JP2000340501A - Device and method for heat-treating substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely control the temperature of a substrate by adjusting the parameters of a heat-treatment gas, that is supplied to the substrate in accordance with a prescribed heat treatment period for adjusting the temperature of the substrate and causing relative rotation of the substrate and a gas supply system. SOLUTION: A substrate support body 16 is rotated at an appropriate speed. Then, while a relatively hot gas and a relatively cold gas are supplied from a heat has source 34 and a cold gas source 36 to a substrate 2 via a gas supply system 18 by a control device 32, while controlling the flow rate, mixing ratio, and temperature, thus obtaining a desired substrate temperature distribution over a long time. Also, the substrate support body 16 may be fixed and the gas supply system 18 may be rotated, thus uniformly controlling the temperature of the substrate 22 by relatively rotating the substrate support body 16 and the gas supply system 18. Also, nonuniformity caused by swelling, shrinkage, or the like of the plate is eliminated, since gas is used as compared with a case where the substrate 22 as a whole is brought into contact with the hot or cold plate as in prior art.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION This application is a co-pending application, filed Mar. 11, 1998, application number 09 / 041,471, incorporated herein by reference, entitled "Thermal Cycling Module." It is related to

[0002]

BACKGROUND OF THE INVENTION The present invention relates to an apparatus and a method for heat treating a substrate.

[0003] Processing of substrates often involves heat treatment (eg, heating and cooling) of the substrate. For example, in order to manufacture an integrated circuit by photolithography, a substrate such as a semiconductor wafer must be covered with a photoresist film and subjected to a heat treatment. The substrate is used to solidify or cure the photoresist film layer as part of the photoresist film processing step, or to accelerate the chemical transition of the photoresist film layer to which an acid used in deep ultraviolet lithography is added as a catalyst. , Subject to a controlled thermal cycle. Typically, the substrate is heated to a high temperature (eg, 70 to 250 ° C.), maintained at the high temperature for a predetermined time (eg, 30 to 120 seconds), and then to a lower temperature (eg, 0 to 30 ° C.). Cooled. These heat treatments include after vapor prime,
It is performed at many points in the photolithography flow, including spin coating, exposure and development steps.
During such heat treatment, the temperature of the substrate should be tightly controlled to achieve high yields.

[0004]

SUMMARY OF THE INVENTION In one aspect, the present invention provides a method for heat treating a substrate. The method comprises the steps of supporting a substrate, supplying a heat treatment gas to the substrate, and adjusting one or more parameters of the heat treatment gas supplied to the substrate over a long period of time according to a predetermined heat treatment cycle. Controlling the temperature of the substrate and generating a relative rotational movement between the substrate support and the gas supply system. Supporting the substrate by a substrate support, supplying a heat treatment gas by a gas supply system,
The temperature of the substrate may be controlled by a controller and the relative rotational motion may be generated by a rotator.

[0005] Implementations may include one or more of the following features.

[0006] The controller may be configured to control the temperature of the substrate through a heating and cooling heat treatment cycle. The substrate support supporting the substrate may be configured to contact only a small portion of the bottom surface of the substrate. For example, when supporting the substrate, the substrate support may be configured to contact only the outer peripheral region of the bottom surface of the substrate, or a plurality of support pins formed to contact the bottom surface of the substrate. May be configured. An actuator may be provided to move the gas supply system closer to or away from the substrate.

[0007] The gas supply system may simply be configured to supply the heat treatment gas to one surface of the substrate. For example, the gas supply system may be configured to supply the heat treatment gas only to the bottom or top surface of the substrate. The gas supply system may consist of separate systems for supplying relatively hot gas to the substrate and for supplying relatively cool gas. A separate gas supply system
At all times, a relatively hot gas may be provided to a first region of the substrate and a relatively cool gas may be provided to a second, different region of the substrate. The gas supply system may be configured to mix a relatively hot gas and a relatively cold gas to obtain a desired mixed gas temperature and supply the mixed gas to the substrate. The gas supply system may be configured to supply the heat treatment gas at a first flow rate to the outer peripheral region of the substrate and at a second flow rate less than the first flow rate to the central region of the substrate. The gas supply system may be configured to direct a flow of the heat treatment gas to the substrate.

[0008] The rotator may be configured to rotate the substrate support, or may be configured to rotate the gas supply system. Further, a temperature sensor for monitoring the temperature of the gas supplied to the substrate by the gas supply system may be provided. Multiple temperature sensors may be located proximate to the substrate to sense supply gas temperatures at multiple distribution sites. These multiple temperature sensors may be configured in combination with a feedback control device that adjusts the flow rate of the heat transfer gas.

The advantages of the present invention are described below. By generating a relative rotational movement between the substrate support and the gas supply system, the present invention provides uniform (angularly uniform and radially uniform) temperature control across the substrate. By heating and cooling the substrate with a heat treatment gas, rather than relying on contact with a hot or cold plate, the present invention provides for expansion and contraction of the plate during thermal cycling, or uneven gaps due to uneven substrates. The resulting non-uniformity problem can be avoided. Furthermore, by directly heating the substrate with a heat treatment gas, the present invention can provide rapid temperature changes of the substrate with low energy consumption.

[0010] Other features and advantages of the invention will be apparent from the following description, including the drawings and the claims.

[0011]

Referring to FIG. 1A, a heat treatment apparatus 10 includes a substrate support 16 and a gas supply system 18 in a housing 12 having a lid 14. The substrate support 16 is provided with a support ring 20 that contacts an outer peripheral edge of a substrate 22 (for example, a semiconductor wafer, a flat panel display, or a rectangular photomask). Support ring 2
The 0 simply contacts a small portion of the bottom surface of the substrate 20 so that the majority of the bottom surface of the substrate will be exposed to the heat treatment gas 24 delivered by the gas supply system 18. Support ring 2
0 is further mounted on a support tube 25 pivotally supported by a bearing assembly 26.
Also, a magnet 28 mounted on the bearing assembly 26 is magnetically coupled to a magnet 30 mounted on the drive ring 32. During operation, the rotation of the drive ring 31 causes the support tube 2 to rotate via the magnetic coupling.
5 and the support ring 20 are rotated. In an alternative embodiment, the bearing assembly 26 and magnets 28 and 30 may be replaced by a sealed drive assembly.
The housing 12 is preferably water-cooled to avoid non-repetitive temperature treatments.

As shown in FIG. 1B, in another embodiment, the substrate 22 may be supported on a plurality of support pins 23.

The gas supply system 18 is configured to supply a heat treatment gas 24 to the substrate 22. The controller 32 is coupled to a hot gas source 34 of a relatively hot gas and a cold gas source 36 of a relatively cold gas. Control device 3
2, adjust one or more parameters of the heat treatment gas over a long period of time to control the temperature of the substrate according to the heat treatment cycle described above. The heat treatment gas 24 is removed from the housing 12 via the exhaust pipe 38. The temperature of the substrate 22 is
It is monitored by a proximity temperature sensor 40 (eg, a thermocouple). As shown in FIG. 1B, the temperature sensor 40
May include a plurality of thermocouple probes 41 located adjacent to the back surface of the substrate 22. Signals are sent from these probes 41 to the control device 32 so that the control device 32 can adjust one or more parameters of the heat treatment gas.

In operation, the substrate 22 is first placed in the heat treatment apparatus 10 and placed on the support ring 20 above the gas supply system 18. The lid 14 is closed and the substrate support 16 is rotated at a suitable speed (eg, 60 rpm). As will be described in more detail below, the controller 32 may control the relatively hot gas from the source 34 (e.g., by controlling the flow rate, mixing ratio, and / or temperature of the gas from the sources 34 and 36), and The supply of the relatively cool gas from the source 36 is controlled to obtain a desired substrate temperature distribution over a long period of time. The substrate 22 is rapidly (eg, 5 ° C. per second).
May be uniformly heated to a high temperature (eg, about 70 ° C. to about 250 ° C.) and maintained at that temperature for a predetermined time (eg, about 30 to 90 seconds). Thereafter, the substrate 22 is rapidly (eg, at 5 ° C. per second) cold (eg, about 0 ° C.).
(From about 30 ° C. to about 30 ° C.). Thereafter, the substrate 22 may be maintained at that temperature for a certain period of time, or may be immediately removed from the apparatus 10.

The gas supply system 18 includes an actuator 43 (for example, a worm or the like) that moves the gas supply system 18 toward or away from the substrate 22.
A screw mechanism). Thereby, the substrate 22
The thermal interaction between the gas supply system 18 and the substrate 22 (e.g., convective heat transfer to the substrate 22 causing local temperature fluctuations) is reduced before the substrate is removed from the thermal processing apparatus 10 after the processing. I do. A water cooling tube may be provided around the gas supply path of the gas supply system 18 to control the outer surface temperature of the gas supply system 18. Further, a heat insulating material may be used to insulate the gas supply path of the gas supply system 18.

Referring to FIG. 2, in another embodiment, the gas supply system 42 is rotated relative to a fixed substrate support 44 mounted directly to the housing 12 so that the gas supply system 42 and the substrate 22 are rotated. Allows relative movement between and. The gas supply system 42 extends through a sealed bearing assembly 46 in the bottom wall of the housing 12 and is coupled to a rotator 48 (eg, a rotary motor). The rotator 48 rotates, directly or indirectly via a transmission belt, a drive shaft 50 coupled to the gas supply system 42.

Referring to FIGS. 3A and 3B,
In this embodiment, gas supply system 60 includes separate paths 62 and 64 for supplying relatively hot gas from source 34 and relatively cool gas from source 36, respectively, to the bottom surface of substrate 22. For this reason, source 36
A relatively cool gas is supplied to one region of the substrate bottom (cold region 66), and a relatively hot gas is supplied from source 34 to a different region of the substrate bottom (hot region 68). The substrate 22 is rotated (or alternatively, the gas supply system 60 is rotated).
Is rotated) to bring the bottom surface of the substrate 22 into the cold region 6.
By uniformly exposing the substrate 6 and the thermal region 68, a desired average substrate temperature can be obtained. By adjusting the gas flow rates through paths 62 and 64 and / or adjusting the temperature of the gas supplied from sources 34 and 36, controller 32 allows controller 32 to adjust the substrate 22 according to a predetermined heat treatment cycle. May be controlled. For example, to increase the temperature of the substrate 22, the controller 32 may increase the gas flow rate through the path 62 relative to the gas flow rate through the path 64, or alternatively, the substrate 2
To reduce the temperature of 2, the gas flow rate through path 64 may be increased relative to the gas flow rate through path 62. The controller 32 may adjust the parameters of the heat treatment gas supplied to the substrate 22 according to a signal received from the temperature sensor 40 according to an appropriate (open loop or closed loop) control algorithm.

As shown in FIG. 3B, a plurality of hot regions 70 to 74 and a cold region 76 on the bottom surface of the substrate 22 are provided.
The gas distribution system 60 may be configured to supply a heat treatment gas from to. The heat zones 70 to 74 each have a gas supply pipe 86 connected to the path 62 (FIG. 3A).
And 88 formed by a plurality of orifices 84 passing through the walls. Similarly, cold zones 76-82 each have a path 6
4 (FIG. 3 (a)) connected to gas supply pipes 90 and 92
Are formed by a plurality of orifices 84 passing through the wall of the orifice.
In one embodiment, the opening density (unit length of the gas supply pipe) is taken into account in consideration of the fact that the volume of the substrate passing over the outer orifice is larger than the volume of the substrate passing over the orifice located near the center of the substrate. Number of orifices per hit)
Is formed to be larger in the outer peripheral region of the gas supply system.

In another embodiment shown in FIGS. 4 (a) and 4 (b), the gas supply system 100 includes a path 10 for supplying a mixed heat treatment gas 104 to the bottom surface of the substrate 22.
2 inclusive. In this case, the substrate 22 is rotated (or, alternatively, the gas supply system 60 is rotated) to uniformly expose the bottom surface of the substrate 22 to the mixed heat treatment gas 104 to obtain a desired average substrate temperature. By adjusting the mixing ratio of the cold gas and the hot gas, adjusting the temperature of the gas supplied from the sources 34 and 36, or both, the control device 32 allows the control unit 32 to May be controlled. For example, in order to increase the temperature of the substrate 22, the controller 32 may increase the flow rate of the hot gas received from the hot gas source 34 with respect to the flow rate of the cold gas received from the cold gas source 36, or First, the substrate 22
In order to lower the temperature, the flow rate of the cold gas received from the cold gas source 36 may be increased with respect to the flow rate of the hot gas received from the hot gas source 34. The controller 32 follows the appropriate (open loop or closed loop) control algorithm and
The parameters of the mixed heat treatment gas to be supplied to the substrate 22 may be adjusted according to a signal received from the temperature sensor 106 provided on the substrate 02.

As shown in FIG. 4B, the gas supply system 100 includes a cruciform member 108 having four gas supply arms 110 projecting from a hub 112 and connected to a support ring 114. Each arm 110 is provided with a plurality of orifices 116 (or nozzles). These orifices 116 connect to a path in each arm 110, which in turn connects to a path 102 for receiving the mixed heat treatment gas 104. In one embodiment, taking into account that the substrate volume passing over the outer orifice is larger than the substrate volume passing over the orifice located near the center of the substrate, the opening in the outer peripheral region of the gas supply system. It is formed so that the density (the number of orifices per unit length formula of the gas supply arm) is increased.

The heat treatment gas 24 is made of air, nitrogen, or an inert gas such as helium or argon. The hot gas source 34 includes a heating system (eg, a hot filament) that actively raises the temperature of the hot gas to a predetermined high temperature (eg, from about 70 ° C. to about 250 ° C.). The cold gas source 36 simply supplies air at room temperature (eg, 25 ° C.), or cools the temperature of the cold gas by actively lowering the temperature of the cold gas to a predetermined low temperature (eg, about 0 ° C. to about 30 ° C.). A system may be included. The cold gas source 36 may also include a heating system that selectively raises the temperature of the cold gas to a temperature above a predetermined low temperature. The bottom surface of the substrate 22 is at a distance of about 2 cm from the orifice (or nozzle) of the gas supply system. During operation, housing 1
2 is at atmospheric pressure, and the heat treatment gas is about 150 minutes per minute.
It flows toward the substrate 22 at a cubic foot flow rate. Generally, this flow rate is less than the flow rate required to lift substrate 22 from the substrate support.

Other embodiments are possible within the scope of the present invention. For example, in another embodiment shown in FIG. 5, the heat treatment gas 24 may be supplied to the upper surface of the substrate 22. For other features of this embodiment, see FIG.
This is the same as that described in the embodiment (a). The proximity temperature sensor 40 is directly connected to a witness piece (ie, a sample of substrate material including an embedded thermocouple probe), or a thermocouple embedded in the support pin 23 (FIG. 1B), or the temperature of the substrate. It may be replaced with a pyrometer having an appropriate configuration for performing the measurement. Also, the number, shape and direction of the gas supply arms and orifices may vary depending on the size, shape and direction of the substrate, and the particular configuration of other parts of the heat treatment apparatus.

Still other embodiments are possible within the scope of the present invention.

[Brief description of the drawings]

FIG. 1 (a) is a schematic side view showing an apparatus for heat-treating a substrate supported on a rotatable edge ring or substrate support ring, and FIG. 1 (b) is pivotable on a plurality of support pins. FIG. 3 is a schematic side view showing an apparatus for heat-treating a substrate supported on a substrate.

FIG. 2 is a schematic side view showing an apparatus for heat treating a substrate, including a rotatable gas supply system.

3A and 3B are a schematic side view and a plan view, respectively, showing a gas supply system.

4 (a) and (b) are schematic side and plan views showing an alternative gas supply system.

FIG. 5 is a schematic side view showing an apparatus for heat treating a substrate, including a gas supply system arranged to supply a gas to an upper surface of the substrate.

Claims (29)

[Claims] An apparatus for heat treating a substrate, comprising: a substrate support configured to support the substrate; and a gas supply configured to supply a heat treatment gas to the substrate supported by the substrate support. A controller configured to control the temperature of the substrate by adjusting one or more parameters of the heat treatment gas supplied to the substrate over a long period of time according to a predetermined heat treatment cycle; An apparatus comprising: a rotator configured to cause relative rotational movement between the substrate support and the gas supply system. 2. The apparatus according to claim 1, wherein the controller is configured to control the temperature of the substrate via a heating and cooling heat treatment cycle. 3. The apparatus of claim 1, wherein the substrate support is configured to contact a small portion of a bottom surface of the substrate to support the substrate. 4. The apparatus of claim 3, wherein the substrate support is configured to contact only an outer peripheral area of a bottom surface of the substrate to support the substrate. 5. The apparatus of claim 3, wherein the substrate support includes a plurality of support pins configured to contact a bottom surface of the substrate when supporting the substrate. 6. The apparatus of claim 1, wherein the gas supply system is configured to supply the heat treatment gas only to one surface of the substrate. 7. The apparatus of claim 6, wherein the gas supply system is configured to supply the heat treatment gas only to a bottom surface of the substrate. 8. The apparatus according to claim 6, wherein the gas supply system is configured to supply the heat treatment gas only to an upper surface of the substrate. 9. The apparatus of claim 1, wherein the gas supply system includes an actuator configured to move the gas supply system closer to or away from the substrate. 10. The apparatus according to claim 1, wherein the gas supply system is water-cooled. 11. The apparatus of claim 1, wherein the gas supply system includes separate systems for providing a relatively hot gas to the substrate and a relatively cool gas. 12. The separate gas supply system supplies a relatively hot gas to a first area of the substrate at a predetermined time and a relatively cool gas to a second different area of the substrate. The apparatus according to claim 11, wherein the apparatus is configured as follows. 13. The gas supply system is configured to mix a relatively hot gas and a relatively cool gas to obtain a desired hybrid gas temperature, and to supply the hybrid gas to the substrate. An apparatus according to claim 1. 14. The gas supply system supplies a heat treatment gas to a peripheral region of the substrate at a first flow rate and to a central region of the substrate at a second flow rate less than the first flow rate. The apparatus of claim 1, wherein the apparatus is configured. 15. The apparatus of claim 1, wherein the gas supply system is configured to supply a flow of a heat treatment gas to the substrate. 16. The apparatus of claim 1, wherein the rotator is configured to rotate the substrate support. 17. The apparatus of claim 1, wherein the rotator is configured to rotate the gas supply system. 18. The apparatus according to claim 1, further comprising a temperature sensor configured to monitor a temperature of a gas supplied to the substrate by the gas supply system. 19. The apparatus of claim 1, further comprising a temperature sensor disposed adjacent to the substrate and configured to monitor a temperature of the substrate. 20. An apparatus for heat-treating a substrate, comprising: means for supporting the substrate; means for supplying a heat-treatment gas to the substrate; and Means for controlling the temperature of the substrate by adjusting one or more parameters of the supplied heat treatment gas; and means for causing relative rotational movement between the substrate support and the gas supply system. apparatus. 21. A method for heat-treating a substrate, comprising: a step of supporting the substrate; a step of supplying a heat-treatment gas to the substrate; and a step of supplying a heat-treatment gas to the substrate for a long time according to a predetermined heat-treatment cycle. Controlling the temperature of the substrate by adjusting one or more parameters; and causing a relative rotational movement between the substrate support and the gas supply system. 22. The method of claim 21, wherein the step of supplying a gas comprises supplying a relatively hot gas to the substrate and supplying a relatively cool gas to the substrate. 23. The method of claim 21, wherein the step of controlling the temperature of the substrate includes selectively coupling the gas supply system to a source of relatively hot gas or to a source of relatively cold gas.
The method described in. 24. The method of claim 21, wherein the step of controlling the substrate temperature comprises mixing a relatively hot gas with a relatively cool gas to obtain a desired hybrid gas temperature. 25. The method of claim 21, wherein said gas supplying step comprises supplying a gas as a gas flow to said substrate. 26. The method of claim 21, wherein said step of relative moving comprises rotating said substrate support. 27. The method of claim 21, wherein said step of relative moving comprises rotating said gas supply system. 28. The method of claim 21, further comprising monitoring a temperature of a gas supplied to the substrate. 29. The method of claim 21, further comprising monitoring a temperature of said substrate.