Solder transfer integrated circuit packaging
View Patent ↗An approach for transferring solder to a laminate structure in IC (integrated circuit) packaging is disclosed. The approach comprises of a device and method of applying the device. The device comprises of a substrate, a laser ablation layer and solder layer. The device is made by depositing a laser ablation layer onto a glass/silicon substrate and plenty of solder powder/solder pillar is further deposited onto the laser ablation layer. The laminate packaging substrate includes pads with a pad surface finishing layer made from gold. The solder layer of the device is bonded to the laminate packaging substrate. Once bonded, using laser to irradiate the laser ablation layer, the substrate is removed from the laminate.
1. A method of transferring solder onto a laminate, the method comprising:
applying a first flux;
positioning solder structure over target, wherein the solder structure comprises:
a substrate;
a laser ablation layer;
an adhesive layer; and
a solder layer made with solder;
lowering the solder structure towards the target, wherein the target comprises:
a laminate substrate;
one or more pads located on the laminate substrate; and
one or more pad surface finishing layers located on a top surface of the one or more pads;
bonding solder of the solder structure to the target;
debonding the solder structure; and
cleaning residue of the first flux, the adhesive layer, and the laser ablation layer.
2. The method of claim 1 , wherein:
the target comprises of one or more pads located on a laminate layer and one or more pad surface finishing layers located on the one or more pads.
3. The method of claim 1 , wherein:
the one or more pad surface finishing layers comprises of a material made of gold.
4. The method of claim 1 , wherein applying the first flux further comprises:
depositing the first flux onto the solder layer or the one or more pad surface finishing layers.
5. The method of claim 1 , wherein bonding solder of the solder structure to target further comprises:
adhering, using TCB (thermo compression bonding), the solder layer to the one or more pad surface finishing layers, wherein temperature used by TCB is lower than a melting point of the solder layer.
6. The method of claim 1 , wherein debonding the solder structure further comprises:
removing the substrate made of glass from the target by ablating the laser ablation layer with a laser, wherein the laser has a wavelength of between 350 nm to 360 nm.
7. The method of claim 1 , wherein debonding the solder structure further comprises:
removing the substrate made of silicon from the target by ablating the laser ablation layer with a laser, wherein the laser has a wavelength of the infrared energy is in a range of 1.12 μm to 5 μm.
8. The method of claim 1 , further comprising:
applying a second flux and reflowing.