Dicing saws

Individual 2 cm chips were diced using a Disco DAD-321 (Disco Corporation, Japan) dicing saw. Dicing lines were included on the electrode layer. 

Baseline TDR measurements were made for two samples in their entirety and then the two samples were ablated. In one case a laser was used to make a cut perpendicular to the direction of the track formed by the dielectric seal material. In the second sample, a dicing saw was used to cut through the top plate of the sample and remove a portion of the dielectric seal. After the samples were ablated, a second set of TDR measurements were made for comparison with the baseline. In both cases, there were no visible differences between the baseline and the second measurement. 

In a third sample, two dicing saw cuts were made perpendicular to the track direction and parallel to one another as shown in Figure 4-9, allowing a section of the ceramic top plate and a print of the dielectric seal material to be removed. In this sample, TDR measurements comparing the same sample in cases both with the ceramic lid in place and with the lid removed showed a visible phase-shift in the time-domain signal. 

After IC devices are manufactured on a substrate wafer, a dicing saw is used to break the wafers into smaller chips. The chips are then bonded to a metal frame (called a lead frame) using epoxy. The lead frame is often made of Cu-Ni-Fe alloys with a thermal expansion coefficient matched with that of the silicon substrate as well as of the plastic compound. Wire bonding is used to connect contact pads on the device to the lead frame. The device (and the lead frame) is then put into a mold. The plastic compound, with a thermal expansion coefficient matched with silicon, is molded around the deviceAead frame to form a protective case. 

The primary benefit of laser cutting is the ability to cut complex shapes with roxmded or curved edges. For example, singulation of a large panel into small roxmd substrates is impossible with a dicing saw but can easily be accomplished with a laser. Likewise, complex cavities can be nibbled out with a computer numerical control (CNC) mechanical pxmch however, the edge quality tends to be poor, and the process is very slow. In contrast, a laser can easily and rapidly cut these types of features. 

After the polyimide layer is cured, the conductive polymer paste is printed to the substrate in order to fill the holes over the metal pads and then cured (Fig. 32(b)). Using the same stencil and conducting paste, the polymer bumps are then screen printed on top of the conductive polymer pads and cured (Fig. 32(c)). Current printing techniques allow production of 50-100 p,m diameter bumps, 30-50 p.m high, with a centre-to-centre pitch of 125-150 p,m, and flat, conic, or hemispherical shapes. Once the bumps are cured and the dice sawed,... 

The IC is fabricated by a series of lithographic processes similar to that described in the previous section. Each individual step constitutes a level in the device, the final level being a metalization pattern to interconnect the circuit elements that have been fiibricated in the surface of the silicon wafer. The completed wafer is then diced, a step that involves cutting the wafer, typically with a diamond saw, to separate the individual IC chips. The next step is to package the chips in some way, attach the devices along with other components to the printed wiring board (PWB), and interconnect them to produce the completed circuit board. 

TiCN-alumina Press Gas pressure sintering 1,800 10-15 Grinding Saw or laser dicing... 

After the wafer fabrication is complete, the wafer needs to be diced to separate the individual chips. The method again depends upon the type of semiconductor. The preferred methods of dicing include sawing with a... 

Compared to more conventional techniques, this sawing technique enables 10 times higher production rates and close dimensional tolerances (maximum mass variation for 18 samples 1%), As a result of the dicing operation the cubes thus produced however present burrs, which can be eliminated either by etching (Ti and TiA16V4) or by barrel finishing (Mo). 

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