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  Sawing method for a waferUSPTO Application #: 20080045124Title: Sawing method for a wafer Abstract: The present invention relates to a sawing method for a wafer. The sawing method of the invention comprises: (a) providing a wafer, the wafer having an active surface and a back surface, the active surface having a plurality of sawing lines; (b) coating a protection layer on the active surface and the sawing lines; (c) taping a grinding tape on a surface of the protection layer; (d) grinding the back surface of the wafer to thin the wafer; (e) removing the grinding tape; and (f) sawing the wafer to form a plurality of dice. Whereby, the problems of die cracking, die scratching, die contamination and peeling of the surface of the sawing lines can be avoided. (end of abstract)
Agent: Volentine & Whitt PLLC - Reston, VA, US Inventors: Fu-Tang Chu, Chi-Yuam Chung, Ji-Ping Teng USPTO Applicaton #: 20080045124 - Class: 451 54 (USPTO) The Patent Description & Claims data below is from USPTO Patent Application 20080045124. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND OF THE INVENTION [0001]1. Field of the Invention [0002]The invention relates to a sawing method for a wafer, particularly to a sawing method for a wafer with a protection layer coating on a surface of the wafer. [0003]2. Description of the Related Art [0004]FIGS. 1 to 4 show the steps for a conventional sawing method. Referring to FIG. 1, firstly, a wafer 10 is provided. The wafer 10 has an active surface 101 and a back surface 102, and the active surface 101 has a plurality of sawing lines (not shown). A grinding tape 11 is then taped on the active surface 101. The grinding tape 11 is used to protect the active surface 101 in the following grinding process. [0005]Referring to FIG. 2, the wafer 10 is thinned by grinding the back surface 102. For the conventional sawing method, the wafer 10 is thinned by using the grinding wheel of a grinding machine (not shown) to grind the back surface 102. The grinding tape 11 is then removed, as shown in FIG. 3. Finally, the wafer 10 is sawed by using cutting tools along the sawing lines on the active surface 101 to form a plurality of dice 12, as shown in FIG. 4. [0006]According to the conventional sawing method, there is no protection layer to protect the wafer 10 after the step of thinning the wafer 10, so that the surfaces of the sawing lines peel when sawing the wafer 10. Furthermore, a larger area near the sawing lines may also peel, and the active surface 101 of the wafer 10 will be damaged and scratched. In addition, after the grinding step, the grinding tape 11 must be removed, and the wafer 10 is then sawed. Therefore, when sawing the wafer to form a plurality of dice, the active surface of the dice will be contaminated. [0007]Consequently, there is an existing need for providing a sawing method for a wafer to solve the above-mentioned problems. SUMMARY OF THE INVENTION [0008]One objective of the present invention is to provide a sawing method for a wafer. The sawing method of the invention comprises: (a) providing a wafer, the wafer having an active surface and a back surface, the active surface having a plurality of sawing lines; (b) coating a protection layer on the active surface and the sawing lines; (c) taping a grinding tape on a surface of the protection layer; (d) grinding the back surface of the wafer to thin the wafer; (e) removing the grinding tape; and (f) sawing the wafer to form a plurality of dice. [0009]According to the sawing method of the invention, the protection layer still attaches to the wafer after the step of thinning the wafer, so that the protection layer can provide protection for the wafer. Therefore, the surfaces of the sawing lines will not peel when sawing the wafer. Also, a larger peeling area near the sawing lines can be avoided, and the active surface of the wafer is not damaged and scratched. Furthermore, the protection layer is removed after the wafer is sawed, so that the active surface of the dice will not be contaminated when sawing the wafer to form the dice. BRIEF DESCRIPTION OF THE DRAWINGS [0010]FIG. 1 shows the step for taping a grinding tape on a wafer according to a conventional method; [0011]FIG. 2 shows the step for grinding the wafer according to the conventional method; [0012]FIG. 3 shows the step for removing the grinding tape according to the conventional method; [0013]FIG. 4 shows the step for sawing the wafer according to the conventional method; [0014]FIG. 5 shows a wafer of the present invention; [0015]FIG. 6 shows the step for coating a protection layer on the wafer according to the present invention; [0016]FIG. 7 shows the step for taping a grinding tape on the wafer according to the present invention; [0017]FIG. 8 shows the step for grinding the wafer according to the present invention; [0018]FIG. 9 shows the step for removing the grinding tape according to the present invention; [0019]FIG. 10 shows the step for sawing the wafer according to the present invention; and [0020]FIG. 11 shows the step for removing the protection layer according to the present invention. DETAILED DESCRIPTION OF THE INVENTION Continue reading... Full patent description for Sawing method for a wafer Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Sawing method for a wafer patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Sawing method for a wafer or other areas of interest. ### Previous Patent Application: Sanding system with water based dust collection Next Patent Application: Polishing pad and chemical mechanical polishing apparatus Industry Class: Abrading ### FreshPatents.com Support Thank you for viewing the Sawing method for a wafer patent info. 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