Flip-Chip Bonding Apparatus for Through-Silicon Via Alignment
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Solution Overview
Problem
The challenge in manufacturing stacked semiconductor devices with through-silicon vias is ensuring accurate alignment and connection between semiconductor chips, as positional displacement occurs due to unclear alignment marks and variations in bonding conditions, making it difficult to verify precise connections without destructive inspection.
Innovation Solution
A bonding apparatus equipped with a camera and control unit for image processing and bonding control, which detects relative positions of semiconductor chips based on images of through-silicon vias before and after bonding, allowing for precise alignment and correction of positional displacement during the bonding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If alignment marks are used for positioning semiconductor chips during bonding, then the bonding process can be automated and productivity improved, but positional displacement occurs due to unclear alignment marks and variation in bonding conditions, worsening manufacturing precision
Solution Approach 1:
The patent uses optical images (copies) of alignment marks and through-silicon vias captured by cameras to create virtual models for positioning. The control unit processes these optical copies to determine precise positions, replacing direct physical alignment with image-based virtual alignment, thereby maintaining automation while achieving sub-micron precision.
Solution Approach 2:
The patent replaces mechanical alignment systems with an optical measurement and control system. Instead of relying on physical alignment marks that may be unclear, the system uses high-resolution cameras to capture images, processes them optically to identify through-silicon via positions, and uses this information for precise positioning, substituting mechanical alignment with optical-field alignment.
2Reliability
If through-silicon vias are joined by soldering with molten solder between chips, then electrical connection between semiconductor chips is achieved, but positional displacement occurs before solder hardening, worsening alignment precision
Solution Approach 1:
The patent performs preliminary positioning using optical images of through-silicon vias captured before bonding. The control unit calculates precise positions and determines bonding parameters in advance. This preliminary action ensures that even when molten solder causes temporary displacement during bonding, the chips are pre-positioned with such precision that the final alignment remains within acceptable tolerances after solder hardening.
Solution Approach 2:
The patent implements a feedback mechanism where the control unit continuously monitors the bonding process using optical measurements. By capturing images before, during, and after bonding, the system can detect any positional displacement caused by molten solder and make real-time adjustments to compensate, ensuring that the final position aligns with the target position despite the temporary disruption during soldering.
3Productivity
If conventional alignment methods are used, then the bonding process can proceed efficiently, but it is not possible to easily verify precise connection of through-silicon vias without destructive inspection, worsening measurement capability
Solution Approach 1:
The patent creates optical copies (images) of through-silicon vias and alignment marks at various stages of the bonding process. By capturing and processing these optical copies, the system can virtually inspect the positioning and connection status of through-silicon vias without physically disturbing or destroying the bonded structure, enabling non-destructive verification while maintaining bonding efficiency.
Solution Approach 2:
The patent introduces optical imaging and image processing as an intermediary between the bonding process and verification. Instead of directly inspecting the bonded through-silicon vias (which would require destructive sectioning), the system uses optical fields as an intermediary to capture images that reveal positioning information, allowing verification without destruction and maintaining both productivity and measurement capability.
Data Source
AI summary
Provided is a flip-chip bonding apparatus (500) capable of stacking and bonding a second-layer of the semiconductor chip (30) onto a first-layer of the semiconductor chip (20) having first through-silicon vias, the second-layer of the semiconductor chip (30) having second through-silicon vias at positions corresponding to the first through-silicon vias. The flip-chip bonding apparatus (500) includes: a double-view camera (16) configured to take images of thechips (20) and (30); and a control unit (50) having a relative-position detection program (53) for detecting relative positions of the first-layer of the semiconductor chip (20) and the second-layer of the semiconductor chip (30) that are stacked and bonded based on an image of the first through-silicon vias on a surface of the first-layer of the semiconductor chip (20) taken by the double-view camera (16) before stacked bonding, and an image of the second through-silicon vias on a surface of the second-layer of the semiconductor chip (30) taken by the double-view camera (16) after stacked bonding. This provides accurate connection between through-silicon vias using a simple method.