Fabrication and Performance of MEMS-Based Pressure Sensor Packages Using Patterned Ultra-Thick Photoresists

A novel plastic packaging of a piezoresistive pressure sensor using a patterned ultra-thick photoresist is experimentally and theoretically investigated. Two pressure sensor packages of the sacrifice-replacement and dam-ring type were used in this study. The characteristics of the packaged pressure sensors were investigated by using a finite-element (FE) model and experimental measurements. The results show that the thermal signal drift of the packaged pressure sensor with a small sensing-channel opening or with a thin silicon membrane for the dam-ring approach had a high packaging induced thermal stress, leading to a high temperature coefficient of span (TCO) response of −0.19% span/°C. The results also show that the thermal signal drift of the packaged pressure sensors with a large sensing-channel opening for sacrifice-replacement approach significantly reduced packaging induced thermal stress, and hence a low TCO response of −0.065% span/°C. However, the packaged pressure sensors of both the sacrifice-replacement and dam-ring type still met the specification −0.2% span/°C of the unpackaged pressure sensor. In addition, the size of proposed packages was 4 × 4 × 1.5 mm3 which was about seven times less than the commercialized packages. With the same packaging requirement, the proposed packaging approaches may provide an adequate solution for use in other open-cavity sensors, such as gas sensors, image sensors, and humidity sensors.

[1]  H. S. Wolff,et al.  iRun: Horizontal and Vertical Shape of a Region-Based Graph Compression , 2022, Sensors.

[2]  S.C.O. Mathuna,et al.  Thick photoresist development for the fabrication of high aspect ratio magnetic coils , 2002 .

[3]  C. Hsu,et al.  The Effect of Epoxy Molding Compound on Thermal/Residual Deformations and Stresses in IC Packages During Manufacturing Process , 2006, IEEE Transactions on Components and Packaging Technologies.

[4]  Peter Vettiger,et al.  High-aspect-ratio, ultrathick, negative-tone near-UV photoresist and its applications for MEMS , 1998 .

[5]  Chang-Chun Lee,et al.  Packaging effect investigation of CMOS compatible pressure sensor using flip chip and flex circuit board technologies , 2006 .

[6]  J. Logan,et al.  Two-chip pressure sensor and signal conditioning , 2003, TRANSDUCERS '03. 12th International Conference on Solid-State Sensors, Actuators and Microsystems. Digest of Technical Papers (Cat. No.03TH8664).

[7]  Narasimalu Srikanth,et al.  Development of transfer molding technology for package with die active side partially exposed , 2003, 53rd Electronic Components and Technology Conference, 2003. Proceedings..

[8]  E. Abbaspour-Sani,et al.  A novel method for packaging of micromachined piezoresistive pressure sensor , 2002, ICONIP '02. Proceedings of the 9th International Conference on Neural Information Processing. Computational Intelligence for the E-Age (IEEE Cat. No.02EX575).

[9]  Charles S. Smith.  Piezoresistance Effect in Germanium and Silicon , 1954 .

[10]  Andre Bossche,et al.  Low-cost plastic sensor packaging using the open-window package concept , 1998 .

[11]  N. D. Rooij,et al.  High aspect ratio UV photolithography for electroplated structures , 1999 .

[12]  Zhuangde Jiang,et al.  Analysis of the Packaging Stresses in Monolithic Multi-Sensor , 2007, 2007 2nd IEEE International Conference on Nano/Micro Engineered and Molecular Systems.

[13]  Per Ohlckers,et al.  Measurement of package-induced stress and thermal zero shift in transfer molded silicon piezoresistive pressure sensors , 1998 .

[14]  Y. Kim,et al.  Packaging Effect on MEMS Pressure Sensor Performance , 2007, IEEE Transactions on Components and Packaging Technologies.

[15]  John Wertz,et al.  Analytical techniques for examining reliability and failure mechanisms of barrier-coated encapsulated silicon pressure sensors exposed to harsh media , 1996, Photonics West - Micro and Nano Fabricated Electromechanical and Optical Components.

[16]  Yeong K. Kim,et al.  Finite element simulation of package stress in transfer molded MEMS pressure sensors , 2004, Microelectron. Reliab..

[17]  T. Janczek.  Material investigation for pressure sensor package P-DSOF-8-1 , 1997, Proceedings. The First IEEE International Symposium on Polymeric Electronics Packaging, PEP '97 (Cat. No.97TH8268).

[18]  Chung-Yi Hsu,et al.  A novel packaging process for open-channel sensors , 2007, 2007 International Microsystems, Packaging, Assembly and Circuits Technology.

[19]  P. Vettiger,et al.  Fabrication of photoplastic high-aspect ratio microparts and micromolds using SU-8 UV resist , 1998 .

[20]  Chung-Yi Hsu,et al.  A tiny plastic package of piezoresistive pressure sensors constructed by sacrifice-replacement approach , 2008, 2008 58th Electronic Components and Technology Conference.

[21]  Michael Kraft,et al.  Realization of electroplating molds with thick positive SPR 220-7 photoresist , 2003 .

[22]  Chun-Te Lin,et al.  Performance and package effect of a novel piezoresistive pressure sensor fabricated by front-side etching technology , 2005 .

[23]  Fan-Gang Tseng,et al.  High aspect ratio ultrathick micro-stencil by JSR THB-430N negative UV photoresist , 2002 .

[24]  Jane M. Shaw,et al.  Micromachining applications of a high resolution ultrathick photoresist , 1995 .

[25]  W. Cheng,et al.  A novel plastic package for pressure sensors fabricated using the lithographic dam-ring approach , 2009 .

[26]  M. Despont,et al.  SU-8: a low-cost negative resist for MEMS , 1997 .