JPS5868743A - Radation sensitive organic polymer material - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

The present invention is a positive radiation-sensitive organic polymer material that is highly sensitive to radiation such as electron beams, X-rays, and ion beams and is suitable for forming fine patterns necessary for manufacturing semiconductor devices, magnetic bubble memory device integrated circuits, etc. Regarding. Conventional semiconductor devices, magnetic bubble memory devices. As a pattern forming method for manufacturing electronic components such as integrated circuits, methods using photoresists that are sensitive to ultraviolet or visible light have been widely put into practical use. For the purpose of integration, 1
There is a need for a method of forming patterns with a width of .mu.m or less. However, with the above method of using light, it is extremely difficult to accurately form a pattern with a width of 1 μm or less due to the unique properties of the light, such as diffraction, scattering, and interference, and at the same time, it is difficult to form a pattern with a width of 1 μm or less, and at the same time, the yield is reduced. The degradation was also significant, and methods using ultraviolet or visible light were unsuitable for forming patterns with a width of 1 μm or less.In response to this, recently, microfabrication using ultraviolet or visible light has been developed. As an alternative to photo-etching techniques, lithography techniques using high-energy radiation such as electron beams, The fee is determined by lottery N-J
has been done. Among these, positive-acting radiation-sensitive materials, such as poly(methacrylic acid methyl), poly-(1-butenesulfone), etc., undergo a cross-linking reaction when irradiated with radiation, and the irradiated area becomes non-bathable in the developer and forms a pattern. ,
Because the gamma value calculated from the sensitivity time curve is large,
Generates high-resolution patterns (resist for microfabrication)
This is extremely convenient as an I charge. However, the sensitivity of positive-type sensitive organic polymer abrasives, including the above-mentioned abrasive materials, is 1/10 to 1/1000 lower than that of negative-tone abrasives, and as a result, the time required for pattern formation is longer. It lacked practicality. In addition, in recent years, with the increasing density and integration of semiconductor devices, dry etching using plasma or accelerated ions has been increasingly used in microfabrication technology instead of conventional wet etching. It is becoming essential for polymeric materials to withstand the above-mentioned dry etching. However, positive-type sensitive organic polymeric materials have inferior dry-etching resistance compared to negative-type ones.
This was a decisive practical drawback. The object of the present invention is to overcome the drawbacks of the prior art as described above, and to develop a positive-type radiation-responsive organic polymer that is sensitive to high-energy radiation such as electron beams, X-rays, and ion beams. In particular, positive-acting radiation is characterized in that the irradiated area becomes soluble in an alkaline solution due to the formation of carboxyl groups (-COON) in the molecule by radiation irradiation, so that alkaline development is possible. A) It provides sensitive organic 11 & 1 molecule-4A family. In order to achieve the above purpose, the inventors have developed this type of material by cutting various organic polymer materials that are considered to be radiation sensitive.

[Secondly, CI-II as well. H. (In the formula, 1. represents a methyl group, ethyl group, n-propyl group, or phenyl group, and 1 (2. represents ice water, an argyl group, an aryl group, or an aralkyl group. 1 also represents hydrogen, an alkyl group, an aryl group, an aralkyl group, or a halogen atom. In the formula, 1 represents a methyl group, ethyl group, n-propyl group, or phenyl group, and approximately represents an alkyl group, aryl group, or aralkyl group, and the ratio is hydrogen, an alkyl group, an aryl group, an aralkyl group, or (Represents a halogen atom. n represents a numerical value indicating the degree of polymerization.) An α-substituted acrylic ester polymer was found. It is used as a combination or a copolymer of two or more monomers.Furthermore, a repeating unit consisting of an α-substituted acrylic acid ester polymer represented by the above general formula f+'L and Gl. Co-11 [combinations] containing repeating units obtained by 111-combination of addition-intellectual monoliths with 11-1 can also be used as lj't QJ-ray heat-sensitive organic polymer materials. That is, the above-mentioned IIL combinations are 1 '1 Oji Line, X
In addition to cutting polymer chains by irradiation with high-energy radiation such as ion beams or ion beams, carboxyl groups (-C(ni)II) are generated in molecules, and as a result, the irradiated part Since it is soluble in IJ% solution, it can be used as a positive radiation-sensitive organic polymer that can be developed with alkali. It has excellent resistance to etching 1/j: In addition, since only the irradiated portion becomes soluble due to alkaline development, a resist pattern with extremely high ii4+ l')'I' image quality can be obtained, resulting in radiation sensitivity. 1/l: d) By performing alkaline reaction 1□□□, it becomes extremely ll/I< /:
For example, polymethacrylic acid α, α-dimethylbenzyl (
In the general formula (2) described above, R1 is a methyl group,
The figure shows the change in the infrared absorption spectrum when (, 2 represents a methyl group and R8 represents hydrogen) is irradiated with an electron beam. That is, the infrared absorption spectrum of polymethacrylic acid α,α-dimethylbenzyl before electron beam irradiation is as shown in Figure 1.
o −' C/alr electron beam irradiation, as shown in Figure 2, 1729.1132.764 and 70
The absorption characteristic of α,α-dimethylbenzyl polymethacrylate at 0cm-' decreases, and instead the absorption of 1707.1175 and 1265tyn' characteristic of polymethacrylic acid appears, and the carboxyl group (-(:00H )
was confirmed to be generated. In addition, 6 in the figure is an infrared absorption spectrum of polymethacrylic acid synthesized separately, and is shown as a reference. Since polymethacrylic acid produced by electron beam irradiation is alkali-soluble, only the electron beam irradiated area can be selectively removed by alkaline development.
A positive resist pattern can be obtained. Next, according to the present invention, 1M φ)tj '4-ru4'' book 1
I will explain about it. The radiation-sensitive organic polymer used in the present invention can be obtained as follows. In other words, 1? . , 1 Crystal 1 et al. 1 (6 (In the formula, R represents a methyl group, ethyl group, +1-propyl group, or phenyl group, It represents hydrogen, an argyl group, an aryl group, or an aralgyl group J, l; (an alkyl group substituted with an aryl group), and 几. represents hydrogen, an alkyl group, an aryl group, an aralkyl group, or a halogen atom. 〇 Random = C ■ -0 ζ Hole (In the formula, the value represents a methyl group, ethyl group, n-propyl group, or phenyl group, the ratio represents an alkyl group, aryl group, or aralkyl group, and the ratio represents hydrogen, alkyl group) represents a group, an aryl group, an aralkyl group, or a halogen atom.+
- + one time - one ice cream - table - b - su -
) Polymer monthly yield obtained by combining one or more of the monomers represented by the formula (5) or (1) by radical polymerization or anionic polymerization, or by combining one or more of the monomers represented by the general formula (5) or (1).
A polymeric H material obtained by combining one type of 1- and an addition-polymerizable monomer with C1, =C group -fili l:J,''- by vinyl polymerization is radiation-sensitive. Used as an organic polymer. Incidentally, regarding CI (,=C group-containing monomers which are copolymerized with monomers represented by the general formula (A) or (17), such as methacrylic acid alkyl esters, etc. For those in which a carboxyl group (-00011) is generated in the polymer by irradiation with radiation, any copolymerization composition with the monomer shown in general formula (A) or (1'9) may be used, and α-methyl For polymers such as styrene and isobutylene in which carboxyl groups are not generated in the polymer by irradiation with radiation, the copolymerization composition is as follows: 999 molar ratio, preferably 90 to 001 molar ratio.If it is more than 90 molar ratio, the alkali solubility of the irradiated area after radiation irradiation will not be large, resulting in low radiation sensitivity, making it impractical for practical use. When using the radiation-sensitive organic polymer material of the present invention to form a pattern of a semiconductor element, etc.,
It is used dissolved in a common organic solvent such as toluene, and is usually spin-coated onto a device substrate. After coating, prebaking at appropriate temperature conditions,
After irradiating a desired pattern with radiation, a resist pattern is obtained by dissolving the irradiated portion in a developer. At this time, a methyl isobutyl ketone-isoglobil alcohol organic solvent can also be used as the developing solution, but it is possible to use a high-resolution resist F with a small amount of radiation exposure needle.
To obtain a pattern, use an alkaline developer, for example, a developer prepared by dissolving sodium alcoholade in alcohol, an organic or inorganic basic developer such as pyridine/piperidine, trimethylamine, triethylamine, sodium hydroxide, tetramethylammonium hydroxide, etc. It is extremely convenient to use a liquid solution prepared by dissolving the substance in alcohol or the like. The present invention will be explained in detail below with reference to Synthesis Examples and Examples. Add ethyl yo-tyl and α. α-Dimethylbenzyl alcohol 139. ! I+,)
1) 1) Add 250 ml of ethylamine, press #1, and drop a mixed bath solution of 156 g of methacrylic acid chloride and 200 yy+l of ethyl ether from 7N-1" over a period of about 5 hours. After dropping, continue IW stirring. The upper flask was heated in a water bath, and the reaction mixture was refluxed for about 5 hours. After reflux, 500 Tnl of water was added to stop the reaction. The ether layer was separated by decantation, and saturated ammonium chloride was added. Washed 6 times with an aqueous solution and then 3 times with a saturated sodium carbonate solution.Finally, anhydrous sodium chloride was added to the ether bath solution and left to dry overnight.After separating the desiccant, Ethyl ether is distilled off, θ
, 129 g of α,α-dimethylbenzyl methacrylate (?Jli point: 58-61°C, 10.6 degrees Celsius) was obtained by pouring it onto NI. Put 200ml of ethyl ether into a three-necked flask, add 129g of 1-phenylethanol and 200ml of triethylamine, stir, and add 130ml of methacrylic acid chloride from the dropping funnel. A mixed bath solution of F and 200 ml of ethyl needle was added dropwise over about 2 hours. After the dropwise addition was completed, the flask was heated in a water bath while stirring, and the reaction mixture was refluxed for about 10 hours. After refluxing, 5 DO ml of water was added to stop the reaction, the ether layer was separated by decantation, and diluted 6 times with a 51% salt aqueous solution, followed by 10 wt. of hydrogen carbonate).
Finally, anhydrous sodium sulfate was added to the ether bath solution, and the mixture was left to stand overnight to dry. After separating the drying agent, ethyl ether was distilled off, and α-methylbenzyl methacrylate (boiling point: 60-6
6° C. 10.2 noni(j') 1501 was obtained. Synthesis 1+It 5 methacrylic l'121-(7) Substituted phenyl)ethyl was synthesized in a similar manner to the procedure demonstrated in Synthesis Examples 1-2. The synthetic sugeem is as follows. 1 (However, ltl represents an argyl group, an aryl camphor, an aralkyl group, or a halogen atom.) That is, 1'l' L of 1-(monosubstituted phenyl)ethanol and triethylamine are stirred in ether, and methacrylic acid chloride is added to the mixture. 1-(monosubstituted phenyl)ethyl methacrylate was obtained by adding the mixture dropwise and carrying out an acid-reducing reaction. Synthesis Example 4 Synthesis of 1-methyA-1-(monosubstituted phenyl)ethyl methacrylate was carried out in the same manner as in Synthesis Examples 1 and 2. The synthesis scheme is as follows. C 1゜ri. (However, H represents an alkyl group, an aryl group, an aralkyl group, or a halogen atom.) That is, 1-methyA
-1-(mono-substituted phenyl) 1-methacrylic acid A-1-(mono-substituted phenyl) is obtained by stirring ethanol and triethylamine in ether, adding one volume of methacrylic acid chloride thereto, and performing a dehydrochloric acid reaction. I got Ethyl. Synthesis Example 5 A 11-inch three-bottle flask equipped with a stirrer, a reflux condenser, and a dropping funnel was placed in a Schiff-T Nirno-sized flask. norl 13sy, t-
106 g of IJ ethylamine, 240 ml of dry ether, and 2.4 g of cuprous chloride were added, and a mixed bath solution of 94.9 ml of methacrylic acid chloride and 240 ml of dry ether was added dropwise from the dropping funnel over about 1 hour without stirring. Thereafter, the mixture was heated under reflux for 3 hours to complete the reaction. After distilling the supernatant reaction product into ether M7, the product in the remaining solid was triturated with ether. Both ethers Mi were combined and washed four times with 30 [] ml of water. This wash #Ik was extracted twice with a needle of 150 m/m, combined with the former ether bath solution, and this was washed with a ladle of water of 500 m/m.
once in m1, then 2N-J'AA 111! l730
0yn/dero times, history 0.7N-jg, sodium carbonate i
After washing twice with 600ml of water, it was dried with 50ml of anhydrous 1pIC acid magnesium overnight. Ether was distilled off from this heavy liquid to obtain crude crystals of diphenylmethyl methacrylate. After recrystallizing this from petroleum ether, it was circularly crystallized from seed degree I]-hexane to obtain diphenylmethyl methacrylate 1s2y (melting point near 8-79
- Synthesis Example 6 5 g of α,α-dimethylpendino methacrylic acid obtained in Synthesis Example 1 was subjected to bulk polymerization at 1.4 iOC for 10 hours using 0.04 g of azobisisobutyronitrile as a polymerization initiator. . The polymerization was carried out in a sealed tube filled with N2 gas. The obtained polymer was dissolved in about 20 ml of toluene and filtered through a glass filter to remove a small amount of insoluble matter.
00mA! of methanol to obtain a white powdery polymer. As a result of measuring the N weight average molecular weight of this polymer by liquid chromatography, it was found that the average molecular weight of this polymer was approximately 1
It was 200,000. Synthesis Example 7 5 g of α-methylbenzyl methacrylate obtained in Synthesis Example 2 was subjected to bulk polymerization at 60° C. for 10 hours using 0.04.9 g of azobisisobutyronitrile as a polymerization initiator. The obtained compound 1 was purified in the same manner as in Synthesis Example 6 to obtain poly(α-methylbenzyl methacrylate) having a weight average molecular weight of about 1.5 million. Example 1 Poly(α, α-dimethylbenzyl methacrylate) obtained in Synthesis Example 6 was dissolved in toluene to prepare a 5 mfit% resist solution. Subsequently, the above resist solution was spin-coated on the silicon wafer at 1100 rpm to form a polymer film with a thickness of 07 μm. After silibakeing this at 90° C. for 30 minutes, it was placed in an electron beam irradiation device and irradiated with an electron beam at an acceleration voltage of 20 KV in a vacuum with different irradiation doses depending on the location. After soaking for 6 minutes in a developing solution consisting of a 5% by weight methanol solution of IJ um methylate or a developing solution consisting of methyl isobutyl ketone-isoglobil alcohol (1:3 volume ratio), it was soaked in methanol or inglobil alcohol. The irradiated area was dissolved and removed by rinsing. The film thickness of the remaining polymer film was measured using a thin-film step meter for the irradiated area at various different irradiation doses, and the remaining film thickness (normalized) was expressed as the electron beam irradiation amount (coulombs/cal). On the other hand, Figure 2, which shows the electron beam sensitivity characteristics of the blot film, was obtained.From this, the maximum irradiation amount at which the residual film rate becomes zero was determined.
'Coulomb/C shoulder), when using an organic developer 6
X10-'coulombs/', and it was found that by performing alkaline development, it exhibited a sensitivity that was one order of magnitude higher than that of, for example, polymethyl methacrylate, which is a typical positive resist. Next, when ion etching was performed at an argon gas pressure of 2 x 10-' Torr1 and an ion energy density of 0.25 W/A*I, the ion etching rate of this polymer was 200 A/min, which was lower than the ion etching rate of polymethyl methacrylate. It was about 50%, which was low. The ion etching rate of silicon oxide film is approximately 2004/
Therefore, etching of the substrate is possible by applying a resist film that is at least twice as thick as the silicon oxide film, taking into account the non-uniformity of etching. Example 2 The poly (α-methylbenzyl methacrylate) obtained in Synthesis Example 7 was made into a 6]L% toluene solution and a 1 μm thick polymer film was formed on a silicon wafer in the same manner as in Example 1. Ta. After prebaking at 90°C for 30 minutes, the sample was irradiated with an electron beam at an accelerating voltage of 20 KV, and developed with a 5% methanol solution of sodium menalate.The minimum irradiation dose at which the residual film rate was zero was determined. 5X10-
' Coulomb/II, showed no contrast, had a large gamma value of 5, and was confirmed to have excellent Wr image properties.1. Examples 3 to 8 Radiation of various compositions was prepared in the same manner as in Synthesis Examples 6 and 7. A sensitive polymer material was synthesized and dissolved in toluene in the same manner as in Examples 1 and 2 to prepare a resist bath solution. This was spin-coated onto a silicon wafer to form a polymer film about 1 μm thick. Next, the acceleration voltage is 20! <V electron beam or accelerating voltage 1
Wavelength 4.2A from oKV rotating water-cooled silver countercurrent
Determine the electron beam sensitivity or X-state sensitivity using soft X-rays. The results are summarized in the table, and it was confirmed that all of them had good sensitivity to radiation and excellent resolution, and that an excellent positive resist was obtained. Example 9 0.7% of poly(methacrylic acid (χ, α-dimethylbenzyl)) on a silicon wafer prepared in the same manner as in Example 1
A thin film with a thickness of μ7i is irradiated with electron beams with different irradiation levels at different locations, and a developing solution consisting of a 5% by weight methanol solution of triethylamine, an original image solution consisting of a 5% by weight methanol solution of sodium hydroxide, or The irradiated area was dissolved and removed using a developer consisting of a 5% water bath solution of tetramethylammonium hydroxide. In the same manner as in Example 1, the minimum irradiation dose at which the remaining film rate was determined was 8×10′Ω and 1.2×, respectively.
It was confirmed that the size was 10' x 1.2 x 10' C, and God's alkaline bath solution could be used as the developer. Comparative Examples 1 and 2 Tani 411 in the same manner as in the example! A radiation-sensitive polymer material having a composition (not according to the present invention) was synthesized from Synthesis 1, and the electron beam sensitivity was determined. The results are shown in the table,
All of the samples in this comparative example had poor sensitivity to electron beams (and could not be put to practical use). As is clear from the explanation in Part 1 below, if the radiation sensitizer polymeric material according to the present invention is used, for example, in conjunction with an electron beam resist to produce a chrome mask for semiconductor device production, a mask with extremely high pattern accuracy can be produced. It can be made. In addition, it is possible to form a resist film with extremely high pattern precision by double contact drawing using electron beam irradiation or by batch irradiation with X-rays, and in the field of semiconductor industry, it is possible to form a resist film with extremely high pattern precision. It can be put to practical use in manufacturing semiconductors and the like. As described above, the monomolecular material according to the present invention is extremely effective.

[Brief explanation of drawings]

Figure 1 shows the infrared absorption spectrum of polymethacrylic acid α, α-dimethylbenzyl after electron beam irradiation ll1l and Seiko ray irradiation, and the electron beam sensitive %'+4 of the infrared responsive polymer material of polymethacrylic acid. It is. 1-3: Infrared pure absorption spectrum

Claims (1)

[Claims] 1. Carboxyl groups (-COO
H) A radiation-sensitive organic polymer compound forming a positive resist characterized by being composed of an organic polymer compound produced by H). 2 Organic polymer compounds become 1! CHL too. (In the formula, 1 (1 represents a methyl group, ethyl group, n-propyl group, or phenyl group, R1 is hydrogen, an alkyl group, an aryl group, or an aralkyl group (also σ in which the alkyl group is substituted with an aryl group)) 1 is hydrogen, an alkyl group,
Represents an aryl group, an aralkyl group, or a norogen atom. n represents a numerical value indicating the degree of polymerization. ) ■ C(C+L) li,. 1(,. (In the formula, It represents a methyl group, ethyl group, [1-propyl group, or phenyl group, 1mo represents an alkyl group, aryl group, or aralkyl group [(, represents hydrogen, an alkyl group, an aryl group, an aralkyl group, or a halogen atom.■ represents a numerical value indicating the degree of polymerization). The radiation-sensitive organic polymer material according to Item 1. 6. The organic polymer compound is CHR. It represents an alkyl group, an aryl group, or an aralkyl group (an alkyl group substituted with an aryl group), and R1 represents hydrogen, an alkyl group, an aryl group, an aralkyl group, or a halogen atom. n is a numerical value indicating the degree of polymerization. ) or C (CI 1.) 11. ■tJ (wherein R represents a methyl group, ethyl group, n-propyl group, or phenyl group, and It represents an alkyl group, an aryl group, or an alkyl group. a-substituted acrylic ester polymer having alkyl J, 9; 1% represents hydrogen, an alkyl group, an aryl group, an aralkyl group, or a halogen atom; n represents a numerical value indicating the degree of polymerization) and Cl
-1,=C group containing 111. The radiation-sensitive organic polymeric material according to claim 1, characterized in that it is a copolymer containing a repeating degree obtained by polymerizing a polymerizable mononeedle.