Development of a New Electro-thermal Simulation Tool for RF circuits

Contents
Preface iii
1 The relevance of the electro-thermal phenomena 1
1.1 The electro-thermal analysis idea . . . . . . . . . . . . . . . . . . . . . 7
1.2 The limitations of present simulation codes . . . . . . . . . . . . . . . . 8
2 Thermal models for the electro-thermal simulation 11
2.1 Assumptions for analytical thermal model . . . . . . . . . . . . . . . . 12
2.2 Chip thermal model - mathematical considerations . . . . . . . . . . . 13
2.2.1 Case of multiple heat sources . . . . . . . . . . . . . . . . . . . 16
2.2.2 Analysis of the time-dependent case . . . . . . . . . . . . . . . . 17
2.2.3 Thermal resistance . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.2.4 Thermal impedance . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.3 Analytical thermal model . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.3.1 Case of rectangular heat source (THS) . . . . . . . . . . . . . . 24
2.3.2 Case of volume heat source (VHS) . . . . . . . . . . . . . . . . 25
2.4 Compact Thermal Model . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2.4.1 General considerations . . . . . . . . . . . . . . . . . . . . . . . 27
2.4.2 Methodology for Multi-Cooling Surface Structures . . . . . . . . 28
2.4.3 Multiple Heat Sources . . . . . . . . . . . . . . . . . . . . . . . 33
3 Development of the electro-thermal simulation tool 38
3.1 Applied strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
3.2 External command-line approach . . . . . . . . . . . . . . . . . . . . . 40
3.2.1 Preprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
iv