JPH0820738B2 - Method and developer for improving positive photoresist composition - Google Patents

Description

The present invention relates to an aqueous developer and an improved method of developing a positive photoresist composition.

[Conventional technology]

Numerous water-soluble developers are known for use with positive-working photosensitive compositions such as photoresists. For example, the water-soluble developer described in U.S. Pat. No. 4,423,138 contains tetraethylammonium hydroxide. It is also known to use tetramethylammonium hydroxide (see British Patent 1,367,830) or methyltriethanolammonium hydroxide (see US Pat. No. 4,141,733) as a developer.

[Problems to be solved by the invention]

Although water-soluble developers containing quaternary ammonium hydroxide compounds are widely used, they have problems when used to develop certain positive photoresists containing novolac resins and photosensitizers. obtain. In such applications, it has been found that the residue of the exposed photoresist remains on the substrate at the interface between the edge of the unexposed portion of the photoresist and the substrate. This problem is because as integrated circuit device manufacturers continue to work hard to increase the number of device elements per unit area of silicon, residues tend to interfere with the exact replication of the desired image pattern,
It's getting more serious.

The present invention provides a novel method for developing an image exposure layer to solve the above problems.

[Means for solving problems]

The present invention relates to an image exposure layer comprising contacting an image exposure layer of a positive type photosensitive composition comprising a novolac type resin and a photosensitizer with a water-soluble alkaline developer containing a quaternary ammonium hydroxide developer. The present invention provides a developing method, characterized in that the developer contains an additive compound represented by the following general formula.

In the formula, R ₁ and R ₂ represent H, R, COOH, CHO, OR, COR, COAr or CH ₂ Ar, R ₁ and R ₂ may be the same or different, and R ₁ and R ₂ are An aromatic ring, a substituted aromatic ring, a hetero ring or a substituted hetero ring may be formed, Ar represents a substituted or unsubstituted aryl group, R represents a lower alkyl group, and n is an integer of 1 to 3. Is.

The present invention is also a water-soluble alkaline developer containing a quaternary ammonium hydroxide developer, which is characterized in that it also contains an additive compound represented by the following general formula.

In the formula, R ₁ and R ₂ represent H, R, COOH, CHO, OR, COR, COAr or CH ₂ Ar, R ₁ and R ₂ may be the same or different, and R ₁ and R ₂ are An aromatic ring, a substituted aromatic ring, a hetero ring or a substituted hetero ring may be formed, Ar represents a substituted or unsubstituted aryl group, R represents a lower alkyl group, and n is an integer of 1 to 3. Is.

I. Positive Photosensitive Composition In the present invention, any suitable positive photoresist composition containing a solution of a novolac resin and a photosensitizer in a compatible solvent can be used. The solids content of the photoresist composition used in the present invention can vary within wide limits, but is preferably from about 10 to about 55% by weight,
More preferably, it is about 13 to about 45% by weight.

(Novolak Type Resin) In the photoresist composition used in the practice of the present invention, any suitable novolac type resin can be used. Preferably, the novolac type resin is a cresol-formaldehyde novolac resin or a phenol-formaldehyde novolac resin. Cresol-formaldehyde novolac resins are especially preferred and are prepared as described in US Pat. No. 4,377,631. The novolak type resin useful in the present invention has the following structural formula: (In the above structural formula, R ₇ and R ₈ are independently monovalent C ₁ -C ₄ alkyl, and preferably R ₇ and R ₈ are methyl).

The novolac type resin is preferably present in the photoresist composition in an amount of about 8 to about 8 based on the total weight of the photoresist composition.
It is present in an amount in the range of 44% by weight, more preferably about 10 to about 35% by weight.

(Photosensitizer) The photosensitizer is insoluble in an alkaline aqueous solution and is sensitive to radiation in the near-ultraviolet region of the spectrum, and when exposed to such radiation, it decomposes decomposition products soluble in the alkaline aqueous solution. It is a diazoketone that gives. Diazoketone compounds useful in the practice of the present invention include (In the formula, Q is _{-E- (CH 2) 2 -O-} W or _{-E-CbX '(2b + 1} )
And a, W is -CH ₃ or -C ₂ H ₅ or _{- (CH 2) 2 -O-} C
H ₃ or - (CH _{2) 2} -O-C ₂ H _5, each X 'is, -H independently or -F or -Br or -
Cl or -I, preferably each X'is -H or the same halogen ion, a is 1 or 2, b is 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9, T is-(CO)-or -O- when a is 2.
Or -CH ₂ - or -C (CH _{3) 2} - or -SO ₂ - is or -S-, or -O-Z-O, and when a is 1 is H, Z is - (CH ₂ ) ₂ -or In it, D is -C (O) - or -O- or -CH ₂ -
Or -C (CH _{3) 2} - or -SO ₂ - or a -S-,
Each R _9, R _10, R ₁₁ are, -H independently or -OH or -NH ₂
Or Where at least one R ₈ or R ₉ or R ₁₁ is And T is -O-Z-O
R ₁₁ is H, and when a is 1, R ₁₇ is monovalent C ₁ -C ₉ alkyl or -C (CH ₃ ) ₃ or -H or -OH or -NH ₂ or Preferably monovalent C ₁ -C ₉ alkyl, more preferably -C
(CH ₃ ) _{3 provided} that each E is independently —O— or —NH—, preferably —O.
− And Z is When it is, E is preferably -NH-, is preferably up to four R _9, R _10, R ₁₁ substituent when a is 2 Selected from the group) and mixtures thereof.

The diazoketone is typically present in the photoresist composition based on the total weight of the photoresist composition, typically about 2 to about 12
It is present in an amount in the range of weight percent, preferably in the range of about 3 to about 10 weight percent.

(Solvent) The photoresist composition of the present invention is produced by adding a novolak type resin and a photosensitizer to a solvent in which all of the components are easily soluble. The order of addition is not important. The solvent is preferably selected from the group consisting of aliphatic ketones, aliphatic esters, alkylene glycol monoalkyl ethers, dialkylene glycol monoalkyl ethers, alkylene glycol dialkyl ethers, and mixtures thereof. A particularly preferred class of aliphatic esters are the aliphatic alkylene glycol alkyl ethyl esters. More preferably, the solvent is selected from the group consisting of cyclohexanone, methyl cellosolve acetate, ethyl cellosolve acetate, butyl acetate, xylene and mixtures thereof. A particularly preferred solvent is a mixture of ethyl cellosolve acetate, butyl acetate and xylene. The choice of solvent depends on the particular novolac type resin and diazoketone used.

After adding the novolac type resin and the diazoketone to the solvent, the mixture is stirred until all solids are dissolved. The resulting photoresist solution is placed under a pressure of about 2.109 kg / cm ² (30 psi) in nitrogen or other inert, oxygen-free atmosphere,
Microfiltration is preferably performed using a Millipore microfiltration device.

(Other Components) Additives such as dyes, anti-striation agents, plasticizers, adhesion promoters, sensitizers and nonionic surfactants can be added to this solution before filtration.

Dye additives useful in the photoresist compositions used in accordance with the present invention include methyl violet 2B (CI No. 42535), crystal violet (CI No. 42535) at levels of about 0.1 to about 3% by weight based on the total weight of the photoresist composition. C.
I.No.42555), Malachite Green (CINo.42000),
Includes Victoria Blue B (CINo.44045) and Neutral Red (CINo.50040). Dye additives help increase resolution by preventing backscattering of light from the substrate.

Striation inhibitors can be used up to a level of about 5% by weight, based on the total weight of the photoresist composition.

Plasticizers that can be used include, for example, phosphoric acid tri- (β-chloroethyl) ester, stearic acid, dicamphor, acetal resin at a level of about 1 to about 5% by weight, based on the total weight of the novolac type resin. Phenoxy resin and alkyd resin are included. The plasticizer improves the coating properties of the material and allows a smooth and uniform thickness of film to be applied to the substrate.

Adhesion promoters that can be used include β- (3,3, up to about 5% by weight level, based on the total weight of the photoresist composition.
4-epoxy-cyclohexyl) -ethyltrimethoxysilane, p-methyl-disilane-methyl methacrylate,
Includes vinyltrichlorosilane and amino-propyltriethoxysilane.

Sensitizers that can be used include, for example, picric acid, nicotinic acid or nitrocinnamic acid at levels up to about 5% by weight based on total solids weight in the photoresist composition. These sensitizers tend to increase the solubility of the photoresist coating in both the exposed and unexposed areas, thus developing speed is of paramount importance, although some contrast may be sacrificed. It is used for various purposes. Thus, while the exposed areas of the photoresist coating are more quickly dissolved by the developer, the sensitizer also causes a greater loss of photoresist coating in the unexposed areas.

Nonionic surfactants that can be used include nonylphenoxypoly (ethyleneoxy) ethanol, octylphenoxy (ethyleneoxy) ethanol, at levels up to about 0.5% by weight, based on the total weight of the photoresist composition. Dinonylphenoxy poly (ethyleneoxy) ethanol is included.

The filtered photoresist composition can be applied to a suitable substrate or support by any conventional method known to one of ordinary skill in the art, including dipping, spraying, forwarders, spin coating. Illustrative examples of making a photoresist composition, coating it on a substrate or support and exposing the coated composition are described in US Pat. No. 4,377,631.

II. Water-Soluble Alkaline Developer The exposed photoresist coated substrate is then contacted with the water-soluble alkali developer of the present invention. This contact method is
Preferably, it is carried out by immersing the coated substrate, for example, in a developing solution in a Teflon tank until the entire coating film is dissolved from the image-exposed region. The developer is preferably stirred, for example by nitrogen bubbling.

(Quaternary Ammonium Hydroxide Developer) As described above, the water-soluble alkaline developer used in the practice of the present invention contains a quaternary ammonium hydroxide developer. A stable quaternary ammonium hydroxide compound has the following structural formula (In the above structural formula, R ₃ , R ₄ , R ₅ , and R ₆ are independently C ₁ -C ₄ alkyl or C ₁ -C ₄ hydroxyalkyl). One preferred group of quaternary ammonium hydroxides includes tetramethylammonium hydroxide, trimethylethanolammonium hydroxide, methyltriethanolammonium hydroxide and mixtures thereof. In a particularly preferred embodiment of the invention tetramethylammonium hydroxide is used.

The concentration of quaternary ammonium hydroxide in a water-soluble developer depends on a number of factors such as the particular photoresist composition to which the developer should be applied, the desired development time, the desired exposure time, etc. It can vary widely depending on. However, the concentration of the quaternary ammonium developer in the water-soluble developer is usually about 1 to about 1 based on the total weight of the developer.
It ranges from 30% by weight, preferably from about 2 to about 25% by weight.

(Additive compound) The additive compound that is a feature of the present invention is 1,3,5-trihydroxybenzene or 4-methylesculetin. In a particularly preferred embodiment of the present invention, 1,3,5-
Trihydroxybenzene is used.

The additive compound used in the present invention is used in any amount effective to completely remove the exposed areas of the photoresist composition without leaving a residue of the exposed photoresist composition, as described above. be able to. The optimum usage for a particular application is, in fact, the particular developer used in the developer, the concentration of the developer in the developer, the exact photoresist composition to which the developer is applied. Depends on many factors such as. However, the additive compound is generally present in the developer in an amount of about 0.1, based on the total weight of the developer.
Included in an amount of about 5% by weight, preferably about 0.2 to about 4% by weight.

(Other Components) The developer of the present invention preferably does not contain metal ions such as alkaline earth metals and transition metals. Therefore, in one preferred embodiment of the invention, the developer also contains a chelating agent. Any suitable chelating agent known to those skilled in the art can be used, such as ethylenediaminetetraacetic acid as well as other conventional compounds. Preferably, the chelating agent is used in an amount up to about 1% by weight, based on the total weight of the developer.

The water-soluble alkaline developers of the present invention can optionally include various other standard ingredients, as will be apparent to those skilled in the art. For example, the developer may also contain dyes and / or pigments, nonionic surfactants and the like.

III. Development It should be apparent to those skilled in the art that it is possible to produce water-soluble concentrates that can be diluted before use as developers by the method of the present invention. This can be advantageous as it reduces the amount of water that must be stored or transported. Typical development conditions include a development temperature of about 21 ± 1 ° C., the development time depends on the particular photoresist composition used, the exposure energy, the concentration of the developer in the developer,
It greatly depends on the developing method such as spraying, paddle, nitrogen bubbling or mechanical stirring, pre-baking temperature and time and the like. For example, under mild agitation (magnetic bar), the development time is about 60 seconds for a 1 μm coating prebaked at about 100-105 ° C. for about 30 minutes.

Hereinafter, the present invention will be described with reference to examples. All parts and percentages are by weight unless otherwise noted.

〔The invention's effect〕

According to the present invention, the exposed portion of the positive photoresist layer is effectively removed without leaving any exposure residual photoresist material at the interface between the edge of the unexposed region of the photoresist and the substrate. In addition, the water soluble developers of the present invention provide an enhanced photoresist profile and exhibit acceptable performance with respect to values such as depth of focus, development range, retention of unexposed photoresist layer thickness.

〔Example〕

Example 1-17 and Comparative Example 1-3 Each example and comparative example were performed according to the following method.

In all of the following examples and comparative examples, the photoresist compositions used were commercially available under the trade designation "HPR-204" from Olin Hunt Specialty Products, Inc., Garrett Mountain, NJ, USA, and cresol-formaldehyde. It contains a novolak resin and a naphthoquinonediazide sulfonate of trihydroxybenzophenone as a photosensitizer.

A 76.2 mm (3 in) diameter silicon oxide wafer was spin coated at 5000 rpm for 30 seconds with a headway spinner to give a film thickness of about 1 μm. The coated wafer was then prebaked in a convection oven for 30 minutes at 100-105 ° C. This wafer was exposed through a focus wedge mask with a Perkin Elmer Micralign 111 (slit width 1.0 mm, opening # 1). The exposed wafer was developed by dipping for about 60 seconds using each of the water-soluble alkaline developers shown in Table 1 below.

The removal properties of each developer were examined using a scanning electron microscope. Developed wafer is sputter coated with 250 Å gold and 3μm window size, 17,000 times (sample tilt angle 80
°) inspected. Each developed wafer was then rated on a 0-5 numerical scale. The lowest number (0) indicates complete removal of the exposed areas of the photoresist and the highest number (5) indicates substantial residue of the exposed photoresist at the interface between the edges of the unexposed areas and the oxide substrate. The results are shown in Table 1.

Claims (14)

[Claims] 1. An image exposure layer of a positive photosensitive composition comprising a novolac resin and a photosensitizer of a diazoketone compound,
In a method for developing an image-exposing layer, which comprises contacting with a water-soluble alkaline developer containing a quaternary ammonium hydroxide developer, the developer contains an additive compound represented by the following general formula. A method characterized by the following. In the formula, R ₁ and R ₂ are H, R, COOH, CHO, OR, COR, COAr or
Representing CH ₂ Ar, R ₁ and R ₂ may be the same or different, and R ₁ and R ₂ may form an aromatic ring, a substituted aromatic ring, a hetero ring or a substituted hetero ring, Ar Represents a substituted or unsubstituted aryl group, R represents a lower alkyl group, and n is an integer of 1 to 3. 2. The method according to claim 1, wherein n is 2 or 3. 3. The quaternary ammonium hydroxide developer has the formula (Wherein R ₃ , R ₄ , R ₅ , and R ₆ are independently C ₁ -C ₄ alkyl or or C ₁ -C ₄ hydroxylalkyl). The method according to item (2). 4. A quaternary ammonium hydroxide developer selected from the group consisting of tetramethylammonium hydroxide, trimethylethanolammonium hydroxide, methyltriethanolammonium hydroxide and mixtures thereof. The method according to item 3). 5. The method of claim 4 wherein the quaternary ammonium hydroxide developer is used in an amount in the range of 3-25% by weight, based on the total weight of the developer. 6. A method according to claim 4, wherein said additive compound is used in an amount in the range of 0.2-4% by weight, based on the total weight of said developer. 7. The method according to claim 6, wherein the additive compound is 1,3,5-trihydroxybenzene. 8. A water-soluble alkaline developer containing a quaternary ammonium hydroxide developer for a positive photosensitive composition comprising a novolac type resin and a photosensitizer of a diazoketone compound, which is represented by the following general formula. A developer, which also contains an additive compound to be used. In the formula, R ₁ and R ₂ represent H, R, COOH, CHO, OR, COR, COAr or CH ₂ Ar, R ₁ and R ₂ may be the same or different, and R ₁ and R ₂ May form an aromatic ring, a substituted aromatic ring, a heterocycle or a substituted heterocycle, Ar represents a substituted or unsubstituted aryl group, R represents a lower alkyl group, and n is 1 to 3 It is an integer. 9. The quaternary ammonium hydroxide developer has the formula The development according to claim (8), wherein R ₃ R ₄ , R ₅ and R ₆ are independently C ₁ -C ₄ alkyl or C ₁ -C ₄ hydroxyalkyl. liquid. 10. The quaternary ammonium hydroxide developer comprises:
The developer according to claim (9), which is selected from the group consisting of tetramethylammonium hydroxide, trimethylethanolammonium hydroxide, methyltriethanolammonium hydroxide and mixtures thereof. 11. The developer according to claim 10, wherein the quaternary ammonium hydroxide is used in an amount in the range of 2-25% by weight based on the total weight of the developer. 12. The developer according to claim 11, wherein the additive compound is used in an amount in the range of 0.2-4% by weight based on the total weight of the developer. 13. The developing solution according to claim 12, wherein the additive compound is 1,3,5-trihydroxybenzene. 14. The quaternary ammonium hydroxide developer comprises:
The developer according to claim (13), which is tetramethylammonium hydroxide.