INVENTION SUMMARY: AUTOMATION OF THE WAFER DEMOUNT PROCESS
Original Publication Date: 1994-Jun-01
Included in the Prior Art Database: 2002-Mar-06
The wafer thinning process requires the front side of each wafer to be submerged in wax, wherein, the wax mechanically affixes the wafer to the stain- less steel carrier. Next, the carrier is turned wafer side down and spun on a stainless steel table. A mixture of grit (aluminum oxide) and water are dis- pensed onto the table to aid in the wafer thinning process and to eliminate wafer to table contact. The lapping process continues until the wafers are approx- imately 7 mils thick. At this point, the carriers and attached wafers are submerged in a 5:l:l acid bath to etch the wafers to a final thickness of 5 mils. Finally, the carrier is placed on a hot plate for 10 minutes in an attempt to melt the wax bond be- tween the wafer and the carrier. At the end of this time, an operator attempts to peel (like the skin off a banana) the wafers from the carrier with a hand held vacuum wand by placing the vacuum on the back side ofthe wafer and lifting in an upward motion (Figure 1).