JPH02153521A - Heating process and device therefor - Google Patents

Abstract

PURPOSE:To facilitate the temperature control of heat treatment and to make the even heating feasible by a method wherein an element to be processed is held on three or more holding bodies in the state at an extremely narrow gap between the element and a heating surface. CONSTITUTION:Three or more recessed grooves 3 are formed on the surface region of a hot plate 1 between guide grooves 2a, 2b. Balls 4 made of ceramics, etc., are contained in the grooves 3 so that the balls 4 may protrude from the surface by 50-200mum. The protrusion level of the balls 4 can be freely adjusted by changing the size of the balls 4. Then, guide rails 2 receive a carried wafer 5 further to carry it onto the balls 4. Through these procedures, the gap between the rear surface of the wafer 5 and the surface of the hot plate 1 can be set up extremely narrow and even so that the thermal conductivity from the plate 1 to the wafer 5 may be fluctuated with high precision. Accordingly, the temperature control of the heat treatment can be facilitated thereby making the even heating feasible.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a heating method and a heating device.

(Prior art) In the manufacturing process of semiconductor devices, the photoresist process includes:
There is a baking process for semiconductor wafers (hereinafter simply referred to as wafers). The purpose of this baking process is to dehydrate the wafer surface or remove the solvent in the resist applied to the wafer surface. As for this baking method.

There are direct hot plate methods, batch hot air heating methods, microwave methods, etc. Among these, the direct hot plate method has become mainstream from the viewpoints of making the device more compact, increasing efficiency, shortening processing cycle time, and improving reproducibility and uniformity.

(Problem to be solved by the invention) However, in the direct hot plate method, the wafer is fixed directly on the hot plate and heated directly, so if the adhesion between the wafer and the hot plate is different, uniform heating may not be achieved. Moreover, since the hot plate is usually made of metal such as aluminum, there are problems such as contamination by heavy metals and adhesion of particles to the back side of the wafer. Furthermore, in the baking process after applying the resist, if the wafer is placed directly on a hot plate and baked, several hundred micrometers of dust may adhere to the back side of the wafer, and the next step with the dust attached to the back side of the wafer is When the image is transported to the exposure process, there is a problem in that the area where dust has adhered becomes out of focus.

In order to solve this problem, a proximity method can be considered in which a small gap is provided between the hot plate and the wafer and the wafer is baked without directly contacting the hot plate.

In the case of this proximity method, as shown in FIG. 3, the wafer 30 is heat-treated with a gap d provided between the wafer 30 and the hot plate 10 by a guide 20 called a walking beam provided on the hot plate 10. It is. In this figure, a guide 20 constitutes a wafer transport mechanism.

However, since the guide 20 is originally intended for transporting the wafer 30, in order to transport the wafer 30 smoothly, the gap d between the wafer 30 and the hot plate 10 must be set to 2.
Must be set to 1 or more. but.

When such a large gap d is provided, the speed of heat conduction at the initial stage of heating becomes slow, and the temperature control becomes difficult. Further, the portion of the guide 20 that supports the wafer 30 is a linear region. For this reason, heat transfer from the hot plate 10 to the wafer 30 tends to be linearly non-uniform. Moreover, the gap d cannot be changed.

In order to solve this problem, a ceramic pin is provided on the hot plate 10, and this pin allows the wafer to be
0 may be supported so as to be slightly spaced apart from the hot plate 10. However, there is a problem in that small pins tend to adhere to the wafer after baking.

Furthermore, it is extremely difficult to improve the shape accuracy when processing small pins.

SUMMARY OF THE INVENTION An object of the present invention is to provide a heating method and a heating device that can easily control temperature, can uniformly heat an object to be processed, and can drastically reduce the amount of dust attached.

[Structure of the invention]

(Means for Solving the Problem) That is, the present invention supplies the object to be processed onto at least three spherical supports provided slightly protruding from the heating surface of the heating element, and uses the supports to The method is characterized in that after the object to be processed is supported in a state slightly spaced apart from the heating surface, the object to be processed is subjected to heat treatment for a predetermined period of time.

(Operation and Effect) In this invention, the object to be processed is provided on at least three spherical supports that slightly protrude from the heating surface, and the object to be processed is heated. This has the effect of uniformly heating the object to be processed without causing it to stick.

(Example) Next, it is an explanatory view showing an example in which the baking method of the present invention is applied to a baking step after resist application.

In the figure, 1 is a hot plate made of a heat-resistant metal plate such as aluminum whose surface has been oxidized.

Hot plate 1 has two guide grooves 2a formed in parallel at a predetermined interval on its surface. A guide rail 2 for transporting an object to be processed, such as a semiconductor wafer 5, after being baked is inserted into the guide groove 2a.

The guide rail 2 is inserted into the guide groove 2a so that it can move up and down so that its top slightly protrudes from the surface of the hot plate 1 during loading and unloading of wafers 5, which will be described later. The guide rail 2 sets the wafer 5 transferred from another processing device to a predetermined position on the hot plate 1, and also carries out the wafer 5 after the baking process toward the other subsequent processing device. ing.

The hot plate 1 has a built-in heater, and the heating temperature can be controlled according to the baking contents. For example, if the baking content is hydration baking, the temperature controlled by the hot plate 1 is 200-300℃.
00'C, about 100°C for pre-baking, and room temperature for simple cooling.

For example, three grooves 3.3, 3 are formed in the surface area of the hot plate 1 between the guide grooves 2a, 28. Inside the groove 3.3.3, as shown in FIG. 3.3
The 0 balls 4.4.4, which are housed in contact with or not in contact with the inner wall surface of the wafer 4, support the resist-coated wafer 5 carried in by the guide rail 2 on the back side of the wafer 5. be. The height at which the spheres 4.4.4 protrude from the surface of the hot plate 1 is preferably set in a range of 50 to 200 μs.

The length, width, and depth of the recess i13.3.3 are set to, for example, 4 m, 4+n+++, and 3.9 mm, respectively.

Further, the protrusion height d of each ball 4.4.4 from the surface of the hot plate 1 is set to, for example, 0.1.

As a result, the wafer 5 supported on the sphere 4.4.4 is at a distance of 0.1 mm from the surface of the hot plate 1. Here, by changing the size of the balls 4.4.4, the protrusion height H of the balls 4.4.4 from the surface of the hot plate 1 can be freely adjusted.

It is preferable that the size of the replacement balls 4.4, 4 is set appropriately within the range of 2 to lowφ. Also, ball 4.4.4 is
Shape accuracy during processing can be easily increased. Therefore, the protrusion height H of the balls 4.4.4 from the surface of the hot plate 1 can also be easily adjusted. As a result, the heat transfer characteristics from the hot plate 1 to the wafer 5 can be changed with high precision.

In the baking apparatus configured as described above, the guide rail 2.2 receives the wafer 5 transported from a transport mechanism (not shown), and places it on the ball 4.4.4 at a predetermined position on the hot plate 1. transport.

Since the wafer 5 is thus supported by point contact on the balls 4, 4.4, it is not subjected to large impact or contact pressure during support unlike when supported by pin tips. Moreover, since the wafer 5 is supported at three points by each ball 4.4.4, it is stably supported. As a result, the distance between the lower surface of the wafer 5 and the surface of the hot plate 1 can be set to be extremely narrow and uniform. The support for the wafer 5 is not limited to three points, but can be selected from four or five points as necessary.

With the wafer 5 set in this manner, heat is transferred from the hot plate 1 to the wafer 5 and beta processing is performed.

For example, when the baking process is pre-baking and the distance between the bottom surface of the wafer 5 and the surface of the hot plate 1 is 0.1 m,
The temperature of the wafer 5 reaches about 90° C. in about 20 seconds.

For example, in the case of a pre-baking process, after 2 to 3 minutes have passed at this temperature, the guide rail 2 is driven to carry out the wafer 5 to a processing apparatus for the next process, and the baking process is completed. The baking process is
For example, a simple receiver such as a receiver may be simply transferred to a member without being transferred to a processing device for the next step. The processing device for the next step may be, for example, a cooling device configured with a cooling plate. Ceramic balls 4.4.
4 is relatively heavy, so it does not adhere to the wafer 5 and prevent the wafer 5 from being carried out after the baking process.

Note that the hot plate 1 used in the present invention may be of any type other than the guide rail 2 as long as it is equipped with means for carrying in and out of the wafer 5. Also, hot plate 1
may be a plurality of them interconnected.

As described above, according to the baking method and apparatus of the embodiment, it is possible to perform heat treatment on the wafer 5 without bringing it into direct contact with the hot plate 1, but in a state in which it is brought very close to the hot plate 1. Therefore, the efficiency of heat transfer during baking can be increased, and metal contamination caused by the hot plate 1 and adhesion of particles to the wafer 5 can be prevented.

Further, according to the baking method and its apparatus of the embodiment, since the wafer 5 is supported by the ceramic balls 4.4.4, no shock is applied to the wafer 5 during heating, and
Heat treatment can be easily performed while preventing the generation of particles and the like. By the way, in conventional baking treatment, 0.3
~1μ particles.

Although 700 to 800 particles were adhered to the back surface of the wafer 5, it has been experimentally confirmed that with the method and apparatus according to this example, almost no such particles adhere. This decrease in the amount of attached particles not only affects the next exposure process, but also falls into each transport system and adheres to the next wafer or is carried into the development process, causing uneven development.

Further, according to the baking method and apparatus of the embodiment, by appropriately selecting and using ceramic balls 4.4.4 of different sizes, the distance between the wafer 5 and the hot plate 1 can be made variable. , temperature control during heat treatment can be easily performed.

Furthermore, in the above embodiment, an example was explained in which the application was applied to baking to dry the solvent after resist coating, but it may also be applied to a baking process to dry the developer after development processing, or other processing. It may also be applied to the previous baking step.

Furthermore, it can be applied not only to baking but also to any heating such as baking, sintering, and heating.

Furthermore, the present invention is not limited to the processing of semiconductor wafers, but may be applied to, for example, amorphous-Si processing of liquid crystal display devices.

Furthermore, in addition to resist coating and developing equipment, equipment that heats the object to be processed, such as etching equipment, plasma,
It may also be applied to CVD, or even a wafer prober.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a baking device according to an embodiment of the present invention, FIG. 2 is a sectional view of a main part of the baking device shown in FIG. 1, and FIG. 3 is a perspective view of a conventional baking device. Patent applicant: Tokyo Electron Ltd. Figure 1 Traces Figure 3 Figure 2

Claims (2)

[Claims] (1) supplying the object to be processed onto at least three spherical supports provided slightly protruding from the heating surface of the heating means;
A heating method characterized in that the object to be processed is supported by the support in a state slightly spaced apart from the heating surface, and then the object to be processed is subjected to heat treatment for a predetermined period of time. (2) A heating element that heats the object to be processed, and at least three supporting parts that slightly protrude from the heating surface of the heating element and that support the object to be processed are spherical supports. A heating device featuring: