Title:
PRESERVATION OF SUPERPOSITION MARK IN DIRECT ELECTRON BEAM LITHOGRAPHY
Document Type and Number:
Japanese Patent JPS5825233
Kind Code:
A
Abstract:
PURPOSE:To improve the positioning accuracy of lithography by the preservation of a superposition mark until the final process which is accomplished by overlapping a positive and a negative resist films and over-exposing only that portion of the negative resist fio which the mark is situated thereunder to obtain a gel of that portion so that it can be used as the mark's protective film. CONSTITUTION:A groove is formed on a semiconductor substrate 1, a superposition mark 2 is buried in this groove, and a positive resist film 3 for pattern formation is applied to the entire surface including the groove. A mark-protective negative resist film 4 of polystyrene, etc., with a sensitivity approx. 1/10 of that of the film 3 is applied to the film 3. Specified exposure 5 is first applied to the film 3 through a lithography pattern, then over-exposure 6 is applied to the portion of the mark 2 to obtain a gel of the film 4. The film 4 is then developed by a polystyrene developer, thereby the gel portion is left intact only on the mark 2. Then the film 3 is subjected to development to obtain a specified pattern which is used as a mask for the etching of the substrate 1. After the etching the films 3, 4 are removed.
Inventors:
SHIRAKAWA AKIRA
Application Number:
JP12380081A
Publication Date:
February 15, 1983
Filing Date:
August 06, 1981
Export Citation:
Assignee:
SANYO ELECTRIC CO
International Classes:
H01L21/027; H01J37/304; (IPC1-7): H01L21/30
Attorney, Agent or Firm:
Takuji Nishino (2 outside)