Development of a New Stress Relief Process using Dry Etching
DISCO Corporation (Head office: Ota-ku, Tokyo, President: Hitoshi Mizorogi) has developed the
DFE8040 (for 8" wafers) / DFE8060 (for 300 mm wafers) dry etching equipment using plasma as a new lineup of our stress
relief process to cope with the need for enhancing die strength in semiconductor device manufacturing. This dry etching
equipment will sell as an inline unit for stress relief after wafer backside grinding with the DFG8560 / DFG8540 grinder
or DGP8760 grinder / polisher.
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| DFG8560 (right) and DFE8060 (left) In-line |
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Product Development Background
The tide of downsizing and higher function in electronics devices has further been accelerated and
technology to produce thinner and stronger wafers and IC die is required. At present, to eliminate a mechanical damaged layer
due to backside grinding that emerged together with thinner wafers, various stress relief methods have been proposed. But
in spite of the introduction of these stress relief processes, there is a case where dicing to separate die causes mechanical
damage and ultimately the strength of die is reduced. Especially, as more stress from the outside is applied to die used
for IC cards even after the product has been completed, there is a strong requirement to enhance die strength by eliminating
this mechanical damage due to dicing so as to increase reliability of the devices. In order to meet such needs, DISCO has
developed the new stress relief process using plasma.
Product Features
• Further enhancement of die strength exceeding the normal stress relief process
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The stress relief process using the dry etching developed this time provides an effect which can be
realized even by simultaneous use with the normal grinder. But what we want to particularly introduce here is the point that
the die strength can be enhanced even more by combining the stress relief method using dry etching with the DBG*.
When the dry etching is combined with the DBG process, it is possible to also remove damage caused by the blade
at the die side. With this process, because stress is relieved after dicing (die separation), there is subsequently no mechanical
damage from the dicing.
Namely, if the dry etching is adopted as the stress relief for the DBG process, it is possible to
eliminate mechanical damage of not only the die backside but also of the side, and compared with the stress relief only for
the backside, higher die strength can be obtained. As a result, enhancement of reliability can be expected in devices where
more stress from the outside is applied, such as IC cards.
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| *DBG (Dicing Before Grinding): |
DBG reverses the usual process of fully dicing the wafer after grinding. In DBG, first the wafer is half-cut with a special
dicing saw. Then, die singulation occurs when the wafer is thinned below the level of this cut. |
| DBG Die Side (Before Etching) |
DBG Die Side (After Etching) |
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• Also applicable to quality improvement of backside electrode formation
For a device backside on which a metal film is formed as electrodes such as the discreet type, due to the recent lead-free trend, quality required for the electrodes becomes even more strict. Specifically, improvement of adhesion of the metal film at the time of backside electrode formation and reduction of ohmic resistance* are required. Using the dry-etching technology developed this time by DISCO makes it possible to rougher the surface condition under the clean condition while adjusting the wafer surface before the processing. As a result, we can realize these needs.
| *Ohmic resistance: |
Total of material specific resistance and contact resistance, etc. between materials. Reduction of ohmic resistance is especially important in the case of power MOS and others. The lower the resistance, the more possible to control power loss at the time of element drive and a higher current can be run through the elements. |
| Before Etching |
After Etching |
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Features Plans
Test cutting to evaluate a product is accepted at any time.
The sales of this product has already started and there are several machines that have been sold domestically and overseas inline with the DGP8760 and DFG8560 / 8540.
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Contact:
DISCO Corporation
Corporate Strategy Division
Management Strategy Department
Marketing Communications Team
Phone: 81-3-4590-1090Fax: 81-3-4590-1094 |
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