JP4294893B2 - Substrate heat treatment apparatus, rectifying mechanism thereof, and rectifying method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a substrate heat treatment apparatus that heats or cools a substrate, a rectifying mechanism thereof, and a rectifying method.
[0002]
[Prior art]
In the manufacturing process of a semiconductor device (IC chip) or LCD, a fine pattern is formed with high accuracy and high density on the surface of a substrate such as a semiconductor wafer or a glass substrate by utilizing a photolithography technique.
[0003]
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, and further developed and etched to form a predetermined circuit pattern. Try to form. 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 (a photolithography process), and a resist pattern is formed on the substrate. .
[0004]
The pre-bake process is a process for evaporating excess solvent in the resist solution applied on the substrate, and the post-exposure bake process is a process in which the product generated by the photochemical reaction is uniformly distributed in the resist film. It is a process for diffusing, and the post-bake process is a process for improving dry etching resistance. Hereinafter, pre-baking, post-exposure baking, and post-baking are collectively referred to as heat treatment.
[0005]
By the way, these series of steps are generally performed in a single-wafer system by a coating and developing substrate processing system provided with a transport device for transporting a substrate to each processing unit. FIG. 13 schematically shows a main part of the heat treatment unit of such a coating and developing substrate processing system. The heat treatment unit includes a housing 130, a heat plate 140 disposed in the housing 130 and on which a substrate W such as a semiconductor wafer is placed, and an upper cover 141 that covers the heat plate 140. Heating or cooling means such as a heater, a cooling pipe or a Peltier element is embedded in the hot plate 140, and the substrate W on the hot plate 140 is heated (cooled) (heat treated) by this heating or cooling means. )
[0006]
For example, in the resist baking process, the substrate W coated with the resist is placed on the hot platen 140 via a spacer, then covered with the upper cover 141, and then the substrate W is heated by the heating means of the hot platen 140. When the substrate W is heated, excess solvent in the resist on the substrate W evaporates and fills the inside of the upper cover 141. Here, if the temperature in the upper cover 141 changes due to the outside air entering from the outside, the sublimate from the resist may condense again and adhere to the surface of the resist, which is not preferable.
[0007]
Therefore, heat treatment is generally performed 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, air is supplied from one side to an upper opening 145 of the upper cover 141 from a gas supply source (not shown) through a supply conduit 143, and the opening 145 passes through two porous plates 147 and 149. Air is blown onto the surface of the substrate W, and air is discharged to the outside through an exhaust port 150 provided around the hot platen 140. 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 along with the solvent evaporated from the resist solution on the substrate W in the processing space S.
[0008]
[Problems to be solved by the invention]
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), a large amount of air flows in the processing space S only in the supply direction as indicated by arrows in FIG. As a result, there arises a disadvantage that the spread of air worsens on one side in the processing space S (the side opposite to the air supply direction (left side in FIG. 13)). That is, on one side (the right side in FIG. 13) of the processing space S, sublimates from the resist can be purged well by sufficient air supply, but on the other side (the left side in FIG. 13) of the processing space S, the air supply is insufficient. As a result, the sublimate from the resist cannot be purged well.
[0009]
Thus, when air that is a purge gas is supplied non-uniformly into the processing space S, the solvent volatilization in the resist becomes non-uniform (the resist component volatilization in the substrate surface is biased), and the process performance (on the substrate) It has been pointed out that it adversely affects the resist film thickness uniformity and the pattern line width uniformity after development. For example, the solvent concentration or acid concentration in the processing space S varies, and the amount of solvent in the film and the amount of acid diffusion reaction vary. Therefore, in order to obtain good process performance, it is important to make the airflow in the processing space S uniform.
[0010]
In recent years, with the high integration of semiconductor devices, the pattern formed on the substrate has been miniaturized, and the film thickness uniformity of the resist film applied on the substrate W and the uniformity of the pattern line width after development have been improved. The tolerance is getting stricter. Therefore, there is an urgent need for uniform exhaust balance in the processing space S and uniform air supply amount.
[0011]
The present invention has been made paying attention to the above circumstances, and an object of the present invention is to provide a substrate heat treatment apparatus capable of uniformly supplying a purge gas into a processing space to improve process performance, its rectifying mechanism, and rectification. It is to provide a method.
[0012]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a substrate heat treatment apparatus according to the present invention provides a plate for placing and heat-treating a substrate, a casing surrounding the plate to form a heat treatment chamber, and supplying a purge gas into the heat treatment chamber. A gas supply means for exhausting, an exhaust means for exhausting the gas in the heat treatment chamber, and a gas passage provided in the housing for receiving the gas from the gas supply means and introducing the gas into the heat treatment chamber A gas introduction unit, and a diffusion unit that is provided in the housing and uniformly diffuses the gas from the gas introduction unit in the heat treatment chamber, and the gas introduction unit can be filled with a predetermined amount of the supplied gas. It is characterized by having a buffer chamber and a gas jetting part for flowing the gas in the buffer chamber directly toward the heat treatment chamber.
[0013]
In this way, if the gas introduction part is provided with a buffer chamber and a gas ejection part for flowing gas directly from the buffer chamber toward the heat treatment room, regardless of the supply direction of air supplied to the gas introduction part, Air can flow directly under the heat treatment chamber. That is, it is not necessary to cause a problem that air flows in the heat treatment chamber only in the supply direction and the spread of the air on one side (the side opposite to the air supply direction) becomes worse.
[0014]
Further, as one form of the above configuration, the diffusing means includes two rectifying plates that are arranged in parallel with each other in the casing and divide the heat treatment chamber into three spaces, and are positioned on the upper side. The first rectifying plate is provided with a large number of gas flow holes except for the central region facing the gas ejection portion, and the second rectifying plate located on the lower side has a large number of the entire Gas flow holes are provided.
[0015]
According to such a configuration, the gas can be uniformly diffused and flowed from top to bottom. For example, the sublimate rising from the substrate is cooled and crystallized before being crystallized. In addition to purging from the heat treatment chamber in advance, it is possible to prevent the sublimate from adhering to the current plate, and process performance (for example, the thickness of the coating film on the substrate, the pattern line width after development, etc.) Uniformity can be promoted.
[0016]
In this case, the gas flow hole of the first rectifying plate is provided with a hole so that the gas flow hole of the first rectifying plate and the gas flow hole of the second rectifying plate do not overlap each other. It is desirable that the gas flow holes of the second rectifying plate are arranged in a lattice pattern while being arranged radially around the central region that is not. Moreover, it is desirable that the hole diameter of the gas flow hole of the second rectifying plate is larger than the hole diameter of the gas flow hole of the second rectifying plate. Of the three spaces defined by the first and second rectifying plates, the uppermost first space formed between the gas introduction part and the first rectifying plate is The first rectifying plate and the second rectifying plate are formed as a space that flows around the first rectifying plate while reflecting the gas from the gas introduction portion by the central region of the first rectifying plate. The second space formed between the first and the second rectifying plates is formed as a space that circulates the gas flowing through the gas flow holes of the first rectifying plate directly below the central region and spreads the gas further to the periphery so as to be uniformly diffused. It is desirable that
[0017]
The present invention also provides a rectifying mechanism for rectifying the purge gas supplied into the substrate heat treatment apparatus for performing heat treatment on the substrate. The rectifying mechanism is provided in the casing of the substrate heat treatment apparatus, receives a supplied gas, introduces the gas into the heat treatment chamber of the substrate heat treatment apparatus, and is provided in the casing, and introduces the gas Diffusion means for uniformly diffusing the gas from the heat treatment chamber in the heat treatment chamber, and the gas introduction portion has a buffer chamber capable of filling a predetermined amount of the supplied gas, and directs the gas in the buffer chamber to the heat treatment chamber. And a gas ejection portion that flows directly below.
[0018]
The present invention also provides a rectification method for rectifying purge gas supplied into a substrate heat treatment apparatus for performing heat treatment on a substrate. In this rectifying method, a heat treatment chamber of the substrate heat treatment apparatus is divided into three by first and second rectifying plates, and a purge gas supplied to the substrate heat treatment apparatus is filled in a predetermined amount of gas. The gas in the buffer chamber is introduced into the first space formed between the buffer chamber and the first current plate by flowing the gas in the buffer chamber directly toward the heat treatment chamber. The gas introduced into the space is caused to flow around the first rectifying plate while being reflected by the central region of the first rectifying plate, and the gas in the first space is allowed to flow around the first rectifying plate. The gas introduced into the second space formed between the first rectifying plate and the second rectifying plate through the gas flow hole of the plate, and the gas introduced into the second space is introduced into the first space. And turn it directly under the central area of the current plate. The gas in the second space is spread and uniformly diffused to the third space formed between the second rectifying plate and the substrate through the gas flow holes of the second rectifying plate. It is characterized by introducing.
[0019]
According to such a rectifying mechanism and a rectifying method, air can be flowed directly under the heat treatment chamber regardless of the supply direction of the air supplied to the gas introduction unit, and the gas is directed from top to bottom. Can be diffused and flown uniformly.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0021]
1 to 3 show the overall configuration of a substrate processing system to which the present invention is applied. As shown in these drawings, the coating and developing processing system 1 as a substrate processing system carries a plurality of semiconductor wafers W as substrates to be processed into the system from the outside in a wafer cassette CR in units of 25, for example, 25 units. A cassette station 10 for unloading and loading / unloading the semiconductor wafer W to / from the wafer cassette CR, and various single-wafer type wafers that perform predetermined processing 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 unit 12 for delivering the semiconductor wafer W between an exposure apparatus (not shown) provided adjacent to the processing station 11. It has the structure connected integrally.
[0022]
As shown in FIG. 1, in the cassette station 10, a plurality of wafer cassettes CR, for example, up to four at the position of the projection 20 a on the cassette mounting table 20, with each wafer inlet / outlet facing the processing station 11 side X A wafer transfer body 21 that is placed in one direction and movable in the cassette arrangement direction (X direction) and the wafer arrangement direction (Z direction) of the wafers stored in the wafer cassette CR is selected for each wafer cassette CR. Access. Further, the wafer transfer body 21 is configured to be rotatable in the θ direction. As will be described later, the alignment unit (ALIM) and the extension unit (belonging to the multi-stage unit portion of the third group G3 on the processing station 11 side) EXT) can also be accessed.
[0023]
As shown in FIG. 1, in the processing station 11, a vertical transfer type main wafer transfer mechanism 22 is provided at the center, and all the processing units are multi-staged around one set or a plurality of sets. Is arranged. In this example, it is a multistage arrangement configuration of 5 groups G1, G2, G3, G4, G5, and the multistage units of the first and second groups G1, G2 are juxtaposed on the system front side (front side in FIG. 1), The multistage unit of the third group G3 is arranged adjacent to the cassette station 10, the multistage unit of the fourth group G4 is arranged adjacent to the interface unit 12, and the multistage unit of the fifth group G5 is arranged on the back side. Has been. The fifth group G5 is configured to be movable along the rail 25 for maintenance of the main wafer transfer mechanism 22.
[0024]
As shown in FIG. 2, in the first set G1, two spinner type processing units, for example, a resist coating unit (COT), for performing predetermined processing by placing the semiconductor wafer W on the spin chuck in the cup CP, and Development units (DEV) are stacked in two stages 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. In the resist coating unit (COT), the drainage of the resist solution is troublesome both in terms of mechanism and maintenance, and thus is preferably arranged in the lower stage. However, it can be arranged in the upper stage as required.
[0025]
As shown in FIG. 3, in the third group G3, an oven-type processing unit that performs a predetermined process by placing the semiconductor wafer W on the mounting table, for example, a cooling unit (COL), an adhesion unit ( AD), alignment unit (ALIM), extension unit (EXT), pre-baking unit (PREBAKE), and post-baking unit (POBAKE). Even in the fourth group G4, an oven-type processing unit, for example, two cooling units (COL) in order from the bottom, an extension cooling unit (EXTCOL), an extension unit (EXT), a pre-baking unit (PREBAKE), and a post Baking units (POBAKE) are stacked.
[0026]
In this way, the cooling units (COL) and (EXTCOL) having a low processing temperature are arranged in the lower stage, and the baking unit (PREBAKE) and the post-baking unit (POBAKE) having a high processing temperature are arranged in the upper stage. Mutual interference can be reduced. However, a random multistage arrangement is also possible.
[0027]
The interface unit 12 has the same dimensions as the processing station 11 in the depth direction, but is made smaller in the width direction. A portable pickup cassette CR and a stationary buffer cassette BR are arranged in two stages on the front surface of the interface unit 12, a peripheral exposure device 23 is disposed on the back surface, and a wafer carrier 24 is disposed on the center. Is provided. The wafer transfer body 24 moves in the X and Z directions to access both cassettes CR and BR and the peripheral exposure device 23. Further, the wafer transfer body 24 is configured to be rotatable in the θ direction, and also to the extension unit (EXT) belonging to the multi-stage unit of the fourth group G4 on the processing station 11 side and the wafer delivery on the adjacent exposure apparatus side. A table (not shown) can also be accessed.
[0028]
Next, processing steps of the coating and developing processing system 1 configured as described above will be described.
[0029]
First, in the cassette station 10, the wafer carrier 21 accesses the cassette CR containing the unprocessed wafer on the cassette mounting table 20, takes out one semiconductor wafer W from the cassette CR, and removes it. Transport to alignment unit (ALIM).
[0030]
The wafer W is aligned by this alignment unit (ALIM), then transferred to the adhesion unit (AD) by the main wafer transfer mechanism 22 and subjected to hydrophobic treatment, and then to the cooling unit (COL). Then, after a predetermined cooling process is performed, it is conveyed to a resist coating unit (COT), where a resist coating process is performed.
[0031]
Next, the wafer W is heated at a predetermined temperature for a predetermined time in a pre-baking unit (PREBAKE). 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 transferred by the wafer transfer body 26, and subjected to exposure processing by an exposure apparatus (not shown) via the interface unit 12.
[0032]
Next, the wafer W is transferred to a development unit (DEV), where development processing is performed, and then heated in a post-baking unit (POBAKE) at, for example, 100 ° C. for a predetermined time. Thereby, 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 group G3.
[0033]
FIG. 4 schematically shows the aforementioned pre-baking unit (PREBAKE) 51 as a substrate heat treatment apparatus. As shown in the figure, the unit 51 includes a main body 41, and a hot plate (plate) 62 is disposed in the approximate center of the main body 41. A heater (not shown) is built in the hot plate 62. The hot 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 that covers the heat plate 62. The lid portion 53, together with the main body 41, constitutes a housing that surrounds the hot plate 62 and forms a heating chamber (heat treatment chamber) S.
[0034]
Although not shown, on the surface of the hot plate 62 on which the wafer W is placed, the hot plate 62 does not adhere to the hot plate 62 at a plurality of locations (for example, six locations) on the outer periphery thereof. Proximity sheets that are floated and held above are arranged.
[0035]
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 the vacuum pump 48 via the exhaust valve 70. . That is, the exhaust port 42, the exhaust valve 70, and the vacuum pump 48 constitute an exhaust unit for exhausting the gas in the heating chamber S.
[0036]
Further, a gas introduction part 53 a for introducing, for example, air from the gas supply source 43 into the heating chamber S is provided in the upper center of the lid part 53. As shown in detail in FIG. 6, the gas introduction part 53 a communicates with a buffer chamber 77 as a relatively large air play space capable of filling a predetermined amount of supplied air, and directly below the buffer chamber 77. And a nozzle hole 79 serving as a gas ejection portion narrower than the buffer chamber 77 that allows the buffer chamber 77 to communicate with the heating chamber S. As described above, if the buffer chamber 77 and the nozzle hole 79 extending directly from the buffer chamber 77 toward the heating chamber S are provided, the air is supplied regardless of the supply direction of the air supplied to the gas introduction portion 53a. Can be made to flow directly into the heating chamber S (air flows in the heating chamber S only in the direction of supply thereof, and one side of the heating chamber S (the side opposite to the air supply direction) You do n’t have the inconvenience of poor spread).
[0037]
The gas (air) from the gas supply source 43 is supplied to the gas introduction part 53 a through the supply pipe 65. In this case, the supply pipe 65 is connected to the housing 80 so as to communicate with the buffer chamber 77 from one side of the gas introduction part 53a. A flow rate adjusting valve 50 and a temperature controller 45 that adjusts the temperature of the air supplied to the heating chamber S are interposed in the supply pipe 65. That is, the gas supply source 43, the supply pipe 65, the valve 50, and the temperature regulator 45 constitute gas supply means for supplying gas into the heating chamber S.
[0038]
The heating chamber S is provided with a pressure gauge 49 for measuring the pressure in the heating chamber S. Based on the measurement result by the pressure gauge 49, the control unit 61 adjusts the opening degree of the valve 50 to adjust the heating chamber S. The pressure of S is adjusted. The temperature controller 45 is also controlled by the control unit 61.
[0039]
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, it is desirable to change the temperature of the air according to the temperature of the hot plate 62 by the temperature controller 45.
[0040]
Further, the unit 51 of the present embodiment heats the two improved rectifying plates (diffusion means) 70 and 72 in order to uniformly spread the air discharged immediately below the nozzle hole 79 over the entire heating chamber S. It has in the room S. Specifically, the two rectifying plates 70 and 72 are arranged vertically in parallel to each other, and divide the heating chamber S into three spaces S1, S2, and S3. As shown in detail in FIG. 5 (a), the upper first rectifying plate 70 allows air discharged from the nozzle hole 79 to flow to the surroundings without flowing directly below, so that the center of the first rectifying plate 70 facing the nozzle hole 79 is opposed. It has a holeless region 74 in the part, and has a number of holes 70 a around the holeless region 74. In other words, the first rectifying plate 74 is not provided with a hole 70 a only in a predetermined region (region facing the nozzle hole 79) 74 in the central portion thereof. In this case, if the diameter of the first rectifying plate 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 non-hole region 74 is set to 80 mm. This dimension depends on the flow rate of the supplied air. On the other hand, as shown in FIG. 5 (b), the lower second rectifying plate 72 has a large number of holes 72a throughout.
[0041]
Further, in the present embodiment, the air circulated around the non-hole area 74 of the first rectifying plate 70 is turned directly under the non-hole area 74 and further spread to the circumference to be uniformly in the heating chamber S. In order to diffuse, the nozzle holes 79, the rectifying plates 70 and 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. The hole 70a of the current plate 70 and the hole 72a of the second current plate 72 are prevented from overlapping as much as possible in the vertical direction. Specifically, the distance L1 between the opening of the nozzle hole 79 and the first rectifying plate 70 is 3 mm, the distance L2 between the first rectifying plate 70 and the second rectifying plate 72 is 8 mm, and the second The distance L3 between the current plate 72 and the wafer W is set to 7 mm (see FIG. 4), and the hole 70a of the first current plate 70 and the hole 72a of the second current plate 72 are vertically as low as possible. A large number of holes 70a of the first rectifying plate 70 are arranged radially around the holeless region 74 (see FIG. 5A) so as not to overlap, and a large number of holes of the second rectifying plate 72 are provided. 72a are arranged in a grid pattern (see FIG. 5B), the diameter of the hole 70a of the first rectifying plate 70 is set to 1 mm, and the diameter of the hole 72a of the second rectifying plate 72 is set to 1 mm. It is set to 2 mm (the diameter of the second rectifying plate is 345.5 mm). That is, the size of the hole is set to be larger in the second rectifying plate 72 than in the first rectifying plate 70 (in this embodiment, twice).
[0042]
Next, the operation of the pre-baking unit 51 having the above configuration will be described.
[0043]
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 placed on the hot plate 62 by the main wafer transfer mechanism 22 with the lid 53 raised. Thereafter, the lid 53 is lowered to form the heating chamber S, and the wafer W is heated to a predetermined temperature, for example, 140 ° C. by the hot plate 62 and maintained at the temperature of 140 ° C. for a predetermined time. As a result, the residual solvent is removed by evaporation from the coating film on the wafer W.
[0044]
Further, in this pre-baking process, in order to prevent the sublimate from the resist from condensing again and adhering to the surface of the resist, or from the resist, the sublimate from the resist adheres to the rectifying plates 70 and 72. Heat treatment is performed while discharging a solvent (volatile component) or the like filling the inside of S to the outside. That is, air is supplied from one side to the gas introduction part 53 a through the supply pipe 65 from the gas supply source 43. The air supplied to the gas introducing portion 53 a is once filled in the buffer chamber 77, then discharged from the nozzle hole 79 directly below, and reflected by the non-hole region 74 of the first rectifying plate 70 while being subjected to the first rectification. Along the plate 70, the first space S1 flows around. The air that spreads around in the first space S <b> 1 is then formed between the first rectifying plate 70 and the second rectifying plate 72 through the hole 70 a of the first rectifying plate 70. It flows in S2. At this time, since the distance L2 between the first rectifying plate 70 and the second rectifying plate 72 is large, the air also goes directly under the holeless region 74. As a result, the air spreads uniformly in the second space S2. Further, the uniformly diffused air flows into the third space S3 where the hot plate 62 and the wafer W exist through the holes 72a of the second rectifying plate 72, and is blown to the surface of the wafer W, and in the heating chamber. The solvent evaporated from the resist solution on the wafer W in S (third space S3) is discharged to the outside through an exhaust port 42 provided around the hot plate 62.
[0045]
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 secure a predetermined process performance (process reaction), it is not desirable to supply and discharge air during the heat treatment. This is because air temperature may change during processing due to supply and discharge of air.
[0046]
As shown in the figure, the ON / OFF timing of air purge / exhaust, that is, the opening / closing timing of the valve 50 by the control unit 61 is related to the temperature (bake time) of the wafer W. For example, when the bake time is set to 90 seconds, in the first sequence (lower arrow in FIG. 7) in which the air purge / exhaust is turned ON in the first half of the heat treatment, the first 30 seconds (in the first 20 seconds or so) Air purge / exhaust is performed only when the temperature of the wafer W reaches a predetermined temperature (140 ° C.). In this case, the air flow rate is set to 4 liters / minute m in order to effectively purge the sublimate. However, considering the process performance, it is desirable to reduce the flow rate. On the other hand, in the second sequence (upper arrow in FIG. 7) in which the air purge / exhaust is turned on in the latter half of the heat treatment, the air purge / exhaust is performed in the last 30 seconds, that is, 60 seconds to 90 seconds after the heat treatment starts. Exhaust is performed. In this case, the air exhaust flow rate 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 the second sequence is better in consideration of the line width, and the first sequence is better in consideration of the sublimation.
[0047]
In addition, by supplying and discharging such air, the solvent component volatilized 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 temperature in the heating chamber S The distribution is also made uniform. Thereby, the occurrence of processing unevenness on the surface of the wafer W is prevented. That is, the air (purge gas) is uniformly diffused from top to bottom according to the above-described novel form, so that the sublimate rising from the wafer W is cooled and crystallized before being crystallized. In addition to purging the heating chamber S in advance, not only prevents the sublimate from adhering to the rectifying plates 70 and 72, but also process performance (the film thickness of the resist film on the wafer and the pattern line after development). Promote uniformization of width. That is, when a desired air flow is generated in the heating chamber S by air and a solvent atmosphere / acid atmosphere is purged by a predetermined amount, the inside of the heating chamber S is stirred in a desired state during the baking process, and the wafer W is moved within the surface. The resist component volatilization in the heating chamber S is improved, the saturation amount of the solvent / acid in the heating chamber S can be controlled (saturation concentration can be made constant), and the film quality can be controlled (the film can be made uniform). Can be done. In addition, as a means to stir the inside of the heating chamber S, moving the top plate (it may be a baffle plate) installed in the heating chamber S up and down, or rotating is also considered.
[0048]
As described above, the operational effects described above are provided with the buffer 77 and the non-hole region 74, and the nozzle hole 79, the rectifying plates 70 and 72, and the wafer W are arranged at a specific distance, and the rectifying plates 70 and 72 It is obtained by improving the arrangement and dimensions of the holes. And such an effect is clear also from the experimental data shown by FIGS. These data were performed under the following conditions.
(conditions)
Air supply 3 liters / minute
Current plate diameter 345.5 mm
Hole diameter of the first baffle plate 1 mm
Hole diameter of the second baffle plate 2 mm
FIG. 8 shows the relationship between the resist film thickness at each temperature of the hot plate 62 and the baking time. In the figure, the black circle plot indicates that the temperature of the hot plate 62 is 50 ° C., the white circle plot indicates that the temperature of the hot plate 62 is 70 ° C., and the white triangle plot indicates that the temperature of the hot plate 62 is 90 ° C. The white square plot indicates that the temperature of the hot plate 62 is 110 ° C., and the x plot indicates that the temperature of the hot plate 62 is 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 uniformly throughout the processing time.
[0049]
FIG. 9 shows the influence of the distance between the nozzle hole 79, the current plates 70 and 72, and the wafer W on the line width (CD). In the figure, the measurement points 0 to 48 on the horizontal axis are 24 points on a radial line (line passing through the center of the wafer W) l passing through the notch N for alignment of the wafer W, as shown in FIG. At equal intervals (see (b) of FIG. 11), 24 points are equally spaced on the diameter line m orthogonal to the diameter line l, and each point is set as 1 to 48. In the embodiment, the points on the radial line m are 1 to 24, and the points on the radial line l are 25 to 48. In FIG. 9, the solid line plot indicates that the distance L1 between the opening of the nozzle hole 79 and the first rectifying plate 70 is 3 mm, and the first rectifying plate 70 and the second rectifying plate 72 as described above. Is a data when the distance L2 between the second straightening plate 72 and the wafer W is set at 7 mm, and the broken line plot shows the opening of the nozzle hole 79 and the first straightening. The distance L1 between the plates 70 is 3 mm, the distance L2 between the first current plate 70 and the second current plate 72 is 4 mm, and the distance L3 between the second current plate 72 and the wafer W is 7 mm. Data when set to. As can be seen from these data, according to the distance setting (solid line) of 3-8-7 of the present embodiment, the line width ( CD) is maintained substantially uniform. On the other hand, in the data indicated by the broken line, since the distance between the first rectifying plate 70 and the second rectifying plate 72 is not sufficiently secured, the air is uniformly distributed in the second space S2. Since the air does not diffuse and air does not sufficiently flow directly under the holeless region 74, the line width varies greatly depending on the position on the wafer W.
[0050]
FIG. 10 shows the influence of the presence / absence of the holeless region 74 and the diameter of the holeless region 74 on the line width (CD). In the figure, the solid rhombus plot is for the case where the holeless region 74 is not provided (no block), and the solid square plot is for the case where the diameter of the holeless region 74 is set to 80 mm. Yes, a solid white circle plot is obtained when the diameter of the holeless region 74 is set to 100 mm, and a dashed rhombus plot is obtained when the diameter of the holeless region 74 is set to 120 mm. Also, in the figure, how to take the measurement points 0 to 48 on the horizontal axis is the same as in FIG. As can be seen from this figure, when a holeless region 74 is provided in the center of the first rectifying plate 70 and the diameter of the holeless region 74 is set to 80 mm (the diameter of the first rectifying plate 70 and the nozzle holes 79). The line width (CD) uniformity is best. In addition, in the case where the non-hole region 74 is not provided, or. The greater the diameter of the holeless region 74, the worse the line width uniformity.
[0051]
As described above, according to the rectifying mechanism of the unit 51 of the present embodiment, the gas in the heating chamber S can be replaced uniformly and in large quantities without forming a dead space in the first half or the second half of the heat treatment. Can do. That is, the substitution efficiency of the sublimate can be remarkably improved as compared with the conventional case, and the process performance can be greatly improved.
[0052]
Needless to say, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, the present invention is applied to the pre-baking unit 51, but the present invention can be applied to all other heat treatment apparatuses. In the above-described embodiment, air is used as the purge gas. However, various gases such as nitrogen and inert gas can be used as the purge gas depending on the situation. In the embodiment described above, a plurality of fins 90 are provided in the buffer chamber 77 as shown in FIG. 12, and the flow path from the supply pipe 65 to the nozzle hole 79 is lengthened as shown by the arrows in the figure. You may do it. As a result, the air supplied to the gas introducing portion 53a is stirred in the buffer chamber 77, and a stable amount of air can be discharged from the nozzle hole 79 directly below it.
[0053]
In the above embodiment, the case where a semiconductor wafer is used as the substrate to be processed has been described. However, 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 mask may be used. .
[0054]
【The invention's effect】
As described above, according to the substrate heat treatment apparatus, the rectifying mechanism, and the rectifying method of the present invention, the purge gas can be uniformly supplied into the processing space to improve the process performance.
[Brief description of the 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.
FIG. 3 is a rear view of the substrate processing system of FIG. 1;
FIG. 4 is a schematic cross-sectional view of a substrate heat treatment apparatus according to an embodiment of the present invention.
5A is a plan view of a first current plate provided in the substrate heat treatment apparatus of FIG. 4, and FIG. 5B is a plan view of a second current plate provided in the substrate heat treatment apparatus of FIG.
6A is an operation explanatory view of a rectifying mechanism provided in the substrate heat treatment apparatus of FIG. 4, and FIG. 6B is a cross-sectional view of a gas introduction part constituting the rectifying mechanism of FIG.
7 is experimental data demonstrating the function and effect of the substrate heat treatment apparatus of FIG.
8 is experimental data demonstrating the function and effect of the substrate heat treatment apparatus of FIG.
9 is experimental data demonstrating the function and effect of the substrate heat treatment apparatus of FIG.
10 is experimental data demonstrating the function and effect of the substrate heat treatment apparatus of FIG.
11 is a diagram for explaining how to take measurement points on a substrate in the experimental data of FIGS. 9 and 10. FIG.
FIG. 12 is a schematic view showing a modification of the gas introduction unit.
FIG. 13 is a schematic view showing the flow of purge gas in a conventional substrate heat treatment apparatus.
[Explanation of symbols]
41 ... Body
51 ... Pre-baking unit
53 ... Cover
53a ... Gas introduction part
62 ... Hot plate
70 ... 1st baffle plate (diffusion means)
72. Second rectifying plate (diffusion means)
77 ... Buffer room
79 ... Nozzle hole (gas ejection part)
S ... Heating room (heat treatment room)
W ... Board

Claims (11)

In a substrate heat treatment apparatus for performing heat treatment on a substrate,
A plate for mounting and heat-treating the substrate;
A housing surrounding the plate to form a heat treatment chamber;
Gas supply means for supplying a purge gas into the heat treatment chamber;
Exhaust means for exhausting the gas in the heat treatment chamber;
A gas introduction part provided in the housing for receiving the gas from the gas supply means and introducing the gas into the heat treatment chamber;
A diffusion means provided in the casing and uniformly diffusing the gas from the gas introduction part in the heat treatment chamber;
The gas introduction unit includes a buffer chamber capable of filling a supplied gas with a predetermined amount, and a gas ejection unit for flowing the gas in the buffer chamber directly toward the heat treatment chamber ,
The diffusion means is composed of two rectifying plates that are arranged in parallel with each other in the casing and 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 flow holes except for the central region facing the gas ejection part,
A substrate heat treatment apparatus characterized in that a plurality of gas flow holes are provided in the entire second rectifying plate located on the lower side . The substrate heat treatment apparatus according to claim 1,
The gas flow hole of the first rectifying plate is not provided with a hole so that the gas flow hole of the first rectifying plate and the gas flow hole of the second rectifying plate do not overlap each other. A substrate heat treatment apparatus characterized in that the gas flow holes of the second rectifying plate are arranged in a lattice pattern while being arranged radially around a central region. In the substrate heat treatment apparatus according to claim 1 or 2 ,
The substrate heat treatment apparatus, wherein a diameter of a gas flow hole of the second rectifying plate is larger than a diameter of a gas flow hole of the first rectifying plate . In the substrate heat treatment apparatus according to any one of claims 1 to 3 ,
The apparatus further includes a control unit that controls supply of gas from the gas supply unit to the gas introduction unit, and the control unit supplies gas to the gas introduction unit at an initial stage of heat treatment of the substrate by the plate. Substrate heat treatment apparatus. In a substrate heat treatment apparatus for performing heat treatment on a substrate,
A plate for mounting and heat-treating the substrate;
A housing surrounding the plate to form a heat treatment chamber;
Gas supply means for supplying a purge gas into the heat treatment chamber;
Exhaust means for exhausting the gas in the heat treatment chamber;
A gas introduction part provided in the housing for receiving the gas from the gas supply means and introducing the gas into the heat treatment chamber;
A diffusing means provided in the housing for uniformly diffusing the gas from the gas introduction section in the heat treatment chamber;
A control unit for controlling the supply of gas from the gas supply means to the gas introduction unit ,
The substrate heat treatment apparatus, wherein the control unit supplies gas to the gas introduction unit at a later stage of heat treatment of the substrate by the plate. The substrate heat treatment apparatus according to claim 5,
The diffusion means is composed of two rectifying plates that are arranged in parallel with each other in the casing and 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 flow holes except for the central region facing the gas ejection part,
A substrate heat treatment apparatus characterized in that a plurality of gas flow holes are provided in the entire second rectifying plate located on the lower side. The substrate heat treatment apparatus according to claim 6,
The gas flow hole of the first rectifying plate is not provided with a hole so that the gas flow hole of the first rectifying plate and the gas flow hole of the second rectifying plate do not overlap each other. A substrate heat treatment apparatus characterized in that the gas flow holes of the second rectifying plate are arranged in a lattice pattern while being arranged radially around a central region. In the substrate heat treatment apparatus according to claim 6 or 7,
The substrate heat treatment apparatus, wherein a diameter of a gas flow hole of the second rectifying plate is larger than a diameter of a gas flow hole of the first rectifying plate. In the rectifying mechanism for rectifying the purge gas supplied into the substrate heat treatment apparatus for performing heat treatment on the substrate,
A gas introduction unit that is provided in a housing of the substrate heat treatment apparatus, receives a supplied gas, and introduces the gas into a heat treatment chamber of the substrate heat treatment apparatus;
A diffusion means provided in the casing and uniformly diffusing the gas from the gas introduction part in the heat treatment chamber;
The gas introduction unit includes a buffer chamber capable of filling a supplied gas with a predetermined amount, and a gas ejection unit for flowing the gas in the buffer chamber directly toward the heat treatment chamber ,
The diffusing means includes two rectifying plates which are arranged in parallel with each other in the casing and divide the heat treatment chamber into three spaces. The first rectifying plate located on the upper side is the gas Except for the central region facing the ejection part, 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. The characteristic rectification mechanism. The rectifying mechanism according to claim 9, wherein
The gas flow hole of the first rectifying plate is not provided with a hole so that the gas flow hole of the first rectifying plate and the gas flow hole of the second rectifying plate do not overlap each other. A rectifying mechanism characterized in that the gas flow holes of the second rectifying plate are arranged in a lattice shape while being arranged radially around a central region. In the rectifying mechanism according to claim 9 or 10,
The diameter of the gas flow hole of the second current plate is larger than the diameter of the gas flow hole of the first current plate .

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