Advanced CMP Processes for Special Substrates and for Device Manufacturing in MEMS Applications: Dissertation

Martin Kulawski

Research output: ThesisDissertationCollection of Articles

2 Citations (Scopus)

Abstract

The present work reports on studies and process developments to utilize the chemical mechanical planarization (CMP) technology in the field of micro electrical mechanical systems (MEMS). Approaches have been undertaken to enable the manufacturing of thick film SOI (silicon-on-insulator) substrates with a high degree of flatness as well as utilizing CMP for the formation of several novel MEMS devices. Thick film SOI wafers are of high interest in MEMS manufacturing as they offer obvious benefits as a starting material or foundation for more complex structures. Precise control of the SOI layer thickness as well as the removal uniformity is of critical importance to fully utilize the benefits of this technology. By combining fixed abrasive (FA) pads for polishing and novel grinding techniques it is shown that major improvements can be achieved over the standard manufacturing sequence. Analysis of the material removal rate (MRR) dependency on several process parameters is made. Together with the FA pad vendor a suitable consumable set for SOI is generated, which shows long term stability in the generated process. A comparison with standard methods is undertaken to prove the surface and crystalline quality of the resulting substrate material is equivalent. Analysis is done to understand the microscopic mechanism of removal. The CMP process is applied to several MEMS structures to smooth deposited oxide films and to enable direct wafer bonding (DWB) at low temperatures. This allows the design of bonded multiple stack layers including heat sensitive materials such as metals. FA CMP is applied to large pattern MEMS for total planarization but also for smoothing of the surface of single protruding structures while minimizing edge rounding and preserving the original intended pattern shape. With dedicated CMP steps thick film polysilicon smoothing is demonstrated enabling DWB. The chemo-mechanical particularities of the FA pad are investigated in detail.
Original languageEnglish
QualificationDoctor Degree
Awarding Institution
  • Aalto University
Award date20 Oct 2006
Place of PublicationEspoo
Publisher
Print ISBNs951-38-6855-9
Electronic ISBNs951-38-6856-7
Publication statusPublished - 2006
MoE publication typeG5 Doctoral dissertation (article)

Fingerprint

Chemical mechanical polishing
Abrasives
Thick films
Substrates
Wafer bonding
Silicon
Polishing
Polysilicon
Oxide films
Crystalline materials
Metals
Temperature

Keywords

  • CMP
  • micro electro mechanical devices
  • polishing
  • fixed abrasives
  • MEMS
  • SOI
  • silicon-on-insulator
  • direct wafer bonding
  • DWB
  • low temperature bonding

Cite this

Kulawski, Martin. / Advanced CMP Processes for Special Substrates and for Device Manufacturing in MEMS Applications : Dissertation. Espoo : VTT Technical Research Centre of Finland, 2006. 138 p.
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Advanced CMP Processes for Special Substrates and for Device Manufacturing in MEMS Applications : Dissertation. / Kulawski, Martin.

Espoo : VTT Technical Research Centre of Finland, 2006. 138 p.

Research output: ThesisDissertationCollection of Articles

TY - THES

T1 - Advanced CMP Processes for Special Substrates and for Device Manufacturing in MEMS Applications

T2 - Dissertation

AU - Kulawski, Martin

PY - 2006

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N2 - The present work reports on studies and process developments to utilize the chemical mechanical planarization (CMP) technology in the field of micro electrical mechanical systems (MEMS). Approaches have been undertaken to enable the manufacturing of thick film SOI (silicon-on-insulator) substrates with a high degree of flatness as well as utilizing CMP for the formation of several novel MEMS devices. Thick film SOI wafers are of high interest in MEMS manufacturing as they offer obvious benefits as a starting material or foundation for more complex structures. Precise control of the SOI layer thickness as well as the removal uniformity is of critical importance to fully utilize the benefits of this technology. By combining fixed abrasive (FA) pads for polishing and novel grinding techniques it is shown that major improvements can be achieved over the standard manufacturing sequence. Analysis of the material removal rate (MRR) dependency on several process parameters is made. Together with the FA pad vendor a suitable consumable set for SOI is generated, which shows long term stability in the generated process. A comparison with standard methods is undertaken to prove the surface and crystalline quality of the resulting substrate material is equivalent. Analysis is done to understand the microscopic mechanism of removal. The CMP process is applied to several MEMS structures to smooth deposited oxide films and to enable direct wafer bonding (DWB) at low temperatures. This allows the design of bonded multiple stack layers including heat sensitive materials such as metals. FA CMP is applied to large pattern MEMS for total planarization but also for smoothing of the surface of single protruding structures while minimizing edge rounding and preserving the original intended pattern shape. With dedicated CMP steps thick film polysilicon smoothing is demonstrated enabling DWB. The chemo-mechanical particularities of the FA pad are investigated in detail.

AB - The present work reports on studies and process developments to utilize the chemical mechanical planarization (CMP) technology in the field of micro electrical mechanical systems (MEMS). Approaches have been undertaken to enable the manufacturing of thick film SOI (silicon-on-insulator) substrates with a high degree of flatness as well as utilizing CMP for the formation of several novel MEMS devices. Thick film SOI wafers are of high interest in MEMS manufacturing as they offer obvious benefits as a starting material or foundation for more complex structures. Precise control of the SOI layer thickness as well as the removal uniformity is of critical importance to fully utilize the benefits of this technology. By combining fixed abrasive (FA) pads for polishing and novel grinding techniques it is shown that major improvements can be achieved over the standard manufacturing sequence. Analysis of the material removal rate (MRR) dependency on several process parameters is made. Together with the FA pad vendor a suitable consumable set for SOI is generated, which shows long term stability in the generated process. A comparison with standard methods is undertaken to prove the surface and crystalline quality of the resulting substrate material is equivalent. Analysis is done to understand the microscopic mechanism of removal. The CMP process is applied to several MEMS structures to smooth deposited oxide films and to enable direct wafer bonding (DWB) at low temperatures. This allows the design of bonded multiple stack layers including heat sensitive materials such as metals. FA CMP is applied to large pattern MEMS for total planarization but also for smoothing of the surface of single protruding structures while minimizing edge rounding and preserving the original intended pattern shape. With dedicated CMP steps thick film polysilicon smoothing is demonstrated enabling DWB. The chemo-mechanical particularities of the FA pad are investigated in detail.

KW - CMP

KW - micro electro mechanical devices

KW - polishing

KW - fixed abrasives

KW - MEMS

KW - SOI

KW - silicon-on-insulator

KW - direct wafer bonding

KW - DWB

KW - low temperature bonding

M3 - Dissertation

SN - 951-38-6855-9

T3 - VTT Publications

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Kulawski M. Advanced CMP Processes for Special Substrates and for Device Manufacturing in MEMS Applications: Dissertation. Espoo: VTT Technical Research Centre of Finland, 2006. 138 p.