1. A method of constructing a preformed solder bar made-ready for installing a microchip, comprising:
forming a socket on a first surface of a microchip, such that the socket has predetermined physical dimensions complementary to those of a microchip connection pad footprint occupied by at least one contact pad area on the microchip,
the socket presenting a conductive base capable of bonding to solder;
bonding solder to the conductive base to place a solder bar in the socket and place the microchip in made-ready condition for installation.
2. The method of claim 1, wherein the microchip contains a silicon wafer and the step of forming the socket comprises
depositing an adhesion layer onto the wafer, and
depositing under-bump-metallization (UBM) material contacting the adhesion layer to complete formation of the conductive base.
3. The method of claim 2, wherein the step of depositing the adhesion layer includes depositing a conductor selected from the group consisting of aluminum, nickel-vanadium, titanium, tungsten and copper.
4. The method of claim 2, wherein the step of depositing the UMB material includes depositing a conductor selected from at least one of titanium, tungsten, vanadium, tin, copper, aluminum, gold, silver, and lead.
5. The method of claim 1, wherein the step of forming the socket includes the predetermined dimensions selected from the group consisting of rectangular, \u201cE,\u201d \u201cL,\u201d and \u201cU\u201d shapes.
6. The method of claim 1, wherein the step of forming the socket includes the physical dimensions selected from the group consisting of ring, square, and circular shapes.
7. The method of claim 1, wherein the step of forming the socket includes the physical dimensions being complimentary to the solder bar having a planar rectilinear configuration.
8. The method of claim 1, wherein the step of forming the socket includes the physical dimensions being complimentary to the solder bar having a planar curvilinear configuration.
9. The method of claim 1, wherein the step of forming the socket further comprising a step of forming a passivation layer on substantially all of the first surface, exclusive of an area where the socket is located.
10. The method of claim 9, wherein the step of forming the passivation layer includes the steps of:
applying one or more layers of passivation material to the entire first surface; and
removing selected portions of the passivation material covering the area where the socket is to be located.
11. The method of claim 10, wherein the step of applying one or more layers of passivation material includes applying at least one layer selected from the group consisting of polysilicon, silicon dioxide, and benzocyclobutane.
12. The method of claim 1, further comprises depositing a non-solder base metal in the socket after the step of forming the socket and prior to the step of bonding solder, such that the solder bar contains the non-solder base metal and the solder in respective layers.
13. The method of claim 12, wherein the step of depositing the non-solder base metal includes electroplating the non-solder base metal.
14. A method of claim 12, wherein the step of depositing the non-solder base metal includes screen printing at least one base metal layer.
15. The method of claim 14, wherein the step of depositing the non-solder base metal includes depositing the non-solder base metal layer selected from the group consisting of copper, gold, titanium, tungsten, and vanadium.
16. The method of claim 1, wherein the step of bonding solder includes electroplating one or more solder layers onto the conductive base.
17. The method of claim 1, wherein the step of bonding solder includes screen printing one or more solder layers onto the conductive base.
18. A chip scale package made-ready for installation of a microchip on a printed circuit board or chip-on-chip stack, comprising:
a microchip including a first surface having a connection pad area;
an adhesion layer contacting the connection pad;
an under bump metallization layer contacting the adhesion layer;
at least one passivation layer delineating an opening to the under bump metallization layer to define a socket; and
a solder bar in contact with the under bump metallization layer, the solder bar having dimensions complementary to the socket and a geometric configuration selected from the group consisting of planar curvilinear and planar rectilinear configurations.
19. The chip scale package of claim 18, wherein the solder bar includes a base metal layer in contact with the under bump metallization layer and the solder layer.
20. The chip scale package of claim 18, wherein the geometric configuration includes a geometry selected from the group consisting of rectangular, \u201cE,\u201d \u201cL,\u201d and \u201cU\u201d shapes.
21. The chip scale package of claim 18, wherein the geometric configuration includes a geometry selected from the group consisting of ring, square, and circular shapes.
22. The chip scale package of claim 18, wherein the solder bar comprises a plurality of sublayers having different characteristics.
23. The chip scale package of claim 18, wherein the solder bar contains a base metal layer and a solder layer 24. The chip scale package of claim 23, wherein the base metal layer is selected form the group consisting of copper, gold, silver, lead, tin, titanium, tungsten, and vanadium.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. Method for degassing a liquid of a substantially closed liquid circulation system at a working pressure, comprising
passing at least a partial flow of the liquid through a restriction into a chamber,
allowing the chamber to become partially filled by the partial flow of liquid with a gas head above a level of the liquid accumulated inside the chamber,
maintaining a degassing pressure in the chamber, the degassing pressure being higher than atmospheric pressure and lower than the working pressure,
separating gas withdrawn from the partial flow of liquid from the partial flow,
removing the gas from the chamber, and
pumping the degassed partial flow of the liquid back into the substantially closed circulation system,
wherein the restriction comprises a nozzle, and the step of passing at least the partial flow of the liquid through the restriction into the chamber comprises
spraying at least the partial flow of the liquid through the nozzle into the chamber for obtaining a jet or a mist of the liquid in the chamber, wherein the step of removing the gas from the chamber is effected via a rise pipe having an entry opening allowing escape of gas when the liquid level is below the entry opening and allowing the gas to accumulate in the head when the liquid level is above the entry opening.
2. Method according to claim 1, wherein the chamber is at most partially filled with the liquid, and the nozzle is situated at a level higher than the liquid level.
3. Method according to claim 1, wherein the step of removing the gas from the chamber is effected via a float valve.
4. Method according to claim 1, comprising
adjusting a pump rate of the pump such that the degassing pressure is maintained substantially constant.
5. Method according to claim 1, comprising
adjusting a pump rate of the pump such that the liquid level is maintained substantially constant.
6. Method according to claim 1, wherein the degassing pressure is 0.1 to 0.5 bar higher than atmospheric pressure.
7. Device for degassing a liquid of a substantially closed liquid circulation system at a working pressure, comprising
a chamber for being partially filled by a liquid with a gas head above a level of the liquid accumulated inside the chamber,
a restriction, in fluid communication with the chamber for passing at least a partial flow of the liquid through the restriction into the chamber,
a pump for maintaining a degassing pressure in the chamber and feeding the liquid back into the substantially closed liquid circulation system, the degassing pressure being higher than atmospheric pressure and lower than the working pressure, and
an automatic valve for removing gas separated from the liquid out of the chamber when the amount of gas inside the chamber exceeds a predetermined amount,
wherein the restriction comprises a nozzle for spraying at least the partial flow of the liquid through the nozzle into the chamber for obtaining a jet or a mist of the liquid in the chamber,
the device further comprising a rise pipe for removing the gas from the chamber, the rise pipe having an entry opening allowing escape of the gas when the liquid level is below the entry opening and allowing the gas to accumulate in the head when the liquid level is above the entry opening.
8. Device according to claim 7, wherein the nozzle is situated in an upper part of the chamber.
9. Device according to claim 7, wherein the nozzle is arranged to spray in a direction away from the liquid surface in the chamber.
10. Device according to claim 7, wherein the automatic valve for removing gas comprises a flow switch arranged for switching off the pump to avoid degassing when the flow of gas is below a predetermined threshold level.
11. Heating or cooling system comprising a substantially closed liquid circulation system at a working pressure and a device for degassing according to claim 7.
12. Heating or cooling system according to claim 11, wherein a liquid flow path through the device for degassing forms a branch parallel to a portion of the substantially closed circuit.