Wafer treating method for making adhesive dies

Abstract

A wafer treating method for making adhesive dies is provided. A liquid adhesive with two-stage property is coated on a surface of a wafer. Then, the wafer is pre-cured to make the liquid adhesive transform a thermo-bonding adhesive film having B-stage property which has a glass transition temperature not less than 40° C. for handling without adhesive under room temperature. After positioning the wafer, the wafer is singulated to form a plurality of dies with adhesive for die-to-die stacking, die-to-substrate or die-to-leadframe attaching.

1. A wafer treating method for making adhesive dies comprising the steps of:
 providing a wafer having a surface; 
 coating a liquid adhesive with two-stage property on the surface of the wafer, wherein the surface of the wafer is partially coated with the liquid adhesive; 
 pre-curing the liquid adhesive so that the liquid adhesive transforms into a wafer-level thermo-bonding adhesive film having B-stage property; 
 providing a positioning tape in contact with the wafer-level thermo-bonding adhesive film for positioning the wafer; and 
 singulating the wafer on the positioning tape so as to form a plurality of dies with the wafer-level thermo-bonding adhesive film. 
 
     
     
       2. The wafer treating method for making adhesive dies in accordance with  claim 1 , wherein the liquid adhesive is formed by screen printing, stencil printing or spin coating. 
     
     
       3. The wafer treating methods for making adhesive dies in accordance with  claim 1 , wherein the surface of the wafer is an active surface of the wafer. 
     
     
       4. The wafer treating method for making adhesive dies in accordance with  claim 1 , wherein the surface of the wafer is an inactive surface of the wafer. 
     
     
       5. The wafer treating method for making adhesive dies in accordance with  claim 1 , wherein the surface of the wafer is partially coated with the liquid adhesive. 
     
     
       6. The wafer treating method for making adhesive dies in accordance with claim  5  1, wherein the wafer has cutting paths and bonding pads and wherein the surface is coated with the liquid adhesive without covering the cutting path and the bonding pads of the wafer. 
     
     
       7. The wafer treating method for making adhesive dies in accordance with  claim 1 , wherein the entire surface of the wafer is coated with liquid adhesive. 
     
     
       8. The wafer treating method for making adhesive dies in accordance with  claim 1 , wherein the wafer-level thermo-bonding adhesive film has a glass transition temperature (Tg) not less than 40° C. 
     
     
       9. The wafer treating method for making adhesive dies in accordance with claim 1, wherein the wafer-level thermo-bonding adhesive film has a thickness between 3˜8 mil for die-to-die stacking. 
     
     
       10. The wafer treating method for making adhesive dies in accordance with  claim 1 , wherein the wafer-level thermo-bonding adhesive film has a thickness between 5˜6 mil for die-to-die stacking. 
     
     
       11. The wafer treating method for making adhesive dies in accordance with  claim 1 , wherein the wafer-level thermo-bonding adhesive film has a thickness between 1˜3 mil for die-to-substrate or die-to-leadframe attaching. 
     
     
       12. A wafer treating method for making adhesive dies comprising the steps of:
 providing a wafer having an active surface upwardly, wherein a plurality of bonding pads are formed on the active surface, there are a plurality of cutting paths at the wafer to define dies; 
 coating a liquid adhesive on the partially active surface of the wafer, wherein the liquid adhesive exposes the bonding pads; 
 pre-curing the liquid adhesive so that the liquid adhesive transforms into a wafer-level thermo-bonding adhesive film having B-stage property; and 
 singulating the wafer along the cutting path so as to form a plurality of dies with the wafer-level thermo-bonding adhesive film. 
 
     
     
       13. The wafer treating method for making adhesive dies in accordance with  claim 12 , wherein the liquid adhesive is formed by screen printing or stencil printing method. 
     
     
       14. The wafer treating method for making adhesive dies accordance with  claim 12 , wherein the wafer-level thermo-bonding adhesive film has a glass transition temperature (Tg) not less than 40° C. 
     
     
       15. The wafer treating method for making adhesive dies in accordance with  claim 12 , wherein the wafer-level thermo-bonding adhesive film has a thickness between 1˜3 mil for die-to-leadframe attaching. 
     
     
       16. The wafer treating method for making adhesive dies in accordance with  claim 12 , wherein the coating step of a liquid adhesive, the liquid adhesive exposes the cutting paths.