A new DRIE cut-off material in SOG MEMS process

Chaowei Si; Yingchun Fu; Guowei Han; Yongmei Zhao; Jin Ning; Zhenyu Wei; Fuhua Yang

doi:10.1088/1674-4926/44/4/044101

J. Semicond. > 2023, Volume 44 > Issue 4 > 044101

ARTICLES

A new DRIE cut-off material in SOG MEMS process

Chaowei Si^1,, Yingchun Fu^{2, 3}, Guowei Han¹, Yongmei Zhao^{1, 4}, Jin Ning^{1, 4}, Zhenyu Wei^{1, 4} and Fuhua Yang^{1, 4}

+ Author Affiliations

Corresponding author: Chaowei Si, schw@semi.ac.cn

DOI: 10.1088/1674-4926/44/4/044101

Abstract: The silicon on glasses process is a common preparation method of micro-electro-mechanical system inertial devices, which can realize the processing of thick silicon structures. This paper proposes that indium tin oxides (ITO) film can serve as a deep silicon etching cut-off layer because ITO is less damaged under the attack of fluoride ions. ITO has good electrical conductivity and can absorb fluoride ions for silicon etching and reduce the reflection of fluoride ions, thus reducing the foot effect. The removal and release of ITO use an acidic solution, which does not damage the silicon structure. Therefore, the selection of the sacrificial layer has an excellent effect in maintaining the shape of the MEMS structure. This method is used in the preparation of MEMS accelerometers with a structure thickness of 100 μm and a feature size of 4 μm. The over-etching of the bottom of the silicon structure caused by the foot effect is negligible. The difference between the simulated value and the designed value of the device characteristic frequency is less than 5%. This indicates that ITO is an excellent deep silicon etch stopper material.

Key words: SOG process, DRIE cut-off layer, ITO film, foot effect

References

[1]	Acar C. High-performance 6-Axis MEMS inertial sensor based on through-silicon via technology. 2016 IEEE International Symposium on Inertial Sensors and Systems, 2016, 62 doi: 10.1109/ISISS.2016.7435545
[2]	Tjulkins F, Nguyen A T T, Hoivik N, et al. 3-axis MEMS accelerometer-based implantable heart monitoring system with novel fixation method. 2013 IEEE 63rd Electronic Components and Technology Conference, 2013, 510 doi: 10.1109/ECTC.2013.6575620
[3]	Johnson B, Christ K, Endean D, et al. Tuning fork MEMS gyroscope for precision northfinding. 2015 DGON Inertial Sensors and Systems Symposium, 2015, 1
[4]	Kuisma H. Glass isolated TSVs for MEMS. Proceedings of the 5th Electronics System-integration Technology Conference, 2014, 1 doi: 10.1109/ESTC.2014.6962718
[5]	Taheri-Tehrani P, Defoort M, Chen Y, et al. Epitaxially-encapsulated quad mass resonator with shaped comb fingers for frequency tuning. 2017 IEEE 30th International Conference on Micro Electro Mechanical Systems, 2017, 1111 doi: 10.1109/MEMSYS.2017.7863608
[6]	Rödjegård H, Johansson C, Enoksson P, et al. A monolithic three-axis SOI-accelerometer with uniform sensitivity. Sens Actuat A, 2005, 123/124, 50 doi: 10.1016/j.sna.2005.02.032
[7]	Yang Y, Ng E J, Ahn C H, et al. Mechanical coupling of dual breathe-mode ring resonator. 2013 Transducers Eurosensors XXVII: The 17th International Conference on Solid-State Sensors, Actuators and Microsystems, 2013, 502 doi: 10.1109/Transducers.2013.6626813
[8]	Senkal D, Askari S, Ahamed M J, et al. 100K Q-factor toroidal ring gyroscope implemented in wafer-level epitaxial silicon encapsulation process. 2014 IEEE 27th International Conference on Micro Electro Mechanical Systems, 2014, 24 doi: 10.1109/MEMSYS.2014.6765564
[9]	Kim J, Park S, Kwak D, et al. Robust SOI process without footing and its application to ultra high-performance microgyroscopes. Sens Actuat A, 2004, 114, 236 doi: 10.1016/j.sna.2004.01.022
[10]	Seok S, Lee B, Kim J, et al. A new compensation method for the footing effect in MEMS fabrication. J Micromech Microeng, 2005, 15, 1791 doi: 10.1088/0960-1317/15/10/001/meta
[11]	Ma Z, Wang Y, Shen Q, et al. Key processes of silicon-on-glass MEMS fabrication technology for gyroscope application sensors. Sensors, 2018, 18, 1240 doi: 10.3390/s18041240
[12]	Townsend K, Durston M. Rate sensor with quadrature rejection. USA Patent, US13698339, 2013
[13]	Li Y, Yang Z, Yan G. An improved method to remove anti-footing Al layer after DRIE. 2009 4th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, 2009, 868 doi: 10.1109/NEMS.2009.5068712
[14]	Hu L, Xue Y, Shi F. Interfacial investigation and mechanical properties of glass-Al-glass anodic bonding process. J Micromech Microeng, 2017, 27, 105004 doi: 10.1088/1361-6439/aa83c7
[15]	Hu Y Q, Zhao Y P, Yu T X. Fractal pattern formation in anodic bonding of pyrex glass/Al/Si. Int J Nonlinear Sci Numerical Simul, 2008, 9, 315 doi: 10.1515/IJNSNS.2008.9.4.315
[16]	Zhang J, Huang Q A, Li W H. Simulations for surface evolvement and footing effect in ICP DRIE fabrications. J Phys: Conf Ser, 2006, 34, 522 doi: 10.1088/1742-6596/34/1/086
[17]	Nomura K, Okada A, Shoji S, et al. Application of I-structure though-glass interconnect filled with submicron gold particles to a hermetic sealing device. J Micromech Microeng, 2016, 26, 105018 doi: 10.1088/0960-1317/26/10/105018
[18]	Yang F, Han G, Yang J, et al. Research on wafer-level MEMS packaging with through-glass vias micromachines. Micromachines, 2018, 10, 15 doi: 10.3390/mi10010015
[19]	Gu J, Xia X, Zhang W, et al. A modified MEMS-casting based TSV filling method with universal nozzle piece that uses surface trenches as nozzles. 2018 19th International Conference on Electronic Packaging Technology, 2018, 536 doi: 10.1109/ICEPT.2018.8480697
[20]	Cai M, Si C, Han G, et al. Deep silicon etching of bonded wafer based on ITO mask. J Micronanoelectron Technol, 2020, 57, 11

Fig. 1. (Color online) DRIE process. (a) Foot effect on SOI. (b) DRIE on SOG.

DownLoad: Full-Size Img PowerPoint

Fig. 2. (Color online) The preparation of structures. (a) Etching with glue mask drilling. (b) ITO sputtering. (c) Lift off. (d) Anodic bonding. (e) DRIE. (f) Release.

DownLoad: Full-Size Img PowerPoint

Fig. 3. (Color online) The process of glass cover plate with filled vias. (a) Laser drilling. (b) Electroplating. (c) Active area etching.

DownLoad: Full-Size Img PowerPoint

Fig. 4. (Color online) Package with anodic bonding.

DownLoad: Full-Size Img PowerPoint

Fig. 5. (Color online) The etched silicon wafer on Glass

DownLoad: Full-Size Img PowerPoint

Fig. 6. (Color online) The etched structures. (a) ITO cut-off film. (b) The released and packaged structures.

DownLoad: Full-Size Img PowerPoint

Fig. 7. SEM results of the comb beams in SOG process.

DownLoad: Full-Size Img PowerPoint

Fig. 8. SEM results of the comb beams in SOI processs.

DownLoad: Full-Size Img PowerPoint

Fig. 9. The frequency domain response of a prepared accelerometer.

DownLoad: Full-Size Img PowerPoint

[1]	Acar C. High-performance 6-Axis MEMS inertial sensor based on through-silicon via technology. 2016 IEEE International Symposium on Inertial Sensors and Systems, 2016, 62 doi: 10.1109/ISISS.2016.7435545
[2]	Tjulkins F, Nguyen A T T, Hoivik N, et al. 3-axis MEMS accelerometer-based implantable heart monitoring system with novel fixation method. 2013 IEEE 63rd Electronic Components and Technology Conference, 2013, 510 doi: 10.1109/ECTC.2013.6575620
[3]	Johnson B, Christ K, Endean D, et al. Tuning fork MEMS gyroscope for precision northfinding. 2015 DGON Inertial Sensors and Systems Symposium, 2015, 1
[4]	Kuisma H. Glass isolated TSVs for MEMS. Proceedings of the 5th Electronics System-integration Technology Conference, 2014, 1 doi: 10.1109/ESTC.2014.6962718
[5]	Taheri-Tehrani P, Defoort M, Chen Y, et al. Epitaxially-encapsulated quad mass resonator with shaped comb fingers for frequency tuning. 2017 IEEE 30th International Conference on Micro Electro Mechanical Systems, 2017, 1111 doi: 10.1109/MEMSYS.2017.7863608
[6]	Rödjegård H, Johansson C, Enoksson P, et al. A monolithic three-axis SOI-accelerometer with uniform sensitivity. Sens Actuat A, 2005, 123/124, 50 doi: 10.1016/j.sna.2005.02.032
[7]	Yang Y, Ng E J, Ahn C H, et al. Mechanical coupling of dual breathe-mode ring resonator. 2013 Transducers Eurosensors XXVII: The 17th International Conference on Solid-State Sensors, Actuators and Microsystems, 2013, 502 doi: 10.1109/Transducers.2013.6626813
[8]	Senkal D, Askari S, Ahamed M J, et al. 100K Q-factor toroidal ring gyroscope implemented in wafer-level epitaxial silicon encapsulation process. 2014 IEEE 27th International Conference on Micro Electro Mechanical Systems, 2014, 24 doi: 10.1109/MEMSYS.2014.6765564
[9]	Kim J, Park S, Kwak D, et al. Robust SOI process without footing and its application to ultra high-performance microgyroscopes. Sens Actuat A, 2004, 114, 236 doi: 10.1016/j.sna.2004.01.022
[10]	Seok S, Lee B, Kim J, et al. A new compensation method for the footing effect in MEMS fabrication. J Micromech Microeng, 2005, 15, 1791 doi: 10.1088/0960-1317/15/10/001/meta
[11]	Ma Z, Wang Y, Shen Q, et al. Key processes of silicon-on-glass MEMS fabrication technology for gyroscope application sensors. Sensors, 2018, 18, 1240 doi: 10.3390/s18041240
[12]	Townsend K, Durston M. Rate sensor with quadrature rejection. USA Patent, US13698339, 2013
[13]	Li Y, Yang Z, Yan G. An improved method to remove anti-footing Al layer after DRIE. 2009 4th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, 2009, 868 doi: 10.1109/NEMS.2009.5068712
[14]	Hu L, Xue Y, Shi F. Interfacial investigation and mechanical properties of glass-Al-glass anodic bonding process. J Micromech Microeng, 2017, 27, 105004 doi: 10.1088/1361-6439/aa83c7
[15]	Hu Y Q, Zhao Y P, Yu T X. Fractal pattern formation in anodic bonding of pyrex glass/Al/Si. Int J Nonlinear Sci Numerical Simul, 2008, 9, 315 doi: 10.1515/IJNSNS.2008.9.4.315
[16]	Zhang J, Huang Q A, Li W H. Simulations for surface evolvement and footing effect in ICP DRIE fabrications. J Phys: Conf Ser, 2006, 34, 522 doi: 10.1088/1742-6596/34/1/086
[17]	Nomura K, Okada A, Shoji S, et al. Application of I-structure though-glass interconnect filled with submicron gold particles to a hermetic sealing device. J Micromech Microeng, 2016, 26, 105018 doi: 10.1088/0960-1317/26/10/105018
[18]	Yang F, Han G, Yang J, et al. Research on wafer-level MEMS packaging with through-glass vias micromachines. Micromachines, 2018, 10, 15 doi: 10.3390/mi10010015
[19]	Gu J, Xia X, Zhang W, et al. A modified MEMS-casting based TSV filling method with universal nozzle piece that uses surface trenches as nozzles. 2018 19th International Conference on Electronic Packaging Technology, 2018, 536 doi: 10.1109/ICEPT.2018.8480697
[20]	Cai M, Si C, Han G, et al. Deep silicon etching of bonded wafer based on ITO mask. J Micronanoelectron Technol, 2020, 57, 11

Search

GET CITATION

shu

Export: BibTex EndNote

Article Metrics

Article views: 1041 Times PDF downloads: 78 Times Cited by: 0 Times

History

Received: 13 September 2022 Revised: 25 October 2022 Online: Accepted Manuscript: 09 November 2022Uncorrected proof: 11 November 2022Published: 10 April 2023

Article Navigation > Journal of Semiconductors > 2023 > 44(4): 044101

Chaowei Si, Yingchun Fu, Guowei Han, Yongmei Zhao, Jin Ning, Zhenyu Wei, Fuhua Yang. A new DRIE cut-off material in SOG MEMS process[J]. Journal of Semiconductors, 2023, 44(4): 044101. doi: 10.1088/1674-4926/44/4/044101 ****Chaowei Si, Yingchun Fu, Guowei Han, Yongmei Zhao, Jin Ning, Zhenyu Wei, Fuhua Yang, A new DRIE cut-off material in SOG MEMS process[J]. Journal of Semiconductors, 2023, 44(4), 044101 doi: 10.1088/1674-4926/44/4/044101

Citation:

Chaowei Si, Yingchun Fu, Guowei Han, Yongmei Zhao, Jin Ning, Zhenyu Wei, Fuhua Yang. A new DRIE cut-off material in SOG MEMS process[J]. Journal of Semiconductors, 2023, 44(4): 044101. doi: 10.1088/1674-4926/44/4/044101 ****

Chaowei Si, Yingchun Fu, Guowei Han, Yongmei Zhao, Jin Ning, Zhenyu Wei, Fuhua Yang, A new DRIE cut-off material in SOG MEMS process[J]. Journal of Semiconductors, 2023, 44(4), 044101 doi: 10.1088/1674-4926/44/4/044101

Citation:

PDF( 3235 KB)

A new DRIE cut-off material in SOG MEMS process

DOI: 10.1088/1674-4926/44/4/044101

Chaowei Si^1,,
Yingchun Fu^{2, 3},
Guowei Han¹,
Yongmei Zhao^{1, 4},
Jin Ning^{1, 4},
Zhenyu Wei^{1, 4},
Fuhua Yang^{1, 4}

1.
Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
2.
Beijing Smart-chip Microelectronics Technology Co., Ltd, Beijing 100083, China
3.
Zhongguancun Xinhaizeyou Technology Co., Ltd, Beijing 100049, China
4.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China

More Information

Chaowei Si：got his Ph.D. degree in 2014 at Tsinghua University. Then he joined the Institute of Semiconductors, Chinese Academy of Sciences. His research focuses on MEMS inertial devices and RF devices
Corresponding author: schw@semi.ac.cn
Received Date: 2022-09-13
Revised Date: 2022-10-25

Available Online: 2022-11-09

Abstract

Abstract

The silicon on glasses process is a common preparation method of micro-electro-mechanical system inertial devices, which can realize the processing of thick silicon structures. This paper proposes that indium tin oxides (ITO) film can serve as a deep silicon etching cut-off layer because ITO is less damaged under the attack of fluoride ions. ITO has good electrical conductivity and can absorb fluoride ions for silicon etching and reduce the reflection of fluoride ions, thus reducing the foot effect. The removal and release of ITO use an acidic solution, which does not damage the silicon structure. Therefore, the selection of the sacrificial layer has an excellent effect in maintaining the shape of the MEMS structure. This method is used in the preparation of MEMS accelerometers with a structure thickness of 100 μm and a feature size of 4 μm. The over-etching of the bottom of the silicon structure caused by the foot effect is negligible. The difference between the simulated value and the designed value of the device characteristic frequency is less than 5%. This indicates that ITO is an excellent deep silicon etch stopper material.
- SOG process,
- DRIE cut-off layer,
- ITO film,
- foot effect

FullText(HTML)

References(20)

References

[1]	Acar C. High-performance 6-Axis MEMS inertial sensor based on through-silicon via technology. 2016 IEEE International Symposium on Inertial Sensors and Systems, 2016, 62 doi: 10.1109/ISISS.2016.7435545
[2]	Tjulkins F, Nguyen A T T, Hoivik N, et al. 3-axis MEMS accelerometer-based implantable heart monitoring system with novel fixation method. 2013 IEEE 63rd Electronic Components and Technology Conference, 2013, 510 doi: 10.1109/ECTC.2013.6575620
[3]	Johnson B, Christ K, Endean D, et al. Tuning fork MEMS gyroscope for precision northfinding. 2015 DGON Inertial Sensors and Systems Symposium, 2015, 1
[4]	Kuisma H. Glass isolated TSVs for MEMS. Proceedings of the 5th Electronics System-integration Technology Conference, 2014, 1 doi: 10.1109/ESTC.2014.6962718
[5]	Taheri-Tehrani P, Defoort M, Chen Y, et al. Epitaxially-encapsulated quad mass resonator with shaped comb fingers for frequency tuning. 2017 IEEE 30th International Conference on Micro Electro Mechanical Systems, 2017, 1111 doi: 10.1109/MEMSYS.2017.7863608
[6]	Rödjegård H, Johansson C, Enoksson P, et al. A monolithic three-axis SOI-accelerometer with uniform sensitivity. Sens Actuat A, 2005, 123/124, 50 doi: 10.1016/j.sna.2005.02.032
[7]	Yang Y, Ng E J, Ahn C H, et al. Mechanical coupling of dual breathe-mode ring resonator. 2013 Transducers Eurosensors XXVII: The 17th International Conference on Solid-State Sensors, Actuators and Microsystems, 2013, 502 doi: 10.1109/Transducers.2013.6626813
[8]	Senkal D, Askari S, Ahamed M J, et al. 100K Q-factor toroidal ring gyroscope implemented in wafer-level epitaxial silicon encapsulation process. 2014 IEEE 27th International Conference on Micro Electro Mechanical Systems, 2014, 24 doi: 10.1109/MEMSYS.2014.6765564
[9]	Kim J, Park S, Kwak D, et al. Robust SOI process without footing and its application to ultra high-performance microgyroscopes. Sens Actuat A, 2004, 114, 236 doi: 10.1016/j.sna.2004.01.022
[10]	Seok S, Lee B, Kim J, et al. A new compensation method for the footing effect in MEMS fabrication. J Micromech Microeng, 2005, 15, 1791 doi: 10.1088/0960-1317/15/10/001/meta
[11]	Ma Z, Wang Y, Shen Q, et al. Key processes of silicon-on-glass MEMS fabrication technology for gyroscope application sensors. Sensors, 2018, 18, 1240 doi: 10.3390/s18041240
[12]	Townsend K, Durston M. Rate sensor with quadrature rejection. USA Patent, US13698339, 2013
[13]	Li Y, Yang Z, Yan G. An improved method to remove anti-footing Al layer after DRIE. 2009 4th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, 2009, 868 doi: 10.1109/NEMS.2009.5068712
[14]	Hu L, Xue Y, Shi F. Interfacial investigation and mechanical properties of glass-Al-glass anodic bonding process. J Micromech Microeng, 2017, 27, 105004 doi: 10.1088/1361-6439/aa83c7
[15]	Hu Y Q, Zhao Y P, Yu T X. Fractal pattern formation in anodic bonding of pyrex glass/Al/Si. Int J Nonlinear Sci Numerical Simul, 2008, 9, 315 doi: 10.1515/IJNSNS.2008.9.4.315
[16]	Zhang J, Huang Q A, Li W H. Simulations for surface evolvement and footing effect in ICP DRIE fabrications. J Phys: Conf Ser, 2006, 34, 522 doi: 10.1088/1742-6596/34/1/086
[17]	Nomura K, Okada A, Shoji S, et al. Application of I-structure though-glass interconnect filled with submicron gold particles to a hermetic sealing device. J Micromech Microeng, 2016, 26, 105018 doi: 10.1088/0960-1317/26/10/105018
[18]	Yang F, Han G, Yang J, et al. Research on wafer-level MEMS packaging with through-glass vias micromachines. Micromachines, 2018, 10, 15 doi: 10.3390/mi10010015
[19]	Gu J, Xia X, Zhang W, et al. A modified MEMS-casting based TSV filling method with universal nozzle piece that uses surface trenches as nozzles. 2018 19th International Conference on Electronic Packaging Technology, 2018, 536 doi: 10.1109/ICEPT.2018.8480697
[20]	Cai M, Si C, Han G, et al. Deep silicon etching of bonded wafer based on ITO mask. J Micronanoelectron Technol, 2020, 57, 11

A new DRIE cut-off material in SOG MEMS process

Author Bio:

Chaowei Si got his Ph.D. degree in 2014 at Tsinghua University. Then he joined the Institute of Semiconductors, Chinese Academy of Sciences. His research focuses on MEMS inertial devices and RF devices.

References

Search

GET CITATION

Share:

Article Metrics

History

Catalog

Email This Article

A new DRIE cut-off material in SOG MEMS process

DOI: 10.1088/1674-4926/44/4/044101

Abstract

References

Proportional views

Catalog

A new DRIE cut-off material in SOG MEMS process

Author Bio: Chaowei Si got his Ph.D. degree in 2014 at Tsinghua University. Then he joined the Institute of Semiconductors, Chinese Academy of Sciences. His research focuses on MEMS inertial devices and RF devices.

References

Search

GET CITATION

Share:

Article Metrics

History

Catalog

Email This Article

A new DRIE cut-off material in SOG MEMS process

DOI: 10.1088/1674-4926/44/4/044101

Abstract

References

Proportional views

Catalog

Export File

Citation

Format

Content

Author Bio:

Chaowei Si got his Ph.D. degree in 2014 at Tsinghua University. Then he joined the Institute of Semiconductors, Chinese Academy of Sciences. His research focuses on MEMS inertial devices and RF devices.