US 2006/0134829 A1Published application

Wafer scale integration of electroplate 3D structures using successive lithography, electroplated sacrifical layers, and flip-chip bonding

AssigneePalo Alto Research Center Incorporated

InventorsMichel Rosa, Eric Peeters

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Abstract

Wafer scale fabrication of three dimentional substantially enclosed structures on a MEMS/IC die use a combination of electrodeposition of structural and sacrificial layers and flip-chip alignment and bonding technology. A first wafer contains a die with MEMS and/or IC structures. On this MEMS/IC processed die, a first three dimensional structural component is formed using standard lithographic processes and electrodeposition of a structural layer. A second sacrificial wafer is separately processed using similar lithographic and electrodeposition processes to form a corresponding second three dimensional structural component. The wafers are placed in a flip-chip bonder and aligned. Once aligned, the structural components are bonded together. The bonded wafers are then removed from the bonder and the second sacrificial wafer substrate removed. The resultant die includes a three dimensional structural component with a substantially enclosed cavity as well as MEMS and IC elements.

Claims20

Dependent claims

A wafer scale fabrication process for fabricating three dimensional structures having at least one substantially enclosed cavity on a processed wafer including die elements containing pre-existing MEMS and IC structures thereon, comprising:

applying and patterning a first photoresist mask on a first wafer containing at least one die having pre-existing MEMS and IC structures thereon to define boundaries of a first three dimensional structural element component;
electrodepositing a structural layer of material into the patterned photoresist mask to define walls of the first three dimensional structural element component;
electrodepositing a reflowable bonding layer on top of the structural layer;
removing the first photoresist mask;
applying and patterning a second photoresist mask on a second sacrificial wafer to define boundaries of a second three dimensional structural element component;
electrodepositing a structural layer of material into the patterned second photoresist mask to define a second three dimensional structural element component;
removing the second photoresist mask;
mounting the first and second wafers on stages of a flip-chip alignment and bonding machine;
rotating one of the stages to provide the first and second three dimensional structural element components in a spaced opposed orientation;
precisely aligning the first and second three dimensional structural element components relative to each other;
relatively moving the first and second wafers towards each other until the first and second three dimensional structural element components are substantially abutted;
applying heat to reflow the bonding layer and bond the first three dimensional structural element component to the second three dimensional structural element component;
and
removing the second sacrificial wafer from the second three dimensional structural element component to form an integrated three dimensional structural element on a MEMS/IC containing die.

11 more elements

providing a first wafer containing at least one die having pre-existing MEMS and IC structures thereon;
applying a patterned seed material on the die on the first wafer;
applying and patterning a first photoresist mask on a second wafer to define boundaries of a first three dimensional structural element component;
electrodepositing a structural layer of material into the patterned photoresist mask to define walls of the first three dimensional structural element component;
applying and patterning a second photoresist mask on a second sacrificial wafer to define boundaries of a second three dimensional structural element component;
electrodepositing a second structural layer of material into the patterned second photoresist mask to define a second three dimensional structural element component;
removing the second photoresist mask;
electrodepositing a reflowable bonding layer on top of the second structural layer;
mounting the first and second wafers on stages of a flip-chip alignment and bonding machine;
rotating one of the stages to provide the first and second wafers in a spaced opposed orientation;
precisely aligning the first and second three dimensional structural element components to each other;
relatively moving the first and second wafers towards each other until the first and second three dimensional structural element components are substantially abutted to the first wafer;
applying heat to reflow the bonding layer and bond the second three dimensional structural element component to the seed material of the first wafer;
and
removing the second sacrificial wafer from the second three dimensional structural element component to form an integrated three dimensional structural element on a MEMS/IC containing die.

12 more elements

Dependencies are inferred from the claim text.