JP4618750B2 - Upper surface baking and cooling device - Google Patents

Description

[0001]
The present invention relates to a baking apparatus, a cooling apparatus, and a baking and / or cooling method using the same. More particularly, the present invention relates to a resist processing apparatus and a processing method used for producing a semiconductor integrated circuit device, a printed circuit board, a CD or MD storage disk device and the like.
[0002]
High integration is promoted in semiconductors and printed boards, and the precision required for circuit formation has become severe. In response to this, in the field of photoresists, chemical amplification resists with high resolution are often used instead of conventional resists using novolak resins. Such chemically amplified resists require more precise control of processing conditions. In addition to precise temperature control of pre-bake and post-exposure bake conditions, post-bake cooling conditions, etc., the temperature of the entire substrate can be controlled. There is a need to control uniformity, as well as heating or cooling temperature profiles.
On the other hand, there is an increasing demand for processing a thick substrate such as an MD disk original plate with high accuracy. In an MD disk original plate, a photoresist that is exposed to light is generally applied on a glass substrate or metal substrate having a thickness of 10 to 15 mm, baked, and fine pits are exposed and developed by a laser drawing apparatus. A pit pattern is formed on a glass substrate or a metal substrate. The photoresist is dropped on the rotating substrate, spread on the substrate by centrifugal force, and further rotated at high speed and applied to the thin film. Next, the substrate is placed on a hot plate, heated from below and baked to evaporate the solvent and solidify the film to form a dense film (this is called pre-exposure bake: pre-bake in the meaning of pre-exposure baking) ).
[0003]
Conventionally, in pre-baking, a substrate is placed on a hot plate and heated from below. However, in this method, since the substrate is thick, it takes time until the heat is transferred to the resist, and unevenness in the transfer of heat occurs, resulting in uneven resist baking conditions. Also, when the baking is finished and the process proceeds to the exposure process, the substrate is not cooled immediately, and the substrate is exposed while accumulating heat. There is a problem that uneven exposure occurs in the plane and between the substrates.
Furthermore, a chemically amplified resist requires a reaction for removing a protecting group for preventing the resin from dissolving in a developer after exposure, a so-called deprotection reaction, and baking must be performed after exposure. This baking is referred to as Post Exposure Bake (PEB). This elimination reaction of the protecting group is sensitive to temperature, and the resist P.I. E. B. If there is uneven temperature, there arises a problem that the finished dimensions of the resist change. P.P. E. B. Thereafter, unless the substrate is rapidly cooled to stop the deprotection reaction, the reaction proceeds, and there is a problem that a change (variation) in the finished dimensions occurs. For this reason, when using a chemically amplified resist, it is necessary to strictly control the temperature not only for a thick substrate such as an MD disk original plate but also for a thin substrate such as a wafer.
[0004]
The present invention solves the above-mentioned problems, strictly controls the temperature during baking and cooling, maintains the uniformity of temperature over the entire substrate, and strictly controls the temperature change profile. The present invention provides a cooling device, a baking and cooling device, and a baking method, a cooling method, and a baking and cooling method using the device.
That is, the first aspect of the present invention is a bake plate, a substrate holding device, a means for measuring the distance between the substrate held on the substrate holding device and the bake plate, and held on the substrate holding device. There is provided a baking apparatus having means for uniforming the distance between the heated substrate and the baking plate.
As a second aspect of the present invention, a cooling plate, a substrate holding device, a means for measuring a distance between the substrate held on the substrate holding device and the cooling plate, and a substrate held on the substrate holding device There is provided a cooling device having means for equalizing the distance between the cooling plate and the cooling plate.
As a third aspect of the present invention, there is provided a baking and cooling apparatus having the above baking apparatus and cooling apparatus.
Furthermore, the present invention provides a baking method, a cooling method, and a baking and cooling method using the above-described apparatus.
[0005]
In the present invention, the “bake plate” refers to a plate that can heat the substrate, and any known plate can be used. For example, a hot plate having a heat generating device in an aluminum base can be used.
The “substrate holding device” refers to a device that can hold a substrate on its surface, and any known means such as a vacuum, a clip, or a nail can be used as the holding means. The distance between the baking plate and the baking plate can be changed by “a means for making the distance between the substrate held on the substrate holding device and the baking plate uniform”. The shape of the surface can be appropriately determined according to the substrate to be held. The three-dimensional shape may be any shape as long as the three-dimensional arrangement can be appropriately adjusted by “a means for making the distance between the substrate held on the substrate holding device and the bake plate uniform”. good. For example, the shape may be a hemisphere, a sphere portion, a disk shape, a rectangular parallelepiped, a cone, a quadrangular pyramid, or the like, but is preferably a hemisphere.
[0006]
"Measuring means for distance between substrate held on substrate holding device and bake plate" measures distance between substrate and bake plate at multiple locations on substrate held on substrate holding device Any means can be used as long as it can. Preferably, the bake plate is provided with an optical distance measuring device for distance measurement. A preferred optical distance measuring device is a sensor using a He-Ne laser. “Means for uniforming the distance between the substrate held on the substrate holding device and the bake plate” means that the substrate held on the substrate holding device is based on the signal obtained by the distance measuring means. Any means can be used as long as the distance between the baking plate and the substrate can be made uniform at each point and the surface of the substrate and the surface of the baking plate can be made parallel. For example, a method of supporting by an air micro levitation device or a pin can be used. Preferably, the above two methods are used in combination. In addition to air, nitrogen, argon, or the like can be used as the levitation gas of the air micro levitation apparatus, and nitrogen is preferably used.
[0007]
In the present invention, the “cooling plate” refers to a plate capable of cooling the substrate, and for example, a plate made of a Beltier element can be used.
A substrate holding device, a means for measuring a distance between a substrate held on the substrate holding device and a cooling plate, and a substrate and a cooling plate held on the substrate holding device, which are used in the cooling device of the present invention. The means for equalizing the distance between them is the same as that used in the above baking apparatus.
[0008]
The apparatus of the present invention is characterized in that a bake plate or a cooling plate is arranged on the upper surface, a resist-coated substrate is approached from the lower surface, and the resist coating surface side is baked or cooled.
In the present invention, the resist film on the substrate is baked from the upper surface and baked quickly to eliminate uneven baking and obtain a uniform bake. Further, in the present invention, the resist film on the substrate is cooled from the upper surface and the cooling is performed promptly, so that uneven cooling can be eliminated and uniform cooling can be obtained.
It is desirable that the distance between the substrate and the bake plate or cooling plate be sufficiently close so that temperature unevenness is eliminated. It is preferably within about 1 mm, more preferably within 100 microns, and most preferably within 50 microns.
[0009]
In one embodiment of the present invention, the temperature of the substrate can be measured by attaching a temperature sensor to the bake plate and the cooling plate. In this embodiment, data of a desired temperature change profile can be stored in a computer, and heating and cooling conditions can be controlled in real time while being compared with the measured temperature value of the substrate. Any known temperature sensor can be used. For example, an infrared sensor is preferably used. The temperature sensor is preferably embedded in the bake plate or the cooling plate surface.
[0010]
A configuration example of an apparatus according to the present invention is shown in FIG.
The bake and the cooling plate can be arranged side by side. First, the substrate is transported to the bake unit and baked for a predetermined time. Next, after baking, the substrate is transported to the cooling unit by the transport arm and cooled for a predetermined time.
[0011]
A detailed configuration diagram of the bake unit is shown in FIG.
The bake unit includes a hemispherical air micro positioning stage 5, a stage lifting device 7, and a bake plate 1. The substrate is placed on the positioning microspherical air micropositioning stage 5 by the transfer arm and fixed by vacuum. Next, the stage is raised by the lifting device 7 to bring the substrate close to the bake plate. A sensor 2 using a He—Ne laser for distance measurement is embedded in the bake plate. When the substrate approaches the bake plate, a He—Ne laser is irradiated from the sensor 2 embedded in the bake plate, and the distance between the bake plate surface and the substrate surface is measured. He-Ne laser distance measuring sensors are uniformly embedded in several places on the bake plate surface. The distance data from the distance sensor is sent to a computer, and the air micropositioning stage is automatically moved and adjusted so that a predetermined distance is obtained at all sensor positions. The angle of the air micro positioning stage can be freely controlled by air levitation. When the distance between the bake plate surface and the substrate reaches a predetermined value at all sensor positions, the air micro positioning stage is locked. Further, exhaust from the periphery of the baking plate can be performed so that a solvent gas or a reaction gas from the resist generated during baking does not affect the resist film. After baking for a predetermined time while measuring the substrate surface temperature with a temperature sensor if desired, the air micro positioning stage is lowered by the lifting device, the substrate is lifted by the pin embedded in the stage, and the cooling unit is cooled by the transfer arm Move to. The configuration of the cooling unit is the same as that of the bake unit except that the bake plate is changed to the cooling plate, and the processing sequence is also the same. In addition, since the time from the end of baking to the start of cooling affects the sensitivity of the resist and the effect of the deprotection reaction, strict time management is required. In the apparatus of the present invention equipped with a baking device and a cooling device, by setting the timing for transporting the substrate and controlling the atmosphere during the transportation, the time from the end of baking to the start of cooling, the temperature and atmosphere in between, etc. The environment can be strictly controlled.
This apparatus satisfies the conditions in baking after resist coating, so-called pre-baking, baking after pre-cooling and exposure, cooling so-called Post Exposure Bake (PEB), and Post Exposure Cooling (PEC). It is precisely controlled and enables high-precision machining.
[0012]
Example Example 1
TDUR-P015 (manufactured by TOK) was applied as a resist to the surface of the substrate to a thickness of about 0.5 μm. Heating was performed by a conventional method of heating from the lower surface and the method of the present invention at a set temperature of 110 ° C. A glass substrate having a thickness of 11 mm was used as the substrate, and the distance between the bake plate and the substrate was 52 microns.
The result of measuring the temperature change is shown in FIG. As can be seen from FIG. 3, in the conventional method, it takes 8 minutes for the temperature of the resist surface to reach 100 ° C., but in this method, it reaches in 3.5 minutes. Recognize. FIG. 4 shows the in-plane temperature distribution on the substrate surface when the resist surface temperature at the center position of the substrate reaches 100.degree. It can be seen that this method has higher temperature uniformity.
[0013]
Example 2
FIG. 5 shows the measurement result of the temperature decrease curve on the substrate surface by the cooling apparatus of the present invention. In the conventional method (air cooling by leaving), it takes 20 minutes for the temperature to drop to 25 ° C., but in this method, the temperature drops in 10 minutes. Especially in chemically amplified resists, the deprotection reaction needs to be stopped quickly. E. B. In the subsequent cooling, a rapid temperature reduction is required. E. B. It can be seen that the present method is more effective than conventional methods in cooling at times.
[0014]
Example 3
Under the following conditions, patterning was performed using a laser drawing apparatus using a chemically amplified resist, and in-plane dimensional variations were compared between the conventional method and this method.
Resist: TDUR-P015 (manufactured by TOK)
Pre-baking conditions: 90 ° C., 20 minutes E. B. : 110 ° C, 90 seconds, 10 minutes Resist film thickness: 200nm
Exposure: 248 nm laser irradiation apparatus Drawing pattern: Isolated pattern with dimensions of 200 nm Development: Tetramethylammonium hydroxide (TMAH) 2.38% (23 ° C.) The results of paddle development 60 seconds are shown in FIG.
According to the method of the present invention, it can be seen that in-plane dimensional variations can be reduced as compared with the conventional method.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration example of an apparatus according to the present invention.
FIG. 2 is a cross-sectional view showing a detailed configuration of the apparatus according to the present invention.
FIG. 3 is a graph showing the results of Example 1.
FIG. 4 is a diagram showing the results of Example 1.
FIG. 5 is a graph showing the results of Example 2.
FIG. 6 is a diagram showing the results of Example 3.
[Explanation of symbols]
1: Bake or cooling plate 2: He-Ne laser distance sensor 3: He-Ne laser light (633 nm)
4: Substrate 5: Air float spherical seat stage 6: Air float spherical seat stage receiver 7: Stage lifting device 8: Air float outlet 11: Bake furnace 12: Cooling unit 13: Device set station 14: Operation panel 15: Slide Part

Claims (8)

A baking apparatus having a baking plate, a substrate holding device, and a means for measuring a distance between the substrate held on the substrate holding device and the baking plate,
A baking apparatus comprising the distance measuring means at at least five measurement points, and further comprising means for making the distance between the substrate and the bake plate uniform at each measurement point based on the measured distances. The apparatus according to claim 1, further comprising means for measuring a temperature of the substrate surface. The apparatus according to claim 1 or 2, wherein the means for equalizing the distance between the substrate and the bake plate is an air micro levitation device or a pin. A cooling device having a cooling plate, a substrate holding device, and a means for measuring a distance between the substrate held on the substrate holding device and the cooling plate,
Means for measuring the distance between the substrate and the cooling plate at at least five measurement points, and means for making the distance between the substrate and the cooling plate uniform at each measurement point based on the measured distance A cooling device comprising: The apparatus according to claim 4, further comprising temperature measuring means for the substrate surface. 6. An apparatus according to claim 4 or 5, wherein the means for equalizing the distance between the substrate and the cooling plate is an air micro levitation device or a pin. A bake and cooling apparatus comprising the apparatus according to any one of claims 1 to 3 and the apparatus according to any one of claims 4 to 6. A baking and cooling method using the apparatus according to claim 7 to manage a time from the end of baking to the start of cooling.

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