These wafers should be protected from dicing contaminants. For other applications, we can consult blade manufacturers for recommendations. For a list of commonly diced materials, see the materials section. The rate at which the wafer is moved into the blade or under a scribe. Feed rate should be determined by your desired cut quality, material hardness, density, and thickness. Most dicing operations require cutting as much material as possible, in shortest period of time possible.
Frequently most gains in cutting speed and output are done at the expensive of cut quality. You should maintain the feed rate best suited for your required cut quality. Too high feed rates can also cause excessive chipping and material cracking, increasing die rejection rates. The rate that the saw blade is rotated in revolutions per minute. Causing softer dicing action, where each diamond particle grinds out a larger portion of material.
This will result in higher blade wear but will expose new, fresh diamonds, resulting in a cleaner cut. Each diamond particle will grind away a small portion of material, creating harder dicing action. The distance from the chuck that the blade is positioned during cutting. It could also be the distance from the top of the wafer. Can also apply to a scribe tool. This way the Electronic semiconductor manufacturers are facing new and more difficult challenges in improving or keeping dicing quality and productivity.
Simac helps you to choose the right blade, give you detailed technical advice for the right set up of your dicing procedure and ultimately attaining higher profitability. Can Simac be of assistance to you in choosing the right dicing blade for your dicing application? Click on button below. Improving quality of primary packaging components Detecting defects in pharmaceutical glass vials Validation of machine vision following GAMP Contamination of rubber stoppers in production Contamination of rubber plungers in production Minimizing downtime in stopper production with SLA Detecting defects on vial closures.
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Combining these parameters and ensuring optimum throughput is the challenge. It has been shown that all process parameters correlate with blade torque Table 1. For each set of process parameters, there is a torque value limit. Dicing quality deteriorates and back-side chipping appears above the limit.
By measuring the torque on-line, the other process parameters can be set in such a way that the torque limit will not be exceeded and maximum feed rate will be obtained without chip formation. Many experimental variables have to be considered during process optimization. Testing each variable separately is tedious and consumes many wafers. The DOE method is used to reduce the number of tests needed and to provide the combined effect of several parameters.
The DOE is a statistical method for evaluation of multi-variable processes. All experimental variables are arranged in a matrix and tested in at least two settings. The outcome of the tests is measured and recorded. The DOE tests and analysis reveal the major factors that affect the response e. In general, the optimization process should start with blade selection, and process parameter optimization should follow.
The blade dimensions are limited by wafer demands; required kerf width determines blade thickness. The thickness of the wafer determines the blade height. Other parameters to choose are blade bonding material hardness, diamond size and concentration, and the shape of the blade edge and hub. During blade selection, two factors should be considered: blade life and cut quality.
Blade life is an important factor in the cost of ownership of a dicing system. Blade life depends on blade bonding material properties.
Blades with softer bond material typically provide better cut quality, especially regarding control of BSC. These blades also wear much faster than hard bonded blades. A trade-off is required between blade wear and cut quality. The chip size should be acceptable and blade life suYcient. Use of DOE can determine this required compromise without numerous trial and error tests. However, to monitor the formation of back-side chips, the diced wafer must be inspected off the machine.
There also is a way to monitor BSC on-line using torque measurements. The torque applied by the blade when cutting the substrate reflects changes in the different factors that affect the process.
Because these changes indicate variation in the process, the torque also reflects conditions that could lead to formation of back-side chipping.
When the torque limits are determined, the torque measurements become an eYcient tool for on-line monitoring of BSC. On-line monitoring of blade torque informs the operator of any deviation. It does not require extra inspection time and alerts in real time when there is danger of yield loss.
Subsequent off-line inspection should be a complementary tool, used to calibrate the on-line monitor or to verify the causes of deviations it detects. To ensure high quality process results, new blades have to be dressed before starting production.
This step is required to expose the cutting diamonds in the blade surface and condition the blade for continuous work without dramatic changes in cut quality. Dressing consists of cutting a certain length of material, starting at low feed rate and increasing the rate until the target is reached Figure 3.
The duration of the dressing process is usually based on post-dicing inspection results. Because the mechanism of this process is not fully understood, it tends to be a lengthy procedure that affects productivity. Chipping may result if dressing time is too short. In many cases, extra dressing time is used to maintain a margin of safety. There is a good method for controlling dressing time that can increase productivity.
Blade torque measurements provide an on-line method for determining the optimal dressing procedure. If the measured torque values follow a predetermined reference pattern during the dressing procedure, the dressing is being done properly and the point of completion can be determined.
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