Manufacturing method of trench Schottky front silver surface metal structure

Abstract

The present invention discloses a manufacturing method of a trench Schottky front silver surface metal structure. The method comprises the following steps of: a. first photoetching on a metal layer ofa Schottky device: gumming, exposure and development; b. first metal etching: etching of part of metal in the metal layer, and removing of photoresist; c. second photoetching: gumming, exposure and development for protection of part of corroded metal; and d. second metal etching: etching of the rest of metal in the metal layer, and removing of photoresist. The manufacturing method of the trench Schottky front silver surface metal structure employs a method for twice photoetching and twice corrosion of multi-layer metal thin films to allow the metal corrosion morphology to be stable, when themetal surface layer is tensioned, it is not easy to generate edge warping and shedding phenomena to facilitate improvement of the product reliability; and moreover, the process provided by the invention is compatible with the current routine process, and does not need a special device and introduction of a new photoresist so as to effectively reduce the manufacturing cost.

Description

technical field [0001] The invention relates to a front silver surface metal technology, in particular to a method for manufacturing a grooved Schottky front silver surface metal structure. Background technique [0002] Schottky barrier diodes have been used in power supply applications for decades as rectifying devices. Compared with PN junction diodes, Schottky barrier diodes have the advantages of low forward turn-on voltage and fast switching speed, which makes them very suitable for switching power supplies and high-frequency applications. [0003] Schottky barrier diodes are manufactured using the principle of a metal-semiconductor junction formed in contact between a metal and a semiconductor. Trench Schottky adopts the principle that the trench structure produces a depletion layer to pinch off the conductive channel, and its high-frequency characteristics and electrical performance are significantly better than those of the planar Schottky. At present, the followin...

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Problems solved by technology

At present, the following methods are mainly used to manufacture trench Schottky barriers: the first method is to use the lift off process to perform photolithography three times, and then evaporate or sputter metal on the surface of the photoresist, and use the method of sticking and peeling off the film The metal on the photoresist is peeled off, the process cost is high, a special photoresist is required, and there are problems such as metal residue when peeling off the metal; the second method is to perform a photolithography on the metal surface, and then engrave Etching its metal, its etched morphology is unstable, prone to over-etching and metal residues

[0004] The following problems occur in the actual manufacture of the grooved Schottky barrier: 1. Due to the existence of the groove and the stress effect between the metal films, the warpage of the wafer is too large and the processing is difficult; 2. The composite metal It is difficult to corrode the film, and it is prone to over-etching and metal residues, and the corrosion morphology is as follows figure 1 The inverted triangle phenomenon is easy to appear, which directly affects the adhesion between metal films and product reliability

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