rotatable and extendable in a horizontal plane relative to the base 14, and a pick 16 that is provided at the tip of the arm 15 and holds a wafer W. The transfer robot 13 loads and unloads wafers W into and from each FOUP and each load lock chamber 17, which will be described later, by moving the base 14 and rotating and extending the arm 15. The arm 15 is configured to be movable also in the vertical direction relative to the base 14.

[0013] Furthermore, three load lock chambers 17 are arranged as substrate transfer chambers on the opposite side of each load port 11 with the loader chamber 12 in between. Each load lock chamber 17 has an exhaust system (not shown) that can selectively switch the interior between a vacuum atmosphere and an atmospheric pressure atmosphere. The interior of the load lock chamber 17 is set to an atmospheric pressure atmosphere when communicating with the loader chamber 12, and is set to a vacuum atmosphere when communicating with the substrate transfer chamber 18 described below. The load lock chamber 17 functions as an intermediate transfer chamber for transferring wafers W between the loader chamber 12 and the substrate transfer chamber 18, but in this embodiment, it also functions as a substrate heating device, as described below.

[0014] A substrate transfer chamber 18 is disposed on the opposite side of the loader chamber 12, with each load lock chamber 17 sandwiched between them. The substrate transfer chamber 18 has a substantially rectangular parallelepiped shape, and the interior of the substrate transfer chamber 18 is maintained in a vacuum atmosphere. A transfer robot 19 for transferring wafers W is disposed inside the substrate transfer chamber 18.

[0015] The transfer robot 19 has a base 20 that is movable in the longitudinal direction of the substrate transfer chamber 18, an arm 21 that is rotatable and extendable in a horizontal plane relative to the base 20, and a pick 22 that is provided at the tip of the arm 21 and holds a wafer W. The transfer robot 19 moves the base 20 and rotates and extends the arm 21 to load and unload the wafer W into and from each load lock chamber 17 and each substrate processing chamber 23, which will be described later.

[0016] Four substrate processing chambers 23 are connected to the substrate transfer chamber 18 via gate valves 24, and the gate valves 24 control communication between each substrate processing chamber 23 and the substrate transfer chamber 18. A vacuum atmosphere is maintained inside each substrate processing chamber 23, and wafers W accommodated therein are subjected to etching and film formation processes.

[0017] The substrate processing system 10 also includes a control unit 25 that controls the operation of each component of the substrate processing system 10. The control unit 25 has a CPU, memory, etc., and the CPU performs etching processing and film formation processing in each substrate processing chamber 23 according to recipes stored in the memory, etc. The CPU also performs heating of the wafer W in the load lock chamber 17 according to programs stored in the memory, etc.

[0018] Fig. 2 is a cross-sectional view schematically showing the configuration of the load lock chamber 17 in Fig. 1. In Fig. 2, the load lock chamber 17 has a substantially rectangular parallelepiped accommodation chamber 26 that accommodates a wafer W, and a transparent window 27 provided in a ceiling 26a (wall) of the accommodation chamber 26. The load lock chamber 17 also has an LED light source 28 (heating light source) that irradiates LED light (irradiation light), and a mounting table 29 (cooling source) on which the wafer W is placed and cooled.

[0019] The mounting table 29 is disposed at the bottom inside the accommodation chamber 26, and the LED light source 28 is disposed outside the accommodation chamber 26, specifically above the ceiling portion 26a, so as to face the mounting table 29 across the transparent window 27. The LED light source 28 irradiates the wafer W mounted on the mounting table 29 with LED light through the transparent window 27. Note that the LED light source 28 may be attached to the accommodation chamber 26 as long as it faces the mounting table 29 across the transparent window 27.

[0020] The mounting table 29 is provided with a plurality of lift pins 30 that can protrude relative to the upper surface of the mounting table 29. A transfer port 31 (a transfer port for substrate replacement) that is opened and closed by a gate valve (not shown) is provided in a side wall of the accommodation chamber 26 on the loader chamber 12 side. When each lift pin 30 lifts the wafer W from the mounting table 29, the arm 15 of the transfer robot 13 enters the accommodation chamber 26, and the pick 16 receives the lifted wafer W. When the arm 15 of the transfer robot 13 transfers the wafer W into the accommodation chamber 26, each lift pin 30 protrudes the wafer W from the mounting table 29 and receives the wafer W from the pick 16. At this time, the arm 15 of the transfer robot 13 enters the accommodation chamber 26 through the transfer port 31. Another transfer port (not shown) that is opened and closed by a gate valve (not shown) is provided in a side wall on the opposite side of the transfer port 31. Then, as each lift pin 30 protrudes from the mounting table 29, the arm 21 of the transport robot 19 enters the interior of the accommodation chamber 26 through another entrance / exit, thereby transferring the wafer W between the mounting table 29 and the transport robot 19.

[0021] The load lock chamber 17 also has a mask member 32 made of a light-transmitting plate-like member and a rack portion 33 protruding from the side wall of the accommodation chamber 26. The mask member 32 is made of quartz, sapphire, borosilicate glass (heat-resistant glass), a transparent resin, or the like. The rack portion 33 is made of a plurality of protruding members protruding horizontally and supports the peripheral portion of the mask member 32 from below between the transparent window 27 and the mounting table 29. This positions the mask member 32 between the transparent window 27 and the wafer W mounted on the mounting table 29. The mask member 32 is preferably large enough to completely cover the wafer W mounted on the mounting table 29 when viewed from the transparent window 27 side.

[0022] The rack section 33 is installed in a position where the mask member 32 supported by the rack section 33 can be replaced by the arm 15 of the transport robot 13, which enters the inside of the storage chamber 26 through the loading / unloading entrance 31, moving up and down. When replacing the mask member 32, the arm 15 of the transport robot 13 enters the inside of the storage chamber 26 and then moves upward, causing the pick 16 to lift up and receive the mask member 32 supported by the rack section 33. In addition, the arm 15 of the transport robot 13, which holds the mask member 32, enters the inside of the storage chamber 26 with the pick 16 and then moves downward, causing the mask member 32 to be supported by the rack section 33 and handed over.

[0023] When the wafer W is heated in the load lock chamber 17, the wafer W is loaded into the accommodation chamber 26 and placed on the mounting table 29, and then the interior of the accommodation chamber 26 is evacuated to a vacuum atmosphere by the exhaust system. Furthermore, the LED light source 28 irradiates the wafer W with LED light through the transparent window 27 and the mask member 32. The irradiation of this LED light overheats the wafer W, and impurities remaining inside the various films formed on the surface of the wafer W are vaporized and released. The vaporized and released impurities are then released to the outside of the accommodation chamber 26 by the exhaust system.

[0024] At this time, some of the vaporized and released impurities may move toward the transparent window 27. However, in the load lock chamber 17, the mask member 32 is interposed between the transparent window 27 and the wafer W placed on the mounting table 29, and therefore the vaporized impurities moving toward the transparent window 27 are blocked by the mask member 32 and hardly reach the transparent window 27. This makes it possible to suppress the impurities from adhering to the transparent window 27 and prevent a decrease in the transmittance of the transparent window 27. As a result, it is possible to suppress a decrease in the efficiency of heating the wafer W by the LED light from the LED light source 28.

[0025] On the other hand, because the mask member 32 blocks the vaporized impurities, the impurities adhere to the mask member 32, reducing the transmittance of the mask member 32, which may also reduce the efficiency of heating the wafer W with the LED light from the LED light source 28. However, as described above, the mask member 32 can be easily replaced by the transfer robot 13. Therefore, by replacing the mask member 32 when a certain amount of impurities have adhered to the mask member 32 and the transmittance has decreased, the transmittance of the mask member 32 can be restored. As a result, a decrease in the efficiency of heating the wafer W with the LED light from the LED light source 28 can be suppressed.

[0026] The wafer W may be heated in the load lock chamber 17 before various processes are performed on the wafer W in each substrate processing chamber 23, or after various processes are performed on the wafer W in each substrate processing chamber 23.

[0027] 3 is a diagram showing the LED light source 28 in FIG. 2 as viewed from below. In FIG. 3, the LED light source 28 has a generally circular disk shape overall, and a plurality of light source chips 34 are concentrically and radially arranged on the lower surface facing the transparent window 27 (all rectangles in the figure represent light source chips 34). In addition, one radiation thermometer 35 pointing downward is arranged in the center of the lower surface. Note that the number of radiation thermometers 35 is not limited to one, and there may be multiple. In this case, radiation thermometers 35 are arranged not only in the center of the lower surface but also on the periphery of the lower surface.

[0028] Incidentally, the light absorptance of silicon (Si) constituting the wafer W rapidly deteriorates when the light wavelength exceeds approximately 1000 nm, but the wavelength of the LED light emitted by each light source chip 34 is 400 nm or less, for example, 395 nm. Furthermore, since the wavelength of LED light does not vary, LED light with a wavelength of approximately 1000 nm or more is not emitted from each light source chip 34. As a result, the deterioration of the light absorptance in the wafer W due to the wavelength of the LED light does not occur, and the heating efficiency of the wafer W by the LED light is not reduced.

[0029] Furthermore, the radiation thermometer 35 measures the temperature of the wafer W by converting light with a wavelength of approximately 950 nm (hereinafter referred to as "temperature measurement light") emitted from the wafer W into a temperature. Here, since the wavelength of the LED light emitted by each light source chip 34 is 400 nm or less, the radiation thermometer 35 does not erroneously convert the LED light emitted by each light source chip 34 into a temperature. This also makes it possible to avoid erroneous measurements by the radiation thermometer 35.

[0030] Furthermore, the characteristics of LED light with a wavelength of 400 nm or less are similar to those of ultraviolet light, and because the light energy is high, it is expected that the light energy itself will be effective in decomposing substances. This can particularly promote the decomposition of impurities adhering to the surface of the wafer W. Also, because LEDs have very little standby power, the LED light source 28 consumes little power when not heating the wafer W, which can be expected to have an energy-saving effect.

[0031] 4 is a cross-sectional view schematically illustrating the configuration of the mounting table 29 in FIG. 2. The mounting table 29 in this embodiment has a function of cooling the wafer W. For example, the mounting table 29 may be configured with a main body 36 made of a plate-shaped member made of a metal with high thermal conductivity, such as an aluminum plate-shaped member, and a coolant flow path 37 may be built into the main body 36, through which a coolant flows (FIG. 4(A)). The coolant flowing through the coolant flow path 37 may be, for example, water, ethanol (C2H6O), a mixture of water and a saturated gas, or a mixture of ethanol and a saturated gas. When the coolant flows through the coolant flow path 37, heat is transferred from the heated wafer W toward the coolant flow path 37 (see the white arrow in the figure), thereby cooling the wafer W.

[0032] Alternatively, the mounting table 29 may be configured as a vapor chamber (FIG. 4(B)). In this case, the main body of the mounting table 29 is configured as a hollow heat exchange chamber 38, the inner surface of which is covered with a capillary structure 39, and a working fluid is poured into the heat exchange chamber 38. The working fluid filled in the upper part of the heat exchange chamber 38, i.e., the capillary structure 39 directly below the wafer W, vaporizes due to heat transfer from the heated wafer W. The working fluid then absorbs heat from the wafer W due to cooling caused by the heat of vaporization. The vaporized working fluid flows downward within the heat exchange chamber 38 (see the white arrows in the figure). When it reaches the capillary structure 39 at the bottom of the heat exchange chamber 38, the heat is absorbed by a heat exchange mechanism in contact with the underside of the mounting table 29, and the working fluid is re-liquefied. The liquefied working fluid flows through the capillary structure 39 and circulates to the upper part of the heat exchange chamber 38 (see the black arrows in the figure) and is re-evaporated by heat transfer from the wafer W. This repeated evaporation and liquefaction of the working fluid allows the wafer W to be continuously cooled by the mounting table 29. Furthermore, since the working fluid is uniformly distributed and vaporized in the capillary structure 39 above the heat exchange chamber 38, the mounting table 29 is cooled uniformly, and the wafer W mounted on the mounting table 29 can be uniformly cooled across its surface. The flow of refrigerant in the heat exchange mechanism in contact with the underside of the mounting table 29 is indicated by thick arrows, with thick black arrows indicating the flow of low-temperature refrigerant and thick white arrows indicating the flow of high-temperature refrigerant. Furthermore, since gas heat exchange is generally more efficient than heat transfer in metal, configuring the mounting table 29 as a vapor chamber allows the wafer W to be cooled more quickly, thereby quickly completing heating of the wafer W in the load lock chamber 17. As a result, throughput can be improved.

[0033] Fig. 5 is a diagram for explaining the configuration of the mask member 32 in Fig. 2. As shown schematically in Fig. 5(A), the mask member 32 is interposed between the LED light source 28 and the wafer W. Therefore, the mask member 32 is irradiated with LED light (solid arrow) from the LED light source 28, and also irradiated with infrared light (dashed arrow) emitted by the heated wafer W.

[0034] If the upper surface of the mask member 32 facing the LED light source 28 reflects the LED light, the amount of LED light passing through the mask member 32 may decrease, potentially reducing the efficiency of heating the wafer W with the LED light. To address this issue, an anti-reflection film 40 that prevents reflection of the LED light is formed on the upper surface of the mask member 32 facing the LED light source 28. The anti-reflection film 40 is made of, for example, magnesium fluoride (MgF), titanium (IV) oxide (TiO), zirconia (ZrO), or aluminum oxide (AlO), and suppresses reflection of the LED light. This prevents a decrease in the amount of LED light passing through the mask member 32.

[0035] Furthermore, if the mask member 32 transmits infrared light emitted from the wafer W, the LED light sources 28 may be heated by the infrared light, which may change the wavelength of the LED light emitted by each light source chip 34. To address this issue, a transmission control film 41 that reflects infrared light and controls the transmission of infrared light is formed on the underside of the mask member 32 facing the wafer W. The transmission control film 41 is made of gold (Au), silver (Ag), titanium nitride (TiN), tungsten (W), or ruthenium (Ru), and controls the transmission of infrared light to prevent it from reaching the LED light sources 28. This prevents the LED light sources 28 from being heated by infrared light. As described above, the LED light emitted by the LED light sources 28 has a wavelength of 400 nm or less. However, since gold reflects light with a wavelength of 800 nm or more and silver only reflects light with a wavelength of 450 nm or more, the transmission of the LED light is not inhibited. Therefore, it is preferable to form the transmission control film 41 from gold or silver from the viewpoint of suppressing a decrease in the efficiency of heating the wafer W by the LED light. When the anti-reflection film 40 is not formed on the upper surface of the mask member 32, the transmission control film 41 may be formed on the upper surface of the mask member 32.

[0036] The radiation thermometer 35 of the LED light source 28 measures the temperature by converting the temperature measurement light emitted from the wafer W into a temperature value. If the transmission control film 41 were made of gold or silver, the transmission control film 41 would reflect the temperature measurement light with a wavelength of approximately 950 nm, which could interfere with the measurement of the temperature of the wafer W by the radiation thermometer 35. To address this issue, a through-hole 42 is formed in the mask member 32 so as to face the radiation thermometer 35. As described above, the radiation thermometer 35 is disposed in the center of the lower surface of the LED light source 28, and therefore the through-hole 42 is formed in the center of the mask member 32, and the radiation thermometer 35 faces the wafer W via the through-hole 42 ( FIG. 5(B) ). This allows the temperature measurement light emitted from the wafer W to pass through the through-hole 42 and reach the radiation thermometer 35, preventing the transmission control film 41 from interfering with the measurement of the temperature of the wafer W by the radiation thermometer 35. When multiple radiation thermometers 35 are also arranged around the periphery of the lower surface of the LED light source 28, multiple through holes 42 are formed in the mask member 32 so as to face the respective radiation thermometers 35 (FIG. 5(C)).

[0037] As described above, a plurality of light source chips 34 are disposed on the underside of the LED light source 28 facing the transparent window 27 (wafer W). The ideal arrangement of the light source chips 34 is one in which the wafer W is uniformly heated across its surface by the LED light emitted from each light source chip 34. However, due to the shape of each light source chip 34 and the routing of the wiring to each light source chip 34, limitations are placed on the arrangement of the light source chips 34, making it difficult to achieve the ideal arrangement. To address this issue, the mask member 32 may be provided with a lens function that adjusts the distribution of the LED light. Specifically, a plurality of convex lenses or a plurality of concave lenses are formed on the underside of the mask member 32 facing the wafer W so that the LED light transmitted through the mask member 32 uniformly heats the wafer W across its surface. The arrangement of the convex lenses or concave lenses formed on the underside of the mask member 32 is changed depending on the arrangement of the light source chips 34 in the LED light source 28 (see the cross-sectional views of the mask member 32 in FIGS. 6(A) to 6(C)).

[0038] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications and changes are possible within the scope of the gist of the present disclosure.

[0039] For example, in this embodiment, each load lock chamber 17 functions as a substrate heating device, but the substrate heating device may be configured as an independent substrate heating module, and the substrate heating module may be connected to the loader chamber 12 or the substrate transport chamber 18.

[0040] In addition, in this embodiment, a wafer is heated as a substrate in the load lock chamber 17, but a substrate other than a wafer, for example, a glass substrate, may be heated in the load lock chamber 17. Furthermore, in this embodiment, the LED light source 28 is used as the heating light source, but a halogen light source that irradiates halogen light toward the wafer W may also be used as the heating light source. [Explanation of symbols]

[0041] W wafer 17 Load lock chamber 26 Containment Room 26a Ceiling section 27 Transparent Window 28 LED light source 32 Mask material

Claims

1. a chamber for accommodating a substrate; a transparent window provided on a wall of the accommodation chamber and facing the accommodated substrate; a heating light source that irradiates the substrate with irradiation light through the transparent window to heat the substrate; a light-transmitting mask member interposed between the transparent window and the accommodated substrate.

2. 2. The substrate heating apparatus according to claim 1, wherein the mask member is made of quartz, borosilicate glass, sapphire, or a transparent resin.

3. The substrate heating apparatus according to claim 1 , wherein the mask member has a lens function for adjusting the distribution of the irradiation light.

4. 2. The substrate heating apparatus according to claim 1, wherein said mask member is made of a plate-like member and has an anti-reflection film formed on a surface facing said transparent window.

5. The anti-reflection film is made of magnesium fluoride (MgF ２ ), titanium(IV) oxide (TiO ２ ), zirconia (ZrO ２ ) or aluminum oxide (Al ２ O ３ 5. The substrate heating device according to claim 4, comprising:

6. 2. The substrate heating apparatus according to claim 1, wherein the mask member is made of a plate-like member and has a transmission control film formed on a surface facing the substrate.

7. 7. The substrate heating device according to claim 6, wherein the transmission control film is made of gold (Au), silver (Ag), titanium nitride (TiN), tungsten (W), or ruthenium (Ru).

8. the heating light source has a radiation thermometer, the mask member has a through hole that opens to face the radiation thermometer, The substrate heating device according to claim 1 , wherein the radiation thermometer faces the substrate via the through hole.

9. The substrate heating apparatus according to claim 1 , further comprising a rack portion that supports the mask member between the transparent window and the accommodated substrate.

10. 10. The substrate heating device according to claim 9, wherein the rack section is installed in a position where the mask member supported on the rack section can be replaced by a substrate transport mechanism that enters the interior of the storage chamber through a substrate replacement entrance / exit provided in the storage chamber.

11. The substrate heating apparatus according to claim 1 , further comprising a cooling source for placing and cooling the accommodated substrate.

12. The substrate heating apparatus according to claim 11 , wherein the cooling source is configured by a plate-like member or a vapor chamber having a built-in coolant flow path.

13. The refrigerant flowing through the refrigerant flow path and the working liquid used in the vapor chamber are water, ethanol (C ２ H ６ 13. The substrate heating apparatus of claim 12, wherein the gas is a mixture of water and a saturated gas, or a mixture of ethanol and a saturated gas.

14. 2. The substrate heating device according to claim 1, wherein the irradiated light is LED light having a wavelength of 400 nm or less.

15. The substrate is accommodated in the accommodation chamber; The accommodated substrate is placed facing a transparent window provided in a wall of the accommodation chamber; a light-transmitting mask member is interposed between the transparent window and the accommodated substrate; A substrate heating method comprising: irradiating the substrate with light from a heating light source through the transparent window to heat the substrate.

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