Experiences in flip chip production of radiation detectors

Satu Savolainen-Pulli (Corresponding Author), Jaakko Salonen, Jorma Salmi, Sami Vähänen

Research output: Contribution to journalArticleScientificpeer-review

8 Citations (Scopus)

Abstract

Modern imaging devices often require heterogeneous integration of different materials and technologies. Because of yield considerations, material availability, and various technological limitations, an extremely fine pitch is necessary to realize high-resolution images. Thus, there is a need for a hybridization technology that is able to join together readout amplifiers and pixel detectors at a very fine pitch. This paper describes radiation detector flip chip production at VTT. Our flip chip technology utilizes 25-μm diameter tin–lead solder bumps at a 50-μm pitch and is based on flux-free bonding. When preprocessed wafers are used, as is the case here, the total yield is defined only partly by the flip chip process. Wafer preprocessing done by a third-party silicon foundry and the flip chip process create different process defects. Wafer-level yield maps (based on probing) provided by the customer are used to select good readout chips for assembly. Wafer probing is often done outside of a real clean room environment, resulting in particle contamination and/or scratches on the wafers. Factors affecting the total yield of flip chip bonded detectors are discussed, and some yield numbers of the process are given. Ways to improve yield are considered, and finally guidelines for process planning and device design with respect to yield optimization are given.
Original languageEnglish
Pages (from-to)314-319
Number of pages6
JournalNuclear Instruments and Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Volume565
Issue number1
DOIs
Publication statusPublished - 2006
MoE publication typeA1 Journal article-refereed
EventInternational Workshop on Semiconductor Pixel Detectors for Particles and Imaging - Bonn, Germany
Duration: 5 Sep 20058 Sep 2005

Fingerprint

Radiation detectors
radiation detectors
chips
wafers
Detectors
Clean rooms
Process planning
Foundries
Image resolution
Soldering alloys
readout
Contamination
Pixels
Availability
Fluxes
clean rooms
Imaging techniques
Silicon
Defects
foundries

Keywords

  • flip chip
  • solder bump
  • yield
  • pixel detector

Cite this

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title = "Experiences in flip chip production of radiation detectors",
abstract = "Modern imaging devices often require heterogeneous integration of different materials and technologies. Because of yield considerations, material availability, and various technological limitations, an extremely fine pitch is necessary to realize high-resolution images. Thus, there is a need for a hybridization technology that is able to join together readout amplifiers and pixel detectors at a very fine pitch. This paper describes radiation detector flip chip production at VTT. Our flip chip technology utilizes 25-μm diameter tin–lead solder bumps at a 50-μm pitch and is based on flux-free bonding. When preprocessed wafers are used, as is the case here, the total yield is defined only partly by the flip chip process. Wafer preprocessing done by a third-party silicon foundry and the flip chip process create different process defects. Wafer-level yield maps (based on probing) provided by the customer are used to select good readout chips for assembly. Wafer probing is often done outside of a real clean room environment, resulting in particle contamination and/or scratches on the wafers. Factors affecting the total yield of flip chip bonded detectors are discussed, and some yield numbers of the process are given. Ways to improve yield are considered, and finally guidelines for process planning and device design with respect to yield optimization are given.",
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Experiences in flip chip production of radiation detectors. / Savolainen-Pulli, Satu (Corresponding Author); Salonen, Jaakko; Salmi, Jorma; Vähänen, Sami.

In: Nuclear Instruments and Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 565, No. 1, 2006, p. 314-319.

Research output: Contribution to journalArticleScientificpeer-review

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