Bonding area design for transient liquid phase bonding process
View Patent ↗Devices, methods and systems are disclosed herein to describe the wettability characteristics of the material forming a bonding area, a non-bonding area, and a melted bonding material. The melted bonding material may have a high degree of cohesion and may result in a very high contact angle (e.g., between 90°- 180°) in the non-bonding area thereby preventing or limiting the flow of a melted material into the non-bonding area, which often results when the melted bonding material forms a low contact angle (e.g., between 0°-90°) in the bonding area. In other words, by choosing a material for the non-bonding area to have low wettability characteristics when compared to the melted materials of the bonding area or by treating the material forming the non-bonding area to have much lower wettability characteristics, the melted materials of the bonding area may be prevented from flowing into the non-bonding area.
1. An apparatus formed as a result of a transient liquid phase (TLP) bonding process, the apparatus comprising:
a homogenous bondline alloy formed of a first bonding material,a second bonding material, and a melted bonding layer formed of a material having a first wettability characteristic; and
a non-bonding layer forming a perimeter about the bonding layer, the non-bonding layer formed of a material having a lower wettability characteristic than the material of the melted bonding layer, the non-bonding layer limiting the melted bonding layer from flowing into the non-bonding layer.
2. The apparatus of claim 1 , wherein the material forming the melted bonding layer and the material forming the non-bonding layer are different materials.
3. The apparatus of claim 1 , wherein the material forming the melted bonding layer and the material forming the non-bonding layer are the same materials, further wherein the material forming the melted bonding layer is treated to increase its wettability characteristic by changing the its hydrophobic surface to a hydrophilic surface.
4. The apparatus of claim 1 , wherein the material forming the melted bonding layer and the material forming the non-bonding layer are the same materials, further wherein the material forming the non-bonding layer is treated to decrease its wettability characteristic by changing its hydrophilic surface to a hydrophobic surface.
5. The apparatus of claim 1 , wherein the material forming the melted bonding layer and the material forming the non-bonding layer are the same materials, further wherein a surface where the melted bonding layer contacts the non-bonding layer is treated to increase its wettability characteristic by increasing the smoothness of the surface.
6. The apparatus of claim 1 , wherein the material forming the melted bonding layer and the material forming the non-bonding layer are the same materials, further wherein a surface of the non-bonding layer where the melted bonding layer contacts the non-bonding layer is treated to decrease its wettability characteristic by increasing the roughness of the surface.
7. The apparatus of claim 1 , wherein the apparatus is a substrate to be bonded to a die, the apparatus further comprising a substrate layer on which is formed the melted bonding layer and the non-bonding layer, the melted bonding layer bonding the substrate to the die.
8. The apparatus of claim 1 , wherein the apparatus is a die to be bonded to the substrate, the apparatus further comprising a layer on which is formed the melted bonding layer and the non-bonding layer, the bonding layer bonding the substrate to the die.
9. The apparatus of claim 1 , wherein the apparatus is a first wafer to be bonded to a second wafer, the apparatus further comprising a layer on which is formed the melted bonding layer and the non-bonding layer, the melted bonding layer bonding the first wafer to the second wafer.
10. The apparatus of claim 1 , wherein the apparatus is a first die to be bonded to a second die, the apparatus further comprising a layer on which is formed the melted bonding layer and the non-bonding layer, the melted bonding layer bonding the first die to the second die.
11. The apparatus of claim 1 , wherein the apparatus is a die to be bonded to a wafer, the apparatus further comprising a layer on which is formed the melted bonding layer and the non-bonding layer, the melted bonding layer bonding the die to the wafer.
12. An assembly formed as a result of transient liquid phase (TLP) bonding of a substrate to a die, the assembly comprising:
a die having a bottom surface attached to a TLP bonding material;
a substrate including:
a second substrate metal layer,
an insulation layer positioned on the second substrate metal layer, and
a first substrate metal layer positioned on the insulation layer;
a bonding layer positioned on the first substrate metal layer the bonding layer formed of a first material;
a homogeneous bondline alloy formed of the first substrate metal layer, the TLP bonding material of the die, and a melted bonding layer between the first substrate metal layer and the TLP bonding material of the die; and
a non-bonding layer positioned on the first substrate metal layer and surrounding the homogeneous bondline alloy, the non-bonding layer formed of a second material having lower wettability characteristics than the homogeneous bondline alloy, the non-bonding layer limiting the melted bonding layer from flowing into the non-bonding layer during a TLP bonding process.
13. The assembly of claim 12 , wherein the material forming the melted bonding layer and the material forming the non-bonding layer are different materials.
14. The assembly of claim 12 , wherein the material forming the melted bonding layer and the material forming the non-bonding layer are the same materials, further wherein the material forming the melted bonding layer is treated to increase its wettability characteristic by changing the its hydrophobic surface to a hydrophilic surface.
15. The assembly of claim 12 , wherein the material forming the melted bonding layer and the material forming the non-bonding layer are the same materials, further wherein the material forming the non-bonding layer is treated to decrease its wettability characteristic by changing its hydrophilic surface to a hydrophobic surface.
16. The assembly of claim 12 , wherein the material forming the melted bonding layer and the material forming the non-bonding layer are the same materials, further wherein a surface where the melted bonding layer contacts the non-bonding layer is treated to increase its wettability characteristic by increasing the smoothness of the surface.
17. The assembly of claim 12 , wherein the material forming the non-bonding layer and the material forming the non-bonding layer are the same materials, further wherein a surface of the non-bonding layer where the melted bonding layer contacts the non-bonding layer is treated to decrease its wettability characteristic by increasing the roughness of the surface.