Method of thinning a semiconductor die
A method for thinning a semiconductor die includes providing the semiconductor die having electrical contacts electrically connected to and protruding from a top surface of the semiconductor die. The electrical contacts are spaced from one another on the top surface of the semiconductor die. The electrical contacts are encapsulated and a portion of the top surface of the semiconductor die is covered by a semisolid filler. The semisolid filler fills the space between the electrical contacts. An adhesive layer is applied to a top surface of the semisolid filler, and a backgrinding process is performed on a bottom surface of the semiconductor die. The method allows for thin semiconductor dies to be manufactured while reducing the risk of manufacturing defects associated with backgrinding.
1. A method for thinning a semiconductor die, the method comprising:
providing a semiconductor die having a top planar surface, a bottom planar surface opposite the top planar surface, and a plurality of electrical contacts electrically connected to and protruding from the top planar surface, each electrical contact of the plurality of electrical contacts spaced from one another on the top planar surface of the semiconductor die;
encapsulating the plurality of electrical contacts and covering at least a portion of the top planar surface of the semiconductor die with a semisolid filler, wherein the semisolid filler fills the space between the electrical contacts and fills a space above the electrical contacts defined by a top surface of the semisolid filler, wherein the top surface of the semisolid filler has a first height from the top planar surface of the semiconductor die that is greater than a second height of the electrical contacts from the top planar surface of the semiconductor die;
applying an adhesive layer to the top surface of the semisolid filler after the semisolid filler has hardened to a solid state, causing the adhesive layer to be in contact with the top surface of the semisolid filler at the first height;
performing a backgrinding process on the bottom planar surface of the semiconductor die after applying the adhesive layer, wherein performing the backgrinding process includes backgrinding the bottom planar surface of the semiconductor die until the semiconductor die has a decreased thickness measured in a direction perpendicular to the bottom planar surface; and
removing the adhesive layer from the semiconductor die after performing the backgrinding process, wherein removing the adhesive layer from the semiconductor die causes the semisolid filler to be removed from the semiconductor die.
2. The method of claim 1 , wherein an adhesion strength of the adhesive layer to the semisolid filler is greater than an adhesion strength of the semisolid filler to the plurality of electrical contacts and the top planar surface of the semiconductor die.
3. The method of claim 1 , wherein the decreased thickness is 45-55 micrometers.
4. The method of claim 1 , wherein the semiconductor die following the backgrinding process has a total thickness variation of less than 3 micrometers.
5. The method of claim 1 , wherein the semisolid filler is a mixture including alginate.
6. A method for thinning a semiconductor die comprising a solder joint array including a plurality of solder bumps, the method comprising:
applying a semisolid filler to the plurality of solder bumps, wherein the semisolid filler encapsulates the solder bumps, fills gaps between the solder bumps, and fills a space above the solder bumps defined by a top surface of the semisolid filler, wherein the top surface of the semisolid filler has a first height from a top planar surface of the semiconductor die that is a greater than a second height of the solder bumps from the top planar surface of the semiconductor die;
applying backgrinding tape to the top surface of the semisolid filler after the semisolid filler has hardened to a solid state, causing the backgrinding tape to be in contact with the top surface of the semisolid filler at the first height;
performing a backgrinding process on a bottom planar surface of the semiconductor die after applying the backgrinding tape, wherein performing the backgrinding process includes backgrinding the bottom planar surface of the semiconductor die until the semiconductor die has a decreased thickness measured in a direction perpendicular to the bottom planar surface; and
removing the backgrinding tape from the semiconductor die after performing the backgrinding process, wherein removing the backgrinding tape from the semiconductor die causes the semisolid filler to be removed from the semiconductor die.
7. The method of claim 6 , wherein an adhesion strength of the backgrinding tape to the semisolid filler is greater than an adhesion strength of the semisolid filler to the plurality of solder bumps.
8. The method of claim 6 , wherein the decreased thickness is 45-55 micrometers.
9. The method of claim 6 , wherein the semiconductor die following the backgrinding process has a total thickness variation of less than 3 micrometers.
10. The method of claim 6 , wherein the semisolid filler is a mixture including alginate.