Holding tool

Claim 1

In a tool for placing planar semiconductor chips, the chips having a predetermined thickness on the order of a few thousandths of an inch and having parallel, oppositely directed broad faces of a predetermined form having corners, the tool comprising a body member having a cavity for receiving the chip and a suction port for evacuating the cavity to hold the chip against surfaces bounding said cavity, the improvement wherein said cavity comprises a first section having a cross section similar to and slightly larger than said predetermined form of said chip, for receiving one face of said chip, said first section having a depth less than said predetermined thickness of said chip, and a second section immediately adjacent to, inwardly of said first section, said second section being of cross sectional shape similar to that of said first section but having a changing shape in the corner regions, proceeding from said first section inwardly cross sections of said second section having progressively smaller corner dimensions from that of said first section, said corner dimensions being smaller than the predetermined corner dimensions of said chip at a total cavity depth less than the thickness of said chip whereby upon entry of a chip into said cavity under the influence of vacuum therein the corners of said chip only seat upon said smaller dimension corner regions of said cavity, simultaneously closing substantially the cavity from entry of air and positioning said chip with its outer face located beyond the limits of said cavity, whereby said chip is held with a face exposed for joining to a substrate.

Claim 8

The method of forming a holding tool for semiconductor chips of a predetermined shape, comprising providing a bar of electrode stock with an end portion in the form of a prism corresponding in cross section to said predetermined chip shape and forming rounded surfaces on the end of said prism at the corners where adjacent sides of the prism intersect, said rounded surfaces conforming generally to the projection of a cone pointed outwardly from said end, whereby to provide a male electrode form having flat sides and conically-surfaced corners at the end-most region immediately joined to a portion of full prismatic form, thereafter positioning said electrode adjacent a blank of hard metal, forming therein by EDM process an impression of the form of said electrode and thereafter machining the surfaces surrounding said impression to define thin walls.

Claim 9

The method of forming a holding tool for semiconductor chips of a predetermined shape, comprising providing a bar of electrode stock with an end portion in the form of a prism corresponding in cross section to said predetermined chip shape and forming rounded surfaces on the end of said prism at the corners where adjacent sides of the prism intersect, said rounded surfaces conforming generally to the projection of a cone pointed outwardly from said end, whereby to provide a male electrode form having flat sides and conically-surfaced corners at the end-most region immediately joined to a portion of full prismatic form, thereafter positioning said electrode adjacent a blank of hard metal, forming therein by EDM process an impression of the form of said electrode and thereafter machining the surfaces surrounding said impression to define thin walls.