Advanced Plasma Technology. High precision film thickness trimming for the TFH industry. Roth & Rau AG September 2009

Transcription

1 Advanced Plasma Technology High precision film thickness trimming for the TFH industry Roth & Rau AG September 2009

2 Product Overview IonScan Equipment for ultra-precise Surface Processing IonScan 800 Wafer based processing in semiconductor industry Applied for localized ion beam trimming and figuring Basically described in this presentation 2

3 Principle of IonScan Equipment Principle Ion beam based surface processing capable for all thin film materials Focused ion beam for locally controlled processing Velocity controlled meander scan for local removal control 3

4 Principle of IonScan Process Flow for Ion Beam Trimming 20 nm 20 nm/s 40 ms Frequency / Film thickness error of BAW wafer Etch profile and focus of ion beam (Material dependent) Calculation of residence time data Wafer specific control data for axis system 1 nm Process recipe data (Ion beam parameters, Cooling, Handling) Required input data: Velocity modulated wafer scan Film thickness error after ion beam processing Wafer specific thickness or frequency error file (Supplied by customer metrology) Etch profile function from system calibration (Sheet film calibration data) Material specific recipe data (beam settings, cooling, gas flow, ) 4

5 Components & System Layout System Layout Cluster Platform Configurable cluster tool design with 4 port handling unit Process Chamber Process chamber with high performance axis Separate ion source housing for easy source access Large front door for easy system access System Control Cluster and process module controller (Windows XP) SECS/GEM host interface Recipe and protocol database (MS SQL Server) Process module 1 Robot platform Cassette load-lock 1 Ion source Process module 2 Cassette load-lock 52

6 Components & System Layout Process Chamber Rectangular chamber of 800 x 800 x 550 mm 3 Chamber and port dimensions capable for processing of up to 200 mm wafers Chamber completely covered by sputter shields for maintenance Separately accessible ion source housing for size and maintenance optimization Turbo pumped (2400 l/s) viton sealed system (doors double sealed, differently pumped) with base pressure < 10-6 mbar Ion Source x Axis y Axis Faraday Array z Axis Tilt Axis Wafer Chuck Handling Port 6

7 Trimming Performance Challenge in Post CMP Step Height Reduction IonScan 800 allows to overcome problems in CMP Up-scaling for larger wafer areas causes homogeneity problems for CMP IonScan has no scaling problems Polishing of different materials causes arbitrarily distributed step heights at interface to be created IonScan is able to remove step functions by adjusted process selectivity Rate [ nm/s ] Incidence Angle [ deg ] Insulator Metal Selectivity control by ion incident angle 7

8 Trimming Performance Step Height Reduction by using High Selectivity Rate [ nm/s ] Incidence Angle [ deg ] Insulator Metal Al 2 O 3 NiFe thickness variation over wafer Al 2 O 3 NiFe localized trimming 8

9 Trimming Performance Step Height Reduction Top: Step heights reduction across of the wafer before (pre) and after (post) ion beam trimming Bottom left: Histogram graph of step height distribution Bottom right: Trimming function of actual removal versus target removal 9

10 Trimming Performance Smoothing by using Low Selectivity Rate [ nm/s ] Incidence Angle [ deg ] Insulator Metal Al 2 O 3 NiFe thickness variation over wafer Al 2 O 3 NiFe localized trimming 10

11 Trimming Performance Al 2 O 3 Trimming Demo Top: Thickness across the wafer before (pre) and after (post) ion beam trimming Bottom left: Histogram graph of thickness distribution Bottom right: Trimming function of actual removal versus target removal 11

12 Trimming Performance Etching to define Steps thickness variation over wafer Mask Al 2 O 3 Mask defined step high Substrate localized trimming Substrate Etching through different materials in one process step 12

13 Thank you very much for your attention! Roth & Rau AG Gewerbering 3 OT Wüstenbrand Hohenstein-Ernstthal Germany Roth & Rau AG Juli