JP2005311024A - Method for forming pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a semiconductor which realizes the prevention of exposure of the side wall of copper wiring in a damascene process without reducing the number of chips to be obtained. <P>SOLUTION: A chemical amplification type positive resist 104 is rotationally applied onto a semiconductor wafer 102 depositing a film to be etched 101 from a resist discharging nozzle 103 to form a resist film 105. In addition, a light shielding agent 107 with absorbent to an exposed light source is discharged onto the resist film 105 surrounding the wafer 102 from a chemical nozzle 106 during the rotation of the wafer to form a light-shielding film 108 by heating treatment. Thereafter, after exposure and irradiation by a prescribed pattern to the resist 104, etching is carried out. Since a resist pattern under the light-shielding film is not developed but remains at a wafer periphery, a copper wiring layer in the damascene process is prevented from being exposed without reducing the number of chips to be obtained by dummy shot. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a process for forming a pattern on a positive resist by irradiation with light and radiation.

  As a conventional method of forming a resist dummy pattern on the periphery of a wafer, for example, there is a method described in Patent Document 1. This will be described below.

A negative resist film is formed on the aluminum film of the semiconductor substrate by spin coating. And an acid solution is apply | coated on the negative resist of the peripheral part of a semiconductor substrate, and a negative resist is bridge | crosslinked. Thus, it is described that a dummy pattern is formed on the periphery of the semiconductor substrate.
JP 11-168042 A

  In general, when a damascene process is performed in the wiring process, copper is exposed at the pattern end, and thus copper contamination occurs. On the other hand, by limiting the effective shot at the time of exposure, the exposure of copper can be prevented, but the number of chips can be reduced and the cost is increased. For this reason, in order to prevent contamination from exposure of copper without reducing the number of chips, it is necessary to leave a resist pattern at the edge of the wafer.

  However, the conventional technique has a problem that is limited to the chemically amplified negative resist. In general, there are two types of resists: a positive resist in which an exposed portion is soluble in a developer, and a negative resist in which the exposed portion is polymerized by a crosslinking reaction and becomes insoluble in the developer. In consideration of desired characteristics and resist design in the lithography process, such as depth of focus, exposure margin, and edge shape, positive resists are more useful. There is no report. In Patent Document 1, it is limited to a chemically amplified negative resist, and further, a portion that is cross-linked by acid application to the peripheral portion of the wafer is limited to the resist surface. There was a problem that the purpose of could not be achieved.

  The present invention solves the conventional problems and provides a method for forming a resist dummy pattern at the periphery of a wafer in a positive resist without causing film peeling during development. And it aims at preventing generation | occurrence | production of copper contamination from a pattern cutting part.

  In order to solve the above problems, a pattern forming method of the present invention includes a step (a) of forming an etching target film on a semiconductor substrate, and a step (b) of forming a positive resist film on the etching target film. After the step (c) of forming a light-shielding film on the resist film at the periphery of the semiconductor substrate, the step (d) of exposing the pattern to the entire surface of the semiconductor substrate, and the step (d) And a step (f) of developing the resist film exposed to the pattern.

  The light-shielding film absorbs or captures at least one of light and radiation.

  The light-shielding film contains a resin.

  The light-shielding film contains a water-soluble polymer and is dissolved in the step (f).

  The light-shielding film contains an amine.

  According to the pattern forming method of the present invention, when exposing a positive resist coating surface by irradiating light or radiation, a light shielding film is formed on the resist around the wafer, thereby developing the resist around the wafer. It remains without being melted by the liquid, and by forming a wiring pattern in the damascene process, it is possible to increase the number by removing the entire surface and to prevent the occurrence of copper contamination from the pattern cutting portion.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a pattern forming method according to an embodiment of the present invention.

  An etching target film 101 is formed on the silicon wafer 102. A chemically amplified positive resist 104 is spin-coated from a resist discharge nozzle 103 on a silicon wafer 102 on which an etching target film 101 is deposited. Then, the resist solvent is evaporated by heat treatment, and the resist film 105 is formed. After the resist film 105 is formed, a light shielding agent 107 containing a pigment and a polymer resin is discharged from a light shielding agent discharge nozzle 106 provided above the wafer peripheral portion, and spin coating is performed on the resist film 105 in the wafer peripheral portion. On the apparatus, the position of the light-shielding agent discharge nozzle is variable and can be moved from the wafer center to the wafer end. Usually, it is used between 0.1 mm and 10 mm from the wafer edge. Then, a heat treatment is performed after the coating to form a light shielding film 108 made of a polymer film containing a dye on the resist film 105 at the periphery of the wafer. At this time, the polymer film applied to the peripheral portion of the wafer becomes the light-shielding film 108 by selecting materials that absorb light with respect to the exposure light source for the dye and the polymer resin.

  The light shielding film 108 is composed of a dye and a polymer resin. Specific materials are shown below.

  For example, azo dyes, benzoquinone dyes, naphthoquinone dyes, anthraquinone dyes, symmetric cyanine dyes, asymmetric cyanine dyes, squarylium dyes, croconium dyes, merocyanine dyes, stilbene dyes, diphenylmethane dyes, triphenyl dyes There are phenylmethane dyes, fluorane dyes, spiropyran dyes, phthalocyanine dyes, indigo dyes, fulgide dyes, and the like, and dyes that absorb light with respect to the exposure wavelength are used.

  Polymers represented by phenolic polymers, acrylic polymers, methacrylic polymers, novolak polymers, etc. are used as polymer resins. The polymer film can be dissolved during the treatment, and an effect equivalent to the etching characteristics obtained conventionally can be obtained.

  For example, the water-soluble polymer is polyvinyl alcohol, polyvinyl phenol, polyacrylamide, polyethylene oxide, polyvinyl pyrrolidone, polyvinyl methyl ethyl ether, carboxy vinyl polymer, polyethylene glycol, ethylene oxide, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, carboxymethyl cellulose. , Methyl hydroxypropyl cellulose, soluble starch, carboxymethyl starch, methyl starch, alginate, guar gum, locust bean gum, carrageenan, gum arabic, draggant, pectin, starch, dextrin, gelatin, casein, collagen Represented.

None of the above-described polymers has transparency to exposure wavelengths of 200 nm or less, and therefore, in ArF excimer laser lithography and F ₂ excimer laser lithography, no dye is contained. Can be used.

  Also in X-ray and electron beam lithography, the base resist pattern can be insolubilized in the developer by applying the light shielding agent. Any of the light-shielding agents has an electron-trapping ability and inhibits the reaction of the resist.

  The polymer can improve adhesion to the resist interface by introducing side chains represented by methyl group, ethyl group, propyl group, phenyl group, amino group, and alcohol group according to the underlying resist. I can do it.

  When a chemically amplified resist is used as the resist, an acid is deactivated at the resist interface by containing an amine in the light-shielding agent. Therefore, in addition to the light-shielding effect against light, the acid amplification reaction stops, and the developer Since it becomes insoluble, it is possible to obtain an effect that is greater than that obtained by shading.

  As the amine, an amine typified by dimethylamine, diethylamine, diphenylamine, trimethylamine, triethylamine, triphenylamine or the like is used.

  The resist film 105 on the silicon wafer 102 is exposed with a desired light source to form a pattern. Here, since the light shielding film 108 is formed on the peripheral portion of the wafer, a photoreaction does not occur in the resist film on the peripheral portion of the wafer, and a resist dummy pattern that is insoluble in the developer is formed on the peripheral portion of the wafer later by development processing. To do.

  Then, the etching target film 101 is etched using the resist film 105 on which the pattern is formed as a mask, and a copper wiring pattern is formed by a damascene process. At this time, the peripheral portion of the wafer is completely covered with the mask, so that the etching target film 101 remains without being etched. Thereby, since a copper wiring pattern is not formed at the wafer edge, there is no exposure of copper as a wiring material, and there is no contamination due to copper leakage.

  The pattern forming method according to the present invention is useful as a method for forming a pattern also in a peripheral portion of a semiconductor substrate in manufacturing a semiconductor device using a positive resist.

Sectional drawing which shows the pattern formation method in embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Film to be etched 102 Silicon wafer 104 Positive resist 105 Resist film 106 Light shielding agent discharge nozzle 107 Light shielding agent 108 Light shielding film

Claims (5)

A step (a) of forming a film to be etched on a semiconductor substrate;
A step (b) of forming a positive resist film on the film to be etched;
Forming a light-shielding film on the resist film in the periphery of the semiconductor substrate;
A step (d) of exposing a pattern to the entire surface of the semiconductor substrate after the step (c);
And (f) developing the resist film exposed to the pattern after the step (d). The pattern forming method according to claim 1, wherein the light shielding film absorbs or captures at least one of light and radiation. The pattern forming method according to claim 1, wherein the light shielding film contains a resin. The pattern forming method, wherein the light shielding film contains a water-soluble polymer and is dissolved in the step (f). The pattern formation method according to claim 1, wherein the light shielding film contains an amine.

Images