JP3247976B2 - Heat treatment equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment apparatus for supplying heat to an object placed on a heating element to perform processing.

[0002]

2. Description of the Related Art Generally, in a semiconductor device manufacturing process, a circuit pattern is reduced and transferred to a photoresist by using a photolithography technique, and this is developed and subjected to an appropriate heat treatment.

In performing such processing, a processing system shown in FIG. 7 is used. This processing system includes a semiconductor wafer W (hereinafter, referred to as a wafer) as an object to be processed.
Loader unit 40 for loading and unloading wafers, brush cleaning device 42 for brush cleaning wafer W, jet water cleaning device 44 for cleaning wafer W with high-pressure jet water, and adhesion treatment device for hydrophobizing the surface of wafer W 46, a cooling processing device 48 for cooling the wafer W to a predetermined temperature, and a resist coating device 50 for coating a resist on the surface of the wafer W
In addition, a heat treatment device 52 for heating the wafer W before and after resist coating to perform pre-baking or post-baking, a developing device 54 for developing the wafer W, and the like are integrally assembled to improve work efficiency.

A wafer transfer path 56 is provided along the longitudinal direction at the center of the processing system configured as described above, and each of the devices 40 to 54 is disposed on the wafer transfer path 56 so as to face the front. , The wafer carrier 58 is connected to each of the devices 40 to 54.
The wafer W can be moved on the wafer transfer path 56 to transfer the wafer W.

[0005] The heat treatment apparatus 52 includes a wafer transfer path 5.
Numerous heat treatment devices 5 having openings 52A facing the side 6
2 are provided as one block body stacked in multiple stages, and a plurality of block bodies are juxtaposed. And
As shown in FIG. 8, for example, each heat processing apparatus 52 includes a heating plate 60 serving as a mounting table for mounting the wafer W, a heating element 62 for supplying heat to the wafer W via the heating plate 60, and a heating plate. The wafer W is inserted through a cover member 66 for exhausting gas generated during the heat treatment, a hot plate 60 and a through hole 68 formed in the heating element 62, while being arranged to form a processing space 64 above the wafer W. Support pin 70 for transferring the heat on hot plate 60
And the main part is constituted. In this case, the hot plate 60 and the heating element 62 are fixed, and the support pins 70 are connected to the pistons 78 of the support pin elevating cylinder 76 so as to be able to protrude and retract on the hot plate 60. A cylindrical shutter 80 is provided on the outer periphery of the hot plate 60 so as to be able to move up and down. The shutter 80 is connected to a piston 84 of a shutter elevating cylinder 82 to partition the processing space 64 from the outside. I am getting it.

[0006]

However, in a conventional heat treatment apparatus of this type, if a heat treatment is performed after the application of a resist solution containing a large amount of a solvent or an additive (hereinafter referred to as a solvent or the like), the solvent evaporated by the heating is removed. The cover member 66
The solvent adheres to the cover member 66 and condenses and dries to form particles, which drop onto the surface of the wafer W, thereby lowering the product yield. There was a problem.

Further, since the lower surface of the wafer W is heated and the air is exhausted from the upper center of the cover member 66, the accuracy of the temperature distribution on the surface of the hot plate 60 is not sufficient, and the accuracy of the in-plane film thickness of the wafer W is reduced. There was also the problem of lowering. Further, when heating only from the back surface of the wafer W, the surface of the resist film and the portion near the surface are less likely to dry than the portion near the surface of the wafer W. Therefore, as shown in FIG. There is also a problem that the resist pattern P is melted at the time of development to lower the accuracy of the circuit pattern.

The present invention has been made in view of the above circumstances, and reduces generation of particles on an object to be processed, improves a product yield, and improves uniformity of heating processing and heating accuracy. An object of the present invention is to provide a heat treatment apparatus capable of improving the heat treatment.

[0009]

In order to achieve the above object, a heat treatment apparatus according to the present invention is directed to a heat treatment apparatus for heating and processing an object to be processed. And a second heating element disposed above the first heating element, and forming a processing section of a sealed space with the first heating element, and a side of the processing target in the processing section. Gas supply means for supplying a purge gas from above to above the object to be processed,
An annular exhaust passage formed in the outer peripheral portion of the sealed space to exhaust the inside of the processing section from above the object to be processed and increasing pressure loss, and an exhaust port provided in the annular exhaust passage. And an exhaust mechanism provided.

In the present invention, the temperature of the second heating element is a temperature not lower than the temperature at which the solvent of the resist which evaporates due to the heating of the first heating element does not adhere and not higher than the heating temperature of the first heating element. Is more preferable.

The annular exhaust passage is formed by an upper ring member having a hanging wall and a lower ring member having an upright wall. The hanging wall and the upstanding wall define a sealed space and the inside of the annular exhaust passage. It is preferable to form an annular bypass passage therebetween.

Further, one of the first heating element and the second heating element is formed so as to be able to advance and retreat with respect to the other, so that the gap between the first heating element and the second heating element can be adjusted. Alternatively, the temperature between the first heating element and the second heating element is detected by the temperature detecting means, a signal from the temperature detecting means is transmitted to the temperature controlling means, and the temperature is controlled by the temperature controlling means. It is also possible to control the heating temperature of the object to be processed by controlling the temperature of the heating means of the heating element based on the signal subjected to the arithmetic processing.

[0013]

According to the heat treatment apparatus of the present invention configured as described above, the first heating element on which the object to be processed is placed, and the first heating element disposed above the first heating element and having the first heating element A second heating element that forms a processing unit in a sealed space between the processing unit and a gas supply unit that supplies a purge gas from above the processing object in a side of the processing object in the processing unit; Formed in the outer periphery of the sealed space to exhaust the processing unit from
By providing an annular exhaust passage to be increased, and an exhaust mechanism having an exhaust port provided in the annular exhaust passage, heat treatment can be performed from both the front and back surfaces of the object to be processed, and the resist evaporated by heating can be removed. It is possible to prevent the solvent or the like from condensing and adhering to the inner surface of the cover located above the object to be processed in a dew-condensed manner. Therefore, the generation of particles can be reduced, and the yield of products can be improved by preventing attachments from falling onto the surface of the object to be processed. Further, by supplying the purge gas from above the object to be processed from the side of the object to be processed in the processing section (closed space), the airflow in the closed space can be made laminar, and the purge gas and the exhaust amount can be reduced. Can be changed, so that the heat treatment of the surface of the object to be processed can be made uniform, and the film thickness of the surface of the object to be processed can be made uniform. Further, since the gas is uniformly exhausted by the annular exhaust passage, it is possible to prevent the film thickness formed on the object to be processed from being partially increased. Further, by forming an annular bypass passage between the sealed space and the inside of the annular exhaust passage, the pressure loss of the exhaust can be increased, so that the exhaust in the sealed space can be performed more uniformly over the entire circumference. Can be.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. Here, a description will be given of a case where the heat treatment apparatus of the present invention is applied to the heat treatment apparatus used in the semiconductor wafer coating and developing apparatus shown in FIG.

First Embodiment FIG. 1 is a schematic perspective view of a heat treatment apparatus of the present invention, FIG. 2 is a plan view showing a part of the heat treatment apparatus in a cross section, and FIG. 3 is a side view showing a part of the heat treatment apparatus in a cross section. ing.

In the heat treatment apparatus of the present invention, a mounting table 10 having a built-in heater 11 as a heating means, which is a first heating element for mounting an object to be processed, eg, a wafer W, faces the mounting table 10 with respect to the wafer W. A heat-generating plate 12 having a flat surface and a temperature-controllable opposing surface, which includes a second heating element disposed at an upper position, for example, a heater 13 as a heating means, and a cover 14 having the heat-generating plate 12 mounted on the inner surface. The main part is configured.

In this case, the wafer W penetrates the mounting table 10 and can be separated from the mounting table 10 while being supported by a plurality of (for example, three) support pins 16 which are moved up and down by an elevating mechanism (not shown). Further, it is supported by, for example, three proximity pins 16A buried on the mounting table 10, and is mounted on the mounting table 10 with a gap of about 0.3 mm. Further, a processing space (processing section) between the mounting table 10 and the heat generating plate 12 is a sealed space 18 that is shielded from the outside air, and an outer circumference of the sealed space 18 has an annular exhaust passage forming an exhaust mechanism. 20 are provided. Exhaust ports 22 are provided at four locations in the annular exhaust passage 20 (see FIG. 4), and an exhaust duct 26 is connected to the exhaust port 22 via an exhaust pipe 24, and the exhaust port 22 communicates with the exhaust duct 26. The inside of the sealed space 18 can be evacuated by driving a vacuum pump (exhaust device) which is not used. Thus, by providing the exhaust mechanism on the outer peripheral portion of the sealed space 18 (processing section), the inside of the sealed space 18 (processing section) can be exhausted from above the wafer W in the sealed space 18.

The annular exhaust passage 20 is formed by upper and lower ring members 20a and 20b made of, for example, aluminum whose surface is toughened and fixed to the cover 14 side. An annular bypass passage 20e having a narrow interval is formed between the sealed space 18 and the inside of the annular exhaust passage 20 by the hanging wall 20c provided and the upright wall 20d provided on the lower ring member 20b to reduce the pressure loss of the exhaust. The exhaust in the sealed space 18 can be uniformly performed over the entire circumference. In the figure, reference numeral 28 is a sealing member made of, for example, a fluororesin.

A supply pipe 30 (gas supply means) for a purge gas such as nitrogen (N 2) gas is inserted into the sealed space 18 from the side of the sealed space 18 (processing section). An N2 gas as a purge gas is supplied above the wafer W (see FIG. 4).
As described above, by discharging the N2 gas or air at a constant flow rate, the airflow in the sealed space 18 is made laminar, and the thermal effect on the wafer W can be reduced. Further, the balance between the amount of N2 gas or air and the amount of exhaust gas is changed, and the wafer W
The conditions for minimizing the thermal effect on the surface can be set, and the discharge and exhaust can be performed under those conditions. The supply of the N2 gas is used, for example, in order to prevent uneven baking at the time of baking when applying non-photosensitive PIQ (polyimide). For photosensitive PIQ, air is used.

On the other hand, the cover 14 is mounted on a mounting plate 32d which is mounted on an intermediate portion of a pair of rotating arms 32c which are rotatably mounted on a pair of brackets 32a standing on the side of the apparatus main body 32 with pivot pins 32b. It is attached via a fixing screw 32e and a level adjusting screw 32f, and the level of the cover 14, that is, the heat generating plate 12 with respect to the mounting table 10 can be adjusted by adjusting the level adjusting screw 32f. Thus, the level adjusting screw 32
By adjusting the horizontality of the heat generating plate 12 by f, the bias of the heating temperature from above the wafer W is prevented, uniform heating is possible over the entire surface of the wafer W, and the resist film thickness can be made uniform. During normal use, the cover 14 is fixed to the apparatus main body 32 by a clamp 32g. When the cover 14 is opened during maintenance, the clamp 32g is released from the fastening state, and then the rotating arm 32c is opened.
Cover 1 with lever 32h connected to the tip of
4 can be pivoted upward to open the sealed space 18. In addition, a shutter mechanism (not shown) is provided in the apparatus main body 32, and opens and closes the opening 52 </ b> A when the wafer W is loaded and unloaded.

Next, the operation of the heat treatment apparatus of the present invention configured as described above will be described. Here, the heat treatment (prebaking) of the wafer W after the application of the resist will be described.

First, the wafer W after resist application is held by the wafer carrier 58, and the wafer W is carried to a fixed position above the mounting table 10 through the opening 52A. After the wafer W is supported and received at its leading end and the wafer carrier 58 is retracted, the opening 52A is closed and the wafer W is placed on the mounting table 10 in the sealed space 18 (processing space). In this state, a purge gas is supplied from the supply pipe 30 above the wafer W, and is also supplied into the sealed space 18 and the inside of the sealed space 18 is replaced with N2 gas. The front and back surfaces of the wafer W are heated by the heat from the heater 11 of the mounting table 10 whose driving has been adjusted and the heater 13 of the heat generating plate 12 whose driving has been adjusted to a predetermined temperature, for example, 100 ° C. in advance. At this time, since the vacuum pump provided in the exhaust duct 26 operates, the air used for the heat treatment in the sealed space 18 is uniformly exhausted from above the wafer W toward the bypass passage 20e, and the annular exhaust is performed. After flowing into the passage 20, the exhaust port 2
2 is exhausted by flowing through an exhaust duct 26 via an exhaust pipe 24. Therefore, the solvent and other generated gases of the resist applied to the surface of the wafer W evaporated by the heating process do not condense because the heating plate 12 is heated to a high temperature, and are not heated. Detour passage 20 at
e. Therefore, the condensation in the sealed space 18 can be prevented, and the gas is exhausted from the annular exhaust passage 20 without adhering to the cover 14 in the form of condensation. Even if dew forms, the dew forms on the side of the annular exhaust passage 20 and is discharged, so that there is no possibility that the particles fall on the wafer W. Furthermore, since the gas is uniformly exhausted, the one-sided phenomenon that the film thickness is partially increased due to uneven exhaust gas flow can be prevented.

Second Embodiment FIG. 5 is a sectional view of a heat treatment apparatus according to a second embodiment of the present invention. In the second embodiment, the heating temperature of the wafer W in the sealed space 18 is controlled so that the film thickness on the surface of the wafer W can be further made uniform. That is, the spacer 31 is replaceable with the cover 14 which is attached to the elevating arm 29a, which is provided to be able to elevate and lower by the elevating cylinder 29, with the fixing screw 32e and the level adjusting screw 32f.
The heating plate 12 is attached to the mounting table 10 according to the height H of the spacer 31 and is adjusted to a constant temperature.
The gap S between the two can be adjusted arbitrarily (specifically, 2 to 40 m
m), the gap S between the mounting table 10 and the heating plate 12 is adjusted to control the heating temperature of the wafer W. In this case, a height adjusting mechanism (not shown) may be provided instead of the spacer 31 so that the height can be adjusted automatically or manually. Furthermore, by controlling the adjusting mechanism, for example, the timing of ascending and descending, the distance and speed of ascending and descending, the number of times of ascending and descending may be arbitrarily operated according to the type of the resist.

In the heat treatment apparatus shown in FIG. 5, a punching hole 33a for introducing outside air is formed in an upper portion of the side wall 33 of the apparatus main body 32, and an intermediate portion of the side wall 34 facing the punching hole 33a. Is provided with an exhaust port 35. Further, a heat insulating plate 36 is attached to an upper side of the apparatus main body 32.

In the second embodiment, other parts are the same as those in the first embodiment, and the same parts are denoted by the same reference characters and description thereof will be omitted. Further, in the second embodiment, the heating plate 12 is formed so as to be able to move forward and backward with respect to the mounting table 10. However, the heating plate 12 is fixed and the mounting table 10 is formed so as to be able to move forward and backward with respect to the heating plate 12. May be.

As described above, by controlling the heating temperature of the wafer W in the sealed space 18 by arbitrarily adjusting the distance between the mounting table 10 and the heating plate 12, the upper layer of the circuit pattern on the surface of the wafer W can be controlled. The heat treatment of the portion and the lower layer portion can be performed equally, and the accuracy of the circuit pattern on the surface of the wafer W can be improved.

Next, in the heat treatment apparatus of the second embodiment, the cover 1 is changed by arbitrarily changing the gap between the mounting table 10 and the heating plate 12.
The results of an experiment conducted on contamination of No. 4 (heating plate 12), that is, the degree of resist adhesion will be described.

The temperature of the mounting table 10 is set to 140 ° C.
Temperature of the heating plate 12: 23 ° C. (actual value: 50 ° C.) to 14 ° C.
Experiments were conducted on the degree of resist adhesion of the 100 wafers W after the heat treatment to the heating plate 12 in a range of 0 ° C. and a gap between the mounting table 10 and the heating plate 12 of 10 mm to 35 mm. The result as shown in FIG. In the experiment, the case where air was exhausted from the center of the cover 14 and the case where air was not exhausted were performed.

[0029]

[Table 1]

As a result of the above experiment, in Comparative Example 1, a rectangular crystal was observed on the photograph, and the tendency was particularly noticeable in the vicinity of the exhaust port. In Comparative Example 2, although not confirmed in the photograph, when the surface of the heat generating plate 12 was wiped off with a bencot (a kind of dustproof cloth) moistened with alcohol, the resist was slightly adhered. It is considered that this occurred because the gap between the mounting table 10 and the heat generating plate 12 was wide, so that the exhaust efficiency was reduced. In Comparative Examples 3 to 5, rectangular type crystals were observed on the photographs, and adhesion in the vicinity of the center of the heating plate 12 was particularly frequently observed. However, this tendency can be eliminated by increasing the temperature of the heating plate 12. In Comparative Example 5, although crystals could not be confirmed, it was confirmed by wiping inspection that Bencot was slightly yellow. In contrast, Examples 1 to
In the case of No. 3, there was no particular problem in the wiping inspection and the microphotograph judgment. Therefore, the temperature of the mounting table 10 is set to 1
When the temperature is set to 40 ° C. and the temperature of the heat generating plate 12 is set to 100 to 140 ° C., by setting the gap between the mounting table 10 and the heat generating plate 12 to be 10 mm, the adhesion of the resist to the heat generating plate 12 can be prevented.

The above experiment is an example. When the temperature of the mounting table 10 and the heating plate 12 is changed, the gap between the mounting table 10 and the heating plate 12 is adjusted so that the resist adheres to the surface of the heating plate 12. What is necessary is just to set an optimal gap for preventing the above.

Third Embodiment FIG. 6 is a schematic sectional view of a heat treatment apparatus according to a third embodiment of the present invention.

In the third embodiment, the distance between the heating plate 12 and the mounting table 10 is fixed, and the temperature of the heating plate 12 itself is controlled to an arbitrary predetermined temperature so that the film thickness on the surface of the wafer W can be made uniform. This is the case. That is, a temperature detecting means, for example, a thermocouple 37 is inserted into the sealed space 18 through the heating plate 12 to detect the temperature between the mounting table 10 and the heating plate 12, and a detection signal from the thermocouple 37 is converted into a temperature. To the temperature controller 38 which is a control means, and
This is a case where the heater power supply 39 is driven based on a control signal arithmetically processed by the temperature controller 38 to control the temperature of the heater 13 of the heating plate 12.

Since the other parts of the third embodiment are the same as those of the first and second embodiments, the same parts are designated by the same reference numerals and their description is omitted.

Therefore, by controlling the heating temperature of the wafer W in the sealed space 18 by controlling the heating temperature of the heating plate 12 as described above, the upper and lower circuit portions of the circuit pattern on the surface of the wafer W are formed. The heat treatment can be performed equally, and the accuracy of the circuit pattern on the surface of the wafer W can be improved.

In the above embodiment, the case where the heat treatment apparatus of the present invention is applied to a semiconductor wafer coating and developing apparatus has been described. However, the present invention is not limited to this apparatus and can be applied to a heat processing apparatus other than the coating and developing apparatus. Of course, the present invention can also be applied to heat treatment of an object other than a semiconductor wafer, such as an LCD glass substrate or a CD.

[0037]

As described above, according to the heat treatment apparatus of the present invention, since it is configured as described above, the following effects can be obtained.

Heat treatment can be performed from both the front and back surfaces of the object to be processed, and it is possible to prevent the solvent and the like of the resist evaporated by heating from adhering to the inner surface of the cover located above the object to be condensed. In addition, the generation of particles can be reduced, and the yield of products can be improved by preventing attachments from falling onto the surface of the object to be processed. Further, by supplying the purge gas from above the object to be processed from the side of the object to be processed in the processing section (closed space), the airflow in the closed space can be made laminar, and the purge gas and the exhaust amount can be reduced. Can be changed, so that the heat treatment of the object surface can be uniform,
The thickness of the surface of the object to be processed can be made uniform. Also,
Since the exhaust gas is uniformly exhausted by the annular exhaust passage, it is possible to prevent the film thickness formed on the object to be processed from being partially increased.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a heat treatment apparatus of the present invention.

FIG. 2 is a plan view showing a cross section of a part of the heat treatment apparatus.

FIG. 3 is a side view showing a part of the heat treatment apparatus in cross section.

FIG. 4 is an enlarged sectional view showing a sealed space and an annular exhaust passage according to the present invention.

FIG. 5 is a sectional view of a heat treatment apparatus according to a second embodiment of the present invention.

FIG. 6 is a sectional view of a heat treatment apparatus according to a third embodiment of the present invention.

FIG. 7 is a perspective view showing a processing system to which the heat treatment apparatus of the present invention is applied.

FIG. 8 is a sectional view of a main part of a conventional heat treatment apparatus.

FIG. 9 is an explanatory view showing a heat treatment state by a conventional heat treatment.

[Explanation of symbols]

 Reference Signs List 10 Mounting table 11 Heater 12 Heating plate (heating body) 13 Heater 14 Cover 18 Sealed space 20 Annular exhaust passage 22 Exhaust port 29 Elevating cylinder 30 Supply pipe (gas supply means) 31 Spacer 37 Thermocouple (temperature detection means) 38 Temperature controller (Temperature control means) 39 Heater power supply W Semiconductor wafer (workpiece) H Spacer height S Gap between mounting table and heating plate

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Junichi Nagata 2655 Tsukure, Kikuyo-cho, Kikuchi-gun, Kumamoto Prefecture Tokyo Electron Kyushu Co., Ltd. Tokyo Electron Kyushu Co., Ltd. Kumamoto Office (56) References JP-A-3-269714 (JP, A) JP-A-3-69111 (JP, A) JP-A 63-75132 (JP, U)

Claims (2)

(57) [Claims] 1. A heat treatment apparatus for heating and processing an object to be processed, comprising: a first heating element on which the object to be processed is mounted; a first heating element disposed above the first heating element; A second heating element that forms a processing section in a sealed space between the heating element and the heating element; a gas supply unit that supplies a purge gas from above the processing object in a side of the processing object in the processing section; An annular exhaust passage formed on the outer peripheral portion of the sealed space to exhaust the inside of the processing section from above the processing body and increasing pressure loss, and an exhaust port provided in the annular exhaust passage are provided. A heat treatment apparatus, comprising: an exhaust mechanism. 2. The annular exhaust passage is formed by an upper ring member having a hanging wall and a lower ring member having an upright wall. The hanging wall and the upstanding wall define a sealed space and an inside of the annular exhaust passage. 2. The heat treatment apparatus according to claim 1, wherein an annular bypass path is formed between the heat treatment apparatuses.