# US 7,607,560 B2 · Semiconductor die attachment for high vacuum tubes

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- Number: US 7,607,560 B2
- Document ID: US7607560B2
- Status: Granted
- Kind: B2
- Application number: 11/193,065
- Filed: 2005-07-28
- Published: 2005-11-24
- Granted: 2009-10-27
- Earliest claimed: 2004-05-14
- Assignees: Intevac, Inc.
- Inventors: Kenneth A Costello
- Web page: https://patentgrep.com/patent/US7607560B2

## CPC

- B23K 1/0016: {Soldering of electronic components}
- H01J 31/26: Image pick-up tubes having an input of visible light and electric output (tubes without defined electron beams and having a light ray scanning photo-emissive screen H01J40/20)
- H10F 39/011: {Manufacture or treatment of image sensors covered by group H10F39/12}
- H10F 39/804: {Containers or encapsulations}
- B23K 2101/40: Semiconductor devices
- H10W 70/682: {comprising holes having chips therein}
- H10W 72/07232: {Compression bonding, e.g. thermocompression bonding}
- H10W 72/07236: {Soldering or alloying}
- H10W 72/07251: {characterised by changes in properties of the bump connectors during connecting}
- H10W 72/20: Bump connectors, e.g. solder bumps or copper pillars; Dummy bumps; Thermal bumps
- H10W 72/252: {comprising solid metals or solid metalloids, e.g. PbSn, Ag or Cu}
- H10W 72/9223: {with redistribution layers [RDL]}
- H10W 72/923: {Bond pads having multiple stacked layers}
- H10W 72/9415: {relative to the surface, e.g. recessed, protruding}
- H10W 72/942: {relative to underlying supporting features, e.g. bond pads, RDLs or vias}
- H10W 72/952: {comprising metals or metalloids, e.g. PbSn, Ag or Cu}
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

Bonding and interconnect techniques including a spacer for use with semiconductor die for the creation of thermally efficient, physically compliant Ultra High Vacuum Tubes and the tube resulting therefrom.

## Claims

### Claim 1

The method of manufacturing a high vacuum tube in which a semiconductor die is bonded onto an inner surface of a package comprising:
creating multiple bonding pads at a first surface of a die,
creating multiple matching bonding pads at the inner surface of the package, said package comprising a different material from said first surface of said die,
placing between said sets of bonding pads a die bond material with a melting point of less than about 150° C.,
aligning the surfaces with said bonding pads together,
placing a photocathode into a facing relationship with a second surface of said die,
placing a spacer between said photocathode and said second surface of said die, and
carrying said photocathode, said spacer, and said die while in a contacting relationship and aligned together through a brazing cycle and then through an ultra high vacuum processing cycle resulting in a sealed vacuum tube.

### Claim 2 (depends on 1)

The method of claim 1 including sealing said tube with a seal material by pressing said seal material between package sections while said seal material is in a solid state.

### Claim 3 (depends on 2)

The method of claim 2 including performing said sealing step during said ultra high vacuum processing cycle while elevating the tube body to a temperature of above the melting point of the die bond material but below the melting point of said seal material.

### Claim 4 (depends on 2)

The method of claim 2 where the vacuum seal material is Indium and the die bond material is an alloy of Indium and Tin.

### Claim 5 (depends on 3)

The method of claim 3 including sealing said tube while maintaining said tube body at a temperature of between 118° C. and 156° C.

### Claim 6 (depends on 3)

The method of claim 3 including connecting conductive bonding wires between said bonding pads at the inner surface of said package and at said first surface of said die.

### Claim 7 (depends on 6)

The method of claim 6 including bonding said wires between said pads prior to sealing said tube package.

### Claim 8 (depends on 2)

The method of manufacturing a vacuum tube in accordance with claim 2 including performing the step of sealing while the die bond material between said pads is in a molten stage.