TSV Technology Trends and Fabrication Details: A Short Course

3D/TSV technology has been the subject of intense development over the last 10-15 years. During this time, many process advancements were made and several basic questions were answered regarding when and how TSVs would be integrated. After tremendous progress on the technology side, much of the current focus is on 3D product launches and remaining commercialization issues, primarily cost reduction. 2015 has been an important year, with several new products released, including a variety of TSV-based stacked memory modules and graphics processors. Several products are now using 3D chip stacking and/or 2.5D interposer solutions and these are quickly moving into increased production volumes.

In this exciting time of change and continued advancement for 3D/TSV technologies, many organizations in the electronics community are closely watching the status of the market and the technology. At last year’s conference on 3D Architectures for Semiconductor Integration and Packaging (3DASIP- Dec. 2014, Burlingame, CA), TSV technology trends were reviewed in a pre-conference symposium titled “3D Integration: 3D Process Technology” (chaired by Phil Garrou- IEEE Fellow and Consultant, Microelectronic Consultants of NC). This session began with a 2.5/3D market status update by Dr. Garrou, then included technology overviews on TSV formation, temporary bonding and TSV reveal, and 2.5/3D assembly. RTI International was pleased to present the TSV formation overview, which is being made available to 3DInCites readers through this post.

This presentation begins with an introduction, reviewing the basic TSV formation steps, examples of TSV implementation in 2.5D Si interposers and 3DIC applications, and how the requirements may differ among 2.5/3D applications. Next, the primary process steps for TSV formation are covered in more detail, including: TSV etching, insulator/barrier/seed, filling, stabilization anneal, and chemical mechanical planarization (CMP). For each step, the preferred methods, key requirements, and recent advances are reported. A section on TSV process equipment and providers is also included.

The later part of the presentation goes into forward-looking TSV trends, which are largely driven by cost, reliability, and yield requirements for high volume product manufacturing. It covers the plans for further scaling of TSVs to smaller diameter, along with emerging process methods and equipment required to fabricate these higher aspect ratio TSVs. Finally, some emerging substrate technologies are mentioned, which are now being proposed as lower cost alternatives to TSV-based Si interposers. 

Download the presentation, TSV Formation: Drilling and Filling, here.