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Title Page

Contents

NOMENCLATURE 13

초록 16

ABSTRACT 20

I. Introduction 23

II. Research Background 36

A. Limitation of Conventional Steinberg's Theory 36

B. Limitations of Fatigue Life Prediction Methodologies 41

III. PCB Strain-based Structural Design Methodology 43

A. Description of Design Methodology 43

B. Methodology Validation (PBGA324 & TSSOP48) 45

1. Description of PBGA388 PCB Sample 45

2. Fatigue Life Tests 48

C. Mechanical Safety Evaluation 66

D. Methodology Validation (PBGA388 Package) 85

1. Description of PBGA388 PCB Sample 86

2. Fatigue Life Tests 91

3. Mechanical Safety Evaluation 102

IV. PCB Strain-based Structural Design Methodology for Rapid Evaluation of Spacebome Electronics 119

A. Description of Design Methodology 121

1. FEM Construction & Modal Analysis (Step 1-2) 125

2. Estimation of TTFreq for Survival in Vibration Test and Launch Process (Step 3-4)[이미지참조] 126

3. DF Estimation & MoS Calculation with respect to PCB Strain (Step 5-6) 130

B. Fatigue Life Tests 131

1. Description of PBGA388 PCB Sample (Sample Set #1) 131

2. Results of Fatigue Life Tests 135

C. Methodology Validation 140

1. FEM Modeling Technique of PCB 142

2. Mechanical Safety Evaluation 147

D. Methodology Validation on Various Packages 167

1. Sample Set #2: CCGA624 Package 167

2. Sample Set #3: QFP208 Package 169

3. Sample Set #4: PBGA388 Package 179

E. Considerations in Practical Structural Design of Spaceborne Electronics 183

V. Conclusion 195

VI. Future Study 199

References 201

Research Achievements 208

List of Tables

Table III-1. Specifications of PBGA324 & TSSOP48 packages 47

Table III-2. Specifications of random vibration (20 Grms)[이미지참조] 54

Table III-3. Summary of crack propagation state and time to failure on each package 65

Table III-4. Material properties used for analysis 73

Table III-5. Comparison of MoS calculated using STT-RV-1 and CST-RV-1 methodologies 76

Table III-6. Comparison of MoS calculated using STT-QS-1 and CST-QS-1 methodologies 77

Table III-7. Comparison of MoS calculated using STT-QS-2 and CST-QS-2 methodologies 79

Table III-8. Comparison of computation time between various methodologies 80

Table III-9. Results of MoS and time to failure of CCGA package calculated using CST-... 84

Table III-10. Specifications of PBGA388 package 88

Table III-11. Random vibration test specification (14.1 Grms)[이미지참조] 95

Table III-12. Summary of fatigue life test results 101

Table III-13. Material properties for structural analysis 106

Table III-14. First eigenfrequencies of PCB samples obtained from detailed and... 109

Table III-15. Analyzed volume-weighted average values of Von-mises stresses of solder... 112

Table III-16. Comparison of MoS estimated by M.CST-1 and M.STT-1 methodologies 117

Table III-17. Comparison of MoS estimated by M.CST-2 and M.STT-2 methodologies 118

Table IV-1. Specifications of PBGA388 package 132

Table IV-2. Specifications of input random vibration 137

Table IV-3. TTFtest of PCB samples measured from fatigue life test[이미지참조] 139

Table IV-4. Summary of measured and analyzed responses of bare PCBs 152

Table IV-5. Analyzed values of fn for each sample PCB assembly[이미지참조] 155

Table IV-6. Estimation results of TTFreq for survival of solder joint in test and launch processes[이미지참조] 156

Table IV-7. Comparison between methodologies based on MoS of sample PBGA388... 161

Table IV-8. Comparison between methodologies based on MoS of sample PBGA388... 163

Table IV-9. Comparison between methodologies based on MoS of sample PBGA388... 165

Table IV-10. Comparison between methodologies based on MoS of sample CCGA624 package 168

Table IV-11. Specifications of QFP208 package 172

Table IV-12. Comparison between methodologies based on MoS of sample QFP208... 178

Table IV-13. Comparison between methodologies based on MoS of sample PBGA388... 182

Table IV-14. Comparison between N0+ and fn of bare PCBs[이미지참조] 188

Table IV-15. Estimation results of TTFreq for assumed development scenarion 1[이미지참조] 190

Table IV-16. Estimation results of TTFreq for assumed development scenarion 2[이미지참조] 192

Table IV-17. Estimation results of TTFreq for assumed development scenarion 3[이미지참조] 194

List of Figures

Fig. I-1. Various types of integrated electronic packages 31

Fig. I-2. Typical launch and ascent process of launcher 32

Fig. I-3. Conventional fatigue life prediction approach for solder joint under vibration 33

Fig. I-4. Fatigue life prediction approach using Sherlock tool 34

Fig. I-5. Number of small satellite development in 2000-2020 35

Fig. II-1. Geometrical factors for Steinberg's empirical formula (Eq. (II-1)) 37

Fig. II-2. Example of complex mode shapes of PCB 39

Fig. II-3. Example of PCB with irregular fixation points, making ambiguous to determine... 40

Fig. III-1. Configuration of PCB sample with PBGA packages and TSSOPs 46

Fig. III-2. Representative X-ray inspection results on U5 BGA solder joints 51

Fig. III-3. Representative optical inspection results on U3 TSSOP solder joints 52

Fig. III-4. Random vibration fatigue test set-up 53

Fig. III-5. Configuration of daisy-chain circuit for PBGA324 package 55

Fig. III-6. Configuration of daisy-chain circuit for TSSOP48 56

Fig. III-7. Time profiles of daisy-chain resistance on each packages of PBGA324 &... 57

Fig. III-8. Time profiles of daisy-chain resistance on each packages of PBGA324 &... 58

Fig. III-9. SEM micrographs on solder joint of U2 package of PCB sample #2 59

Fig. III-10. SEM micrographs on solder joint of U1 package of PCB sample #2 60

Fig. III-11. SEM micrographs on solder joint of U4 package of PCB sample #2 61

Fig. III-12. SEM micrographs on solder joint of U5 package of PCB sample #2 62

Fig. III-13. SEM micrographs on solder joint of U6 package of PCB sample #2 63

Fig. III-14. SEM micrographs on solder joint of U9 package of PCB sample #2 64

Fig. III-15. Evaluation scheme for structural design methodology (w.r.t PBGA324 &... 71

Fig. III-16. Configuration of detailed FEM of PBGA324 & TSSOP48 PCB sample 72

Fig. III-17. Representative mode shapes of PCB sample 75

Fig. III-18. Configuration of simplified FEM of PBGA324 & TSSOP48 PCB sample 78

Fig. III-19. Random vibration fatigue test set-up of PCB sample with CCGA package 81

Fig. III-20. Time profile of daisy-chain resistance of CCGA package 82

Fig. III-21. Representative optical micrograph of CCGA solder joints 83

Fig. III-22. Case 1 PCB sample with PBGA388 package 87

Fig. III-23. Configurations of PCB samples in each case (Cases 1, 1-1 and 1-2) 89

Fig. III-24. Configurations of PCB samples in each case (Cases 1, 2 and 3) 90

Fig. III-25. Fatigue life test set-up for PBGA388 PCB samples 93

Fig. III-26. Configuration of daisy-chain circuit for PBGA388 package 94

Fig. III-27. Time profiles of daisy-chain resistance on each PBGA388 PCB samples 96

Fig. III-28. SEM microphotograph of cracked BGA solder joints of Case 1 sample 97

Fig. III-29. SEM microphotograph of cracked BGA solder joints of Case 1-1 sample 98

Fig. III-30. SEM microphotograph of cracked BGA solder joints of Case 2 sample 99

Fig. III-31. SEM microphotograph of cracked BGA solder joints of Case 3 sample 100

Fig. III-32. Configuration of (a) detailed and (b) simplified FEMs of Case 1 sample 105

Fig. III-33. Mode shapes of Case 1 PCB ((a) 213.5 Hz, (b) 408.1 Hz, (c) 538.7 Hz) 108

Fig. III-34. Von-mises stress distributions of Case 1 PCB sample 110

Fig. III-35. Von-mises stress distributions of Case 1-2 PCB sample 111

Fig. III-36. Summary of fatigue life prediction results on solder joints of PCB samples 113

Fig. III-37. Evaluation scheme for structural design methodologies (w.r.t PBGA388 packages) 116

Fig. IV-1. Evaluation approach on structural design of spaceborne electronics using Oh-... 124

Fig. IV-2. Assumed scenario of test and launch processes for spaceborne electronics 129

Fig. IV-3. Representative configuration of sample PCB assembly in Case 1 133

Fig. IV-4. Configuration of daisy-chain circuit for PBGA388 package 134

Fig. IV-5. Fatigue life test set-up for a set of PCB samples 136

Fig. IV-6. Time profile of measured daisy-chain resistance for each sample during... 138

Fig. IV-7. Validation scheme for Oh-Park methodology 141

Fig. IV-8. Example of FEM of PCB assembly with Case 1 modeling technique for... 144

Fig. IV-9. Various simplified modeling techniques for electronic package ((a) Type 1 (4... 145

Fig. IV-10. Calculation method to derive εpmax from simplified FEM[이미지참조] 146

Fig. IV-11. Measured and analyzed PSD acceleration responses of bare PCB in Case 1... 149

Fig. IV-12. Measured and analyzed PSD acceleration responses of bare PCB in Case 2... 150

Fig. IV-13. Measured and analyzed PSD acceleration responses of bare PCB in Case 3... 151

Fig. IV-14. Mode shapes of sample PCB in Case 1 with Type 3 package modeling ((a) 1st... 154

Fig. IV-15. Estimated DF for estimated TTFreq as a function of fn[이미지참조] 157

Fig. IV-16. Comparison between TTFtest and TTFpred calculated by methodologies...[이미지참조] 162

Fig. IV-17. Comparison between TTFtest and TTFpred calculated by methodologies...[이미지참조] 164

Fig. IV-18. Comparison between TTFtest and TTFpred calculated by methodologies...[이미지참조] 166

Fig. IV-19. Illustration of PCB sample with QFP208 package 171

Fig. IV-20. Random vibration test set-up for QFP208 PCB sample (sample set #3) 173

Fig. IV-21. Time profile of daisy-chain resistance for QFP208 package (sample set #3) 174

Fig. IV-22. Simplified FEM modeling technique for QFP package 175

Fig. IV-23. Representative mode shapes of QFP208 PCB ((a) 119.0 Hz, (b) 216.1. Hz, (c) 374.1 Hz) 177

Fig. IV-24. Illustration of PCB sample with PBG388 package 180

Fig. IV-25. Time profile of daisy-chain resistance for PBGA388 package (sample set #4) 181

Fig. IV-26. Assumed electronics development scenario 1 (Typical QM-FM approach) 189

Fig. IV-27. Assumed electronics development scenario 2 (PFM approach) 191

Fig. IV-28. Assumed electronics development scenario 3 (for reusable launch vehicle) 193