DBI Wafer-to-Wafer Hybrid Bonding

DBI® is a low temperature hybrid direct bonding technology that allows wafers to be bonded with exceptionally fine pitch 3D electrical interconnect. The DBI alignment and bonding process is performed at room temperature. It leverages industry-standard wafer bonding equipment, enabling the high-throughput, low cost-of-ownership fabrication process required for high volume market applications.

DBI can also minimize the need for Thru Silicon Vias (TSVs) by allowing interconnection to occur at the bonding surface, improving electrical performance. Incorporating dielectric bonding eliminates the need for underfill while providing excellent thermal performance, reliability and hermeticity, if required.

 

  • USAGE: Wafer-to-wafer bonding with electrical interconnect
  • HOW: Wafer surface is planarized and bond pads are recessed in a dielectric layer; wafers are aligned and bonded at room temperature; metal interconnect is formed during low-temperature batch anneal
  • SOLUTIONS: BSI Image Sensor, DRAM, MEMS, RF
  • MARKETS: Consumer electronics (smartphones, tablets, laptops, digital cameras, televisions, gaming consoles) IoT, industrial, automotive and medical

Differentiators

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Very fine pitch interconnect

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Chemical bond without external bond pressure

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Low temperature process

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Minimal warpage or delamination problems

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Bond between wafers with same or different thermal expansion rate

Details

During processing, industry-standard dielectrics surfaces such as silicon oxide and silicon carbide nitride, with embedded metal bond pads that are typically of copper or nickel, are polished to achieve minimal surface roughness. Simultaneously, the metal bond pads are slightly dished. Polishing and dishing are readily achieved using standard chemical mechanical polishing (CMP) tools. Nitrogen-based chemistries are applied through conventional plasma etch tools. Prepared wafers can then be simply aligned and placed together, resulting in the spontaneous formation of strong chemical bonds between the prepared surfaces. After a moderate batch anneal, the DBI bond pads expand together to form a homogeneous metallic interconnect with grain growth across the bond interface. The chemical bond between oxides is significantly strengthened, ensuring high reliability without requiring underfill.

Process Flow

Related Resources

High Density Low Cost Stacked 3D NAND with Hybrid Bonding

Pixel-Level 3D Integration for Advanced Stacked CMOS Image Sensors

3D Integration for MEMS Devices

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