JP2007165936A - Heat treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve in-plane uniformity of a substrate in a heat treatment apparatus which performs heat treatment for a mask substrate, for example. <P>SOLUTION: When a substrate G on which coating liquid (resist liquid) is applied is put on a heating plate 4 to heat the substrate G in the heat treatment apparatus (heat treatment unit 3), a frame 5 is prepared above the heating plate 4 around the substrate G so that its inner surface faces the sides of the substrate and a space is formed between the surface of the heating plate. This frame 5 prevents dissipation of heat from the substrate sides and improves in-plane uniformity of the substrate temperature. The space between the frame 5 and the heating plate 4 prevents particles from staying this region and suppresses sticking of particles to the substrate G. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat treatment apparatus for performing a heat treatment on a substrate such as a mask substrate after applying a resist solution, for example.

  In the semiconductor device manufacturing process, when forming a semiconductor mask, a resist solution is applied to a square mask substrate, the resist film is exposed using a photomask, and further developed to produce a desired resist pattern. To be done. As the substrate, for example, a glass substrate having a square shape with a side length of 152 mm, a thickness of 6.35 mm, and a side length of 6 inches is used.

  The resist solution is obtained by dissolving the components of the coating film in a solvent, and after the resist solution is applied, a heat treatment for volatilizing the solvent by heating the substrate to a predetermined temperature is performed. This heat treatment is performed by placing the substrate on a hot plate provided with a heater. However, in the case of a substrate having a thickness as described above, the in-plane uniformity of the substrate temperature tends to deteriorate. That is, in a thick substrate, heat radiation increases from the side surface of the substrate, so that the temperature in the peripheral region of the substrate tends to be lower than that in the central region. Thus, when the substrate temperature differs in the plane, the volatilization amount of the solvent changes in the plane, and as a result, the in-plane uniformity of the resist film thickness deteriorates.

  Therefore, for example, as shown in FIG. 18, a recess 11 is formed in the hot plate 10, and the substrate 12 is heated by the hot plate 10 in a state in which the substrate 12 is stored in the recess 11, thereby heating a region near the substrate side surface. Heating by the plate 10 is performed to suppress heat radiation from the side surface. In the figure, 13 is a heater. However, with this method, particles may accumulate in the corners of the recess 11, but it is difficult to remove the particles and the particles may adhere to the substrate 12. Moreover, in order to form the recessed part 11 in the hotplate 10, much time and expense are required and there exists a problem that manufacturing cost becomes high.

  Therefore, the present inventors are considering to suppress heat radiation from the side surface of the substrate by providing a side plate 14 around the substrate 12 placed on the hot plate 10 as shown in FIG. As such a method, a configuration in which an outer frame higher than the object to be processed is provided so as to surround the object to be processed is disposed on the target object arrangement portion of the heating plate (for example, see Patent Document 1), or mounted on the heat plate. A configuration in which a side plate having a height higher than or equal to the thickness of the mask is disposed around the placed mask, a side heat plate is provided around the mask placed on the hot plate, and heat is radiated from the side surface of the mask. The structure which prevents (for example, refer patent document 2) is proposed.

Japanese Patent Laid-Open No. 11-204428 (see claim 3, paragraph 0021, paragraph 0042, paragraph 0050, FIG. 2) JP 2002-1000056 (see paragraphs 0034, 0042, FIGS. 4 and 6)

  However, in the configuration of Patent Document 1, the outer frame is provided to prevent air from entering the periphery of the substrate. For this reason, the outer frame is provided so as not to form a gap on the hot plate. Also in the configuration of Patent Document 2, as shown in FIGS. 4 and 6, the side plate and the side heat plate are provided so as not to form a gap between them. Here, since the outer frame of Patent Document 1 and the side plate of Patent Document 2 and the like are provided so as to be higher than the surface of the object to be processed and the mask, as shown in FIG. If the air scatters on the air current, it scatters to the surface of the substrate 12 as it is, which may cause a defect. Further, when the particle 15 enters between the substrate and the side plate 14 or the like, the particle 15 cannot escape anywhere, and eventually accumulates in the corner between the side plate 14 or the like and the hot plate 10, and the substrate 12 is caused by the particle 15. There are concerns about contamination.

  The present invention has been made under such circumstances, and its purpose is to improve the in-plane temperature uniformity of the substrate while suppressing particle contamination of the substrate when the substrate is placed on a heating plate and heated. It is to provide the technology to make.

The heat treatment apparatus of the present invention comprises a heating plate for heating the substrate,
Heating means for heating the heating plate;
A frame provided around the substrate placed on the heating plate so that the inner surface faces the side surface of the substrate and forms a gap with the surface of the heating plate; It is characterized by.

  In such a configuration, since the frame is provided around the substrate when the substrate is heated by the heating plate, heat radiation from the side surface of the substrate is suppressed, and the in-plane uniformity of the substrate temperature is improved. At this time, since the frame body is provided so as to form a gap between the surface of the heating plate, it is possible to prevent particles from being accumulated between the frame body and the heating plate, and to prevent adhesion of particles to the substrate. Is done.

  Furthermore, in the present invention, the frame body may be provided via a support portion in front of the heating plate, and may be configured by a member different from the heating plate. Further, the frame body may be provided with a drive mechanism for moving the inner surface of the frame body so that the distance between the inner surface of the frame body and the side surface of the substrate placed on the heating plate changes. The drive mechanism is controlled so that the inner surface of the frame is closer to the side surface of the substrate placed on the heating plate when the substrate temperature is at a constant temperature than when the temperature is increased. You may make it provide a control part. Moreover, the said frame may be divided and comprised in the circumferential direction, and the structure provided with the heating part for heating the said frame may be sufficient.

  Here, the substrate is a substantially square glass substrate having a side length of 6 inches, and the heating plate can be a circular plate for heating a semiconductor wafer having a diameter of 12 inches.

  According to the present invention, when the substrate is heated by the heating plate, the periphery of the substrate is surrounded by the frame body while forming a gap between the heating plate and the substrate temperature. Uniformity can be improved. According to another invention of the present invention, since the substrate is heated by the heating plate while surrounding the substrate with the frame, the in-plane uniformity of the substrate temperature can be enhanced.

  Hereinafter, an embodiment of a coating film forming apparatus in which the heat treatment apparatus of the present invention is incorporated will be described. Here, FIG. 1 is a plan view showing an overall configuration according to an embodiment of the coating film forming apparatus of the present invention, and FIG. 2 is a schematic perspective view thereof. In the figure, B1 is a carrier block for carrying in / out a carrier C in which, for example, five substrates, for example, a mask substrate G are accommodated, and this carrier block B1 is transferred to and from the carrier placing portion 21 on which the carrier C is placed. And means 22.

  The mask substrate G is, for example, a glass substrate for forming a semiconductor mask. For example, the mask substrate G is a square having a side length of 152 ± 0.5 mm, a thickness of 6.35 mm, and a side length of 6 mm. An inch-size square glass substrate is used. The delivery means 22 takes out the substrate G from the carrier C, and can move left and right, back and forth, move up and down, vertically so as to deliver the taken-out substrate G to the processing unit B2 provided on the back side of the carrier block B1. It is configured to be rotatable around its axis.

  A main transport unit 23 is provided at the center of the processing unit B2. For example, the coating unit 24 and the developing unit 25 are disposed on the right side and the cleaning unit 26 is disposed on the left side when viewed from the carrier block B1, for example. However, shelf units U1 and U2 in which heating / cooling units and the like are stacked in multiple stages are arranged on the front side and the back side, respectively. The coating unit 24 is a unit that performs a process of coating a resist solution on a substrate, and the developing unit 25 is a unit that deposits the developer on an exposed substrate and performs the developing process for a predetermined time, and a cleaning unit 26. Is a unit for cleaning the substrate before applying the resist solution.

  The shelf units U1 and U2 are configured by stacking a plurality of units. For example, as shown in FIG. 2, in addition to the heat treatment unit 3 and the cooling unit 27, the substrate G delivery unit 28 and the like are assigned vertically. Yes. The main transport means 23 is configured to be movable up and down, reciprocated and rotatable about a vertical axis, and serves to transport the substrate G between the shelf units U1 and U2, the coating unit 24, the developing unit 25, and the cleaning unit 26. have. However, in FIG. 2, the delivery means 22 and the main transport means 23 are not drawn for convenience.

  The processing unit B2 is connected to an exposure apparatus B4 through an interface unit B3. The interface part B3 is provided with a delivery means 29. The delivery means 29 is, for example, configured to be movable up and down, movable left and right, back and forth, and rotatable about a vertical axis, and the processing block B2 and the exposure apparatus B4. The board | substrate G is delivered between.

  The flow of the substrate G in such a coating film forming apparatus will be described. First, the carrier C is carried into the carrier mounting portion 21 from the outside, and the substrate G is taken out from the carrier C by the transfer means 22. The substrate G is transferred from the transfer means 22 to the main transfer means 23 via the transfer unit 28 of the shelf unit U1, and is sequentially transferred to a predetermined unit. For example, a predetermined cleaning process is performed in the cleaning unit 26, heat drying is performed in one of the heat treatment units, and then the temperature is adjusted to a predetermined temperature in the cooling unit 27. Application of a resist solution in which is dissolved in a solvent is performed.

  Subsequently, the substrate G is heated to a predetermined temperature in one of the heat treatment units and subjected to a pre-baking process for evaporating and removing the solvent in the resist solution. After the adjustment, the main transfer means 23 passes the transfer unit 28 of the shelf unit U2 to the transfer means 29 of the interface unit B3 and is transferred to the exposure apparatus B4 by the transfer means 29 to perform a predetermined exposure process. Is called. Thereafter, the substrate G is transported to the processing unit B2 via the interface unit B3, heated to a predetermined temperature by one of the heat treatment units, and subjected to a post-exposure baking process. Next, after cooling to a predetermined temperature by the cooling unit 27 and adjusting the temperature, the developer is accumulated in the developing unit 25 and a predetermined development process is performed. The substrate G on which the predetermined circuit pattern is thus formed is returned to, for example, the original carrier C through the main transport unit 23 and the transfer unit 22 of the carrier block B1.

Next, a heat treatment unit 3 which is a heat treatment apparatus of the present invention will be described with reference to FIG. In the heat treatment unit 3, after the resist solution is applied to the substrate G, a process for removing the solvent contained in the resist solution is performed. In the figure, 31 is a processing container,
On the side surface, for example, an opening 31a is formed over the entire circumference, and the main transfer means 23 can be accessed inside the processing container 31 through the opening 31a. An upper side of the opening 31a is configured as an exhaust part 32 for exhausting the inside of the processing container 31, and an exhaust port 32a is formed in a substantially central region of the ceiling part of the processing container 31. An exhaust means (not shown) is connected so that the atmosphere in the processing space can be exhausted to the outside.

  In such a processing container 31, for example, the heating plate 4 is provided at a position where the substrate G can be transferred to and from the main transfer means 23 through the opening 31a. The substrate G is placed on the heating plate 4 via, for example, proximity pins 41 in a state of slightly floating, for example, about 0.5 mm from the heating plate 4, and is heated by the heating plate 4. .

  For example, as shown in FIGS. 4 and 5, the heating plate 4 is constituted by a heating plate used for heating a wafer having a diameter of 12 inches. That is, the heating plate 4 is a circular plate having a diameter of about 330 mm and a thickness of about 30 mm, and is made of, for example, an aluminum alloy or stainless steel.

  A heater 42 serving as a heating means is built in the heating plate 4, and the substrate G is heated to about 100 ° C. to 250 ° C. by the heater 42. For example, as shown in FIG. 6, the heater 42 includes three heaters 42a: a circular planar heater 42a for heating the substrate G, and annular heaters 42b and 42c provided concentrically around the heater 42a. To 42c. These heaters 42a to 42c are provided so that not only the area where the substrate G is placed but also the entire surface of the heating plate 4 is heated uniformly. For example, in this example, the annular heaters 42b and 42c are placed on the substrate G. It is provided outside the region. The number and shape of the heaters 42 are not limited to this example, and the planar heater 42a may be rectangular, and the annular heaters 42b and 42c may also be rectangular annular bodies. Further, the number of the annular heaters in this example may be increased or decreased, or the substrate G may be heated by a plurality of annular heaters without providing a planar heater.

  Such a heating plate 4 is provided with, for example, four support pins 43 for transferring the substrate to and from the main transport unit 23. The support pins 43 are connected to an elevating mechanism 44 via a holding plate 44 a provided below the heating plate 4, so that the tips of the support pins 43 can be raised and lowered so that they can protrude and retract with respect to the surface of the heating plate 4. It is configured.

  Further, as shown in FIGS. 4 and 5, a frame 5 is provided around the substrate G placed on the heating plate 4 so as to surround the substrate G with a slight gap A therebetween. The frame body 5 is formed of, for example, a rectangular annular body, and is mounted on the surface of the heating plate 4 with a slight gap B by a support portion 51 that supports the lower surface, for example. The frame 5 and the support portion 51 are made of a material having thermal conductivity such as a metal such as an aluminum alloy.

  Here, the gap A formed between the side surface of the substrate G and the inner peripheral surface of the frame 5 is, for example, about 1 mm to 10 mm, and the gap B formed between the lower surface of the frame 5 and the surface of the heating plate 4 is For example, it is preferably set to about 0.1 mm to 0.5 mm. The height C of the frame 5 is preferably set to be substantially the same as or slightly lower than the surface of the substrate G. For example, the height C to the surface of the frame 5 is, for example, 5 mm to 5 mm higher than the heating plate 4. The width D of the frame 5 is set to about 10 mm, for example.

  The opening 31 a of the processing container 31 is configured to be opened and closed by a cylindrical shutter 33. The shutter 33 has a shape in which an inward horizontal piece 33 b is provided at the upper end of a cylindrical main body 33 a provided outside the heating plate 4. The shutter 33 is configured such that the horizontal piece 33b is positioned in the vicinity of the lower side of the opening 31a and the horizontal piece 33b is located above the opening 31a. It is located in the vicinity of the side and is configured to be movable up and down with respect to a position that substantially closes the opening 31a. Here, the shutter 33 is stopped from rising at a position where a slight gap E is formed between the lower surface of the exhaust part 32. In the figure, reference numeral 35 denotes a stopper for stopping the shutter 33 at a predetermined height position.

  In such a heat treatment unit 3, the shutter 33 is lowered and the main transport means 23 is caused to enter the inside of the processing container 31 through the opening 31 a, and the main transport means 23 and the support pins 43 cooperate with each other. The substrate G is transferred to the heating plate 4. After placing the substrate G in the predetermined position of the heating plate 4 in this way, the main transport means 23 is retracted, the shutter 33 is raised, and a gap E is left between the exhaust part 32 and the shutter 33 and is cut off incompletely. Then, while exhausting in a so-called semi-closed state, the substrate G is heated to a temperature of, for example, about 120 ° C. by the heating plate 4 to perform a predetermined heat treatment.

  In this embodiment, since the frame body 5 is provided so as to surround the substrate G, heat dissipation from the side surface of the substrate can be suppressed by the frame body 5, and the in-plane uniformity of the substrate temperature can be improved. Since the frame body 5 and the support part 51 have thermal conductivity, heat from the heating plate 4 is transmitted to the frame body 5 through the support part 51 or by radiant heat from the heating plate 4, and the frame body 5 itself is Heated. Since the inner peripheral surface of the frame body 5 exists in the vicinity of the side surface of the substrate G, the vicinity of the side surface of the substrate G is heated by the frame body 5, and even when the thickness of the substrate G is large, the substrate side surface This is because the heat radiation from the can be suppressed.

  By the way, in the processing container 31, since an air flow entering the gap E between the shutter 33 and the exhaust part 32 and moving toward the exhaust port 32 a is formed, particles are generated along the air flow from the outside to the inside of the substrate G. May be scattered. At this time, if the height of the frame 5 is set lower than the height of the surface of the substrate G, the particles 100 collide with the side surface of the substrate G and enter the gap A between the side surface and the frame 5 as shown in FIG. Since it enters, the adhesion of the particles 100 to the surface of the substrate G is suppressed. Further, since a gap B is formed between the frame body 5 and the heating plate 4, the particles 100 that have entered between the substrate G and the frame body 5 are contained in the processing container 31 through the gap B. It is discharged in the exhaust stream. For this reason, the particles 100 can be prevented from accumulating in the corners between the frame 5 and the heating plate 4, and particle contamination of the substrate G can be suppressed.

  In this example, since an existing circular plate for heating a wafer having a diameter of 12 inches is used as the heating plate 4, a new heating plate is used for a square substrate having a side length of 6 inches. There is no need to prepare, which is advantageous in terms of cost. At this time, one side of a square substrate having a size of 6 inches is about 152 mm, whereas the heating plate 4 is as large as about 330 mm in diameter, so that in-plane uniformity of the substrate temperature can be further improved.

  The reason is considered as follows. When the shutter 33 is closed after the substrate G is placed on the heating plate 4 and processing is started, the inside of the shutter 33 is cooled and the airflow from the outside to the inside of the substrate G is cooled by the shutter 33. The phenomenon occurs. Here, when the heating plate is slightly larger than the substrate G, the cold wind reaches the substrate G as it is, and the temperature of the outer peripheral portion of the substrate G decreases. Further, since the heating plate 4 also radiates heat outward from the peripheral region, heat radiation from the side surface of the substrate G is promoted, and this also causes the temperature of the outer peripheral portion of the substrate G to decrease. If an attempt is made to increase the heater temperature in the peripheral region of the heating plate 4 in order to compensate for this heat dissipation, the temperature in the peripheral region of the substrate G becomes too high because it is close to the region on which the substrate G is placed. The in-plane uniformity is deteriorated.

  On the other hand, when the heating plate 4 is sufficiently larger than the substrate G and a heater is provided in an area outside the mounting area of the substrate G, the entire heating plate 4 is heated. Since the air cooled by 33 is sufficiently warmed by the heating plate 4 until it reaches the substrate G, the cool air does not reach the substrate G, and the temperature drop at the outer peripheral portion of the substrate G can be suppressed. Further, even if heat is radiated from the peripheral area of the heating plate 4, the peripheral area of the heating plate 4 is heated so as to compensate for this heat dissipation, but the peripheral area of the heating plate 4 is from the area where the substrate G is placed. Since it is far away, the temperature of the substrate G is not affected, and as a result, the temperature of the outer peripheral portion of the substrate G is hardly lowered, and the in-plane uniformity of the substrate G temperature is improved.

  Next, another example of the frame body 5 will be described. The frame body 5 of this example is configured such that the inner surface (the surface facing the side surface of the substrate G) is curved. FIG. 8 is an example in which the inner surface 61 (the surface facing the side surface of the substrate G) of the frame 5A is formed to be curved concavely. In this example, the inner surface 61 of the frame 5A is formed so that the region near the corner of the substrate is close to the frame 5A, and the region near the center of the side of the substrate G is separated from the frame 5A. Accordingly, the substrate G is selectively heated near the corners by the frame 5A.

  Such a frame 5A is effective, for example, when the processing temperature is as high as 200 ° C. or higher and the radiant heat from the heating plate 4 is large. When the processing temperature is high in this way, the heat radiation from the four corners of the substrate G becomes large, so that the frame 5A approaches this region and the frame 5A is separated in the central region of the side of the substrate G. The corners of the substrate G are selectively heated by the frame 5A, so that heat radiation from this region can be suppressed, and the in-plane uniformity of the substrate temperature can be improved.

  In the example shown in FIG. 9, the inner surface 62 of the frame 5B is formed to be curved in a convex shape. In this example, the inner surface 62 of the frame 5B is formed so as to be close to the frame 5B in the region near the center of the side of the substrate G and away from the frame 5B in the region near the corner of the substrate G. Accordingly, the substrate G is selectively heated in the vicinity of the center of the side by the frame 5B.

  Such a frame 5B is effective, for example, when the processing temperature is as low as about 100 ° C. and the substrate G is heated mainly by heat conduction from the heating plate 4 via the proximity pins 41. Thus, when the board | substrate G is heated by the heat conduction by the proximity pin 41, the temperature of the contact area | region of the proximity pin 41 and the board | substrate G will become high compared with another area | region. Here, the proximity pin 41 is often provided in a region near the corner of the substrate G, and thereby the temperature in the region near the corner is higher than in other regions. Accordingly, if the heat dissipation from the four corners of the substrate G is increased, the region 5B is separated from the frame 5B in this region, and the frame 5B is approximated in the central region of the side of the substrate G. It is selectively heated by the body 5B, and the in-plane uniformity of the substrate temperature can be improved.

  Further, the frame body 5 (5A, 5B) may be configured such that the inner surface facing the substrate G is a mirror surface. In this way, the radiant heat from the side surface of the substrate G is reflected by the inner surface of the frame 5 or the like, and further a temperature drop from the side surface of the substrate G can be prevented. Furthermore, you may make it the frame 5 grade | etc., Comprise the surface facing the board | substrate G with a satin finish. The satin is a slightly rough surface having a surface roughness of Ra = 100 μm, for example. If it does in this way, the radiant heat from inner surfaces, such as the frame 5, will increase, the substrate G side surface will be heated by this radiant heat, and also the temperature fall from the substrate G side surface can be prevented.

  In the example in which the inner surfaces of the frame bodies 5A and 5B are curved or formed with a mirror surface or a satin finish, the frame bodies 5A and 5B may be provided without forming a gap with the heating plate 4.

  Next, still another example of the frame will be described. The frame 5C of this example is configured to be movable so that the distance between the inner surface of the frame 5C and the side surface of the substrate G placed on the heating plate 4 changes. Specifically, for example, the frame 5C is formed by combining four rod-like plates 71 (71a to 71d) facing the side surface of the substrate G, and each plate 71 is interposed, for example, via a support member 72 that penetrates the heating plate 4. Thus, for example, the drive mechanism 73 provided on the lower side of the heating plate 4 causes the inner surface of the plate 71 to be substantially horizontal so as to approach or separate from the side surface of the substrate G placed on the heating plate. It is configured to be movable in the direction.

  The drive mechanism 73 is made of, for example, a ball screw, an air cylinder, or the like. For example, the control unit 200 sets a separation distance between the side surface of the substrate G and the inner surface of the frame 5C between about 1 mm to 10 mm according to the processing temperature and processing time. It is controlled to change at.

  In such a configuration, when the temperature of the substrate G is raised, the temperature of the peripheral region of the substrate G tends to increase, so that the plate 71 is placed at a position away from the side surface of the substrate G as shown in FIG. 11 (b), since the temperature of the peripheral region of the substrate G tends to decrease when the temperature of the peripheral region of the substrate G is suppressed and the temperature of the substrate G is in a constant temperature state after the temperature rise. As shown in FIG. 5, the plate 71 is brought close to the side surface of the substrate G to suppress the temperature drop in the peripheral region of the substrate G. For this reason, the in-plane uniformity of the substrate temperature can be further improved.

  Further, as shown in FIG. 12A, the frame 5D divides the plates 71a to 71d shown in FIG. 10 into a plurality of, for example, three pieces in the length direction, and each of the divided plates 81 (81a to 81d) to 83 (83a). ˜83d) may be configured to change the distance from the side surface of the substrate G by a horizontal driving mechanism. Thus, as shown in FIG. 12B, the separation distance from the division plate 82 in the vicinity of the central region of the side of the substrate G and the separation distance from the division plates 81 and 83 in the vicinity of the corners of the substrate G are appropriately set. By disposing each of the divided plates 81 to 83 so as to set the amount, the heat radiation amount of the central region and the corner of the side of the substrate G is controlled, and thereby the temperature is adjusted according to the part of the substrate G. Therefore, the in-plane uniformity of the substrate temperature can be further improved.

  Furthermore, in the present invention, as shown in FIG. 13, a heater 91 that constitutes a heating portion made of a resistance heating element is built in the frame 5E, and the temperature of this heater is controlled according to the processing temperature and processing time by a control section (not shown). May be changed. Here, since the amount of heat released from the substrate G changes depending on the temperature of the frame 5E, the temperature of the frame 5E is adjusted to an optimum temperature at each of the temperature rise time, the temperature drop time, and the constant temperature time of the substrate G. Thus, the heat radiation amount from the substrate G is controlled in an optimal state, and the in-plane uniformity of the substrate temperature can be improved.

  10 to 13, the frame bodies 5C, 5D, and 5E may be provided without forming a gap with the heating plate 4.

Next, examples performed to confirm the effects of the present invention will be described.
Example 1
A square substrate with a temperature sensor with a side length of 6 inches is placed on a circular heating plate with a diameter of 330 mm used for heating a semiconductor wafer with a diameter of 12 inches, and is composed of an aluminum alloy around the substrate. The frame was provided, and the substrate was heated to 120 ° C. by a heating plate and kept at a constant temperature, and the temperature in the substrate surface in this state was detected. At this time, the distance between the side surface of the substrate and the inner surface of the frame is 2 mm, the height of the frame from the surface of the heating plate is 6 mm, the width of the frame is 10 mm, and the distance between the lower surface of the frame and the surface of the heating plate is 0. It was 1 mm.

In the square substrate with the temperature sensor, temperature sensors are provided at 31 locations in the plane, and a temperature distribution in the substrate plane is created based on the measured values from the temperature sensor. This result is shown in FIG. 14A, and the range width of the substrate in-plane temperature was 1.07 ° C. The smaller the range width, the higher the in-plane temperature uniformity.
(Comparative Example 1)
An experiment was performed under the same conditions as in Example 1 except that no frame was provided around the substrate, and a temperature distribution in the substrate surface was created. The result is shown in FIG. 14B, and the range width of the in-plane temperature of the substrate was 1.51 ° C.
(Comparative Example 2)
The heating plate was changed to a circular heating plate having a diameter of 270 mm used for heating a semiconductor wafer having a diameter of 8 inches, and an experiment was performed under the same conditions as in Example 1 without providing a frame around the substrate. A temperature distribution in the substrate surface was created. The result is shown in FIG. 14C, and the range width of the substrate in-plane temperature was 1.93 ° C.

  From these results, in view of each temperature distribution and range width, the in-plane temperature uniformity of the substrate in Example 1 and Comparative Example 1 is higher than that in Comparative Example 2, so that the length of one side is 6 It is understood that heating an inch-sized square substrate with a circular heating plate for heating a 12 inch diameter wafer is effective.

  Further, comparing Example 1 and Comparative Example 1, in the graph of Comparative Example 1, the temperature near the center of the substrate is high, and the temperature tends to decrease as it goes to the outer periphery. It is recognized that the temperature difference at the outer peripheral portion is small, and the in-plane uniformity of the substrate temperature can be improved by providing the frame around the substrate. Furthermore, in the configuration of Example 1, generation of particles was not recognized between the frame and the heating plate.

(Example 2)
A square substrate with a temperature sensor having a 6-inch size on one side is placed on a circular heating plate having a diameter of 330 mm used for heating a 12-inch diameter semiconductor wafer, and a frame made of an aluminum alloy around the substrate. A body was provided, the substrate was heated to 150 ° C. with a heating plate, and kept at a constant temperature, and the temperature in the substrate surface in this state was detected. At this time, the substrate is supported by a proximity pin provided on the surface of the heating plate in a state of being floated by 80 μm from the surface of the heating plate, the distance between the substrate side surface and the inner surface of the frame is 2 mm, The height was 6 mm, the width of the frame was 10 mm, and the distance between the lower surface of the frame and the surface of the heating plate was 0.1 mm.

FIG. 15A shows the change over time of the temperature measurement values of the 31 temperature sensors on the substrate. The temperature curves of the measurement values of all the temperature sensors are included in the range of the two temperature curves shown here. ing. When the same experiment was performed twice, the range width of the in-plane temperature from 400 seconds to 600 seconds when the temperature was stabilized was 0.95 ° C. and 1.04 ° C.
(Comparative Example 3)
The experiment was performed under the same conditions as in Example 2 except that no frame was provided around the substrate. FIG. 15B shows the change over time of the temperature measurement value of the temperature sensor. The range of the in-plane temperature range from 400 seconds to 600 seconds when the temperature was stable was 1.27 ° C.
(Example 3)
The experiment was performed under the same conditions as in Example 2 with the substrate temperature heated to 220 ° C. FIG. 16A shows the change over time of the temperature measurement value of the temperature sensor. The range of the temperature within the substrate surface from 400 seconds to 600 seconds when the temperature was stabilized was 1.50 ° C.
(Comparative Example 4)
The experiment was performed under the same conditions as in Example 3 except that no frame was provided around the substrate. FIG. 16B shows the change over time of the temperature measurement value of the temperature sensor. The range of the in-plane temperature range from 400 seconds to 600 seconds when the temperature was stable was 2.30 ° C.

  As a result, when the substrate is heated to 150 ° C. and when heated to 220 ° C., the frame body has a smaller range width of the substrate in-plane temperature when the temperature is stabilized. It is recognized that the in-plane uniformity with a high substrate temperature can be ensured by providing. Further, in the configurations of Examples 2 and 3, generation of particles was not recognized between the frame and the heating plate.

  In the above, the present invention secures in-plane uniformity with a high substrate temperature by suppressing heat dissipation from the side surface of the substrate, and the greater the thickness, the greater the amount of heat dissipation from the side surface of the substrate. Is particularly effective for heat treatment of a substrate having a large thickness of, for example, 3 mm or more.

  Further, in the present invention, the frame body 5 (5A to 5E) does not necessarily have to surround the entire circumference of the substrate, and may be any shape as long as it surrounds the periphery of the substrate to some extent, and forms a region that does not intentionally surround the substrate. It may be a thing. Moreover, it does not necessarily need to be an annular body, and may be divided, or may be a frame 5F formed in a well shape as shown in FIG. Further, as shown in FIG. 17B, a box-shaped tray-like frame 5G is formed, the substrate G is held therein, and a part of the lower edge of the frame 5G is cut away to form a gap 50. It may be a configuration. Furthermore, the heating plate 40 may be configured such that a step or an inclined surface is formed on the substrate mounting surface, as shown in FIG.

  In the present invention, as long as a predetermined heat treatment is performed, the heat treatment unit is not limited to the above-described configuration, and may be a chamber type configuration other than the type in which the wafer transfer port is opened and closed by the shutter. Further, the present invention can be applied not only to the heating of the substrate after applying the resist solution, but also to heat treatment such as heat drying after washing, post-exposure baking after exposure, post-baking after development, and the like. Further, in the above-described embodiment, the apparatus for processing a square substrate for a semiconductor mask has been described. However, an apparatus for processing a substrate for an FPD (flat panel display), for example, a thick circular substrate processed for a special purpose. The present invention is also applicable to.

It is a top view which shows the whole structure of one Embodiment of the coating film forming apparatus concerning this invention. It is a schematic perspective view which shows the whole structure of the said coating film formation apparatus. It is sectional drawing which shows an example of the heat processing unit provided in the said coating film formation apparatus. It is a schematic perspective view which shows the heating plate provided in the said heat processing unit, a frame, and a board | substrate. It is the top view and side view which show the said heating plate, a frame, and a board | substrate. It is a top view which shows the heater provided in the said heating plate. It is a side view for demonstrating the effect | action of the said frame. It is the top view and schematic perspective view which show the other example of the said frame. It is the top view and schematic perspective view which show the other example of the said frame. It is the top view and side part sectional view which show the other example of the said frame. It is a top view for demonstrating the effect | action of the frame shown in FIG. It is a top view which shows the other example of the said frame. It is a side view which shows the other example of the said frame. It is a top view which shows the temperature distribution of the board | substrate which shows the result of Example 1, the comparative example 1, and the comparative example 2 performed in order to confirm the effect of this invention. It is a characteristic view which shows the result of Example 2 and Comparative Example 3 performed in order to confirm the effect of this invention. It is a characteristic view which shows the result of Example 3 performed in order to confirm the effect of this invention, and the comparative example 4. FIG. It is a side view which shows the further another example of the frame and heating plate of this invention. It is a side view which shows an example of the heating plate of the conventional heat processing unit. It is a side view which shows the other example of the heating plate of the conventional heat processing unit. It is a side view which shows the effect | action of the heating plate of the conventional heat processing unit.

Explanation of symbols

G Mask substrate B1 Carrier block B2 Processing block
23 substrate transport means 24 coating unit 3 heat treatment apparatus 31 processing container 33 shutter 4 heating plate 42 heater 5 (5A to 5G) frame 51 support part 73 horizontal direction drive mechanism

Claims (2)

A heating plate for heating the substrate;
Heating means for heating the heating plate;
A frame provided around the substrate placed on the heating plate so that the inner surface faces the side surface of the substrate and forms a gap with the surface of the heating plate; A heat treatment apparatus characterized by 2. The heat treatment apparatus according to claim 1, wherein the frame body is provided through a support portion in front of the heating plate, and is configured by a member different from the heating plate.

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