JP2007158075A - Substrate heat treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate heat treatment apparatus capable of efficiently suppressing the bending of an adsorbed substrate. <P>SOLUTION: Supporting members 11 projecting from the top surface of a heat treatment plate 1 are each arranged on each of apices of each of regular triangles arranged regularly and continuously. A minute space to be formed between a substrate W to be supported with the supporting members 11 and the heat treatment plate 1 is sealed with a sealing member 15. The pressure in the minute space is made into negative pressure using an exhaust port 15 to suck the substrate W. In this case, since the distances between adjacent supporting members 11 are all the same, the bending quantity of the substrate W between the supporting members 11 are also the same. Arrangement of the supporting members 11 in such a way can efficiently suppress the bending quantity of the substrate W with the smaller number of parts. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a substrate heat treatment apparatus for performing heat treatment on a semiconductor substrate, a glass substrate for a liquid crystal display device, a glass substrate for a photomask, a substrate for an optical disk (hereinafter simply referred to as “substrate”), and more particularly, a heat treatment plate. The present invention relates to a technique for performing heat treatment in a state in which a substrate placed through a minute space is sucked.

  In recent years, with the miniaturization of the line width dimension of the pattern formed on the substrate, the required value of the uniformity of the required line width has become strict, and photolithography baking heat treatment, especially post exposure baking (PEB: Post Exposure Bake) There is an increasing demand for temperature uniformity. However, the substrate warpage that occurs during the semiconductor manufacturing process increases due to the larger diameter of the substrate, and the proximity heating method that performs heat treatment only by placing the substrate at a small space from the heat treatment plate satisfies the requirement of temperature uniformity. It has become difficult to make.

Therefore, an adsorption baking method has been proposed so that a uniform heat treatment can be performed even on a warped substrate. Examples of this type of apparatus include a heat treatment plate provided with a heater, a support member and a seal provided on the upper surface of the heat treatment plate, and a discharge hole formed on the upper surface of the heat treatment plate ( For example, see Patent Document 1). In this apparatus, the side of the space formed between the substrate supported by the support member and the heat treatment plate is sealed with a seal portion, and the substrate is adsorbed by discharging gas from the space through the discharge hole. Thereby, since the curvature of a board | substrate can be corrected, a board | substrate can be heated uniformly.
JP-A-10-284360

However, the conventional example having such a configuration has the following problems.
That is, in the conventional apparatus, the adsorbed substrate bends between the support portions. This will be specifically described with reference to FIG. FIG. 8 is a partial cross-sectional view of the heat treatment plate 1. As illustrated, the substrate W is supported by a plurality of support members 11. In addition, the minute space ms between the substrate W and the heat treatment plate 1 is sealed by the seal portion 15 and is brought into a negative pressure state by discharging the gas in the minute space ms from a discharge hole (not shown). It has become. At this time, the substrate W bends so as to bend in a direction approaching the heat treatment plate 1 between the support members 11 (shown by a solid line). Here, the difference between the maximum value and the minimum value of the separation distance between the substrate W and the heat treatment plate 1 is referred to as a deflection amount b. In FIG. 8, the substrate when the amount of deflection is 0 μm is indicated by a dotted line.

  Therefore, it is necessary to reduce the amount of bending by arranging a large number of support members 11 and shortening the interval between them. However, the shorter the interval between the support members, the more the substrate comes into contact with the support members, so that the contact site becomes a particle source.

  This invention is made in view of such a situation, Comprising: It aims at providing the board | substrate heat processing apparatus which can suppress the bending of the adsorbed board | substrate efficiently.

In order to achieve such an object, the present invention has the following configuration.
That is, the invention according to claim 1 is a substrate heat treatment apparatus for performing heat treatment on a substrate, wherein the heat treatment plate and the lower surface of the substrate are abutted and supported in a state of protruding from the upper surface of the heat treatment plate. The support means arranged at the positions of the respective vertices of the regular triangles arranged regularly and continuously, and provided in a ring shape on the upper surface of the heat treatment plate, by contacting the peripheral side of the substrate, It is characterized by comprising sealing means for sealing the space formed between the heat treatment plate and a discharge hole for discharging the gas in the space.

  [Operation / Effect] According to the invention described in claim 1, since the support means is arranged at the position of each vertex of the equilateral triangles arranged regularly and continuously, the support means between adjacent support means. All distances are equal. Therefore, the amount of bending of the substrate between the support means is equal. Such an arrangement of the support means can efficiently suppress the amount of bending of the substrate with a smaller number of points. Incidentally, a pattern in which support means is arranged at the position of each vertex when squares and regular hexagons are regularly arranged continuously is also conceivable, but in order to suppress the amount of bending of the substrate to the same level, the present invention is applied. Compared to this, a lot of support means is required, and it cannot be efficiently suppressed.

  In addition, “regularly arranged continuously” means that an arbitrary regular triangle and another regular triangle adjacent thereto are arranged so as to coincide with each other only on one side.

  According to a second aspect of the present invention, there is provided a substrate heat treatment apparatus for performing a heat treatment on a substrate, wherein the heat treatment plate and the lower surface of the substrate are in contact with and supported by the upper surface of the heat treatment plate. Each intersection of a first imaginary line group passing through the upper surface of the heat treatment plate and parallel to each other at equal intervals, and a second imaginary line group obtained by rotating the first imaginary line group by 60 degrees on the upper surface of the heat treatment plate And a seal that is provided in a ring shape on the upper surface of the heat treatment plate and seals a space formed between the substrate and the heat treatment plate by contacting the peripheral edge of the substrate. And a discharge hole for discharging the gas in the space.

  [Operation / Effect] According to the invention described in claim 2, the support means includes a first imaginary line group parallel to each other at equal intervals and a first imaginary line group rotated by 60 degrees on the upper surface of the heat treatment plate. Since they are arranged at the positions of the respective intersections with the two imaginary line groups, the distances between the adjacent support means are all equal. Therefore, the amount of bending of the substrate between the support means is equal. Such an arrangement of the support means can efficiently suppress the amount of bending of the substrate with a smaller number of points.

  In each of the inventions, it is preferable that the position of any one of the support means is a center point of the heat treatment plate. The respective support means can be respectively arranged at positions symmetrical with respect to the center point with the center point of the heat treatment plate as the center of symmetry.

  In each invention, the substrate is a circle having a diameter of 300 mm, the pressure in the space is set to −4 kPa or more and less than 0 Pa by discharging from the discharge hole, and the interval of the support means is 35 mm to 40 mm. (Claim 4). When the substrate has a circular shape with a diameter of 300 mm, the substrate can be appropriately adsorbed even if the substrate is warped by setting the pressure in the space to -4 kPa or more and less than 0 Pa. Furthermore, the amount of bending of the substrate can be suppressed to 0.006 mm or less by setting the distance between the support means to 35 mm or more and 40 mm or less. As a result, the temperature variation in the plane of the substrate can be made ± 0.03 ° C. or less.

  According to the substrate heat treatment apparatus of the present invention, the support means is arranged at each vertex position of the regular triangles arranged regularly and continuously, so that the distances between the adjacent support means are all equal. . Therefore, the amount of bending of the substrate between the support means is equal. Such an arrangement of the support means can efficiently suppress the amount of bending of the substrate with a smaller number of points.

Embodiment 1 of the present invention will be described below with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a schematic configuration of a substrate heat treatment apparatus according to an embodiment, and FIG. 2 is a plan view of a heat treatment plate.

  A heat treatment plate 1 on which a substrate W to be processed is placed is provided with a heating element 3 such as a mica heater. A plurality of heat pipes (not shown) are embedded in the heat transfer section 5 between the heating element 3 and the upper surface of the heat treatment plate 1. A cooling groove (not shown) is formed between a plurality of heat pipes (not shown), and a cooling fluid is circulated.

  Please refer to FIG. A plurality of support members 11 for abutting and supporting the lower surface of the substrate W are provided on the upper surface of the heat treatment plate 1. These support members 11 are assumed to be regular triangles arranged regularly and continuously on the upper surface of the heat treatment plate 1 (in FIG. 2, each regular triangle is indicated by an alternate long and short dash line), and the positions of the vertices of these regular triangles are supported. The arrangement position of the member 11 is used. Here, “regularly continuously” means “repeating a pattern in which two adjacent regular triangles coincide at two vertices”. In other words, the arrangement position of the support member 11 is such that the first imaginary line group passing through the upper surface of the heat treatment plate 1 and parallel to each other at equal intervals is rotated 60 degrees on the upper surface of the heat treatment plate 1. It corresponds to each intersection with the second virtual line group. In addition, the dashed-dotted line shown in FIG. 2 is also corresponded to these 1st, 2nd virtual line groups.

  Furthermore, in the present embodiment, one of the support members 11 is disposed so as to be the center point P of the heat treatment plate 1.

  The support member 11 has a spherical shape, and its material is exemplified by ceramic. On the upper surface of the heat treatment plate 1, a recess is formed at each position where the support member 11 is disposed, and the support member 11 is fitted and fixed in this recess. The support member 11 corresponds to the support means in this invention.

  In addition, a ring-shaped seal portion 15 having an inner diameter slightly smaller than the outer diameter of the substrate W in plan view is provided on the upper surface of the heat treatment plate 1. The height of the seal portion 15 is equal to the protruding height of the support member 11. The minute space (also referred to as proximity gap) ms formed between the substrate W supported by the support member 11 and the heat treatment plate 1 is made airtight by the peripheral side of the substrate W coming into contact with the seal portion 15. . As the seal part 15, for example, a polyimide resin having heat resistance and elasticity is preferable. In addition, a fluororesin can be used. The seal portion 15 corresponds to the sealing means in this invention.

  Furthermore, a discharge hole 17 for discharging the gas in the minute space ms is formed on the upper surface of the heat treatment plate 1. There are four discharge holes 17, which are provided at equal intervals in the circumferential direction. Each discharge hole 17 penetrates to the lower end side of the heat treatment plate 1. One end side of the discharge pipe 21 is commonly connected to the discharge holes 17, and a vacuum suction source 23 is connected to the other end side. The vacuum suction source 23 is, for example, a vacuum utility provided in a clean room. The discharge pipe 21 is provided with a pressure adjusting valve 25 that adjusts the pressure (negative pressure) in the minute space ms, and a pressure gauge 27 that measures the pressure. Further, an open / close valve including a vacuum breaker valve may be provided. The discharge pipe 21 and the vacuum suction source 23 function as discharge means.

  Further, the heat treatment plate 1 is provided with a delivery member 31 that delivers the substrate W to and from a transport means (not shown). The shape of the delivery member 31 is a rod-like body, and examples of the material include ceramic. In the present embodiment, the three through holes 33 penetrate the heat treatment plate 1 up and down at the positions of the vertices of the equilateral triangle centered on the center point P of the heat treatment plate 1 in plan view and avoiding the support member 11. The transfer member 31 is inserted into each through hole 33. The lower end of each delivery member 31 is connected to a single support base 35 in common. The support base 35 is connected to the operating shaft of the air cylinder 37. The air cylinder 37 drives the support base 35 up and down. The delivery member 31, the support base 35, and the air cylinder 37 function as a substrate delivery unit.

  The control unit 41 comprehensively operates the output of the heating element 3, the opening / closing of the pressure adjustment valve 25, the driving of the vacuum suction source 23, and the driving of the air cylinder 37. These operations are performed based on prestored recipes. Furthermore, the opening / closing operation of the pressure regulating valve 25 is performed based on the detection result of the pressure gauge 27. The control unit 41 is realized by a central processing unit (CPU) that executes various types of processing, a RAM (Random-Access Memory) that is a work area for arithmetic processing, a storage medium such as a fixed disk that stores various types of information, and the like. ing.

  Here, for a circular substrate W having a diameter of 300 mm, the pressure in the minute space ms is preferably adjusted to a negative pressure of −4 kPa or more and less than 0 Pa. Furthermore, the pressure in the minute space ms is more preferably adjusted to −4 kPa. In the present embodiment, the control unit 41 controls the pressure in the minute space ms to be −4 kPa.

  Further, when the pressure in the minute space ms is a negative pressure of −4 kPa or more and less than 0 Pa, it is a distance corresponding to the distance d of the support member 11 (“the length of one side of a virtual equilateral triangle”, It is preferable that it is 35 mm or more and 40 mm or less. Furthermore, when the pressure in the minute space ms is −4 kPa, the interval d is preferably 35 mm. In the present embodiment, the support member 11 is arranged with the distance d being 35 mm. In this case, 55 support members 11 are provided.

  Next, the operation of the substrate heat treatment apparatus configured as described above will be described with reference to FIG. FIG. 3 is a flowchart showing a processing procedure by the substrate heat treatment apparatus. Note that the temperature control and the like of the heating element 3 are already performed according to the recipe, and are omitted in the following description.

<Step S <b>1> Loading the Substrate W When the horizontal substrate W is loaded by a transport unit (not shown), the control unit 41 drives the air cylinder 37 to raise the support base 35. The transfer member 31 protrudes upward from the upper surface of the heat treatment plate 1 and receives the substrate W. Thereafter, the air cylinder 37 is driven in the reverse direction to lower the delivery member 31. The substrate W is supported by the support member 11, and a minute space ms is formed between the substrate W and the heat treatment plate 1. Further, the substrate W is supported by the seal portion 15 at the peripheral edge portion.

<Step S2> The controller 41 that adsorbs the substrate W drives the vacuum suction source 23 and operates the pressure adjustment valve 25. Thereby, the gas (air or nitrogen) in the minute space ms is discharged through the discharge hole 17 and the discharge pipe 21, and the pressure in the minute space ms is adjusted to a predetermined negative pressure (−4 kPa). Is sucked to the heat treatment plate 1 side. Therefore, even if the substrate W is warped, it is corrected so as to follow the support member 11 and the seal portion 15.

  This will be specifically described with reference to FIG. 4 and FIG. As the warp of the substrate W, as shown in FIG. 4A, the center of the substrate W is warped so as to protrude upward (mountain warp), and as shown in FIG. There is a warp (valley warp) so that the central part protrudes downward.

  In the substrate W whose central portion protrudes upward, since the substrate W and the seal portion 15 are already in contact with each other on the peripheral side when the substrate W is placed, the minute space ms is airtight. The part is drawn toward the heat treatment plate 1 until it comes into contact with each support member 11. As a result, the warpage of the substrate W is corrected substantially flat as shown in FIG. On the other hand, in the substrate W whose central portion protrudes downward, the seal portion 15 does not come into contact with the substrate W when the substrate W is placed, so that the side of the minute space ms is open. However, by sucking in this state, gas flows into the minute space ms from the periphery through the space between the substrate W and the seal portion 15 to generate the Bernoulli effect, and the peripheral edge of the substrate W is drawn downward (FIG. 5). In (a), the air flow is indicated by a two-dot chain line). Eventually, when the seal portion 15 comes into contact with the peripheral portion of the substrate W, the minute space ms becomes airtight, and the warpage of the substrate W is corrected substantially flat as shown in FIG.

  Here, the warpage of the substrate W is said to be 300 μm or less when the substrate W has a circular shape with a diameter of 300 mm. Even if the substrate W has a valley warp of 300 μm, if the pressure in the minute space ms is −4 kPa, the substrate W can be adsorbed and the warp can be corrected.

  Further, even when the warp can be corrected in this manner, strictly speaking, the substrate W is bent between the support members 11 so as to bend toward the heat treatment plate 1 side. However, by disposing the support members 11 at the positions of the vertices of the regular triangles arranged in a regular and continuous manner, no matter which support member 11 is noticed, the periphery thereof is spaced by a distance d. There are other supporting members 11 and there is no portion that is greatly bent. Therefore, the bending of the substrate W can be efficiently suppressed with a smaller number of support members 11.

  Specifically, another arrangement method is illustrated and compared with this. FIG. 6A is a first comparative example in which the support members 11 are arranged at the positions of the vertices when the squares are regularly arranged, and FIG. The 2nd comparative example which arrange | positions the supporting member 11 in the position of each vertex when arranging is shown. The distance between one side of the square and regular hexagon in the first and second comparative examples is defined as the distances d1 and d2 between the support members 11. In the present example and the first and second comparative examples, the necessary number of support members 11 (hereinafter simply referred to as the number of support points) and the amount of deflection of the substrate W when the intervals d, d1, and d2 are changed. The characteristic with b is schematically shown in FIG. The horizontal axis in FIG. 7 is the number of support points (the number of necessary support members 11), and the vertical axis is the amount of bending b of the substrate W. Further, the values of the distances d, d1, and d2 at that time are plotted on the curves of the present example, the first comparative example, and the second comparative example. In FIG. 7, the substrate W is a circle having a diameter of 300 mm, and the pressure in the minute space ms is −4 kPa.

  As shown in the figure, it can be seen that when the substrate W is suppressed to the same deflection amount b, the present embodiment can be achieved with a smaller number of support points than the first and second comparative examples. Further, when the same number of supporting points is provided, the amount of bending b of the substrate W can be further reduced in the present embodiment compared to the first and second comparative examples. In this example, the first comparative example, and the second comparative example, it is considered that the bending amount b of the center point of the polygon is larger than the bending amount b of the intermediate point of each side. According to the present embodiment, it is considered that the variation according to the position of the bending amount b is the smallest.

  Further, as can be seen from FIG. 7, in this example, when the distance d is 35 mm, the bending amount b of the substrate W is reduced to 6 μm or less.

<Step S3> Heat-treating the substrate W The substrate W is subjected to a predetermined heat-treatment by holding this state for a predetermined time with respect to the substrate W supported by suction. At this time, since the deflection amount b of the substrate W is 6 μm or less, the variation in temperature across the surface of the substrate W is set to 0.03 degrees or less from the correlation between the deflection amount b and the temperature difference between the substrates W. it can.

<Step S4> Unloading the Substrate W When the heat treatment for a predetermined time is finished, the control unit 41 stops the vacuum suction source 23 and closes the pressure adjustment valve 25 to stop the exhaust in the minute space ms, The pressure in the minute space ms is set to atmospheric pressure. Thereby, the suction of the substrate W is released. Next, the air cylinder 37 is driven to raise the transfer member 31 and lift the substrate W upward. In this state, the substrate W is unloaded by a transfer means (not shown).

  As described above, according to the substrate heat treatment apparatus, each support member 11 is arranged at each vertex position of regular triangles arranged regularly and continuously, so that the amount of bending of the substrate W is efficiently suppressed. can do.

  Further, by aligning the position of any one of the support members 11 with the center point P of the heat treatment plate 1, the support member 11 is symmetrical with respect to the center point P with respect to the center point P of the heat treatment plate 1. Each can be arranged.

  Further, the warpage of the circular substrate W having a diameter of 300 mm can be corrected by adjusting the pressure in the minute space ms to −4 kPa.

  Further, by setting the distance d between the support members 11 to 35 mm, when the circular substrate W having a diameter of 300 mm is adsorbed with a negative pressure of −4 kPa, the bending amount b of the substrate W can be reduced to 6 μm or less. it can. Thereby, the temperature variation in the surface of the substrate W can be suppressed to 0.03 degrees or less.

  The present invention is not limited to the above-described embodiment, and can be modified as follows.

  (1) In each of the above-described embodiments, the distance d between the support members 11 is set to 35 mm, and the pressure in the minute space ms is adjusted to −4 kPa, but is not limited thereto. If the pressure in the minute space ms is a negative pressure of -4 kPa or more and less than 0 Pa, the same effect can be obtained even if the design is changed appropriately. In accordance with this, even if the design is appropriately changed within the range of 40 mm to 35 mm as the distance d between the support members 11, the same effect can be obtained.

  (2) In each of the above-described embodiments, the substrate W has a circular shape with a diameter of 300 mm, but is not limited thereto. For example, the present invention can be applied to a substrate heat treatment apparatus that processes a circular substrate having a diameter other than 300 mm or a rectangular substrate.

  (3) In each Example mentioned above, although the supporting member 11 is spherical shape and illustrated the ceramic etc. as the material, it is not restricted to this. For example, the shape can be any shape as long as it protrudes from the upper surface of the heat treatment plate 1. Further, the material may be replaced with a resin or the like.

  (4) In each of the above-described embodiments, the configuration in which the heat pipe is embedded in the heat transfer section 5 has been described as an example, but the present invention can also be applied to a substrate heat treatment apparatus that does not use a heat pipe.

It is a longitudinal cross-sectional view which shows schematic structure of the substrate heat processing apparatus which concerns on an Example. It is a top view of a heat processing plate. It is a flowchart which shows the process sequence by a substrate heat processing apparatus. It is explanatory drawing which shows the process of the board | substrate which the center part protruded and warped on the opposite side to the heat processing plate. It is explanatory drawing which shows the process of the board | substrate which the center part protruded and warped to the heat processing plate side. (A) It is explanatory drawing of a square arrangement pattern, (b) It is explanatory drawing of a regular hexagon arrangement pattern. It is the schematic diagram which compared the number of support points and the amount of board | substrate bending in a present Example and the 1st, 2nd comparative example. It is explanatory drawing which shows the state of the board | substrate currently adsorbed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Heat processing plate 11 ... Support member 15 ... Seal part 17 ... Discharge hole 21 ... Discharge piping 23 ... Vacuum suction source 25 ... Pressure adjustment valve 27 ... Pressure gauge 41 ... Control part W ... Substrate ms ... Micro space d ... Between support members Interval P: Center point of heat treatment plate

Claims (4)

In a substrate heat treatment apparatus for performing heat treatment on a substrate,
A heat treatment plate;
In a state of projecting from the upper surface of the heat treatment plate, the lower surface of the substrate is abutted and supported, and support means respectively disposed at the positions of the vertices of regular triangles arranged regularly,
Sealing means that is provided in a ring shape on the upper surface of the heat treatment plate and seals a space formed between the substrate and the heat treatment plate by contacting the peripheral edge of the substrate;
A discharge hole for discharging the gas in the space;
A substrate heat treatment apparatus comprising: In a substrate heat treatment apparatus for performing heat treatment on a substrate,
A heat treatment plate;
A first imaginary line group parallel to each other at equal intervals passing through the upper surface of the heat treatment plate and supporting the lower surface of the substrate in a state of protruding from the upper surface of the heat treatment plate, and the heat treatment plate Support means arranged at the position of each intersection with the second virtual line group obtained by rotating the first virtual line group by 60 degrees on the upper surface;
Sealing means that is provided in a ring shape on the upper surface of the heat treatment plate and seals a space formed between the substrate and the heat treatment plate by contacting the peripheral edge of the substrate;
A discharge hole for discharging the gas in the space;
A substrate heat treatment apparatus comprising: In the substrate heat treatment apparatus according to claim 1 or 2,
The substrate heat treatment apparatus characterized in that the position of any one of the support means is set as the center point of the heat treatment plate. In the substrate heat treatment apparatus according to any one of claims 1 to 3,
The substrate is a circle with a diameter of 300 mm,
By discharging from the discharge hole, the pressure in the space is set to -4 kPa or more and less than 0 Pa,
The substrate heat treatment apparatus is characterized in that an interval between the support means is 35 mm or more and 40 mm or less.

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