Method of attaching die using self-assembling monolayer and package substrate including die attached thereto using self-assembling monolayer
Disclosed herein are a method of attaching a die using a self-assembling monolayer and a package substrate including a die attached thereto using a self-assembling monolayer. A first self-assembling monolayer formed on a die and a second self-assembling monolayer formed on a substrate are provided with the same hydrophilic or hydrophobic functional group, so that the die is attached to the substrate using an attractive force acting between the first and second self-assembling monolayers. An accuracy of alignment between the die and the substrate can be improved by the simple solution.
1. A method of attaching a die using a self-assembling monolayer, comprising:
(A) forming a first self-assembling monolayer on one side of a die including a pad on the other side;
(B) forming a second self-assembling monolayer on a die attach region on a substrate; and
(C) picking up the die using a robotically-assisted-pick-and-place assembly, and transferring the die to the die attach region of the substrate immersed in an alignment chamber containing solution so that the die is automatically aligned with the substrate using an attractive force acting between the first and second self-assembling monolayers.
2. The method according to claim 1 , wherein the first and second self-assembling monolayers have a hydrophilic or hydrophobic functional group.
3. The method according to claim 2 , wherein, in the (C), the alignment between the die and the substrate is executed by the attractive force acting between the first and second self-assembling monolayers having the same functional group.
4. The method according to claim 1 , wherein the (A) comprises:
(A1) forming an insulating film on the one side of the die including the pad on the other side; and
(A2) forming the first self-assembling monolayer on the insulating film.
5. The method according to claim 1 , wherein the (B) comprises:
(B1) coating a surface of a transfer stamp with a self-assembling molecule;
(B2) applying a gold (Au) thin film on the substrate; and
(B3) bringing the transfer stamp into contact with the substrate through a contact printing process thus forming the second self-assembling monolayer.
6. The method according to claim 5 , wherein, in the (B1), the transfer stamp is made of silicon rubber or polydimethylsiloxane.
7. The method according to claim 1 , wherein the (B) comprises:
(B1) applying a gold (Au) thin film on the die attach region of the substrate; and
(B2) dipping the substrate into a solution which is prepared by dissolving self-assembling molecules such as alkane thiol in ethanol solvent, so that the second self-assembling monolayer is formed on the gold (Au) thin film on the substrate.
8. The method according to claim 1 , wherein the (C) comprises:
(C1) disposing the substrate in a solution contained in an alignment chamber;
(C2) picking up the die in a face-up manner using a pickup head and transferring the die into the alignment chamber; and
(C3) automatically aligning the die with the substrate using the attractive force acting between the first and second self-assembling monolayers having a hydrophobic functional group.
9. The method according to claim 8 , wherein, in the (C2), the die is transferred near the second self-assembling monolayer on the substrate using the pickup head.
10. The method according to claim 1 , wherein the (C) comprises:
(C1) forming a solution drop on the second self-assembling monolayer on the substrate;
(C2) picking up the die in a face-up manner using the pickup head and transferring the die into the solution drop; and
(C3) automatically aligning the die with the substrate using an attractive force acting between the first and second self-assembling monolayers having a hydrophilic functional group.
11. The method according to claim 10 , wherein, in the (C1), the solution drop is a water drop.