Air cavity packages and methods for the production thereof

Patent metadata

Field	Value
Publication number	US-9922894-B1
Application number	US-201615269629-A
Country	US
Kind code	B1
Filing date	Sep 19, 2016
Priority date	Sep 19, 2016
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

Air cavity packages and methods for producing air cavity packages containing sintered bonded components, multipart window frames, and/or other unique structural features are disclosed. In one embodiment, a method for fabricating an air cavity package includes the step or process of forming a first metal particle-containing precursor layer between a base flange and a window frame positioned over the base flange. A second metal particle-containing precursor layer is further formed between the base flange and a microelectronic device positioned over the base flange. The metal particle-containing precursor layers are sintered substantially concurrently at a maximum processing temperature less than melt point(s) of metal particles within the layers to produce a first sintered bond layer from the first precursor layer joining the window frame to the base flange and to produce a second sintered bond layer from the second precursor layer joining the microelectronic device to the base flange.

First claim

What is claimed is:

1. A method for fabricating an air cavity package, comprising:
forming a first metal particle-containing precursor layer between a base flange and a window frame positioned over the base flange;
forming a second metal particle-containing precursor layer between the base flange and a microelectronic device positioned over the base flange, each containing metal particles of the first metal particle-containing precursor layer and the second metal particle-containing precursor layer having one or more melt points; and
sintering the first metal particle-containing precursor layer and second metal particle-containing precursor layer substantially concurrently at a maximum processing temperature less than the one or more melt points of the metal particles to produce a first sintered bond layer from the first metal-particle containing precursor layer joining the window frame to the base flange and to produce a second sintered bond layer from the second metal-particle containing precursor layer joining the microelectronic device to the base flange.

2. The method of claim 1 wherein the base flange remains interconnected with a plurality of other base flanges as a base flange panel following the sintering of the first metal particle-containing layer, and wherein the method further comprises singulating the base flange panel to separate the base flange from the plurality of other base flanges after the sintering.

3. The method of claim 1 further comprising selecting the metal particles to comprise at least one of silver particles, gold particles, and copper particles.

4. The method of claim 1 further comprising selecting the first metal particle-containing precursor layer and second metal particle-containing precursor layer to contain an organic binder in addition to the metal particles.

5. The method of claim 4 wherein sintering comprises sintering the first metal particle-containing precursor layer and second metal particle-containing layer under process conditions at which the organic binder decomposes, at least in substantial part, such that a first sintered bond layer and a second sintered bond layer are essentially free of the organic binder.

6. The method of claim 1 further comprising:
forming a third metal particle-containing precursor layer between the window frame and a lead positioned over the window frame opposite the base flange; and
the sintering comprises sintering the third metal particle-containing precursor layer to produce a third sintered bond layer joining the window frame and the lead.

7. The method of claim 6 wherein sintering comprises sintering the first metal particle-containing precursor layer, second metal particle-containing precursor layer, and third metal particle-containing precursor layer substantially concurrently utilizing a common sintering process.

8. The method of claim 1 further comprising selecting the window frame to include a plurality of leads embedded through the window frame.

9. The method of claim 1 further comprising depositing a sinter containment bead along a periphery of the first sintered bond layer.

10. The method of claim 1 further comprising assembling the window frame from multiple widow frame pieces, each window frame piece bonded to the base flange following the sintering of the first metal particle-containing precursor layer.

11. The method of claim 10 further comprising:
forming additional metal particle-containing precursor layers at interfaces between the multiple window frame pieces; and
sintering the additional metal particle-containing precursor layers to produce sintered bond joints at the interfaces between the multiple window frame pieces.

12. A method for fabricating an air cavity package, comprising:
positioning multiple window frame pieces over a base flange to assemble a multipart window frame having a plurality of window frame joints;
sealing the plurality of window frame joints, the sealing comprising:
forming metal particle-containing precursor layers between the window frame pieces at the plurality of window frame joints, the metal particle-containing precursor layers containing metal particles having one or more melt points;
sintering the metal particle-containing precursor layers at a maximum processing temperature less than a lowest melt point of the one or more melt points of the metal particles to transform the metal particle-containing precursor layers into sintered bond layers sealing the plurality of window frame joints; and

during or after the positioning and the sealing, bonding the window frame pieces to the base flange.

13. The method of claim 12 wherein at least one of the window frame pieces has a substantially L-shaped planform geometry.

14. The method of claim 12 further comprising attaching a cover piece to the window frame opposite the base flange to enclose a sealed air cavity located within the air cavity package, at least one of the multiple window frame pieces integrally formed with the cover piece.

Assignees

• Freescale Semiconductor Inc
• Nxp Usa Inc

Inventors

• Viswanathan Lakshminarayan
• Molla Jaynal A
• Abdo David
• Mahalingam Mali
• D'Acosta Carl

Classifications

• H10W90/756

  between a chip and a stacked lead frame, conducting package substrate or heat sink · CPC title

• H10W90/755

  between a chip and a laterally-adjacent insulating package substrate, interpose or RDL · CPC title

• H10W90/736

  between a chip and a stacked lead frame, conducting package substrate or heat sink · CPC title

• H10W90/734

  between a chip and a stacked insulating package substrate, interposer or RDL · CPC title

• H10W76/10

  Containers or parts thereof · CPC title