JPS5893236A - Formation of microminiature pattern - Google Patents

Abstract

PURPOSE:To improve accuracy of processings by forming a flat surface organic substance film to a material having a stepped part or dents or projected areas to be processed, forming an organic substance mask providing an inorganic substance film mask and by etching such material to be processed. CONSTITUTION:A photo resist 8 is rotatingly coated on an Al-Si alloy film 6 of MOSFET, such photo resist is exposed by ultra violet ray using a mask having thick and thin areas in accordance with high and low levels and developed. Thereby the surface is almost flattened. Then, an Al film 9 is vacuum deposited, a thin resist film 10 is formed and these are exposed and developed. Thereby, the surface becomes flat, Al 9 prevents disturbed reflection from the base material and a highly accurate mask can be obtained. The Al 9 is anisotropically etched by CCl4 and O2. Thereafter, the resist film 8 is etched by the gas mainly composed of O2, and Al-Si alloy 6 is etched by the gas mainly composed of CCl4. According to this constitution, a highly accurate pattern can be produced without deformation of pattern due to stepped parts and dent or projected portions of base material and without any disable resolution.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field: The present invention relates to a method for forming four fine turns, and more particularly, to a method for forming fine main turns with high f# on a workpiece having steps or irregularities. .

Prior art and its problems Recently, in the field of semiconductor technology, efforts have been made to establish microfabrication technology with a minimum dimension of 1 [μ9] due to the development of various types of lamination. However, if the surface of the workpiece has steps, irregularities, etc., it is difficult to perform the above-mentioned fine processing of W[. This is because unevenness in the resist film thickness occurs due to steps and unevenness on the surface of the workpiece.
This is because a decrease in resolution occurs due to. In other words, it is difficult to perform exposure and development at the bottom of a recess or a step, thereby reducing the degree of processing.

Furthermore, there is also the problem that the resolution is reduced due to diffused reflection from the surface of the workpiece.

Therefore, in order to solve the problems of non-uniformity and diffused reflection of the resist film 1, we proposed a three-layer structure method for fine-grained
The parable turn formation method is Yang Rui. For example, 130
th FiC8 (1976 Fall) Meeting
Fxtended Abstracta Vo+ 76
-2,743 to 744 or J, Vac, 8ci.

Technology 1 6 (61Nov/De
c 1979, P1620. These strips are used to spin-code an organic substance on the workpiece, and to provide a # coating material film and a resist on the impurity film, and to apply the resist to the desired iJ? After 4 photo-developments in one turn, selectively etching a non-material film using the renost as a mask, then selectively etching an organic U film using an inorganic material film as a mask, and then selectively etching a workpiece using an organic material as a mask. This is the way to do it. In addition, the influence of the surface level difference of the underlying workpiece can be reduced, and the resist and organic substance film can be patterned with high precision.

This makes it possible to measure the machining fit rK of the workpiece.

However, even with such a 3+- structure method for forming fine arm turns, the flatness of the resist and the uniformity of the film thickness cannot be said to be sufficient, and sufficient resolution cannot be obtained. That is, the surface of the organic @'f(form) has a clear slope over a wide area, and the surface of the organic material layer laminated thereon also has a smooth slope.For this reason.

The thickness of the resist layered on the inorganic film is not uniform enough, and the resolution of resist gloss and turns is thereby reduced. In addition, the surface of an organic material film formed sufficiently thickly by the spin-coding method will be flat with almost no difference in height in areas where there are dense steps and unevenness on the underlying workpiece. In such a region, there will be a difference in height that reflects the difference in height of the underlying workpiece. For this reason.

Resist gloss and turn resolution deteriorates in areas where the underlying workpiece has sparse steps and unevenness.

On the other hand, in order to obtain a sufficiently smooth surface using the spin code method, it is necessary to form the organic material film to be at least twice as thick as the underlying step. However, when the thickness of the organic material film is increased in this way, it is difficult to process the workpiece faithfully to the resist glossy turn formed at the highest kfd due to the difference between seeds and processing time. .

Purpose of the Invention The present invention has been made in consideration of the above circumstances, and its purpose is to reliably prevent a decrease in the resist resolution due to steps, irregularities, etc. on the surface of the workpiece. The object of the present invention is to provide a method for cutting a fine, main turn shape, which can greatly improve the processing accuracy of a workpiece.

Summary of the Invention The present invention involves spin-coding an organic material film on a workpiece having steps or irregularities, and then selectively etching the surface of the organic material film to make the surface flat with no difference in height. After the material film and the resist are sequentially provided, the renost is exposed and developed in the desired direction (as desired), and then the inorganic material film is selectively etched using the resist as a mask using a dry etching method. In this method, the material to be processed is selectively etched (1), and then the workpiece is selectively etched using the organic material film as a mask.

That is, in order to completely flatten the surface of an organic material film in a normal 3 mm manufacturing method for forming fine patterns, the present invention selectively etches the surface by subjecting the surface of the organic material film to, for example, an exposure treatment. This is how I did it.

Effects of the Invention According to the present invention, the surface of the organic material film bifurcated on the workpiece is almost completely flattened, so that the flatness and film thickness of the inorganic material film and resist laminated thereon are improved. The uniformity is sufficiently good.

Therefore, it is possible to reliably prevent a decrease in the resolution of 4-turns caused by steps, unevenness, etc. on the surface of the workpiece, thereby significantly improving the processing accuracy of the workpiece. Furthermore, since the surface of the organic material film is planarized by selective etching, the thickness of the organic material film can be made thinner than in the case of the conventional three-layer structure method. , the etching process can be facilitated.

Examples of the invention The details of the present invention will be explained below with reference to the illustrated embodiments.

- Figures 1 to 6 are MOSs according to an embodiment of the present invention)
FIG. 3 is a cross-sectional view showing a transistor manufacturing process. First, using a well-known technique, as shown in FIG. 1, a silicon wafer 11 is coated with a field oxide film 2, an r-) oxide film 3, and a polycrystalline silicon wafer 11 for device isolation. -) 4 is deposited, and an acid 1 arsenic film 5 is further deposited on these L. Then, a contact hole is formed in the oxide film 5, and an A7 for wiring is formed on this oxide film 5.
- A Si alloy film 6 (workpiece) was deposited. Note that 2 in the figure indicates the source/drain overnight region.

Next, as shown in FIG.
The thickness was spin-coded to the thickness of [μ milk]. In this state, the surface of the organic acid film 8 is A-! Although it is quite flat compared to the surface of the -8i alloy film 6, it is not completely flat.
There was a difference in performance between the two. Tsugumi, what machine material membrane 8
The lowest part was not exposed, and the other parts were exposed to four ultraviolet rays using a mask having shading according to the flatness difference. Thereafter, when the organic material film was opened and developed at a predetermined time using a special developer, the surface crystal height difference of the organic material film 8 was 1.
/3, and the surface became approximately flat as shown in FIG.

Next, as shown in FIG. 4, 0.15 [μ
m] Thick A! At the same time as the film 9 was sputter-deposited, a resist 10 was applied on the Ai film 9 to a thickness of about (1.5 μm).

Then, the V cyst 10 was exposed and developed to a desired i+ turn to form a resist glossy turn as shown in FIG. Here, the resist 10 has a thin film thickness, extremely small film thickness fluctuations, and is provided on a good flat surface with no difference in height, so that proper exposure and development can be performed, and its resolution is high. It was very early in the day. In addition, since the resist base was sufficiently flat, there was very little negative influence from the A1 surface, and furthermore, A! ++Dui 9 had sufficient light-shielding properties, no diffused reflection from the base was observed, and the processed Mll' of the resist pattern was extremely good.

Next, CCノ, and 0. The A film 9 was selectively etched using the resist 10 as a mask, as shown in Fig. g6, using an anisotropic dry etching method using a mixed gas. At this time, A111%9 was processed faithfully to the resist gloss and turn with excellent accuracy.

Next, the organic material film 8 was selectively etched using an AAAg3 mask as shown in FIG. The pattern formed at this time had a shape having vertical walls faithful to the A 7 /4' turn, and was not affected by the stepped shape of the A1-8i alloy film 6. Also, resist 10
had disappeared, but the A7 membrane 9 was not damaged in any way.

Next, the A7(-8+ alloy film 6 was selectively etched using an anisotropic dry etching method mainly containing C(, #) and using the organic material 1 to 8 as a mask, as shown in FIG.

At this time, the A7 pattern had already disappeared, but the resist number and turn were not crossed at all. Thereafter, by removing the organic film 8, desired wiring and nine turns were obtained.

The wiring] and turns thus formed were faithful to the designed/IP turns, which were perfectly transcribed. In other words, there are no problems such as pattern deformation or inability to resolve due to differences in base level or unevenness, and it is now possible to perform highly opaque processing.

In this way, according to the method of this embodiment, the person 7-
After the organic material film 8 is spin-coded on the Si alloy film 67, the surface of the organic material film 8 is selectively etched according to the height difference, and the surface is almost completely flattened. -A deposited! It is possible to significantly improve the film ItiT uniformity and surface flatness of the film 9 and the resist 10.

Therefore, the resolution of the resist 10 can be improved,
&, the machining accuracy of the #-8i alloy film 6 can be measured. In addition, since the film thickness of the organic material '1tHIX8 can be made thinner than in the conventional three-layer structure method of forming thin strips, the etching process for the organic material film 8 can be made more commercially viable. There is.

Note that the present invention is not limited to the embodiments described above. For example, an A4-84 alloy film 1 may be used as an abrasion-broken workpiece, but the present invention is not limited to this, and may be a polycrystalline silicon film, a silicon alloy film, or any other film provided on a substrate having unevenness or steps.

Furthermore, the present invention is not limited to wiring processing, but can be applied to an r-) electrode formation process and various other semiconductor element manufacturing processes. Also, @Inorganic material membranes are people! The material is not limited to a film, and may be any metal, metal oxide, glassy material, silicon compound, or the like. Further, the organic material film is not limited to a photoresist as long as it is a normal one-type resist, and deep UV resists and negative resists can also be processed under well-adjusted exposure conditions. The pond, of the present invention.

Various modifications can be made without departing from the spirit of the invention.

[Brief explanation of drawings]

FIGS. 1 to 8 are cross-sectional views showing the manufacturing process of a MOS transistor according to an embodiment of the present invention. 1...8L wafer, 2...field oxidation 1 conversion,
3...? -) Oxide film, 4... Polycrystalline silicon gate, 5... Oxide film, 6... A7-8+ alloy film (workpiece), 7... Source/drain region, 8... Organic material membrane. 9...AA membrane (inorganic substance film), 10... Renost. Applicant's agent: Takehiko Suzue, patent attorney
(NW & Yabu 0 size w &
taste

Claims (1)

[Claims] On a workpiece having steps or irregularities (two organic material films are provided, the surface of this organic material film is selectively etched, the surface is processed into a flat surface with no difference in height, and then an inorganic material film is formed on the organic material film). and a resist are sequentially provided, and then the above-mentioned resist (as desired) is exposed to light in the main turn.Then, the inorganic material film (1) is dry-etched using the resist (1) as a mask, and the organic material film is etched using the inorganic material film (1) as a mask. 1. A method for forming fine f-turns, comprising dry etching, and then dry etching the liquid-processed product using the organic material film as described above as a mask.