Planarization of Passivation Layers during Manufacturing Processes of Image Sensors

Transcription

1 Planarization of Passivation Layers during Manufacturing Processes of Image Sensors A. Sheikholeslami 1, F. Parhami 2, H. Puchner 2, and S. Selberherr , NUSOD 2006, Singapore 1 Institute for Microelectronics Gußhausstraße 27-29/E360, 1040 Wien 2 Cypress Semicondoctr Corporation San Jose, CA 95134, USA

2 Introduction Motivation 2

3 Introduction Motivation Topography simulation tool 2

4 Introduction Motivation Topography simulation tool Optimization tool 2

5 Introduction Motivation Topography simulation tool Optimization tool Simulation results 2

6 Introduction Motivation Topography simulation tool Optimization tool Simulation results Conclusion 2

7 Introduction Motivation Topography simulation tool Optimization tool Simulation results Conclusion 2

8 Motivation Sensitivity of image sensor processes to passivation planarization 3

9 Motivation Sensitivity of image sensor processes to passivation planarization A good passivation planarization leads to 3

10 Motivation Sensitivity of image sensor processes to passivation planarization A good passivation planarization leads to preventing the clear layer coating issues 3

11 Motivation Sensitivity of image sensor processes to passivation planarization A good passivation planarization leads to preventing the clear layer coating issues shortening the optical path between color surface and active surface 3

12 Motivation Sensitivity of image sensor processes to passivation planarization A good passivation planarization leads to preventing the clear layer coating issues shortening the optical path between color surface and active surface Achieving a good planarization needs: 3

13 Motivation Sensitivity of image sensor processes to passivation planarization A good passivation planarization leads to preventing the clear layer coating issues shortening the optical path between color surface and active surface Achieving a good planarization needs: optimizing the height and width of trenches to obtain sufficient: 3

14 Motivation Sensitivity of image sensor processes to passivation planarization A good passivation planarization leads to preventing the clear layer coating issues shortening the optical path between color surface and active surface Achieving a good planarization needs: optimizing the height and width of trenches to obtain sufficient: sidewall coverage, 3

15 Motivation Sensitivity of image sensor processes to passivation planarization A good passivation planarization leads to preventing the clear layer coating issues shortening the optical path between color surface and active surface Achieving a good planarization needs: optimizing the height and width of trenches to obtain sufficient: sidewall coverage, bottom coverage, and 3

16 Motivation Sensitivity of image sensor processes to passivation planarization A good passivation planarization leads to preventing the clear layer coating issues shortening the optical path between color surface and active surface Achieving a good planarization needs: optimizing the height and width of trenches to obtain sufficient: sidewall coverage, bottom coverage, and planarization margin 3

17 The Level Set Method This method provides means for describing the moving boundaries 4

18 The Level Set Method This method provides means for describing the moving boundaries Viewing the moving boundary at the time t as the zero level set of u(t, x) 4

19 The Level Set Method This method provides means for describing the moving boundaries Viewing the moving boundary at the time t as the zero level set of u(t, x) The initial boundary is the set of {x u(0, x) = 0} 4

20 The Level Set Method This method provides means for describing the moving boundaries Viewing the moving boundary at the time t as the zero level set of u(t, x) The initial boundary is the set of {x u(0, x) = 0} Moving the boundary points with a speed F (t, x) normal to the boundary 4

21 The Level Set Method This method provides means for describing the moving boundaries Viewing the moving boundary at the time t as the zero level set of u(t, x) The initial boundary is the set of {x u(0, x) = 0} Moving the boundary points with a speed F (t, x) normal to the boundary The boundary at a later time t 1 is the zero level set function {x u(t 1, x) = 0} 4

22 The Level Set Method This method provides means for describing the moving boundaries Viewing the moving boundary at the time t as the zero level set of u(t, x) The initial boundary is the set of {x u(0, x) = 0} Moving the boundary points with a speed F (t, x) normal to the boundary The boundary at a later time t 1 is the zero level set function {x u(t 1, x) = 0} This leads to the level set equation 4

23 The Level Set Method This method provides means for describing the moving boundaries Viewing the moving boundary at the time t as the zero level set of u(t, x) The initial boundary is the set of {x u(0, x) = 0} Moving the boundary points with a speed F (t, x) normal to the boundary The boundary at a later time t 1 is the zero level set function {x u(t 1, x) = 0} This leads to the level set equation u t + F (t, x) x u = 0 4

24 Simulation Flow The simulator is called ELSA (Enhanced Level Set Applications) 5

25 Simulation Flow The simulator is called ELSA (Enhanced Level Set Applications) Construction of the initial level set function as the signed distance function 5

26 Simulation Flow The simulator is called ELSA (Enhanced Level Set Applications) Construction of the initial level set function as the signed distance function Performing the time step in physical model 5

27 Simulation Flow The simulator is called ELSA (Enhanced Level Set Applications) Construction of the initial level set function as the signed distance function Performing the time step in physical model Finding the speed function on the trench 5

28 Simulation Flow The simulator is called ELSA (Enhanced Level Set Applications) Construction of the initial level set function as the signed distance function Performing the time step in physical model Finding the speed function on the trench Using a fast marching method for extension of the speed function 5

29 Simulation Flow The simulator is called ELSA (Enhanced Level Set Applications) Construction of the initial level set function as the signed distance function Performing the time step in physical model Finding the speed function on the trench Using a fast marching method for extension of the speed function Performing the level set step in the narrow band 5

30 Simulation Flow The simulator is called ELSA (Enhanced Level Set Applications) Construction of the initial level set function as the signed distance function Performing the time step in physical model Finding the speed function on the trench Using a fast marching method for extension of the speed function Performing the level set step in the narrow band Iteration till reaching the end of simulation time 5

31 Simulation Flow of ELSA ELSA (Enhanced Level Set Applications) Construct initial level set function as the signed distance function Perform radiosity time step Find speed function on surface Construct signed distance function and simultaneously extend the speed function to the whole narrow band Perform level set in narrow band Extract final surface 6

32 Example: Boundary Evolution Simulation of a deposition process leading to void formation 7

33 Advancing the Level Set Function Using Narrow Banding 2 z x y 150 The level set function at time step 0, intermediate steps, and final step 8

34 Advancing the Level Set Function Using Narrow Banding 0.05 z x y 150 The level set function at time step 0, intermediate steps, and final step 8

35 Advancing the Level Set Function Using Narrow Banding 0.05 z x y 150 The level set function at time step 0, intermediate steps, and final step 8

36 Advancing the Level Set Function Using Narrow Banding 0.05 z x y 150 The level set function at time step 0, intermediate steps, and final step 8

37 Advancing the Level Set Function Using Narrow Banding 0.05 z x y 150 The level set function at time step 0, intermediate steps, and final step 8

38 Advancing the Level Set Function Using Narrow Banding 0.05 z x y 150 The level set function at time step 0, intermediate steps, and final step 8

39 Optimization Tool SIESTA Simulation Environment for Semiconductor Technology Analysis Simulation Flow Scorefunction Optimizer Init Values Reference Config 9

40 Geometrical Parameters of Investigations Deposition of silicon nitride: D 10

41 Geometrical Parameters of Investigations Deposition of silicon nitride: D = 0.5, 1.0, 2.0, 3.0, and 4.0µm D 10

42 Geometrical Parameters of Investigations Deposition of silicon nitride: D = 0.5, 1.0, 2.0, 3.0, and 4.0µm H = 2.0, 3.0, and 4.0µm D 10

43 Geometrical Parameters of Investigations Deposition of silicon nitride: D = 0.5, 1.0, 2.0, 3.0, and 4.0µm H = 2.0, 3.0, and 4.0µm T = 0.3, 0.6, and 0.9µm D 10

44 Geometrical Parameters of Investigations Deposition of silicon nitride: D = 0.5, 1.0, 2.0, 3.0, and 4.0µm H = 2.0, 3.0, and 4.0µm T = 0.3, 0.6, and 0.9µm Deposition of silicon dioxide: D 10

45 Geometrical Parameters of Investigations Deposition of silicon nitride: D = 0.5, 1.0, 2.0, 3.0, and 4.0µm H = 2.0, 3.0, and 4.0µm T = 0.3, 0.6, and 0.9µm Deposition of silicon dioxide: D = 0.3, 0.5, 0.8, 1.0, 1.4, 2.0, and 3.0µm D 10

46 Geometrical Parameters of Investigations Deposition of silicon nitride: D = 0.5, 1.0, 2.0, 3.0, and 4.0µm H = 2.0, 3.0, and 4.0µm T = 0.3, 0.6, and 0.9µm Deposition of silicon dioxide: D = 0.3, 0.5, 0.8, 1.0, 1.4, 2.0, and 3.0µm H = 0.3, 0.5, and 0.9µm D 10

47 Geometrical Parameters of Investigations Deposition of silicon nitride: D = 0.5, 1.0, 2.0, 3.0, and 4.0µm H = 2.0, 3.0, and 4.0µm T = 0.3, 0.6, and 0.9µm Deposition of silicon dioxide: D = 0.3, 0.5, 0.8, 1.0, 1.4, 2.0, and 3.0µm H = 0.3, 0.5, and 0.9µm T = 0.3, 0.7, and 1µm D 10

48 The Goal of Simulations Deposition of silicon nitride Planarization Margin 300 nm 11

49 The Goal of Simulations Deposition of silicon nitride Sufficient sidewall and bottom coverage Planarization Margin 300 nm 11

50 The Goal of Simulations Deposition of silicon nitride Sufficient sidewall and bottom coverage Deposition of silicon dioxide Planarization Margin 300 nm 11

51 The Goal of Simulations Deposition of silicon nitride Sufficient sidewall and bottom coverage Deposition of silicon dioxide Sufficient planarization margin Planarization Margin 300 nm 11

52 Simulation Results: Silicon Nitride Passivation (1) D0.5H2T0.3 D0.5H2T0.6 D0.5H2T0.9 D0.5H3T0.3 VoidD0.5H2T0.6&0.9 D0.5H3T0.6 VoidD0.5H3T0.6&0.9 D0.5H3T0.9 D0.5H4T0.3 VoidH4T D0.5H4T0.6 D0.5H4T D2H2T0.3 D2H2T0.6 D2H2T0.9 D2H3T0.3 D2H3T0.6 D2H3T0.9 D2H4T0.3 D2H4T0.6 D2H4T D1H2T0.3 D1H2T0.6 D1H2T0.9 VoidH2T0.9 D1H3T0.3 D1H3T0.6 D1H3T0.9 VoidH3T0.9 D1H4T0.3 D1H4T0.6 D1H4T0.9 VoidH4T D4H4T0.9 D4H4T0.6 D4H4T0.3 D4H3T0.3 D4H3T0.6 D4H3T0.9 D4H2T0.9 D4H2T0.6 D4H2T

53 Simulation Results: Silicon Nitride Passivation (2) T(µm) H(µm) D(µm) a(µm) s(µm) b(µm) NA NA NA NA NA NA NA NA

54 Simulation Results: Silicon Nitride Passivation (3) Planar topside is obtained: 14

55 Simulation Results: Silicon Nitride Passivation (3) Planar topside is obtained: narrowing down the trench width to 1µm and with 0.9µm nitride thickness 14

56 Simulation Results: Silicon Nitride Passivation (3) Planar topside is obtained: narrowing down the trench width to 1µm and with 0.9µm nitride thickness narrowing down the trench width to 0.5µm and with 0.6µm nitride thickness 14

57 Simulation Results: Silicon Nitride Passivation (3) Planar topside is obtained: narrowing down the trench width to 1µm and with 0.9µm nitride thickness narrowing down the trench width to 0.5µm and with 0.6µm nitride thickness No planar topside when thinning down nitride to 0.3µm for 14

58 Simulation Results: Silicon Nitride Passivation (3) Planar topside is obtained: narrowing down the trench width to 1µm and with 0.9µm nitride thickness narrowing down the trench width to 0.5µm and with 0.6µm nitride thickness No planar topside when thinning down nitride to 0.3µm for trench height of 2µm 14

59 Simulation Results: Silicon Nitride Passivation (3) Planar topside is obtained: narrowing down the trench width to 1µm and with 0.9µm nitride thickness narrowing down the trench width to 0.5µm and with 0.6µm nitride thickness No planar topside when thinning down nitride to 0.3µm for trench height of 2µm trench height of 3µm 14

60 Simulation Results: Silicon Nitride Passivation (3) Planar topside is obtained: narrowing down the trench width to 1µm and with 0.9µm nitride thickness narrowing down the trench width to 0.5µm and with 0.6µm nitride thickness No planar topside when thinning down nitride to 0.3µm for trench height of 2µm trench height of 3µm Avoiding voids by means of making trenches to 2µm and more 14

61 Simulation Results: Silicon Dioxide Passivation (1) 2.5 D0.8H0.3T0.3 D0.8H0.3T0.7 D0.8H0.3T1 D0.8H0.5T0.3 2 D0.8H0.5T0.7 D0.8H0.5T1 D0.8H0.9T0.3 D0.8H0.9T0.7 D0.8H0.9T1 1.5 Void-D0.8H0.5T0.3-1 Void-D0.8H0.9T D2H0.3T0.3 D2H0.3T0.7 D2H0.3T1 D2H0.5T0.3 2 D2H0.5T0.7 D2H0.5T1 D2H0.9T0.3 D2H0.9T0.7 D2H0.9T D1.4H0.3T0.3 D1.4H0.3T0.7 D1.4H0.3T1 D1.4H0.5T0.3 2 D1.4H0.5T0.7 D1.4H0.5T1 Void-D1.4H0.5T1 D1.4H0.9T0.3 D1.4H0.9T Void-D1.4H0.9T1 D1.4H0.9T1 2.5 D3H0.3T0.3 D3H0.3T0.7 D3H0.3T1 D3H0.5T0.3 2 D3H0.5T0.7 D3H0.5T1 D3H0.9T0.3 D3H0.9T0.7 D3H0.9T

62 Simulation Results: Silicon Dioxide Passivation (2) Polishing down from 1µm to 0.3µm by TEOS: 16

63 Simulation Results: Silicon Dioxide Passivation (2) Polishing down from 1µm to 0.3µm by TEOS: sufficient planarization margin by 0.3µm trench height 16

64 Simulation Results: Silicon Dioxide Passivation (2) Polishing down from 1µm to 0.3µm by TEOS: sufficient planarization margin by 0.3µm trench height nonplanar surface with 0.5µm and 0.9µm trench heights 16

65 Conclusion Development and implementation of a general topography simulator 17

66 Conclusion Development and implementation of a general topography simulator Accurate and fast using several sophisticated techniques such as 17

67 Conclusion Development and implementation of a general topography simulator Accurate and fast using several sophisticated techniques such as Narrow banding 17

68 Conclusion Development and implementation of a general topography simulator Accurate and fast using several sophisticated techniques such as Narrow banding Fast marching method 17

69 Conclusion Development and implementation of a general topography simulator Accurate and fast using several sophisticated techniques such as Narrow banding Fast marching method Capable of handling different processes such as 17

70 Conclusion Development and implementation of a general topography simulator Accurate and fast using several sophisticated techniques such as Narrow banding Fast marching method Capable of handling different processes such as Optimizing the features causing nonplanar passivation in 17

71 Conclusion Development and implementation of a general topography simulator Accurate and fast using several sophisticated techniques such as Narrow banding Fast marching method Capable of handling different processes such as Optimizing the features causing nonplanar passivation in planar nitride surface including sufficient sidewall and bottom coverages 17

72 Conclusion Development and implementation of a general topography simulator Accurate and fast using several sophisticated techniques such as Narrow banding Fast marching method Capable of handling different processes such as Optimizing the features causing nonplanar passivation in planar nitride surface including sufficient sidewall and bottom coverages sufficient planarization margin for TEOS 17