JPS6125140A - Polymer resist sensitive to energy rays - Google Patents

Abstract

PURPOSE:To enhance a glass transition point, oxygen plasma resistance, and heat resistance, and to enable this resist to be used for double layer resist process by using a silicone resin type resist specified in structural units. CONSTITUTION:The resist uses a polymer compd. composed of structural units represented by formulae I, II, III, and VI in which X is halogen, -O-CO-CH= CHR, -O-CH2-CH=CHR, or the like; R, R', and R'' are each H or alkyl; n is 1-5; when plural groups of -(CH2X) are combines with the units I, each X is same or different; the total number of the units I, II, and III are >=50, and a rate of ( I +II)/( I +II+III+IV) is <=80%, I /II=10-30%, III/( I +II+III+ IV)=5-10%. Such a resist can be improved in oxygen plasma resistance by the silicone structure, enhanced in glass transition point by the presence of naphthalene rings, and controllex in exposure characteristics by the presence of benzene rings enhanced in sensitivity by chloromethylation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to energy-sensitive polymeric materials, particularly to polymeric materials sensitive to electron beams, X-rays, ion beams, deep ultraviolet light, or ultraviolet light.

(Prior art and its problems) In recent years, improvements in the element characteristics and functionality of semiconductor devices have been extremely remarkable, but as the fields of use thereof have expanded, further improvements in performance have been required.

Although this can be achieved to some extent by devising circuits and increasing the size of chips, it is known that the most effective method is to miniaturize the elements. Conventionally, such processing has used photolithography technology that forms a resist pattern by irradiating ultraviolet light, but since there is a limit to processing accuracy on the order of the wavelength of light, it has been necessary to use deep ultraviolet, Xi, s-sonant, etc. The fine processing used has become important.

As a result of research on these new exposure technologies, we found that unless the resist film is exposed with a thin and uniform thickness,
Even using these new technologies, it has been found that processing of dimensions of 1 μm or less is difficult due to scattering phenomena and variations in the development process. However, in reality, complex steps are gradually formed on the substrate depending on the device manufacturing process, so making the resist thin enough to sufficiently improve resolution will allow the resist to wrap around the steps. Met.

Therefore, a three-layer resist process was proposed by Mr. J.M. Moran et al. of Bell Laboratories in the United States in a paper from Jakare ψ of Vacuum Science and Technology, Vol. 16, page 1620. It was done.

Although this method is extremely effective, since the process is complicated, an attempt was made to create two layers as shown in Japanese Patent Application No. 57-090639.

In this invention, a phenyl group is introduced to improve the glass transition point of the silicone resin, but it is difficult to achieve a glass transition point of 150°C or higher, and high melting point metal pastes such as refractory metals are difficult to achieve.・Some processes had drawbacks that made them difficult to use.

(Object of the invention) The present invention provides a silicone resin resist that can be used in two-layer resist processes, has a glass transition point higher than 150°C, and provides a polymer resist and process that can also be used in high-temperature processes. .

(Summary of the Invention) The present invention is an energy ray-sensitive polymer resist consisting of the following structural units (CH2X)n represented by the following general formulas:
In the formula, X is halogen, -U-0-OH=OHR.

-0-OH,0H=OI(R,-N)1-OH,0H=
O) 11-L.

And 1(,,)! , ', R'' are hydrogen or an alkyl group, n is a value of 1 to 5, and when multiple OH, X) are bonded to the structural unit α), X are the same or different. A substituent, which is the structural unit (I).

The sum of the numbers of ■ and [phase] is greater than or equal to (capital), and the ratio of the total number of structural units (I) and ■ to the total number of structural units is (
energy sensitivity, characterized in that the ratio of the number of (I) to the structural unit ■ is 10 to 30%, and the ratio of the structural unit - to the total number of structural units is 5 to 10q6. It was already known that introducing phenyl groups into silicone resin, which is a polymeric resist, improves the glass transition point. We can provide resist materials that are easy to use in two-layer resist processes, etc.

(Example) A copolymer of methylphenyl silicone and methyl, and a copolymer of naphthyl silicone and dimethyl silicone with a polymerization degree of 500 to 2.
After the phenyl group of the silicone resin No. 500 was chloromethylated with chloromethyl methyl ether, the resulting solution was made into a solution using chloromethyl methyl ether (isoamide acetate) to prepare a resist solution. Silicone is synthesized by hydrolyzing the corresponding chlorosilane compound in ethyl ether and polymerizing it with ammonium hydroxide. FIGS. 1 to 4 are drawings for explaining the case where the resist of the present invention is used in the Ge-1 wiring formation process, which is one of the steps of manufacturing a semiconductor device, and sequentially shows schematic cross-sections of the semiconductor device. It is a diagram.

11 is a silicon substrate, 12 is an isolation silicon oxide film, and 13 is a gate oxide film. First, apply novolac resin 14 to a film thickness of 1 to 10% as a base organic film for surface flattening.
Spin coating to a thickness of 5 μm.

15 is an example of the resist of the present invention.
．． It was spin-coated to a thickness of 2 μm to 1 μm. (Fig. 1) Then, for example, electrons Is with an acceleration voltage of 20 KV are selectively irradiated at a dose of about 5 x 10 clones/sl.
Developed with isoamyl acetate to obtain a negative tone/paddle turn, 0.0. I Torr -0,01 Torr
The underlying organic film is anisotropically processed by reactive sputter etching in a moderate oxygen atmosphere. (FIG. 2) The oxygen plasma resistance of the dimethylnaphthyl silicone film 15, which is obtained by chloromethylating a phenyl group, is about 10 times that of novolak resin, and it has been demonstrated that it exhibits sufficient resistance as an etching mask. Thereafter, a film 31 of a high melting point metal such as molybdenum is deposited by vacuum evaporation. The resist of the present invention has high heat resistance, does not change in quality even when a high melting point metal is vapor deposited, and acts as a protective material for the underlying organic film. (FIG. 3) Then, when it is immersed in a heated acetone solution, the underlying organic film is dissolved, and by a so-called lift-off process, the desired gate wiring pattern 41 is left and the high melting point metal and resist are removed in unnecessary parts.

As described in detail above, this is a high-resolution negative resist with a silicone structure that improves resistance to plasma, a naphthalene ring that raises the glass transition point, and a benzene ring that improves sensitivity through chloromethylation and adjusts exposure characteristics. However, the above examples are illustrative, and the improvement in the glass transition point due to the naphthalene group can be obtained for each composition ratio. It is clear that the substituents of the components can be varied.

In the present invention, the sum of the numbers of structural units (I) and 1 (n) l movements is set to 50 or more in order to form a uniform film when applied to a substrate.

Setting the proportion of structural units (T) to 5 to 10% is several tens of percent.
Desirably, the higher the number, the higher the glass transition temperature; however, if the number is too large, the sensitivity decreases.

The reason why the ratio of σ to the structural unit (■) is set to 10 to 3096 is that the lower limit wants to ensure sensitivity, and the upper limit wants to reduce dispersion.

Structural unit @, [D only has adhesion to the substrate.

Since coating properties deteriorate, the ratio of (I) to the total structural units is limited to a maximum of 10%, and the remainder is determined as a structural ratio.

Further, as X, halogen, -0-0-OH=OHR.

^ 10-OH,OH,=OHR,-NH-OH20H=O
When HR is used, it can be used for electron beams, It is also clear that improvements can be made through

(Effects of the Invention) Development of the high glass transition point, high oxygen plasma resistance resist of the present invention - As a result, the two-layer resist process, etc. has become extremely simple, and submicron exposure, which is essential for VLSI manufacturing, has become a reality. Ta.

[Brief explanation of the drawing]

FIGS. 1 to 4 sequentially show schematic cross-sections of a semiconductor device during the main steps of manufacturing the device in order to explain the effectiveness of the high glass transition point, plasma-resistant, energy-ray-sensitive polymer resist of the present invention. It is a diagram. The numbers in the figure indicate the following. 11: Semiconductor substrate 12: Oxide film for separator isolation 13 Niga If film J4: Base organic film for planarization 15: High glass transition point/plasma resistant resist film of the present invention 3I: High melting point metal 41: By lift-off process Patterned gate wiring metal film depth 1 Figure 2 Figure 3

Claims (1)

[Claims] Structural units represented by the following general formulas (I), (II), (III), and (IV) (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) ▲ Numerical formulas, chemical formulas , tables, etc. ▼ (III) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (IV) ▲ There are mathematical formulas, chemical formulas, tables, etc.
In the formula, X is halogen, ▲There are mathematical formulas, chemical formulas, tables, etc.▼
, -O-CH_2CH=CHR, -NH-CH_2CH=
CHR, ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and R, R', R'' are hydrogen or alkyl groups,
n is a value of 1 to 5, and when the structural unit (I) has multiple ▲ mathematical formulas, chemical formulas, tables, etc. ▼ bonded, X is the same or different substituent, and Unit (I)
, (II) and (III) is 50 or more, the ratio of the total number of structural units (I) and (II) to the total number of structural units is 80% or less, and the structural unit (II) The ratio of the number of (I) to the structural unit (I) is 10 to 30%, and the structural unit (
An energy-sensitive polymer resist characterized in that the ratio of III) to the total number of structural units is 5 to 10%.