JPS63181321A - Baking apparatus - Google Patents

Abstract

PURPOSE:To reduce the generation of foreign particles due to recrystallization by heating the surface of the cover for separating the space for baking from the external space. CONSTITUTION:A cover 7 made of a transparent glass plate is provided on side boards 5 provided on a main body 1, and by this cover 7 a space 8 in which the baking is performed is separated from the external space. And from the gaps between the cover 7 and the side boards 5, the atmosphere containing the components volatilizing or subliming from a resist at the baking time is discharged to the exterior. And a heater 9 is provided on the surface of the cover 7 opposite to a hot plate 2, by which the surface of the cover 7 of the hot plate 2 side can be heated to a temperature on the order of or higher than the baking temperature. With this, the components volatilizing or subliming from the resist at the baking time can be prevented from being cooled and recrystallized at the surface of the cover 7, whereby the generation of foreign particles due to this recrystallization can be reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a baking device, and in particular, to a technique effective for use in baking various coating films in the manufacturing process of highly integrated semiconductor integrated circuit devices. .

[Prior art]

In the lithography process in the manufacture of semiconductor integrated circuit devices, there are three steps: ■Pre-treatment of semiconductor wafers, ■Resist coating,
Processing is performed in the following order: ∎Pre-bake, ∎Exposure, ∎Development, and ∎Post-bake. In this case, the prebaking (2) is performed mainly for the purpose of volatilizing the residual solvent in the resist, and is performed within a temperature range of, for example, about 70 to 130°C.

In addition, the post-bake step (■) aims to remove water on the resist surface and strengthen the adhesion with the base.
It is carried out within a temperature range of about 160°C.

Conventionally, there are three types of baking devices known for performing the above-mentioned pre-baking and post-baking, depending on the heating method: thermal resistance, conduction method, and irradiation method.
Vacuum adsorption hot plates, which are baking devices using the conduction method, have become mainstream (for example, "rLSI Process Engineering, edited by Ishitaka").

p, 137-ρ, 138. Published October 25, 1982, Ohmsha.

■ Tokuyama and Hashimoto (eds.) rMO8LsI Manufacturing Technology, p.

151, published June 20, 1985, Nikkei McGraw-Hill Publishing).

This hot plate type baking device directly heats the semiconductor wafer, so there is no need to seal the atmosphere. A cover is provided above the wafer to prevent reaction between the resist and oxygen in case of a hot plate, and a purge gas such as nitrogen is flowed into the space between the cover and the hot plate.

The negative resist using an aromatic bisazide as the photosensitive molecule generates an intermediate nitrene upon exposure or heating, and this has a very strong affinity for oxygen, so it has a strong tendency to oxidize.

[Problem that the invention seeks to solve]

However, according to the study results of the present inventor, in the hot plate type baking device having the above-described structure, some of the components of the resist volatilize or sublimate during baking, and this is cooled by the cover and recrystallized. This recrystallized material falls onto the wafer and becomes foreign matter. As a result, pattern formation defects occur during exposure, development, or etching. fI
There was M.

This makes it possible, in particular, for example to use 1 Mbit dynamic R
A M (Random Access Men+or
In highly integrated semiconductor integrated circuit devices such as y), a significant decrease in yield occurs.

An object of the present invention is to provide a technique that can effectively prevent the components of the coating film from volatilizing or sublimating and recrystallizing on the cover surface during baking, thereby reducing the generation of foreign matter.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means for Solving the Problems] Among the inventions disclosed in this application, a brief overview of typical inventions is as follows.

That is, the surface of the cover is configured to be heatable.

[Effect]

According to the above-mentioned means, by heating the cover surface, it is possible to effectively prevent the components of the coating film from volatilizing or sublimating during baking and recrystallizing on the cover surface. The generation of foreign matter can be reduced.

〔Example〕

Hereinafter, one embodiment of the present invention will be specifically described using the drawings.

In addition, in all the figures for explaining the embodiment, parts having the same functions are given the same reference numerals, and repeated explanations thereof will be omitted.

FIG. 1 is a perspective view of a hot plate type baking device according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line X--X in FIG. 1.

As shown in FIGS. 1 and 2, in the hot plate type baking apparatus according to the present embodiment, a hot plate 2 is provided in the baking apparatus main body 1, and on this hot plate 2, for example, resist (Fig. A semiconductor wafer 3 coated with (not shown) is placed thereon. A heater 4 is provided below the hot plate 2 so that the hot plate 2 can be heated and the semiconductor wafer 3 can be heated by thermal conduction. Note that during this heating, the semiconductor wafer 3 is vacuum-adsorbed onto the hot plate 2 by evacuating through a vacuum suction hole (not shown) provided in the hot plate 2. ing. Also, although not shown,
The hot plate type baking device according to this embodiment usually includes:
For example, the semiconductor wafer 3 is installed connected to a resist coating device or a developing device, and after resist coating or development by this resist coating device or developing device, the semiconductor wafer 3 is conveyed onto the hot plate 2 by, for example, a belt conveyance, and then vacuum-adsorbed. The resist is now baked.

On the other hand, a side plate 5 is provided on the main body 1, and a cover 7 made of, for example, a transparent glass plate is provided on the side plate 5 with a spacer 6 in between. This cover 7 separates a space 8 in which baking is performed from an outside space. Moreover, this cover 7 can prevent dust from outside the apparatus from falling onto the semiconductor wafer 3. The distance between the cover 7 and the hot plate 2 is selected so that the semiconductor wafer 3 is not heated to a temperature higher than the temperature of the hot plate 2 due to radiant heat from the heated cover 7. Through the gap between the cover 7 and the side plate 5 formed by the spacer 6, an atmosphere containing components volatilized or sublimated from the resist during baking can be exhausted to the outside of the baking apparatus by natural convection exhaust. In addition,
Forced exhaust may be performed by providing a fan or the like as necessary. As shown in FIG. 3, on the surface of the cover 7 opposite to the hot plate 2, there is a heater 9 made of a predetermined thin film resistor whose both ends are connected to a power source (not shown). This makes it possible to heat the cover 7, particularly its surface on the hot plate 2 side, to a temperature comparable to or higher than the baking temperature, for example, about 50 to 200°C. This can effectively prevent components that volatilize or sublimate from the resist during baking from being cooled and recrystallized on the surface of the cover 7, and therefore reduce the generation of foreign matter caused by this recrystallization. Can be done. Therefore, it is possible to prevent defective pattern formation due to this foreign matter. As a result, the yield can be improved even in the manufacture of highly integrated semiconductor integrated circuit devices with wiring widths of 1.3 μm or less, such as dynamic RAMs of 1 megabit or more and static RAMs of 256 kilobits or more. Note that since the cover 7 is heated, for safety reasons, a wire mesh or the like is actually provided around it to prevent the human body from directly touching the cover 7. Further, reference numeral 10 denotes a coil-shaped heater 1.
1 is a heatable gas introduction pipe, and a heated purge gas such as nitrogen can be introduced into the space 8 from this gas introduction pipe 10. This makes it possible to prevent components that volatilized or sublimed from the resist during baking from condensing in the space 8, thereby also preventing the generation of foreign matter.

The present invention has been specifically explained above based on examples, but
It goes without saying that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the spirit thereof.

For example, the cover 7 in the above embodiment may have a different configuration as long as at least the surface on the hot plate 2 side can be heated.

For example, a metal plate or the like that can be heated with a heater may be used. Note that it goes without saying that this cover 7 does not necessarily have to be transparent. Further, in the above embodiments, a resist baking apparatus was described, but the present invention can be applied to a resist baking apparatus, for example, a spin on glass (spin on glass).
It can be applied to a baking device for various coated film-forming materials such as lass, SOG) and polyimide resin. Further, in the above-described embodiments, a baking device using a conduction method has been described, but the present invention can also be applied to a baking device using an irradiation method that performs baking using, for example, infrared light or microwave irradiation.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

That is, it is possible to reduce the generation of foreign matter due to recrystallization of components volatilized or sublimated from the coating film on the cover surface during baking.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a hot plate type baking device according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line XX in FIG. 1. FIG. 3 is a plan view of the cover of FIG. 1.

Claims (1)

[Scope of Claims] 1. A coating film baking device having a cover for separating a space for baking a coating film by a conduction method or an irradiation method from an external space, which is capable of heating the surface of the cover. A baking device characterized by comprising: 2. The baking device according to claim 1, wherein at least the surface of the cover facing the coating film is configured to be able to be heated to a temperature of 50 to 200°C. 3. The baking device according to claim 1 or 2, wherein the cover is made of a transparent glass plate having a heater provided on one surface thereof. 4. The baking device according to any one of claims 1 to 3, wherein the coating film is resist, spin-on glass, or polyimide resin.