Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Finishing or perfecting composition or product
Reexamination Certificate
2000-01-06
2001-07-31
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Finishing or perfecting composition or product
C430S322000, C510S176000
Reexamination Certificate
active
06268115
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to the use of alkylated polyamines as a wetting agent in aqueous photoresist developer and electronics cleaning compositions.
BACKGROUND OF THE INVENTION
The demands of semiconductor manufacture have required the use of high performance surfactants and wetting agents in photoresist developer formulations. As line features shrink to smaller sizes and photoresist substrate materials become more aliphatic in nature (i.e. having lower surface energy), aqueous developer solutions are being formulated with surface tension reducing agents. Another requirement for these developers is that they have a low tendency to foam. This is accentuated by the movement toward larger wafer sizes. Low foam formation is particularly important when using spray-puddle techniques because microbubble entrainment during spreading of the solution over the photoresist surface can lead to defects. Surfactants that have been used in the past to increase wetting of the photoresist typically lead to higher foam formation. For the most part the industry has focused on the effect of surfactant on photoresist performance, such as contrast, critical dimension, and feature sharpness. Although the cleaning ability of underlying substrates is enhanced by typical surfactants, foam formation still remains a problem.
Tetramethylammonium hydroxide (TMAH) is the chemical of choice in aqueous alkaline solutions for developing photoresists according to
Microlithography, Science and Technology,
edited by J. R. Sheats and B. W. Smith, Marcel Dekker, Inc., 1998, pp 551-553. Surfactants are added to the aqueous TMAH solutions to reduce development time and scumming and to improve surface wetting.
U.S. Pat. No. 5,939,476 discloses the use of alkylated polyamines for reducing equilibrium and dynamic surface tension of water-based compositions.
EP 0 930 346 corresponding to U.S. application Ser. No. 09/009,099 filed Jan. 20, 1998 discloses the use of N,N′-dialkyl alkylenediamines for reducing equilibrium and dynamic surface tension of water-based compositions.
There are few references describing low foam surfactants in developer compositions. JP 10-319606 discloses that commercially available ethylene oxide (EO)/propylene oxide (PO) block polymers give good wetting and low foam.
JP 03-062034 discloses polyoxyalkylene dimethyl polysiloxanes as good surfactants with low foam in developer formulations. Polysiloxanes are known to rearrange or decompose under conditions of high pH.
Although there are a few references to the use of amines in photoresist developer compositions, they are not related to the use of surface active agents. U.S. Pat. No. 5,252,436 discloses the use of relatively high levels of amine additives (3-30 wt %) and U.S. Pat. No. 5,039,595 uses amine additives at levels of 5-50 wt %. Both of these disclosures appear to be using the amines to alter the bulk solvent properties of the developer solution.
U.S. Pat. No. 4,997,748 discloses cyclic nitrogen compounds at levels of 0.1 to 10 wt % to decrease scum formation and enhance image sharpness during photoresist development. Among the cyclic nitrogen compounds taught is the cyclic urea 1,3-dimethyl-2-imidazolidinone. Since the nitrogen compounds are not amphipathic, it is not likely that they will lower surface tensions at low concentrations, and their utility appears to be based on properties other than surface tension reduction. 1,3-dimethyl-2-imidazolidinone is well known as a very good solvent and not as a surface-active material.
U.S. Pat. No. 4,828,965 discloses the use of lower alkanolamines (1-4 carbons) in combination with alcohols at concentrations of 0.40-5 wt %.
U.S. Pat. No. 4,741,989 discloses the use of small amounts of amines to modify the reaction chemistry of the quinonediazide photoactive compounds in photoresists, but only small chain amines are used and no surface active amines are cited.
U.S. Pat. No. 4,628,023 discloses water soluble amines as the alkali source for developer solutions. Because the preferred pH range is above 12.5, the use of organic amines would necessarily be at high concentrations.
JP 61-179651 discloses the use of amine-containing developer solutions with surface tensions of between 25 and 50 dyne/cm. These surface tensions are achieved by the use of relatively large amounts of non-surface-active amines (3-5 wt %) in combination with tetramethylammonium hydroxide as the base.
SUMMARY OF THE INVENTION
This invention provides water-based photoresist developing, or electronics cleaning, compositions having reduced equilibrium and dynamic surface tension by incorporation of an effective amount of an alkylated polyamine compound of the following structures I and II:
R—HN—G—NH—R′ I
where R and R′ are independently C5 to C8 alkyl, G is a C2-C6 linear or cyclic alkylene group which may contain C1-C4 alkyl substituents, m is 2-6, and n is 2 or 3.
By “water-based”, “aqueous” or “aqueous medium” we mean, for purposes of this invention, a solvent or liquid dispersing medium which comprises at least about 90 wt %, preferably at least about 95 wt %, water. Obviously, an all water medium is also included and is most preferred. Also for purposes of the present invention, the terms “photoresist developing” and “electronics cleaning” are interchangeable.
Also provided is a method for developing a photoresist after exposure to radiation by applying to the photoresist surface a water-based developer composition containing an effective amount of an alkylated polyamine compound of the above structures for reducing the dynamic surface tension of the developer composition.
There are significant advantages associated with the use of these alkylated polyamine compounds in water-based photoresist developer, or electronics cleaning, compositions and these advantages include:
an ability to control the foaming characteristics of the water-based compositions; and
an ability to formulate low surface tension aqueous electronics cleaning and processing solutions, including photoresist developer solutions, for the semiconductor manufacturing industry with good wetting and extremely low foam.
The use of these materials in photoresist developer formulations is of particular importance because of their ability to provide all the advantages of surface tension lowering plus outstanding performance in reducing the formation of foam and doing so while maintaining good contrast for photoresist developing applications.
DETAILED DESCRIPTION OF THE INVENTION
This invention relates to the use of compounds of the formulas I and II
R—HN—G—NH—R′ I
where R and R′ are independently C5 to C8 alkyl, and G is a C2-C6 linear or cyclic alkylene group which may contain C1-C4 alkyl substituents, and
where R and R′ are independently C5 to C8 alkyl groups and m is 2-6 and n is 2 or 3, with m being 2 or 3 preferred; for the reduction of equilibrium and dynamic surface tension and low foaming in water-based photoresist developer formulations. It is desirable that an aqueous solution of the dialkylated polyamine demonstrates a dynamic surface tension of less than 45 dynes/cm at a concentration of ≦5 wt % in water at 23° C. and 1 bubble/second according to the maximum-bubble-pressure method. The maximum-bubble-pressure method of measuring surface tension is described in
Langmuir
1986, 2, 428-432, which is incorporated by reference.
The dialkylated polyamines comprising N,N′-dialkyl alkylenediamines and N,N″-dialkyl dialkylenetriamines which are suitable for use in the present invention are those alkylated polyamines taught in EP 0 930 346 and U.S. Pat. No. 5,939,476, respectively. These references also teach how to make these dialkyl polyamines.
Generally, in the practice of this invention, it is desirable to use alkylated polyamines having a solubility in water of at least 0.001 wt %, preferably from 0.001 to 1 wt %, and most preferably from 0.005 to 0.5 wt %.
The alkyl groups may be the same or different. They may be linear or branched, and the point of attachment to
Carr Richard Van Court
Lassila Kevin Rodney
Minnich Kristen Elaine
Air Products and Chemicals Inc.
Le Hoa Van
Leach Michael
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