Stone working – Sawing – Rotary
Reexamination Certificate
2000-12-14
2003-05-13
Hail, III, Joseph J. (Department: 3723)
Stone working
Sawing
Rotary
C125S015000, C451S540000, C451S544000, C451S546000, C451S548000
Reexamination Certificate
active
06561177
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to precision cutting of discrete devices such as semiconductor devices, more particularly, to a diamond dicing blade used for efficient and symmetric cutting with reduced chipping.
DISCUSSION OF THE RELATED ART
There are many prior art discrete devices which are formed as a plurality of substrates integrally formed in a wafer or the like which require intermediate cuts and/or separation into individual subunits as a last step in the fabrication process. Examples of such discrete devices are semiconductor devices. Most, but not all, of the devices are formed in silicon-based wafers. A preferred technique for separating the sub-units is to saw through the wafer in a procedure referred to as “dicing.” The device used to perform the cutting is referred to as a dicing blade. For cutting operations requiring high precision (+/−0.5 micron), diamond blades have been preferred, especially in the production of semiconductor devices, because they form precisely placed cuts.
However, these prior art diamond blades still suffer from performance variability manifested in the asymmetric chipping of the wafer due to the forces generated when pieces of silicon particles loosen from the wafer between the rotating dicing blade and the silicon wafers being cut.
For instance, as shown in
FIG. 1
a
, silicon wafer
8
having a frontside
10
and backside
12
is diced by a dicing blade
6
with large diamond particles
14
, with a mean particle size of about 5-6 microns. Large diamond particles
14
allow for an increased feed rate or throughput and produce good backside chipping
18
. However, when large particles
14
are used they present the problem of poor frontside chipping
16
due to the increased contact area/pressure between the large particle
14
and frontside
10
. Hence, symmetric dicing on the frontside
10
and backside
12
is problematic. The large degree of frontside chipping is especially a problem because of its proximity to the fabricated circuitry which is located on wafer frontside
10
.
In contrast, as shown in
FIG. 1
b
, silicon wafer
8
having a frontside
10
and backside
12
may be diced by a dicing blade
4
with small diamond particles
20
, with a mean particle size of about 1-2 microns. The small particle
20
provides minimal contact area with frontside
10
thereby allowing minimal pressure and producing good frontside chipping
3
. But, small diamond particles
20
do not cut as efficiently as large particles
14
and using small particles
14
creates pressure buildup at the leading edge of the dicing blade
4
thereby causing chips to breakout (“slivering”), creating poor backside chipping
2
.
Therefore what is needed is a diamond dicing blade which produces efficient, symmetric cuts with reduced chipping on both the frontside and backside of a wafer.
SUMMARY OF THE INVENTION
The present invention provides a multi-layered diamond dicing blade. More particularly, the blade is a multi-layered dicing blade comprising an inner layer with a first set of diamond particles and an outer layer overlying the inner layer. The inner layer extends to the outermost periphery of the dicing blade. The outer layer comprises a second set of diamond particles having a size smaller than the first set of diamond particles. The first set of diamond particles makes initial contact with the silicon wafer penetrating the bare silicon. The second set of diamond particles of the dicing blade provides a fine finish.
The above advantages and features of the invention will be more clearly understood from the following detailed description which is provided in connection with the accompanying drawings.
REFERENCES:
patent: 4644703 (1987-02-01), Kaczmarek et al.
patent: 6207294 (2001-03-01), Rutter
patent: 6276995 (2001-08-01), Matsuta et al.
patent: 6286498 (2001-09-01), Sung
Dickstein , Shapiro, Morin & Oshinsky, LLP
Hail III Joseph J.
McDonald Shantese
Micro)n Technology, Inc.
LandOfFree
Wafer dicing blade consisting of multiple layers does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Wafer dicing blade consisting of multiple layers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Wafer dicing blade consisting of multiple layers will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3068398