JPH03154324A - Device and method for pattern exposure - Google Patents

Abstract

PURPOSE:To eliminate instability of a chemical amplification system resist material by providing a baking device for performing bake treatment continuously during and after exposing a substrate. CONSTITUTION:Each wafer 3 after exposure has the same time up to baking by providing a bake device 4 at the inside of an exposure device 15 or around it. Namely, by performing exposure and bake treatment consistently to each wafer, change of a catalysis within a resist with time can be made to be constant for each wafer, thus enabling fluctuation of pattern dimensions between wafers caused by change of catalysis with time which is proper to a chemical amplification system resist material with a high sensitivity, high resolution, and high dry etching resistance to be avoided.

Description

[Detailed description of the invention]

I. Field of Industrial Application The present invention relates to lithography technology in ULSI manufacturing, etc., and more particularly to a pattern exposure apparatus and method for realizing a lithography process using a chemically amplified resist with high controllability and stability.

[Conventional technology]

The integration and density of ULSI is increasing fourfold in three years, and mass production of 4 megabit dRAM and prototype production of 16 megabit dRAM are underway. Along with this, the dimensions required for microfabrication have increased from 0.8 μm to 0.
．． 5 μm, countersunk is becoming increasingly finer than 0.5 μm. Lithography technology plays a role in driving this miniaturization of devices. Lithography technology uses energy beams such as light, X-rays, and electron beams. In other words, lithography forms latent images in the resist by selectively irradiating these energy rays onto a photosensitive resist material, and then processes the base material by converting these latent images into real images through a development process. Usually, a resist mask is formed. Therefore, the resist materials used for this have the following characteristics: ■High resolution, ■High sensitivity, and ■High processing resistance. performance is required. However, there is no conventional resist material that simultaneously satisfies these three elements at a high level, and resist materials must be selected depending on the application, at the expense of one or the other. However, recently 2 e.g. Journal of Vacuum Science and Technology (J, Vac, Sci, Tec
hnol, ) B6 (1), Jan/Feb '8
8ρp319-322. , the same issue of the same magazine, pP379-31
A chemically amplified resist using a catalytic sensitization reaction as shown in No. 13 has been devised. This is a resist material with a new mechanism in which an intermediate substance that serves as a catalyst is generated by irradiation with energy rays, and the subsequent heat treatment efficiently promotes the resist reaction. As a result, high sensitivity can be achieved while maintaining the high resolution and high processing resistance of conventional resists. This is an ideal resist material for lithography. Moreover, such chemically amplified resists are positioned as mainstream resist materials in the future as well.

[Problem M that the invention attempts to solve]

However, when the above-mentioned chemically amplified resist material was used in a manufacturing process such as ULSI, it was found that variations in feature dimensions (thinning) occurred among a large number of wafers, making it impossible to realize a stable and highly controllable lithography process. The above phenomenon will be explained in detail below with reference to FIG. 2(a). Generally, wafer #1 of cassette 2 containing n wafers
The resist coated on the primary wafer #1 is transported to the pattern exposure section 15, and a predetermined pattern is exposed to light. Thereafter, wafer #1 is again transferred and stored in cassette 2. Wafer #2 is selected as the 0th wafer and undergoes a series of processing in the same manner as wafer #1. By repeating this process and completing all the processes up to wafer #n, the exposure process for one batch is completed. After this, these wafers #1 to #n are shown in FIG. 2(b).
As shown in FIG. 3, a resist pattern is formed through a post-exposure bake and development process. However, in this sequence, a significant pattern dimension change occurred between wafer #1 and wafer #n. FIG. 3 shows the amount of deviation from the dimension design value of the fine pattern exposed on each wafer. As shown in the figure, we found that there were large differences in pattern dimensions between wafers. This is due to the fact that the time from exposure to baking is necessarily different for wafers #1 to #n, and it is thought that the catalyst generated in the resist due to exposure changes over time. Chemically amplified resists are ideal resists that can simultaneously achieve extremely high performance in terms of sensitivity and resolution, but due to the above phenomenon, a problem has arisen that they cannot be applied to the ULSIH fabrication process, which requires stability and reproducibility. . Based on the above phenomenon, the present invention eliminates the instability of the chemically amplified resist material and provides ULS with high stability and reproducibility.
The purpose is to realize the I manufacturing process.

[Means for Solving the Problem 1] The above purpose is to arrange a baking device in or around the exposure device, to continuously process each sample from the exposure of the resist material to the baking process, and to measure changes over time for each exposed sample during this period. This is achieved by keeping all of the time constant. [Operation] By providing the baking device 4 inside the exposure device 1 as shown in FIG. 1(a) or around it as shown in FIG. 1(b), each wafer after exposure is They can all be the same. In other words, if exposure and baking are performed consistently on each wafer, as shown in Figure 1(c), and the change in the catalyst in the resist over time is made constant for each wafer, pattern size variations between wafers can be reduced. This makes it possible to realize a process using a chemically amplified resist with high stability and reproducibility. Furthermore, the elapsed time before baking after exposure can be shortened, making it possible to perform patterning with high sensitivity and resolution, thereby bringing out the high performance of the resist.

【Example】

The present invention will be explained in detail below using examples. Embodiment 1 Embodiment 1 is an example in which a hot plate baking function is provided between an exposure chamber and an exchange chamber of an electron beam exposure apparatus. FIG. 4 shows an outline of the electron beam exposure apparatus, which is a variable shaped beam type exposure apparatus with an accelerating voltage of 30 kV. For the exposure sample, a negative chemical amplification resist material 5AL601-ER7 (Sisoplay Microelectronics Co., Ltd.) was coated with a thickness of 0.5 μm on a 4-inch Si substrate. All 10 samples in one batch of exposure light are placed in the sample waiting room shown in FIG. 4, and transported one by one to the exchange room. After bringing the exchange chamber to a high vacuum state of ~1 μT orr or less, comparable to that of the exposure chamber, it was transported and fixed to the exposure stage, and a predetermined fine pattern was exposed at a dose of 8 μC/cm, forming a latent image. The exposed first sample was then transferred to a baking device and baked at 110°C for 2 minutes.After this, the sample was stored in a predetermined location in the waiting room.2.
After the first sheet, processing was carried out in the same manner as for the first sheet, and the processing of the 10-sheet goldstone sample with fixed exposure rate was completed. Next. A pattern was formed by developing with developer MF312 (Sisoplay Microelectronics). The dimensions of this resist pattern were evaluated using a scanning electron microscope.
6000 (Hitachi), it was possible to obtain a good value of 0.02 μm for 710 wafers with dimensional variation between wafers. (Example 2) Example 2 is a case in which a belt heating type baking function is provided between the exposure chamber and the sample special equipment section of an electron beam exposure device.The temperature of the beta device is 110°C and the belt feeding speed is 0. .15c
The same results as in Example 1 were obtained by baking at m/sea. (Example 3) In Example 3, an infrared heating baking function was provided between the exposure section of the optical exposure device using KrF excimer laser light with a wavelength of 248 nm and the sample special equipment section. When the baking process was performed for 1 minute, the same improvement effect of suppressing changes in resist properties over time as in Example 1 was observed in this case as well. [Effects of the Invention] According to the present invention, high sensitivity, high resolution, and high dry etching It is possible to avoid wafer-to-wafer pattern size variations caused by the aging phenomenon of the catalyst inherent in chemically amplified resist materials, which have high resistance.This makes it possible to avoid wafer-to-wafer pattern size variations, which are expected to become increasingly highly integrated in the future
This will strongly promote the production of semiconductor elements such as SI and ultrafine devices.

[Brief explanation of the drawing]

FIG. 1(a) is a schematic side sectional view of an exposure apparatus according to an embodiment of the present invention, FIG. c) is a diagram explaining the resist process flow when using the present invention, FIG. 2(a) is a schematic side sectional view of a conventional exposure apparatus consisting of an exposure section and a sample special section, and FIG. 2(b) Figure 3 shows the resist process flow when using a conventional exposure device, Figure 3 shows the amount of deviation from the dimensional design value of the fine pattern exposed on each wafer in the conventional example, and Figure 4 shows the exposure chamber and FIG. 2 is a schematic side sectional view of an electron beam exposure apparatus provided with a hot plate baking function between it and a sample exchange chamber. Explanation of symbols 2...Cassette, 3...Sample (wafer), 4...
Baking device, 5... stage, 6... light source, 7...
・Electron beam exposure section. 8... Sample special equipment section, 9... Hot plate, 10.
...bulb, 11...electron gun, 15...figure exposure section 2 days

Claims (1)

[Scope of Claims] 1. In a pattern exposure device that uses electron beams, X-rays, or light to form desired patterns on a substrate coated with a radiation-sensitive material, the substrate is continuously exposed during or after exposure. A pattern exposure apparatus having a baking device for baking. 2. In a pattern exposure method in which a desired pattern is formed on a radiation-sensitive material film coated on a substrate using electron beams, X-rays, or light, the step of continuously baking the substrate during or after exposure. A pattern exposure method characterized by equalizing the elapsed time from the exposure step to the baking step among a plurality of substrates. 3. The graphic exposure apparatus according to claim 1, wherein the baking section is of a hot plate type, a belt heating type, a hot air circulation type, an infrared/far infrared type, or a high frequency heating type. 4. The graphic exposure method according to claim 2, wherein the baking temperature is 80 to 140°C. 5. The pattern exposure method according to claim 2, wherein a chemically amplified resist is used as the radiation-sensitive material. 6. The pattern exposure method according to claim 2, wherein the substrate is a wafer, a mask, or a reticle.