Die separation using adhesive-layer laser scribing
A method for wafer dicing and removing separated integrated circuit (IC) dies from a carrier substrate includes mounting a wafer on a substrate using an adhesive layer, laser scribing the adhesive layer to create defect regions in the adhesive layer, and performing a breaking step to separate the laser-scribed adhesive layer into separated adhesive portions corresponding to the IC dies. For a stealth-dicing (SD) technique, defect regions also are created in the wafer using a laser and the breaking step is an expansion step that simultaneously separates the dies and corresponding portions of adhesive. For a dice-before-grind (DBG) technique, the dies are separated by backside grinding before the breaking step. Efficient adhesive-layer separation is achieved with reduced backside chipping associated with conventional blade dicing.
1. A method for manufacturing integrated circuit (IC) dies, the method comprising:
mounting a multi-die wafer onto a substrate using an adhesive layer;
laser scanning the multi-die wafer to introduce defects into the wafer along lines located between die locations on the wafer;
laser scribing the adhesive layer through the substrate to create defects in the adhesive layer along the lines; and
performing a breaking step to separate the laser-scribed adhesive layer into separated adhesive portions corresponding to the IC dies, wherein:
the wafer fractures along the lines corresponding to the defects in the wafer, thereby separating the multi-die wafer into the IC dies.
2. The method of claim 1 , wherein the wafer is mounted backside down onto the substrate, and the adhesive layer secures the wafer backside to the substrate.
3. The method of claim 1 , wherein, after the laser-scribing step, but before the breaking step, the adhesive layer has the defects, but is otherwise contiguous.
4. The method of claim 1 , wherein the breaking step is a substrate-expansion step.
5. The method of claim 4 , wherein the substrate-expansion step is a cool-expansion step.
6. The method of claim 1 , wherein the laser-scribed defects in the adhesive layer correspond to the lines in the wafer.
7. The method of claim 1 , wherein:
the breaking step is a stealth-dicing substrate-expansion step.
8. The method of claim 1 , wherein the mounting step comprises:
partially cutting the wafer front side;
mounting the partially cut wafer front side down onto the substrate; and
thinning the backside of the partially cut wafer to separate the IC dies.
9. The method of claim 8 , wherein:
the mounting step is a dice-before-grind mounting step; and
the breaking step is a substrate-expansion step.
10. A method of separating adjacent integrated circuit (IC) dies formed on a semiconductor wafer, the method comprising:
laser scribing a backside of the wafer along lines located between adjacent ones of the IC dies to form defects in the wafer along the lines;
mounting the laser-scribed wafer onto a substrate using an adhesive layer,
wherein the wafer is mounted backside down onto the substrate, and
the adhesive layer secures the wafer backside to the substrate;
laser scribing the adhesive layer through the substrate to create defects in the adhesive layer along the lines; and
performing a breaking step to separate the laser-scribed adhesive layer and the laser-scribed wafer along the lines into separate adhesive and wafer portions, thereby providing the separated IC dies.
11. The method of claim 10 , wherein, after the adhesive layer laser-scribing step, but before the breaking step, the adhesive layer has the defects but is otherwise contiguous.
12. The method of claim 10 , wherein the breaking step is a substrate-expansion step, and the substrate-expansion step is a cool-expansion step.
13. The method of claim 10 , wherein:
during the breaking step, the wafer fractures along the lines corresponding to the defects.