Carrier Bonding via Surface Modification for Semiconductor Processing
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Solution Overview
Problem
Existing carrier-substrate solutions for semiconductor processing fail to provide sufficient support against warping and temperature-induced damage, especially during high-temperature FEOL processing, and are difficult to debond without damaging the wafer or carrier.
Innovation Solution
A method using surface modification layers on the carrier and thin sheet to control van der Waals and covalent bonding, allowing for strong adhesion during processing while enabling easy separation after high-temperature processing, using materials like hexamethyldisilazane, plasma polymerized fluoropolymer films, and silane treatments to manage bonding energies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is used to bond wafer to carrier, then wafer can be handled and supported during processing, but adhesive fails at high temperatures, outgasses contaminants, and causes warping due to CTE mismatch
Solution Approach 1:
The patent removes the adhesive layer from the bonding interface between carrier and wafer. Instead of using adhesive, it employs direct bonding through surface modification layers (such as silane treatments) that create temperature-stable bonds capable of withstanding high-temperature FEOL processing without outgassing or failing.
Solution Approach 2:
The patent changes the bonding mechanism from adhesive-based to surface-modification-based bonding. By applying surface modification layers (e.g., silane treatments) to the carrier or wafer surfaces, it creates bonds that maintain stable bonding strength across high temperature ranges (up to 400-450°C), eliminating the temperature sensitivity and CTE mismatch issues of adhesive bonding.
2Device complexity
If wafer is thinned to reduce packaging complexity, then packaging becomes simpler, but wafer becomes more fragile and susceptible to damage during handling
Solution Approach 1:
The patent performs wafer thinning before bonding the wafer to the carrier, rather than after. This preliminary thinning action allows the wafer to be processed at its final thin thickness while still being supported by the carrier during subsequent handling and packaging operations, eliminating the need for post-thinning support structures.
Solution Approach 2:
The carrier acts as an intermediary support structure that protects the thinned wafer during handling and packaging. The carrier provides mechanical strength and rigidity to the otherwise fragile thinned wafer, enabling safe transportation and assembly operations without requiring the wafer to maintain its own structural integrity.
3Stability of the object's composition
If carrier provides strong support to prevent warping, then wafer stability improves, but debonding becomes difficult without damaging wafer or carrier
Solution Approach 1:
The patent introduces surface modification layers (such as silane treatments or plasma polymerized fluoropolymer films) as intermediary layers between the carrier and wafer. These layers provide stable bonding during high-temperature processing while being designed to allow controlled debonding afterward, preventing direct strong bonding that would damage the wafer or carrier upon separation.
Solution Approach 2:
The patent modifies the surface properties of the carrier or wafer through surface treatment techniques (silane treatment, plasma treatment, fluoropolymer coating). These surface modifications create bonds with appropriate strength characteristics: strong enough to prevent warping during processing, but with controlled debonding properties that allow clean separation afterward without damaging either component.
4Ease of manufacture
If adhesive is used for bonding, then initial bonding is easy to achieve, but adhesive finds its way into vias and prevents metallization
Solution Approach 1:
The patent removes the adhesive layer from the bonding interface, eliminating the source of contamination that would otherwise migrate into vias and prevent metallization. By using direct surface-modification-based bonding, there is no adhesive material present to interfere with subsequent via filling and metallization processes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the processing of thin substrates through high-temperature semiconductor fabrication without warping or damage, allowing for the reuse of carriers and the preservation of delicate microstructures on the wafer.
Implementation Method 1
surface modification layers on the carrier and thin sheet to control van der Waals and covalent bonding
Implementation Method 2
surface modification layers on the carrier and thin sheet to control van der Waals and covalent bonding
Implementation Method 3
using materials like hexamethyldisilazane, plasma polymerized fluoropolymer films, and silane treatments to manage bonding energies
Data Source
Figure 1~10
Figure 2
Figure 3~5
AI summary
A thin sheet (20) disposed on a carrier (10) via a surface modification layer (30) to form an article (2), wherein the article may be subjected to high temperature processing, as in FEOL semiconductor processing, not outgas and have the thin sheet maintained on the carrier without separation therefrom during the processing, yet be separated therefrom upon room temperature peeling force that leaves the thinner one of the thin sheet and carrier intact. Interposers (56) having arrays (50) of vias (60) may be formed on the thin sheet, and devices (66) formed on the interposers. Alternatively, the thin sheet may be a substrate on which semiconductor circuits are formed during FEOL processing.