US 4,536,470 A · Method and apparatus for making a mask conforming to a ceramic substrate metallization pattern

Abstract

This invention concerns method and apparatus for making a mask conforming to a cured MLC substrate. The mask when made may be used to add layers of metallization to the cured substrate by conventional photolithographic techniques. The method and apparatus feature use of the cured substrate itself to pattern the mask. Particularly, the substrate is aligned with the unpatterned mask and the image of the substrate transferred to the mask such that once patterned, the mask may subsequently be realigned with the substrate. In preferred form, a system of notches and grooves are used to align the substrate and mask and a lens system used to transfer the substrate image to the mask. The invention also includes method and apparatus for making an improved MLC substrate. The improvement is characterized by the use of photolithographic techniques to add successive layers of metallization to the cured substrate. This is accomplished by use of a special fixture for combining and aligning the cured substrate with a conforming mask.

Claims6

Dependent claims

A method of forming a metallization pattern in conformity with an original metallization pattern on a cured multilayer ceramic substrate, said method comprising:

providing a cured multilayer ceramic substrate having an original metallization pattern on at least one principal surface thereof;
forming a rigid custom tailored negative photographic mask bearing the image of the cured multilayer ceramic substrate and the original metallization pattern thereon;
forming a blanket metal layer on said cured substrate including said original metallization pattern;
providing a radiation sensitive film on said blanket metal layer;
aligning the custom mask with the cured substrate having the blanket metal layer and radiation sensitive film thereon such that the mask image pattern is in exact alignment with the original metallization pattern;
exposing the radiation sensitive film through said custom mask to transfer the mask image pattern to the film;
developing said radiation sensitive film to form a patterned mask of said film on said metal layer in complete and exact correspondence with said original metallization pattern;
and
etching said metal layer in accordance with said patterned mask.

6 more elements

A method of photolithographically forming a subsequent metallization pattern overlaying and in perfect registration with an initial metallization pattern on a principal surface of a cured multilayer ceramic substrate, the method comprising:

providing a cured multilayer ceramic substrate having an initial metallization pattern on a principal surface thereof;
forming a custom photolithographic mask bearing an exact image of said initial metallization pattern;
blanket depositing a layer of metallization on said substrate surface including the initial substrate metallization pattern;
forming a layer of photosensitive film on said deposited metal layer;
aligning said custom mask and said substrate such that the mask image pattern is in one-to-one correspondence with the initial metallization pattern on said substrate;
exposing the photosensitive film through said custom mask to transfer the image thereon to the photosensitive film;
developing the photosensitive film to remove the film from the deposited metal layer except where the film is in correspondence with the initial substrate metallization, the remaining photosensitive film serving as an etch mask for said metal layer;
etching the metal layer to remove portions thereof which are not masked by said remaining photosensitive film;
and
removing the remaining photosensitive film;
whereby is formed a subsequent metallization pattern fully mated with said initial metallization pattern.

8 more elements

Dependencies are inferred from the claim text.

Method and apparatus for making a mask conforming to a ceramic substrate metallization pattern

Life of this patent

Method and apparatus for making a mask conforming to a ceramic substrate metallization pattern

Life of this patent

Abstract

Claims6