Curve shape blade for wafer sawing
Original Publication Date: 2003-Jul-25
Included in the Prior Art Database: 2003-Jul-25
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For the die separation of the microelectronic substrates the diamond wafer sawing is the method which is normally used. This method will produce the sharp edge/corners die (figure 1), which leads to a high stress concentration and as a result to cracks and delamination of the die. To reduce the stress it is not allowed in the layout design to place active metallizations or bond pads too close to the corners (within 300µm distance). The sharp edges also prevent the use of shorter wire bonding (closer bond pads on substrate) because of the shorting to the edge. The subject of the invention is firstly an IC die comprising four curved corners/edges with curve angle from 45 degree to 75 degree and secondly the manufacturing process of these IC dies. An innovative design of the blade (figure 2) was developed to make curved corners/edges. This blade produces a die with a curved edge resulting in curved corners after finishing the X and Y direction cut. The whole sawing process contains two steps. In the first step the special shape blade is used which saws 30%-70% of the total wafer thickness. Then the second blade with a normal shape is used to do the full cut (figure 3).