Method for making circular diode chips through glass passivation
AssigneeGoodark Electronic Corp.
InventorChien-Chang Chen
Life of this patent
Estimating the term…
Abstract
A method for making circular diode chips which includes procedures of coating a diffused wafer with a photoresister coating and exposing it to develop the pattern; groove etching with an acid solution; removing the photoresister coating and cleaning it with deionized water; filling up the etched regions on the wafer with a glass slurry and then treating it through a glass firing process; nickel plating and sintering the wafer; mounting a sand substrate and the circular iron plates on the wafer at two opposite sides by melted wax; sand blasting the iron plate and glass substrate attached wafer and removing the iron plate so as to obtain the finished chips.
Claims12
A method for making circular diode chips using a wafer with diffused P and N conductivity type sides, the interface of both diffused sides forming a junction, the N-type conductivity side including an N and N+ region, comprising the steps of:
- (a) coating said diffused wafer with a photoresist coating and covering portions of said photoresist with a photomask;
- (b) sending the wafer with the photomask to an exposure machine for developing a pattern thereon;
- (c) groove etching the unphotosensitized part of the wafer by an acid solution until reaching said N+ region;
- (d) removing the photoresist coating from the wafer;
- (e) cleaning the wafer with a solution;
- (f) filling up said etched grooves formed on the wafer with a glass slurry;
- (g) glass firing the wafer;
- (h) electroplating the wafer with a layer of nickel and sending it to a quartz tube for sintering followed by electroplating the sintered wafer with an additional layer of nickel;
- (i) preparing a glass substrate on an electric hot plate and melting wax on the glass substrate;
- (j) adhering the nickel plated wafer to the glass substrate and covering the melted wax on the resultant structure;
- (k) adhering an adhesive tape with circular iron plates accurately to the wafer;
- (l) removing the wafer from the electric hot plate for air cooling, and then removing the adhesive tape from the wafer;
- (m) sand blasting the glass substrate and iron plate attached wafer to obtain near-finished circular chips;
- (n) dipping the near-finished circular chips in a solution for cleaning after the sand blasting step;
- and
- (o) removing the circular iron plates from the near-finished circular chips by magnetic attraction so as to obtain the finished circular diode chips.
Dependencies are inferred from the claim text.