DD272532A1 - PROCESS FOR ELIMINATING COVERED AND TRANSPARENT DEFECTS ON HARDENING TABLES - Google Patents

Abstract

The invention is applicable to microelectronics in the process of stencil making and to the recovery of stencils worn through use in the cycle I of device manufacturing. For the exposure of the photoresist in the defect region, an iron oxide stencil is used as an aperture according to the invention. In this iron oxide stencil windows of different shape and size are embedded, which allow to optimally adapt the exposure window of the defect shape. Subsequently, the lacquer layer is developed, then partially dissolved or steamed and removed the paint. The use of the iron oxide stencil achieves a high degree of accuracy and a productive elimination of defects on hard-layer stencils by means of a photolithographic process.

Description

Field of application of the invention

The invention serves to remove masked and transparent defects on hard-layer stencils. The method is applicable in the process of template fabrication as well as for recovery of templates worn through use in Cycle I of device fabrication.

Characteristic of the known state of the art

The known methods for eliminating defects on hard-film stencils are based either on a photolithographic process or on the use of high-energy radiation. The photolithographic process is based on the exposure of a photosensitive masking layer by means of an adjustable slit aperture spot microscope in the x and y directions. In the subsequent development process, an area determined by the aperture size of the spot microscope, within which the defect to be eliminated, is exposed. By etching or sputtering and then removing the varnish layer, the process of eliminating the defects is completed. The disadvantage of the method is its low accuracy. To the defect is an edge zone of 5μηι width, in which no structures may be necessary. Otherwise there is a risk of injury to these structures. An improvement in accuracy, but also an increase in equipment costs, brings the use of laser beams to eliminate defects. Here, a rocussed laser beam is used to vaporize covered defects or the laser-induced deposition of a layer of high optical density from the gas phase in the area of transparent defects. The necessary safety zone around the defect is reduced by half compared to the photolithographic process. The most accurate method currently available for eliminating defects on hard film stencils is based on the use of an ion beam that is analogous to the laser beam but can be focussed in the submicrometer, thus allowing defect removal in the submicron, but with even higher equipment costs ,

Object of the invention

The aim of the invention is to bring a cost-effective photolithographic process ^f .u bring, which leads to a higher accuracy than the previously practiced photolithographic processes.

Explanation of the essence of the invention

From this, the technical problem to be solved is derived from developing a method with which defects on hard-layer stencils can be eliminated simply, productively and with high accuracy. According to the invention, this object is achieved in that an iron oxide stencil is used as a diaphragm for the exposure of the photoresist in Deiektberoich. In this iron oxide stencil windows of different shape and size are grooved, which allow to optimally adjust the exposure window the defect shape and size. An adjustment of the Besichtungsfensters to the defect takes place with yellow light, since the iron oxide stencil in the yellow light is optically transparent.

The exposure of the defect is then made with UV light and allows an exact image of the specific window in the photoresist. Subsequently, the lacquer layer is developed, then partially etched or vaporized and removed the paint.

By using the iron oxide stencil with different windows as aperture and adjustment under yellow light, a high accuracy and productive elimination of defects on hard-layer stencils is achieved by means of a photolithographic process.

embodiments

The invention will be explained in more detail below using an exemplary embodiment. The exemplary embodiment has the elimination of defects on hard layer stencils by means of incident light microscope and a photolithographic process to the content. A reflected-light microscope is used with an illumination source whose spectrum covers the near UV range with * (eg xenon high-pressure lamp). On the microscope cross table, the coated with positive varnish, defective template is placed. A yellow filter is swiveled into the reflected light beam path. Subsequently, the reflected light is turned on. After finding the defect on the stencil, the optimal shape and size of the exposure window is selected and the corresponding iron oxide stencil used instead of the field stop in the reflected light beam path. The

Exposure window is adjusted by moving the microscope cross table to the defect. Then a blue filter is pivoted into the reflected light beam path and, after removing the yellow filter, exposes the positive lacquer layer of the defective hard layer stencil for 5 seconds. Analogously, it is possible to proceed with further defects, whereby, however, either all exposed defect areas must have covered defects or all exposed η defect areas must contain transparent defects. Thereafter, the paint layer on the template is developed over the entire surface, so that the defect areas are exposed. In the case of covered defects, partial etching is now carried out; in the case of transparent defects, partial vapor deposition takes place with a vapor deposition mask which leaves only the defect areas exposed. This partial processing largely eliminates the influence of random defects in the lacquer layer, thus avoiding the creation of additional defects on the hardcoat stencil. A final cleanliness check ends the processing cycle.

Claims (2)

1. A method for the removal of muted and transparent defects on hard film stencils by means of photolithographic process, characterized in that for the exposure of the photoresist in the defect region in UV light an iron oxide stencil with different window structures is used as a diaphragm. 2. A method for the removal of muted and transparent defects on hard film stencils according to claim 1, characterized in that the iron oxide stencil is used both in the projection and in the proximity / contact method for exposing the defect area.