Tino Jaeger | X-Fab: What are the key process steps and materials involved in creating a reliable redistribution layer (RDL) for electrically connecting micro-transferred triplets to the underlying substrate?
00:08:21 - 00:08:30
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What are the key process steps and materials involved in creating a reliable redistribution layer (RDL) for electrically connecting micro-transferred triplets to the underlying substrate?
After the micro-transfer printing process, a redistribution layer (RDL) is typically required to electrically connect the transferred triplets to the underlying substrate. This involves a series of process steps to create conductive pathways that route signals from the triplet pads to the desired locations on the target wafer. The RDL process is crucial for enabling functional integration of the transferred devices.
The RDL fabrication process at X-Fab begins with opening the target pads using reactive ion etching (RIE). This step removes any passivation or adhesive residue covering the pads, ensuring good electrical contact. A titanium nitride barrier layer and a copper seed layer are then deposited using physical vapor deposition (PVD) to promote adhesion and provide a conductive base for subsequent copper electroplating.
Following the deposition of the barrier and seed layers, lithography and copper electroplating are performed to define and form the RDL traces. After electroplating, the unwanted barrier and seed layers are removed, and a passivation layer, typically BCB (benzocyclobutene), is applied for protection. Finally, the BCB is opened to expose the contact pads, completing the RDL fabrication process.
In this short video, you can learn:
* The purpose of a redistribution layer (RDL) in micro-transfer printing.
* The key process steps involved in RDL fabrication at X-Fab.
* The materials used for barrier layers, seed layers, and passivation.
📋 **Clip Abstract:** This segment details the process of creating a copper redistribution layer (RDL) to electrically connect the transferred triplets to the target wafer. The process includes etching, deposition, lithography, and passivation steps.
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#RedistributionLayer, #CopperElectroplating, #BCBPassivation, #PVDDeposition, #MicroTransferPrinting, #AdvancedPackaging
This is a highlight of the presentation:
Micro-Transfer Printing: Integrate ultra-thin ASICs to enable sophisticated Applications
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00:04:46 - 00:05:15
How can intrinsic stress within micro-transferred triplets be effectively managed to minimize warpage and ensure planarity?
How can intrinsic stress within micro-transferred triplets be effectively managed to minimize warpage and ensure planarity?
Triplet warpage poses a significant challenge in micro-transfer printing due to intrinsic stresses within the structures. These stresses can arise from various factors, including the materials used and the fabrication processes involved. Managing this warpage is crucial for achieving high-quality printing and alignment during subsequent processing steps.
To mitigate triplet warpage, careful control of process parameters during silicon nitride deposition is essential. By adjusting parameters such as deposition temperature, gas flow rates, and pressure, the stress within the silicon nitride film can be precisely tuned. This allows for the compensation of intrinsic stresses within the triplets, resulting in flatter and more planar structures.
Achieving flat triplets is a key factor in ensuring successful printing and alignment. Planar triplets facilitate uniform contact with the target substrate, leading to improved adhesion and reduced defects. Furthermore, well-aligned triplets enable precise electrical connections during post-processing, enhancing the overall performance and reliability of the integrated system.
In this short video, you can learn:
* How to minimize triplet warpage during micro-transfer printing.
* The importance of stress management during silicon nitride deposition.
* The impact of triplet planarity on printing and alignment quality.
📋 **Clip Abstract:** This segment discusses the critical issue of triplet warpage in micro-transfer printing and how adjusting silicon nitride deposition parameters can mitigate intrinsic stress. Achieving flat triplets is essential for successful printing and alignment.
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#MicroTransferPrinting, #TripletWarpage, #SiliconNitrideDeposition, #IntrinsicStressManagement, #MicroLEDDisplays, #HeterogeneousIntegration
00:07:00 - 00:07:29
Beyond lateral dimensions, how critical is the control of triplet height in micro-transfer printing for specific applications, and what process variations can be employed to tailor this parameter?
Beyond lateral dimensions, how critical is the control of triplet height in micro-transfer printing for specific applications, and what process variations can be employed to tailor this parameter?
While lateral dimensions are important, the height of the transferred triplets is also a critical parameter for many applications. The triplet height, which is essentially the thickness of the transferred chip, can influence the overall system performance and integration strategy. Different applications may require specific triplet heights to meet performance, packaging, or assembly requirements.
X-Fab offers the capability to fabricate triplets with varying backend-of-line (BEOL) layer stacks, allowing for control over the final triplet height. The number of metal layers in the BEOL directly impacts the overall thickness of the triplet. By adjusting the number of metal layers, the triplet height can be tailored to meet specific application needs.
For example, the presentation highlights two comparable triplets fabricated using 180nm and 110nm technologies, both with three metal layers. The 180nm triplet has a height of 10 micrometers, while the 110nm triplet is thinner at 7 micrometers. This demonstrates the ability to achieve different triplet heights through process variations and technology selection.
In this short video, you can learn:
* The importance of triplet height in micro-transfer printing applications.
* How the backend-of-line (BEOL) layer stack influences triplet height.
* The range of triplet thicknesses achievable with X-Fab's technologies.
📋 **Clip Abstract:** This segment emphasizes the significance of controlling triplet height in micro-transfer printing and how X-Fab can tailor this parameter by adjusting the backend-of-line layer stack. Examples of triplet heights achieved with different technologies are provided.
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#TripletHeightControl, #MicroTransferPrinting, #BEOLStack, #ChipThicknessTailoring, #AdvancedPackaging, #HeterogeneousIntegration