Method and apparatus for improving stencil/screen print quality
AssigneeMicron Technology, Inc.
InventorsTongbi Jiang, Chad A. Cobbley, John VanNortwick
Life of this patent
Estimating the term…
Abstract
A method and apparatus for improved stencil/screen print quality is disclosed. The stencil or screen assists in application of a printable material onto a substrate, such as an adhesive to a semiconductor die of a semiconductor wafer during a lead-on-chip (LOC) packaging process. In one embodiment, the stencil includes a coating applied to at least one surface of a pattern of the stencil or screen to retard running of the printable material onto the surface. In another embodiment, the stencil or screen includes a second coating applied to at least one other surface of the pattern to promote spreading of the printable material onto the substrate.
Claims77
A stencil to assist in application of a printable material onto a substrate comprising:
- a pattern;
- a coating applied to at least one surface of the pattern to retard spreading of the printable material onto the at least one surface;
- and
- wherein the coating is applied to a bottom surface of the pattern, and the stencil further comprises a second coating applied to at least one other surface of the pattern to promote spreading of the printable material.
A screen to assist in application of a printable material onto a substrate comprising:
- a pattern;
- a coating applied to at least one surface of the pattern to retard spreading of the printable material onto the at least one surface;
- and
- wherein the coating is applied to a bottom surface of the pattern, and the screen further comprises a second coating applied to at least one other surface of the pattern to promote spreading of the printable material.
A screen to assist in application of a printable material onto a substrate, comprising:
- a pattern having a top surface and a bottom surface;
- a first coating applied to the bottom surface of the pattern to retard spreading of the printable material;
- and
- a second coating applied to the top surface of the pattern to promote spreading of the printable material.
The screen of claim 26 wherein the thermoset adhesive is a phenolic resin.
A stencil to assist in application of a printable material onto a substrate, comprising:
- a sheet of material;
- a plurality of apertures in the sheet of material defining a desired pattern;
- a polymeric coating applied to a first surface of the sheet of material to retard spreading of the printable material;
- and
- a second coating applied to a second surface of the sheet of material to promote spreading of the printable material.
A stencil to assist in application of a printable material onto a substrate, comprising:
- a sheet of material;
- a plurality of apertures in the sheet of material defining a desired pattern;
- a polymeric coating having a surface tension which is less than a surface tension of the sheet of material whereby the polymeric coating being applied to the first surface of the sheet of material to retard spreading of the printable material;
- and
- a second coating having a surface tension which is greater than the surface tension of the sheet of material whereby the second coating being applied to a second surface of the sheet of material to promote spreading of the printable material.
A stencil to assist in application of a printable material in a desired pattern onto a substrate, comprising:
- a sheet of material comprised of a metal of metal alloy;
- a plurality of apertures in the sheet of material defining a desired pattern;
- a first coating applied the top surface of the sheet of material and to side walls of the aperture where the first coating promotes spreading of the printable material across the top surface and into the apertures;
- and
- a second coating applied to the bottom surface of the sheet of material, where the second material retards migration of printable material across the bottom surface.
A stencil to assist in application of a printable material in a desired pattern onto a substrate, comprising:
- a sheet of metal;
- apertures through the sheet of metal defining a pattern;
- a first coating having a first surface tension applied the top surface of the sheet of material and to side walls of the apertures where the first coating has a surface tension selected to promote spreading of printable material across the top surface and into the apertures;
- and
- a second coating having a second surface tension applied to the bottom surface of the sheet of material, where the second material has a surface tension selected to retard migration of printable material across the bottom surface.
A stencil to assist application of a printable material in a desired pattern onto a substrate, comprising:
- a sheet of metal or metal alloy;
- apertures in the sheet defining a pattern;
- a metallic coating having a first surface tension applied the top surface of the sheet and to side walls of the apertures to promote spreading of the printable material;
- and
- a polymeric coating having a second surface tension applied to the bottom surface of the sheet to retard spreading of the printable material.
Dependencies are inferred from the claim text.