JPS62287245A - Method for photoprocessing polycondensed aromatic high polymer - Google Patents

Abstract

PURPOSE:To carry out the photoprocessing the titled polymer with good efficiency, without remaining any heat history by photoprocessing the high polymer contg. the polycondensed aromatic compd. in the greater part of skeleton of the main chain of the polymer with UV rays. CONSTITUTION:The high polymer contg. the polycondensed aromatic compd. such as a naphthalene nucleus or an anthracene nucleus in the greater part of the skeleton of the main chain of the polymer is photoprocessed by the UV rays. the polycondensed aromatic compd. constituting the skeleton of the polymer is the high molecular compd. which has the condensed aromatic compd. such as naphthalene and anthracene, etc., as a special feature. The titled polymer comprises the high polymer of the polycondensed aromatic compd. in which the aromatic nucleus such as naphthalene and anthracene, etc. has the substituent substd. with alkyl group (R group), and has the substituent capable of reducing an electron density of the aromatic nucleus such as the side chain R group substd. by a halogen atom, and also, has the substituent capable of controlling the rate of the photoprocessing by substituting said aromatic nucleus with one or more halogen atoms.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention The present invention is a polymer that is easily photoprocessed by ultraviolet rays, and has at least two or more aromatic nuclei such as a naphthalene nucleus or anthracene nucleus in most of its main chain. The present invention relates to optical processing of polycyclic aromatic polymers.

The method of the invention is (1) Photooxidative decomposition easily occurs when exposed to ultraviolet light.

(2) Photooxidative decomposition occurs efficiently when irradiated with ultraviolet laser.

However, (3) the physical properties of the polymer in the areas that were not irradiated and the areas where the light did not reach hardly change.

Because it has the following characteristics, it can be used for the various purposes listed below.

■ Photoresists for dry etching (in which the side chain alkyl group of the aromatic nucleus is substituted with halogen) used in processes such as the production of semiconductor integrated circuits, photoelectroforming processing, chemical etching of metal plates, and production of printed wiring boards. Direct etching photoresist (if polymer is not used) ■ Read-only memory (Read only memory)
Memory (hereinafter abbreviated as ROM)) organic polymer base material (R that can potentially integrate memory in a direction that overlaps the surface)
OM) III Organic polymer materials for microporous membranes (tape-like ribbon tape materials for thermal transfer (used multiple times), etc.; small items such as contact lens materials that are easily permeable to oxygen); Because the processing is unique and easy, it is possible to perform layered processing, and it is possible to perform hole-drilling with ultraviolet rays without leaving any thermal history, surface processing without cutting, and so on. It is something.

Relationship with prior art In recent years, photoetching and optical processing technologies have rapidly advanced.
In addition to efforts to use light beams, many proposals have been made to streamline the process. For example, N. Ueno, etc.
se Journal of Applied Phys.
sics Vol, 20. No, 100ctober
L709-L712 (1981)) has a wavelength of 180-2
They have attempted dry etching of photoresist using 90nmO far ultraviolet rays, and have made an extremely interesting report that the development step can be omitted.

The photoresists used were poly (methyl methacrylate), poly (methyl isopropenyl ketone), and Nohoga AZ-1350 (novolac resin improved with naphthoquinone-〇-siaside), and the discharge lamp was a German thium discharge lamp ( Deuterium D
ischarge lamp).

Furthermore, as a method for three-shot photoetching of a polymer by irradiating the polymer with ultraviolet rays with a wavelength shorter than 220 nm, R. Srinivasan of International Business Machines Corporation (hereinafter abbreviated as 18M Company) Ablative Photo
This is a well-known reaction that is widely known as an effective method for decoaposition.

Also in our country: ・Publication: 1980-12945 Method of etching polyester: Special publication 1987-69931 Method of etching polyimide: Special publication: 1987-105638
A method for deep ultraviolet patterning of resist materials has been filed by IBM.

However, the above-mentioned prior art uses only deep ultraviolet light with a wavelength shorter than 290 nm, and is a photo-processing technology that targets only aliphatic compounds and monocyclic aromatic compounds as organic polymers. is obvious.

For example, the above-mentioned IBM Publication No. 59-12945 clearly states that high-pressure mercury lamps, xenon lamps, and carbon arc lamps are ineffective for the induced photolysis reaction and cannot be used.

Also, the subsequent reports of R Srinivsan and others (e.g. J, Aa, Che positions).

Soc, 19g4,106. 4288-4290+
Journal or Polymer 5c
ience Polym■■ Chemistry Edition, Vol, 22
．． 2601-2609 (1984), etc.), the polymers that are the subject of research are poly(methyl methacrylate), poly(ethylene terephthalate), polycondensation polyimide of benzenetetracarboxylic acid and monocyclic aromatic diamine, and monocyclic Aromatic polycarbonate, i.e. aliphatic.

Limited to monocyclic aromatic polymers.

Polymers mainly used as photoresist materials that utilize ultraviolet light include O-water-soluble colloid photoresists (e.g., poly(vinyl alcohol)); Rubber photoresists (monocyclic aromatic bisazide) and the like are all aliphatic and monocyclic aromatic polymers.

Polycyclic aromatic compounds are used up in quinone/diazide photoresists, but this takes advantage of the property of quinone/diazide to release nitrogen when exposed to light, and polymers such as those of the present invention are used. This is a photoresist that utilizes a photoreaction that is essentially different from the photooxidative decomposition caused by ultraviolet rays.

Further, some photosensitive polymers contain anthracene groups as photosensitive groups, but all of them are photosensitive polymers of the photodimerizable type and are not photodegradable polymers.

The influence of the wavelength of ultraviolet rays differs between aliphatic and monocyclic aromatic polymers and polycyclic fused aromatic polymers.

Report by R Srinivsan (Journal o
f Poly layer er 5science Po
According to Lymer Chemistry Editorial Vol. 22.2601-2609 (1984)), aliphatic polymers (e.g. poly(methyl methacrylate)) and monocyclic aromatic polymers (e.g. poly(ethylene terephthalate)) have a wavelength of 248 nm and 308 nm. etching is carried out by a laser having a wavelength of 193 nm, but it has been reported that when light with a wavelength longer than 193 nm is used, the mechanism of induced decomposition is more dominated by thermal decomposition than by photodecomposition. This suggests that the more efficient etching is attempted, the more the polymer will be etched by thermal decomposition, making it more difficult to process without leaving any thermal history.

Based on the above knowledge, the present inventors have discovered that ultraviolet rays from discharge lamps,
The present invention was achieved as a result of intensive searches for organic polymers that can be easily optically processed (with little contribution from thermal processing) even with lasers that emit wavelengths shorter than 380 nm.

That is, the present invention efficiently photoprocesses a polymer containing a polycyclic condensed aromatic compound such as a naphthalene nucleus or anthracene nucleus in the skeleton of most of the polymer using ultraviolet rays without substantially involving thermal processing. It's a method.

The polycyclic condensed aromatic compound constituting the polymer skeleton is a polymer compound characterized by being a condensed aromatic compound such as naphthalene, anthracene, etc., and an alkyl group in the aromatic nucleus of the naphthalene, anthracene, etc. (hereinafter abbreviated as R group), there is a halogen in the side 11R group! l! Substituted R group, methoalkoxy group, hydroxy group, aniline group, N(
R) 2 groups, NHCOR group.

A monosubstituent that causes electron accumulation in an aromatic nucleus such as, or a nitro group or a sulfone group.

502R group, cyano group, aldehyde group, COR group, carboxylic acid group.

Polycyclic fused aromatics whose photoprocessing speed is adjusted by substituting one or more halogen groups in addition to substituents that reduce the electron density of aromatic nuclei such as carboxylic acid ester groups, NH3 groups, and NR3 groups. Compound-based polymers also belong to the cylindrical portion of the target polymer composition of the present invention. Further, the polymer composition may be synthesized by radical polymerization or condensation polymerization, and may be a crystalline polymer or an amorphous polymer. Crystalline polymers can be used unoriented,
There is no problem in subjecting it to optical processing in a biaxially oriented state or providing it on the market as a final product.

Furthermore, it may be copolymerized with other polymers to the extent that the physical properties of the polymer are not significantly affected or to increase added value.
It cannot be argued that blending or block polymerization, addition of photosensitizers, catalysts such as dyes as photosensitizers, salts of transition metals as catalysts, etc. are outside the scope of the present invention. .

The ultraviolet rays used for optical processing are so-called ultraviolet rays having a wavelength shorter than 380 nm, but there is no problem with light including visible light, such as sunlight.

If it is desired to carry out optical processing over a wide area, sunlight (or light collected by a Fresnel lens or the like) may be used as shown in Example 1.

However, industrially, discharge lamps (high-pressure mercury lamps, xenon lamps, carbon arcs, mercury resonance lamps, etc.) are used, and by stacking multiple of them, a relatively large area can be illuminated with high efficiency. It can be processed.

At this time, if a precise pattern is required, it is possible to achieve the same degree of precision processing by using technologies, processes, and equipment used in integrated circuit processes, such as photomax and wafer exposure aligners. It can be done.

An example of the industrial effects of the present invention is that when the technology accumulated in the integrated circuit process is applied to the target polymer of the present invention, highly functionalized products can be created. That is,
If a photomask with a pattern of an arbitrary shape is used, the arbitrary pattern can be accurately transferred onto the surface of the target polymer of the present invention. In addition, injection molding and thermal processing can cause the workpiece to have a long thermal history. Whereas it is possible to manufacture products only in the same state, the present invention makes it possible industrially to obtain products that leave almost no thermal history.

Furthermore, by continuing the optical processing, a large number of holes having an arbitrary pattern can be formed on the surface of the target polymer of the present invention to an arbitrary depth, if desired.

Microporous membranes using polymers include Voretex,
Products such as Fluorobor, Duraguard, Millipore, and Nuclear Boar (all trade names) have been developed and evaluated in related industries, and there is no shortage of ways to use them that are appropriate for their characteristics.

However, these microporous membranes have the disadvantage that the holes cannot be formed into arbitrary shapes. However, by combining the target polymer of the present invention with existing technology that generates light with a wavelength shorter than 380 nm and technology that utilizes it, a microporous membrane having an arbitrary shape can be created.

Ultraviolet lasers, which are currently reaching the level of technological perfection, can also be used in combination with lasers with wavelengths shorter than 380 nm and the target polymer of the present invention. This results in efficient imparting to the target polymer.

These lasers include N2 (wavelength 337 nm),
XeC1 (wavelength 308 nm), YAG (1/4 wavelength (
4th harmonic) 256nm), KrF (wavelength 248nm)
There are lasers such as ArF (wavelength: 193 nm). When these laser beams are focused using an optical system such as a lens to perform optical processing such as drilling or cutting, the target polymer of the present invention is an extremely suitable polymer as it leaves almost no thermal history. becomes.

Furthermore, if technology under development for semiconductor laser printers and related technology such as optical system technology such as polygon mirrors and Fθ lenses can be utilized, porous films having a large number of micropores per unit area are also covered by the present invention. It can be made using polymers.

On the other hand, technologies that are thought to be possible by dispersing laser light using lenses, etc. or using low-output discharge lamps modify the surface of the target polymer (for example, changing hydrophobicity to hydrophilicity). ).

Another way of combining an ultraviolet lamp or a discharge lamp with a photomask and the target polymer of the present invention is to combine a plurality of photomasks.

In this case, the target polymer of the present invention will have a plurality of etched holes of different depths in the direction perpendicular to the plane, depending on the number of photomasks used.

Therefore, if a method to read out etched holes (memories) with different depths is developed, the memories can be written not only on the plane but also in the vertical direction! This suggests that the polymer targeted by the present invention can be used as a substrate for ROM.

Next, we will discuss optical processing conditions (temperature, irradiation atmosphere).

As for the optical processing temperature, the higher the temperature, the faster the optical processing speed becomes. However, in general, the temperature range may be from room temperature to 100°C. However, in the case of a polymer that is difficult to process, the temperature may be further increased, or other long wavelength light irradiation such as three infrared rays, infrared rays, carbon dioxide laser, etc. may be used supplementarily.

Optical processing can be diluted with nitrogen to reduce its speed.
; Although the irradiation may be carried out in air or under reduced pressure, the processing speed is generally much faster when the partial pressure of oxygen in the atmospheric gas is high, and it is also preferable to carry out the irradiation under pressure.

It has been reported that in the prior art utilizing only deep ultraviolet rays, the processing speed does not change or significantly increase even if the oxygen partial pressure in the irradiation atmosphere is increased.

(For example, N Ueno etc. Japanese Journ
al or Applied Physics Vol.
.

20,Ho1O,0ctober L709-L712
．． R Srinivsan et al. Journal orPol
ymer 5science Po1y@er Che
Mistry Edition Vol, 22.260
1-2609 (1984)). However, for the target polymer of the present invention, the processing speed can be significantly increased by increasing the oxygen partial pressure within a range where oxygen does not significantly change to ozone.

This can be taken as one evidence that the present invention is a technology different from the prior art.

Further, optical processing can also be carried out by immersing the target polymer of the present invention in an aqueous solution, for example, an alkaline aqueous solution.

Hereinafter, poly(ethylene naphthalate-2.6) (hereinafter referred to as P
As a comparative example, poly(ethylene terephthalate) (hereinafter abbreviated as PET) will be shown as an example.

However, the following examples do not in any way limit or restrict the claimed scope of the subject polymer composition of the present invention.

Example 1 Photoprocessing using sunlight A biaxially stretched PEN-2/6 film (100c++xlOOc++) of outdoor grade having the physical properties shown in Table 1 was
x20.3 ul in 101 with a 1cm diameter hole.
The sample was sandwiched between a slate plate measuring 0.00 cm x 100 cm and a slate plate without holes, and the surface with holes was exposed to sunlight while holding the plate vertically.

When the film sample was taken out and examined after 180 days, it was found that the hole was completely formed in the area where the hole had been made in the slate plate. Therefore, on average, 1100N of Esotig was used per day (sunshine hours).

Table - Physical properties of outdoor PEN-2 and 6 films (measured values in the TD direction) (Note) Unless otherwise specified, the measurement methods are the same and the units are expressed in the same units.

Note that TD indicates the width of the film, and MD indicates the direction in which the film is pulled out.

For comparison, general electrical grade biaxially stretched PEN-2/6
Film and biaxially stretched PET film (@ inside, product of company T)
It was tested by exposing it outdoors. In order to examine the physical properties of the remaining film that was not etched by light, a test was conducted by exposing the entire surface of the film to sunlight. Table 2 shows the results of examining changes in film thickness after 3 months.

Table 3 shows the changes in the physical properties of the PEN-2/6 film before and after the test, and Table 4 shows the changes in the physical properties of the PET film before and after the test.

Table 5 Etching test using sunlight PEN-2 and 6 films have PE in both secondary dislocation point and softening point.
It was found that although the heat resistance was higher than that of T film at about 40° C. and about 100° C., the etching speed by sunlight was more than 5 times faster.

Table 5: Etching test using sunlight (changes in physical properties of PEN-2 and 6 films, direction of MD force)
Table 4 Etching test by sunlight (physical property change of PET film, MD force direction measurement) As shown in Tables 5 and 4, PEN-2 and 6 films were etched by sunlight. Despite the ease of etching, the physical properties of the parts not etched by light did not change significantly.

Therefore, although the biaxially oriented PEN-2.6 film is easily etched by ultraviolet rays, its weather resistance under natural conditions is superior to that of the biaxially oriented PET film. (References: I Ouchi et al.

Proc, 17thJapanCongr, Intermediate
, Res, 217 (1974)) Example-2 Optical processing using a high-pressure mercury lamp Biaxially stretched PEN-2 of various thicknesses as shown in Table 5
6 film with high pressure mercury lamp (Toshiba &! H400P 4
00W) and the change in film thickness was measured.

This high pressure mercury lamp has wavelengths of 546nm, 436nm, and 570nm.
, 402 nm.

This lamp emits light with wavelengths of 313 nm, 13020 m, and 209 nm, and its relative intensity also decreases in the above order.

The distance between the mercury lamp and the film sample was 20c1, the atmosphere was air, and the temperature was maintained at 50-60'C.

Table 5: Etching test by high-pressure mercury lamp irradiation (biaxially stretched PEN-2/6 film) Precision injection molding is an industrial technology for precision processing at a depth of about 100 OA in the direction perpendicular to the plane, such as compact desks, It has already been established as a manufacturing method for video desks, and many of its products are already on the market.

As shown in Table 5, the etching rate perpendicular to the plane of a discharge lamp with a wattage of 400 W is as slow as 160 to 240/hr, but industrially
Among lamps, mercury short arc lamps, deep ultraviolet lamps, etc., discharge lamps of 3 to 6 kW or more are available on the market. Therefore, if you select an appropriate lamp from among these lamps depending on the purpose and appropriately select optical processing conditions such as temperature and oxygen partial pressure, it is possible to optically process PEN-2 and 6 under economical processing conditions. .

Procedural amendment September 9, 1986

Claims (1)

[Claims] A method for photo-processing polymers containing polycyclic fused aromatic compounds in most of the main chain of the polymer using ultraviolet rays.