JP2003045790A - Wafer heat treatment apparatus and rectifying mechanism and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer heat treatment apparatus that uniformly supplies a purge gas into treatment space and can improve process performance, and to provide a rectifying mechanism and a method of wafer heat treatment apparatus. SOLUTION: A wafer heat treatment apparatus 51 is equipped with a plate 62 for heat-treating a wafer W, cases 41 and 53 that surround the plate 62 for forming a heat treatment chamber S, a gas inlet section 53a that is provided in the case and receives gas from a gas supply means to introduce the gas into the heat treatment chamber S, and diffusion means 70 and 72 that are provided in the case to make the gas from the gas inlet section diffuse uniformly in the heat treatment chamber S. In this case, the gas inlet section 53a has a buffer chamber 77, that can fill a specific amount of gas to be supplied, and a gas jet section 79 that makes the gas in the buffer chamber 77 flow directly below, toward the heat treatment chamber S.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate heat treatment apparatus for heating or cooling a substrate, a rectifying mechanism therefor, and a rectifying method.

[0002]

2. Description of the Related Art Semiconductor devices (IC chips) and LCDs
In the manufacturing process of (1), a fine pattern is formed with high precision and high density on the surface of a substrate such as a semiconductor wafer or a glass substrate by using photolithography technology.

For example, in the manufacture of semiconductor devices, a resist is applied to the surface of a semiconductor wafer substrate to form a resist film, which is then exposed to a predetermined pattern,
Further, a predetermined circuit pattern is formed by developing and etching. That is, after a resist solution is spin-coated on a substrate, a pre-bake process, an exposure process, a post-exposure bake process, a development process and a post-bake process are performed (photolithography process) to form a resist pattern on the substrate. .

The pre-bake treatment is a treatment for evaporating an excess solvent in the resist solution applied on the substrate, and the post-exposure bake treatment is a product produced by a photochemical reaction in the resist film. And the post-baking treatment is a treatment for improving the dry etching resistance. Hereinafter, the pre-baking process, the post-exposure baking process, and the post-baking process are collectively referred to as a heat treatment.

By the way, these series of steps are generally
The single-wafer processing is performed by a coating / developing substrate processing system including a transfer device that transfers a substrate to each processing unit. FIG. 13 schematically shows a main part of a heat treatment unit of such a coating and developing substrate processing system. This heat treatment unit is provided with a housing 130 and a substrate W such as a semiconductor wafer arranged in the housing 130.
The heating plate 140 is mounted on the heating plate 140, and the upper cover 141 that covers the heating plate 140 is provided. Hot plate 140
A heating or cooling means such as a heater, a cooling pipe, or a Peltier element is embedded in the substrate, and the heating or cooling means heats (cools) the substrate W on the hot plate 140 (heat treatment). Has become.

For example, in the resist baking process, the substrate W coated with the resist is placed on the hot plate 140 via the spacers, covered with the upper cover 141, and then the substrate W is heated by the heating means of the hot plate 140. To heat. When the substrate W is heated, excess solvent and the like in the resist on the substrate W evaporates and fills the inside of the upper cover 141. here,
If the temperature inside the upper cover 141 fluctuates due to the invasion of outside air from the outside, the sublimate from the resist may be condensed again and adhere to the surface of the resist, which is not preferable.

Therefore, it is common practice to perform heat treatment while discharging the solvent (volatile matter) and the like filling the inside of the heat treatment unit to the outside. In the heat treatment unit shown in FIG. 13, the gas supply source (not shown) is connected to the supply pipeline 1.
Air is supplied from one side to the upper opening 145 of the upper cover 141 via 43, and the air is blown from the opening 145 to the surface of the substrate W through the two perforated plates 147 and 149 and is provided around the heat plate 140. Air is exhausted to the outside through the exhaust port 150. In this case, the air supplied to the processing space S is exhausted to the outside from the exhaust port 150 through the exhaust pipe line together with the solvent evaporated from the resist liquid on the substrate W in the processing space S.

[0008]

By the way, when air is supplied to the upper opening 145 of the upper cover 141 from one side (left side in FIG. 13), the air is treated in the processing space S as shown by an arrow in FIG. A large amount of air flows in the inside of the processing space S, and there is a disadvantage that the air spread becomes worse on one side (the side opposite to the air supply direction (the left side in FIG. 13)) in the processing space S. That is, on one side of the processing space S (on the right side in FIG. 13), sublimates from the resist can be satisfactorily purged by sufficient air supply, but the processing space S
On the other side (left side in FIG. 13), a situation occurs in which the sublimate from the resist cannot be satisfactorily purged due to insufficient air supply.

As described above, when the air as the purge gas is nonuniformly supplied into the processing space S, the solvent volatilization in the resist becomes nonuniform (the volatilization of the resist component in the surface of the substrate is uneven), and the process performance ( It has been pointed out that it adversely affects the film thickness uniformity of the resist film on the substrate and the pattern line width uniformity after development. For example, the concentration of the solvent or the concentration of the acid in the processing space S varies, and the amount of the solvent in the film and the amount of the acid diffusion reaction also vary. Therefore, in order to obtain good process performance, it is important to make the air flow in the processing space S uniform.

In recent years, as semiconductor devices have become highly integrated, patterns formed on a substrate have become finer, and the uniformity of the film thickness of a resist film applied on a substrate W and the pattern line width after development have been improved. Uniformity tolerances are tight. Therefore, there is an urgent need to make the exhaust gas balance in the processing space S uniform and the air supply amount uniform.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a substrate heat treatment apparatus capable of uniformly supplying a purge gas into a processing space and improving process performance, and a rectification thereof. It is to provide a mechanism and a rectification method.

[0012]

In order to solve the above-mentioned problems, a substrate heat treatment apparatus according to the present invention comprises a plate on which a substrate is placed and heat-treated, and a housing which surrounds the plate to form a heat-treatment chamber. A gas supply unit for supplying a purge gas into the heat treatment chamber, an exhaust unit for exhausting the gas in the heat treatment chamber, and a gas provided in the housing for receiving the gas from the gas supply unit. A gas introduction part for introducing the gas into the heat treatment chamber, and a diffusing means provided in the housing for uniformly diffusing the gas from the gas introduction part in the heat treatment chamber. A buffer chamber that can be filled with a predetermined amount of gas,
It is characterized in that it has a gas jetting part for flowing the gas in the buffer chamber directly below to the heat treatment chamber.

As described above, if the gas introducing portion is provided with the buffer chamber and the gas jetting portion for flowing the gas directly below from the buffer chamber to the heat treatment chamber, the supply direction of the air supplied to the gas introducing portion is Irrespective of, the air can be directed directly under the heat treatment chamber. That is, a large amount of air flows in the heat treatment chamber only in the supply direction, and the inconvenience that the air spreads poorly on one side (the side opposite to the air supply direction) in the heat treatment chamber does not occur.

As one form of the above-mentioned structure, the diffusing means is composed of two straightening vanes which are arranged in parallel with each other in the housing and which divide the heat treatment chamber into three spaces. The first rectifying plate located on the upper side is provided with a large number of gas circulation holes except for the central region facing the gas ejection portion, and the second rectifying plate located on the lower side is entirely covered. A large number of gas circulation holes are provided.

According to such a structure, the gas can be uniformly diffused and flowed from the upper side to the lower side. For example, the sublimate rising from the substrate is cooled and crystallized before being crystallized. At the stage of, the heat treatment chamber is purged in advance to prevent the sublimate from adhering to the rectifying plate, and process performance (for example, the film thickness of the coating film on the substrate and the pattern line width after development). Etc.) can be promoted.

In this case, the gas flow holes of the first straightening vane are arranged so that the gas flow holes of the first straightening vane and the gas flowing holes of the second straightening vane do not overlap each other in the vertical direction. It is preferable that the gas flow holes of the second flow straightening plate are arranged in a grid pattern while being radially arranged around the central region where no gas is provided. Further, it is desirable that the diameter of the gas flow hole of the second flow straightening plate is larger than the diameter of the gas flow hole of the second flow straightening plate. Further, among the three spaces partitioned by the first and second straightening vanes, the uppermost first space formed between the gas introducing part and the first straightening vane is The first rectifying plate and the second rectifying plate are formed as spaces for flowing the gas from the gas introducing portion to the periphery along the first rectifying plate while being reflected by the central region of the first rectifying plate. And a second space formed between and is formed as a space in which the gas flowing through the gas flow holes of the first straightening vane is circulated immediately below the central region and further spread to the periphery to be uniformly diffused. Is desirable.

Further, according to the present invention, there is provided a rectifying mechanism for rectifying the purge gas supplied into the substrate heat treatment apparatus for heat treating the substrate. The rectifying mechanism is provided in the housing of the substrate heat treatment apparatus, and is provided in the housing and a gas introduction unit that receives a supplied gas and introduces the gas into a heat treatment chamber of the substrate heat treatment apparatus. A diffusion chamber for uniformly diffusing a gas from the heat treatment chamber in the heat treatment chamber, wherein the gas introduction unit directs the gas in the buffer chamber to the heat treatment chamber and a buffer chamber capable of filling a predetermined amount of the supplied gas. And a gas jetting portion which is made to flow directly below.

Further, according to the present invention, there is provided a rectifying method for rectifying the purge gas supplied into the substrate heat treatment apparatus for heat treating the substrate. In this rectifying method, the heat treatment chamber of the substrate heat treatment apparatus is divided into three by the first and second rectifying plates, and the purge gas supplied to the substrate heat treatment apparatus can be filled with a predetermined amount of gas. Flow into the buffer chamber and the gas in the buffer chamber to directly below the heat treatment chamber, so that the buffer chamber and the first
Is introduced into the first space formed between the first straightening vane and the gas introduced into the first space while being reflected by the central region of the first straightening vane to the first straightening vane. A second gas flown around the first space, the gas in the first space is formed between the first straightening plate and the second straightening plate through the gas flow holes of the first straightening plate. The gas introduced into the second space and introduced into the second space is circulated immediately below the central region of the first rectifying plate, and further spread to the periphery to be uniformly diffused. The gas in the second
The gas is introduced into the third space formed between the second rectifying plate and the substrate through the gas flow hole of the rectifying plate.

According to such a rectifying mechanism and rectifying method, the air can be made to flow directly below into the heat treatment chamber regardless of the supply direction of the air supplied to the gas introducing portion, and the gas can be supplied from above. It can be diffused and flowed downward.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show the overall structure of a substrate processing system to which the present invention is applied. As shown in these figures, the coating / developing processing system 1 as a substrate processing system carries in or from the system a plurality of semiconductor wafers W as substrates to be processed in a wafer cassette CR in units of, for example, 25 wafers from the outside. A cassette station 10 for carrying out and carrying in / out the semiconductor wafer W to / from the wafer cassette CR, and a variety of single-wafer type for performing a predetermined process on the semiconductor wafer W one by one in the coating and developing process. A processing station 11 in which processing units are arranged in multiple stages at predetermined positions, and an interface section 12 for transferring a semiconductor wafer W between an exposure apparatus (not shown) provided adjacent to the processing station 11 are provided. It has a structure in which it is connected integrally.

As shown in FIG. 1, in the cassette station 10, a plurality of, for example, up to four wafer cassettes CR are placed at the positions of the protrusions 20a on the cassette mounting table 20.
The respective wafer entrances / outlets are placed in a line in the X direction toward the processing station 11 side, and can be moved in the cassette arrangement direction (X direction) and the wafer arrangement direction (Z direction) of the wafers stored in the wafer cassette CR. The wafer transfer body 21 selectively accesses each wafer cassette CR. Further, this wafer carrier 21
Is configured to be rotatable in the θ direction, so that the alignment unit (ALIM) and extension unit (EXT) belonging to the multi-stage unit section of the third group G3 on the processing station 11 side can be accessed as described later. It has become.

Further, as shown in FIG. 1, in the processing station 11, a vertical transfer type main wafer transfer mechanism 22 is provided in the central portion, and all the processing units are surrounded by the main wafer transfer mechanism 22.
They are arranged in multiple stages over a set or a plurality of sets. In this example, there is a multistage arrangement configuration of 5 groups G1, G2, G3, G4, G5, and the multistage units of the first and second groups G1 and G2 are arranged side by side on the front side of the system (front side in FIG. 1), Three
The multistage unit of the third set G3 is arranged adjacent to the cassette station 10, the multistage unit of the fourth set G4 is arranged adjacent to the interface section 12, and the multistage unit of the fifth set G5 is arranged on the back side. ing. The fifth group G5 is configured to be movable along the rail 25 for maintenance of the main wafer transfer mechanism 22.

As shown in FIG. 2, in the first set G1, two spinner type processing units, for example, a resist coating unit (COT), which place a semiconductor wafer W on a spin chuck in a cup CP and perform a predetermined process. ), And a developing unit (DEV) are stacked in two stages in order from the bottom. Also in the second group G2, two spinner type processing units, for example, a resist coating unit (COT) and a developing unit (DEV) are stacked in two stages in order from the bottom.
Disposing the resist solution in the resist coating unit (COT) is troublesome both mechanically and in terms of maintenance. Therefore, it is preferable to dispose the resist solution in the lower stage. But,
It is also possible to arrange them in the upper stage if necessary.

As shown in FIG. 3, in the third group G3, an oven-type processing unit for placing the semiconductor wafer W on a mounting table and performing a predetermined process, for example, a cooling unit (COL) and an adhering unit in order from the bottom. John Unit (A
D), alignment unit (ALIM), extension unit (EXT), pre-baking unit (PREBAKE) and post-baking unit (P)
OBAKE) is overlaid. Also in the fourth group G4, an oven-type processing unit, for example, a cooling unit (COL) having two stages from the bottom, an extension cooling unit (EXTCOL), an extension unit (EXT), and a prebaking unit (PREBA).
KE) and post-baking unit (POBAKE)
Are stacked.

As described above, the cooling units (COL) and (EXTCOL) having a low processing temperature are arranged in the lower stage, and the baking units (PREBAKE) and the post-baking units (POBAKE) having a high processing temperature are arranged in the upper stage. Thermal mutual interference between them can be reduced. However, a random multi-stage arrangement is also possible.

The interface section 12 has the same dimension as the processing station 11 in the depth direction, but is made small in the width direction. Interface unit 12
A portable pickup cassette CR and a stationary buffer cassette BR are arranged in two stages on the front side of the, a peripheral exposure device 23 is arranged on the rear side, and a wafer carrier 24 is provided on the central part. ing. The wafer carrier 24 is
By moving in the X and Z directions, both cassettes CR and BR and the peripheral exposure device 23 are accessed. further,
The wafer carrier 24 is configured to be rotatable in the θ direction, and is also connected to the extension unit (EXT) belonging to the multistage unit of the fourth group G4 on the processing station 11 side, and the wafer transfer table on the adjacent exposure apparatus side ( (Not shown) is also accessible.

Next, the coating and developing treatment system 1 having the above structure.
The processing steps of will be described.

First, in the cassette station 10, the wafer transfer body 21 accesses the cassette CR containing the unprocessed wafers on the cassette mounting table 20, and takes out one semiconductor wafer W from the cassette CR. , This is conveyed to the alignment unit (ALIM).

After the wafer W is aligned by the alignment unit (ALIM), it is transferred to the adhesion unit (AD) by the main wafer transfer mechanism 22 and subjected to the hydrophobic treatment, and then the cooling unit ( After a predetermined cooling process is performed in (COL), it is conveyed to a resist coating unit (COT), where the resist coating process is performed.

Next, the wafer W is heated in a prebaking unit (PREBAKE) at a predetermined temperature for a predetermined time. Thereby, as will be described later, the residual solvent is evaporated and removed from the coating film on the semiconductor wafer W. Thereafter, the wafer W is cooled in a cooling unit (COL), then carried by the wafer carrier 26, and exposed by an exposure device (not shown) via the interface section 12.

Next, the wafer W is transferred to the developing unit (DE
V), where the development processing is performed, and then the post-baking unit (POBAKE), for example, 1
It is heated at 00 ° C. for a predetermined time. As a result, the resist swollen by development is cured and chemical resistance is improved. Thereafter, the wafer W is returned to the cassette CR in the cassette station 10 via the extension unit (EXT) of the third set G3.

FIG. 4 schematically shows the above-mentioned prebaking unit (PREBAKE) 51 as a substrate heat treatment apparatus. As shown, the unit 51 includes a main body 4
1, and a heat plate (plate) 62 is arranged in the substantial center of the main body 41. A heater (not shown) is built in the heating plate 62. The heating plate 62 is heated by a heater so as to be adjustable in the range of 50 ° C to 250 ° C, for example. Further, the main body 41 is provided with a lid portion 53 as an upper cover which is placed above the heating plate 62. The lid portion 53, together with the main body 41, includes the heating plate 6
A casing that surrounds 2 and forms a heating chamber (heat treatment chamber) S is configured.

Although not shown, on the surface of the heat plate 62 on which the wafer W is placed, the wafer W is not brought into close contact with the heat plate 62 at a plurality of places (for example, six places) on the outer periphery thereof. A proximity sheet that floats and holds the heat plate 62 is arranged.

A plurality of exhaust ports 42 for exhausting the gas in the heating chamber S are provided on the outer peripheral portion of the main body 41, and these exhaust ports 42 are connected to a vacuum pump 48 via an exhaust valve 70. Has been done. That is, the exhaust port 42, the exhaust valve 70, and the vacuum pump 48 constitute exhaust means for exhausting the gas in the heating chamber S.

A gas introduction portion 53a for introducing, for example, air from the gas supply source 43 into the heating chamber S is provided at the center of the upper portion of the lid portion 53. This gas introduction part 5
As shown in detail in FIG. 6, 3a is a buffer chamber 77 serving as a relatively large air play space capable of filling a predetermined amount of supplied air, and is located immediately below the buffer chamber 77 so as to communicate therewith. Moreover, the buffer chamber 77 is set to the heating chamber S.
The housing 80 has a nozzle hole 79 as a gas ejection portion that is narrower than the buffer chamber 77 that communicates with the inside. In this way, the buffer chamber 77 and the buffer chamber 7
7 is provided with a nozzle hole 79 extending directly downward to the heating chamber S, the air is flowed directly downward into the heating chamber S regardless of the supply direction of the air supplied to the gas introduction portion 53a. (A large amount of air flows in the heating chamber S only in the supply direction, so that it is possible to avoid the disadvantage that the air spread is deteriorated on one side (the side opposite to the air supply direction) in the heating chamber S). .

The gas (air) from the gas supply source 43 is
The gas is supplied to the gas introduction portion 53a via the supply pipe 65. In this case, the supply pipe 65 is connected to the gas introduction part 5
3a is connected to the housing 80 so as to communicate with the buffer chamber 77 from one side. Further, in the middle of the supply pipe 65, a flow rate control valve 50 and a temperature controller 45 for controlling the temperature of the air supplied to the heating chamber S are inserted. That is, the gas supply source 43, the supply pipe 65, the valve 5
0, the temperature adjuster 45 constitutes gas supply means for supplying gas into the heating chamber S.

Further, the heating chamber S is provided with a pressure gauge 49 for measuring the pressure of the heating chamber S, and the control unit 61 adjusts the opening degree of the valve 50 based on the measurement result by the pressure gauge 49. The pressure of the heating chamber S is adjusted accordingly. The temperature controller 45 is also controlled by the control unit 61.

In the present embodiment, the temperature of the air supplied to the heating chamber S is adjusted to 23 ° C. to 23.5 ° C., and the humidity is maintained at about 45%. However, in order to improve the process performance, the temperature controller 4
5, it is desirable to change the temperature of the air according to the temperature of the heating plate 62.

Further, in the unit 51 of this embodiment, since the air discharged from the nozzle hole 79 directly below the nozzle hole 79 is evenly spread over the entire heating chamber S, the two improved straightening plates (diffusing means) 70, 72 is provided in the heating chamber S. Specifically, the two straightening vanes 70, 72 are arranged in parallel with each other in the vertical direction, and the heating chamber S is divided into three spaces S1, S2, S.
It is divided into 3. As shown in detail in FIG. 5A, the first straightening vane 70 on the upper side allows the air discharged from the nozzle hole 79 to flow to the surroundings without flowing directly under the nozzle hole 79. Has a hole-free region 74, and a large number of holes 7 around the hole-free region 74.
It has 0a. That is, in the first rectifying plate 74,
The hole 70a is not provided only in a predetermined region (a region facing the nozzle hole 79) 74 at the center thereof. In this case, when the diameter of the first straightening vane 70 is set to 345.5 mm and the diameter of the nozzle hole 79 is set to 4.5 mm, the diameter of the holeless region 74 is set to 80 mm. This size depends on the flow rate of the supplied air. On the other hand, as shown in FIG. 5B, the lower second flow straightening plate 72 is
It has a large number of holes 72a over its entirety.

Further, in this embodiment, the first straightening vane 70
Nozzle holes 79 are provided in order to circulate the air flown around the hole-free region 74 of FIG.
The rectifying plates 70, 72 and the wafer W are arranged at a specific distance so that the hole diameters of the first rectifying plate 70 and the second rectifying plate 72 are different from each other, and the holes 70 of the first rectifying plate 70 are arranged.
A and the hole 72a of the second straightening plate 72 are prevented from vertically overlapping with each other. Specifically, the distance L1 between the opening of the nozzle hole 79 and the first straightening vane 70 is 3 mm, and the distance L2 between the first straightening vane 70 and the second straightening vane 72 is 8 m.
m, the distance L3 between the second flow straightening plate 72 and the wafer W is 7
mm (see FIG. 4), and the first straightening vanes 70
The holes 70a of the first rectifying plate 70 and the holes 70a of the second rectifying plate 72 do not overlap each other as much as possible.
a are arranged radially around the holeless region 74 (see (a) of FIG. 5), and a large number of holes 72 a of the second straightening plate 72 are arranged in a grid pattern (see (b) of FIG. 5). ),
Further, the diameter of the hole 70a of the first straightening vane 70 is set to 1 mm, and the diameter of the hole 72a of the second straightening vane 72 is set to 2 mm (the diameter of the second straightening vane is 345.5 mm). ing. That is, the size of the hole is the same as that of the first straightening vane 7.
The second straightening plate 72 is set to be larger than zero (twice in the present embodiment).

Next, the operation of the prebaking unit 51 having the above structure will be described.

First, the wafer W on which the resist coating process has been performed by the resist coating unit (COT) is transferred into the pre-baking unit 51. In this case, the wafer W is transferred to the main wafer transfer mechanism 2 with the lid 53 raised.
It is mounted on the heating plate 62 by the No. 2 method. After that, the lid portion 53 descends to form the heating chamber S, the wafer W is heated to a predetermined temperature, for example, 140 ° C. by the heating plate 62, and the temperature is maintained at 140 ° C. for a predetermined time. As a result, the residual solvent is evaporated and removed from the coating film on the wafer W.

In this pre-baking process, the sublimate from the resist is re-condensed and adheres to the surface of the resist, or the sublimate from the resist is rectified by the rectifying plate 70 ,.
In order to prevent the adhesion to 72, heat treatment is performed while discharging the solvent content (volatile content) and the like filling the inside of the heating chamber S to the outside. That is, the gas supply source 43
Air is supplied from one side to the gas introduction portion 53a via the supply pipe 65. The air supplied to the gas introduction portion 53a once fills the buffer chamber 77, is then discharged directly below the nozzle hole 79, and is reflected by the non-perforated region 74 of the first flow straightening plate 70 while the first flow straightening is performed. The first space S1 is flown around along the plate 70. The air that spreads around the inside of the first space S1 then passes through the hole 70a of the first flow straightening plate 70 to form the second space between the first flow straightening plate 70 and the second flow straightening plate 72. It flows into S2. At this time, since the distance L2 between the first straightening vane 70 and the second straightening vane 72 is secured to be large, air is
It also comes under the holeless region 74. As a result, the air is spread evenly in the second space S2. Further, the uniformly diffused air passes through the holes 72 a of the second flow straightening plate 72 and the heat plate 62 and the wafer W.
Flows into the third space S3 in which the gas exists, is sprayed onto the surface of the wafer W, and the heating chamber S (the third space S
The solvent evaporated from the resist solution on the wafer W in 3) is discharged to the outside through the exhaust port 42 provided around the hot plate 62.

Such air supply / discharge (air purge /
Exhaust) is performed in the first half or the second half of the heat treatment as shown in FIG. In order to ensure a predetermined process performance (process reaction), it is not desirable to supply and exhaust air during the heat treatment. This is because the temperature change may occur during processing due to the supply and discharge of air.

As shown, air purge / exhaust ON
The / OFF timing, that is, the opening / closing timing of the valve 50 by the control unit 61 is associated with the temperature of the wafer W (baking time). For example, a bake time of 90
When the second is set, in the first sequence (the lower arrow in FIG. 7) in which the air purge / exhaust is turned on in the first half of the heat treatment, the temperature of the wafer W is predetermined for the first 30 seconds (the first 20 seconds or so). The air purging / evacuation is performed only at the temperature (140 ° C.). In this case, in order to effectively purge the sublimate, the flow rate of air is set to 4 liters / minute m. However, considering the process performance, it is desirable to reduce the flow rate lower than this. On the other hand, the second sequence of turning on the air purge / exhaust in the latter half of the heat treatment (see FIG. 7).
In the middle upper arrow), air purging / evacuation is performed in the last 30 seconds, that is, 60 seconds to 90 seconds after the start of heat treatment. In this case, the exhaust flow rate of air is set to 8 to 12 liters / minute so that the sublimate does not adhere to the rectifying plates 70 and 72. Of course, the sequence shown here is merely an example, but considering the line width, the second sequence is better, and considering the sublimate, the first sequence is better.

By supplying and discharging the air as described above, the solvent component evaporated from the coating film on the wafer W and the air are mixed on the wafer W to make the concentration distribution uniform and the heating chamber S. The temperature distribution inside is also made uniform. This prevents the occurrence of processing unevenness on the surface of the wafer W. That is, the air (purge gas) is uniformly diffused and flowed from the top to the bottom by the above-described novel form, so that the sublimate rising from the wafer W is cooled and crystallized at a stage before being crystallized. , The heating chamber S is purged in advance, so that the sublimate is removed from the straightening plates 70, 72.
Not only is it prevented from adhering to the substrate, but also uniformity of process performance (film thickness of the resist film on the wafer, pattern line width after development, etc.) is promoted. That is, when a desired air flow is generated in the heating chamber S by the air and the solvent atmosphere / acidic atmosphere is purged by a predetermined amount, the inside of the heating chamber S is agitated in a desired state during the baking process, and the wafer W surface The deviation of the volatilization of the resist component of is improved, and the saturation amount of the solvent / acid in the heating chamber S can be controlled (the saturation concentration can be made constant), and the film quality can be controlled (uniform in the film). Can be done. In addition, as a means for stirring the inside of the heating chamber S, a top plate installed in the heating chamber S (or a straightening plate may be used)
It is also conceivable to move up and down or rotate.

As described above, the function and effect described above are provided with the buffer 77 and the holeless region 74, the nozzle hole 79, the straightening plates 70 and 72, and the wafer W are arranged at a specific distance, and the straightening plate 70 is provided. , 72 holes are improved in arrangement and size. And such an effect is clarified also from the experimental data shown in FIGS. These data were obtained under the following conditions. (Conditions) Air supply amount 3 liters / minute Diameter of rectifying plate 345.5 mm Hole diameter of first rectifying plate 1 mm Hole diameter of second rectifying plate 2 mm FIG. 8 shows the resist film thickness of the heating plate 62 at each temperature. And the baking time. In the figure, the black circle plots indicate that the temperature of the heat plate 62 is 50 ° C., the white circle plots indicate that the temperature of the heat plate 62 is 70 ° C., and the white triangle plots indicate that the temperature of the heat plate 62 is 90 ° C. The plots with open squares are for the temperature of the heating plate 62 of 110 ° C., and the plots with × are for the temperature of the heating plate 62 of 130 ° C. As shown in the figure, it can be seen that the resist film can be controlled by the temperature of the hot plate 62 and the resist film thickness is maintained uniform over the entire processing time.

FIG. 9 shows a nozzle hole 79 and straightening plates 70 and 72.
3 shows the influence of the distance between the wafer W and the wafer W on the line width (CD). In the figure, the measurement points 0 to 48 on the horizontal axis are 2 on the radial line (line passing through the center of the wafer W) 1 passing through the notch N for alignment of the wafer W, as shown in FIG.
Four points were set at equal intervals (see (b) of FIG. 11), and 24 points were set at equal intervals on the radial line m orthogonal to the radial line l, and each point was set as 1 to 48. In the present embodiment, the points on the radial line m are 1 to 24,
Points on the radial line 1 are set to 25 to 48. In addition, in FIG.
As described above, the solid line plot indicates that the distance L1 between the opening of the nozzle hole 79 and the first straightening vane 70 is 3 mm,
The distance L2 between the current plate 70 and the second current plate 72 is set to 8
mm, the data when the distance L3 between the second straightening plate 72 and the wafer W is set to 7 mm, and the broken line plot indicates the distance between the opening of the nozzle hole 79 and the first straightening plate 70. L1 is 3 mm, the first straightening plate 70 and the second straightening plate 72
And the distance L2 between the second rectifying plate 72 and the wafer W are set to 4 mm, and the distance L2 is set to 7 mm. As can be seen from these data, 3 of the present embodiment
According to the distance setting (solid line) of -8-7, the line width (CD) is maintained substantially uniform over the entire wafer W except the peculiar region at the end of each radial line l, m. On the other hand, in the data indicated by the broken line, since the distance between the first straightening vane 70 and the second straightening vane 72 is not sufficiently secured, the air is evenly distributed in the second space S2. Since the air does not diffuse and the air does not sufficiently flow right under the holeless region 74, the line width varies greatly depending on the position on the wafer W.

FIG. 10 shows the influence of the presence or absence of the holeless region 74 and the diameter of the holeless region 74 on the line width (CD). In the figure, the solid-line rhombus plot is for the case where the holeless region 74 is not provided (no blockage), and the solid-line square plot is for the case where the diameter of the holeless region 74 is set to 80 mm. The solid white circle plot is for the case where the diameter of the holeless region 74 is set to 100 mm, and the dashed rhombus plot is for the case where the diameter of the holeless region 74 is set to 120 mm. Further, in the drawing, the way of taking measurement points 0 to 48 on the horizontal axis is the same as in the case of FIG. As you can see from this figure,
When a hole-free region 74 is provided in the center of the straightening vane 70 and the diameter of the holeless region 74 is set to 80 mm (depending on the diameter of the first straightening vane 70 and the diameter of the nozzle hole 79), the line The width (CD) uniformity is best. In addition, when the holeless region 74 is not provided, or. The larger the diameter of the hole-free region 74, the worse the uniformity of the line width.

As described above, the unit 51 of this embodiment is
According to the rectifying mechanism, the gas in the heating chamber S can be replaced uniformly and in a large amount in the first half or the second half of the heat treatment without forming a dead space. That is, the substitution efficiency of the sublimate is remarkably improved as compared with the conventional one, and the process performance can be significantly improved.

It is needless to say that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention. For example, in the above-described embodiment, the present invention uses the prebaking unit 51.
However, the present invention can be applied to all other heat treatment apparatuses. Further, in the above-described embodiment,
Although air is used as the purge gas, various gases such as nitrogen and an inert gas can be used as the purge gas depending on the situation. Moreover, in the above-described embodiment, as shown in FIG.
A plurality of fins 90 may be provided inside and the flow path from the supply pipe 65 to the nozzle hole 79 may be lengthened as indicated by the arrow in the figure. As a result, the air supplied to the gas introduction portion 53a is agitated in the buffer chamber 77, and a stable amount of air can be discharged directly below the nozzle hole 79.

Further, in the above embodiment, the case where the semiconductor wafer is used as the substrate to be processed has been described, but the present invention is not limited to this, and other substrates to be processed such as a glass substrate for LCD and a reticle substrate for a mask may be used. May be.

[0054]

As described above, according to the substrate heat treatment apparatus, the rectifying mechanism and the rectifying method thereof of the present invention, the purge gas can be uniformly supplied into the processing space to improve the process performance.

[Brief description of drawings]

FIG. 1 is a plan view of a substrate processing system including a substrate heat treatment apparatus of the present invention.

FIG. 2 is a front view of the substrate processing system of FIG.

3 is a rear view of the substrate processing system of FIG.

FIG. 4 is a schematic sectional view of a substrate heat treatment apparatus according to an embodiment of the present invention.

5A is a plan view of a first straightening plate provided in the substrate heat treatment apparatus of FIG. 4, and FIG. 5B is a plan view of a second straightening plate provided in the substrate heat treatment apparatus of FIG.

6 (a) is an operation explanatory view of a rectifying mechanism provided in the substrate heat treatment apparatus of FIG. 4, and FIG. 6 (b) is a cross-sectional view of a gas introducing portion constituting the rectifying mechanism of (a).

7 is experimental data demonstrating the effect of the substrate heat treatment apparatus of FIG.

8 is experimental data demonstrating the effect of the substrate heat treatment apparatus of FIG.

9 is experimental data demonstrating the effect of the substrate heat treatment apparatus of FIG.

10 is experimental data demonstrating the effect of the substrate heat treatment apparatus of FIG.

FIG. 11 is a diagram for explaining how to set measurement points on the substrate in the experimental data of FIGS. 9 and 10.

FIG. 12 is a schematic view showing a modified example of the gas introduction unit.

FIG. 13 is a schematic diagram showing a flow of a purge gas in a conventional substrate heat treatment apparatus.

[Explanation of symbols]

41 ... Main body 51 ... Pre-baking unit 53 ... Lid 53a ... Gas introduction section 62 ... Hot plate 70 ... First straightening plate (diffusing means) 72 ... Second straightening plate (diffusing means) 77 ... Buffer room 79 ... Nozzle hole (gas ejection part) S ... Heating room (heat treatment room) W ... substrate

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masatoshi Deguchi             TBS release, 5-3-6 Akasaka, Minato-ku, Tokyo             Sending Center Tokyo Electron Limited F-term (reference) 2H096 AA25 AA27 GA21 GB03                 5F046 KA04 KA10

Claims (12)

[Claims] 1. A substrate heat treatment apparatus for performing heat treatment on a substrate, a plate on which a substrate is placed and heat-treated, a housing surrounding the plate to form a heat treatment chamber, and a purge gas is supplied into the heat treatment chamber. A gas supply unit for discharging the gas in the heat treatment chamber, and a gas provided in the housing for receiving the gas from the gas supply unit and introducing the gas into the heat treatment chamber. An introducing part and a diffusing means provided in the housing for diffusing the gas from the gas introducing part uniformly in the heat treatment chamber, wherein the gas introducing part is a buffer capable of filling a predetermined amount of the supplied gas. A substrate heat treatment apparatus comprising: a chamber; and a gas jetting section for flowing a gas in the buffer chamber directly below the heat treatment chamber. 2. The substrate heat treatment apparatus according to claim 1, wherein the diffusion means are vertically arranged in the housing in parallel with each other, and two flow rectifying plates partition the heat treatment chamber into three spaces. The first rectifying plate located on the upper side is provided with a large number of gas circulation holes except for the central region facing the gas ejection portion, and the second rectifying plate located on the lower side is A substrate heat treatment apparatus, characterized in that a large number of gas circulation holes are provided throughout the entire structure. 3. The substrate heat treatment apparatus according to claim 1, wherein the gas flow holes of the first straightening vane and the gas flow holes of the second straightening vane do not vertically overlap with each other.
The gas flow holes of the straightening vane are arranged radially around the central region where no holes are provided, and
The gas flow holes of the straightening plate are arranged in a grid pattern. 4. The substrate heat treatment apparatus according to claim 2, wherein the gas flow hole of the second flow straightening plate has a hole diameter larger than that of the gas flow hole of the second flow straightening plate. A substrate heat treatment apparatus. 5. Any one of claims 2 to 4
The substrate heat treatment apparatus according to the item 1, wherein among the three spaces partitioned by the first and second straightening vanes, the uppermost one formed between the gas introducing part and the first straightening vane is formed. The first space is formed as a space for flowing the gas from the gas introducing portion to the periphery along the first straightening vane while being reflected by the central region of the first straightening vane. And a second space formed between the second straightening vane and the gas flowing through the gas flow holes of the first straightening vane are circulated immediately below the central region and further spread to the periphery to be uniform. A substrate heat treatment apparatus, which is formed as a space that diffuses into a substrate. 6. Any one of claims 1 to 5
The substrate heat treatment apparatus according to the item 1, further comprising a control unit that controls the supply of gas from the gas supply unit to the gas introduction unit, wherein the control unit is the gas introduction unit at the initial stage of heat treatment of the substrate by the plate. A substrate heat treatment apparatus, characterized in that gas is supplied to the substrate. 7. Any one of claims 1 to 5
The substrate heat treatment apparatus according to the item 1, further comprising a control unit that controls the supply of gas from the gas supply unit to the gas introduction unit, wherein the control unit is the gas introduction unit at a later stage of heat treatment of the substrate by the plate. A substrate heat treatment apparatus, characterized in that gas is supplied to the substrate. 8. A rectifying mechanism for rectifying a purge gas supplied into a substrate heat treatment apparatus for heat-treating a substrate, wherein the purge gas is provided in a casing of the substrate heat treatment apparatus and receives the gas supplied to the substrate. A gas introducing unit for introducing into the heat treatment chamber of the heat treatment apparatus, and a diffusion unit provided in the housing for uniformly diffusing the gas from the gas introducing unit in the heat treatment chamber, the gas introducing unit being supplied. A rectifying mechanism comprising: a buffer chamber capable of being filled with a predetermined amount of gas, and a gas jetting part for causing the gas in the buffer chamber to flow directly under the heat treatment chamber. 9. The rectifying mechanism according to claim 8, wherein the diffusing means are arranged in parallel with each other in the housing in the vertical direction, and include two rectifying plates that divide the heat treatment chamber into three spaces. The first rectifying plate located on the upper side, except for the central region facing the gas ejection part,
A rectifying mechanism characterized in that a large number of gas flow holes are provided, and the second rectifying plate located on the lower side is provided with a large number of gas flow holes throughout. 10. The flow regulating mechanism according to claim 9, wherein the gas flow holes of the first flow straightening plate and the gas flow holes of the second flow straightening plate do not vertically overlap each other.
The gas flow holes of the straightening vane are arranged radially around the central region where no holes are provided, and
The gas flow holes of the straightening plate are arranged in a grid pattern. 11. The rectifying mechanism according to claim 9, wherein the gas flow hole of the second flow rectifying plate has a larger diameter than the gas flow hole of the second flow rectifying plate. Characterizing rectifying mechanism. 12. A rectifying method for rectifying a purge gas supplied into a substrate heat treatment apparatus for heat-treating a substrate, wherein a heat treatment chamber of the substrate heat treatment apparatus is divided into three by a first and a second rectifying plate, The purge gas supplied to the substrate heat treatment apparatus is caused to flow into a buffer chamber capable of being filled with a predetermined amount of gas, and the gas inside the buffer chamber is caused to flow directly below toward the heat treatment chamber, whereby the buffer chamber and the first Is introduced into the first space formed between the first straightening vane and the gas introduced into the first space while being reflected by the central region of the first straightening vane to the first straightening vane. A second gas formed in a space between the first rectifying plate and the second rectifying plate through the gas flow holes of the first rectifying plate. Introduced into the space of the second The gas introduced into the space is circulated immediately below the central region of the first straightening vane, further spread to the periphery and uniformly diffused, and the gas in the second space is divided into the second space and the second space. A rectifying method, characterized in that the gas is introduced into a third space formed between the second rectifying plate and the substrate through a gas flow hole of the rectifying plate.