臺灣博碩士論文加值系統

軟性電子是一種將電子電路製作於軟性基板上的一種技術，例如塑膠甚至紙張上。而顯示面板可能是軟性電子最重要的應用之一。事實上，現在所謂主動矩陣式的顯示面板，都是由薄膜電晶體(TFT)為單元的設計。然而，薄膜電晶體也是電晶體的一種，很多面板的驅動電路也已經透過薄膜電晶體來直接製作於玻璃基板上。當越來越多不同用途的電路被設計及製作於面板上，面板將不再僅是面板，而成為所謂的面板系統(System-On-Panel)。在此之前，已經有研究將數位電路透過連續單結晶矽(CG-Silicon)以及低溫多晶矽(LTPS)的方式實作於軟性基板上。除此之外，非晶矽薄膜電晶體(a-Si TFT)同樣廣泛的應用於各種顯示面板上，因此如何以非晶矽薄膜電晶體來製作電路將是非常值得研究的方向。於此論文中，我們提出一個非同步的有限脈衝響應濾波器(FIR)以及一個採用多處理器的影像處理系統，都是採用非晶矽薄膜電晶體製程所實作。而我們主要有三個貢獻，第一我們提供非晶矽薄膜電機體完整的特性分析，並建立數位電路所需的矽智財元件庫；第二我們證明非同步電路設計方式對於製程變異很大的軟性電子製程有穩定的效果；最後，採用提高平行度的多處理器設計，包含一個影像控制單元及兩個數位信號處理器所組成的系統，有效提升了軟性電路的運算速度。
以上所提出的設計技巧及電路架構都已經透過工研院所提供的非晶矽薄膜電晶體製程實作並製作於玻璃基板以及塑膠基板上。實作結果顯示非同步的有限脈衝響應濾波器能夠正常的工作並於10 伏特的工作電壓下達到每秒500 個訊號的處理速度。模擬結果顯示採用多處理器的影像處理系統可以達到1KHz 的操作速度，並能在每個時脈週期同時處理兩筆影像資料。我們相信這些設計經驗及技巧，對往後實作更複雜的軟性數位電路將有很大的幫助。

Flexible electronics is the technique where circuits are designed and fabricated on a flexible substrate, for example, plastic or paper substrates. Display panel is the
most important application of flexible electronics. In many panels, each pixel is drived by a thin-film-transistor(TFT), which are named as active matrix flat panel display. In fact, TFTs are also transistors, and in many panels, they are also used to implement driver circuits on the same glass substrate of pixels. When more and more circuits are designed and integrated on TFT process, a panel becomes a system, which is so-called System-on-Panel (SOP) or System on-Glass (SOG). Besides driver circuits, there are some previous works in the implementation of digital circuits by use of TFT process on the glass substrates and flexible substrates, where CG-silicon TFTs and LTPS TFT technologies are used respectively. Other than these two kinds of TFTs processes, amorphous-silicon (a-Si) TFT is widely used in many large-area electronics as well, such as liquid-crystal-display (LCD). It is worth to consider the circuit design on flexible a-Si TFT technology. In this thesis, an asynchronous FIR filter design and a multi-core image display system using a-Si TFTs process on flexible substrate are proposed. There are three major contributions in this thesis. First, the characteristic of a-Si TFTs on digital circuit design are analyzed, and some basic cell libraries have been built. Second, we also verify that asynchronous circuit design can deal with the problems due
to the flexible process variation. Finally, it is also proved that for the low mobility process, the high parallelism structure, can improve the circuit performance.
Based on this concept, an image display system, which is composed of a image control unit core and several DSP cores, is developed.
The proposed design techniques are verified by ITRI a-Si TFTs process and fabricated on glass substrate and plastic substrate. Implementation results show that the asynchronous FIR filter design can work correctly, and the processing speed is 500 samples/s with 10V supply voltage. Experiential results show that the multicore image display systemcan work at 1KHz and output two pixels per cycle when
executing simple image processing algorithms. We believe that the design experiences described in this thesis can be the base for the larger flexible electronics design in the future.

Contents

Abstract ix

1 Introduction 1
1.1 Introduction.........................................1
1.1.1 What is Flexible Electronics.....................1
1.1.2 Application of Flexible..........................2
1.2 Motivation...........................................2
1.3 Thesis Organization..................................3

2 Basic Concept and RelatedWorks .5
2.1 Basic Concepts.......................................5
2.1.1 Introduction to TFTs.............................5
2.1.2 Some Type of TFTs................................6
2.1.3 Fabrication of Flexible Electronics..............6
2.2 A CPU On A Glass Substrate Using CG-Silicon TFTs.....7
2.3 A Flexible 8b AsynchronousMicroprocessor Based On LTPS TFT Technology........................................8
2.4 Design Challenge....................................10

3 Asynchronous FIR Filter design using a-Si TFTs Process 13
3.1 Why Using Asynchronous Design on Flexible Electronics...............................................13
3.2 Overview of Asynchronous Circuit Design.............14
3.2.1 Muller C-Element................................14
3.2.2 Handshake Protocols.............................15
3.3 FIR Filter Architecture Overview....................17
3.3.1 Asynchronous Control Unit.......................18
3.3.2 Dual-Rail Type Adder............................19
3.3.3 Hybrid Type Design..............................20
3.4 Design Flow for Asynchronous Design.................20
3.4.1 Filter Design...................................20
3.4.2 HDL Simulation..................................22
3.4.3 Spice Simulation................................26
3.4.4 Physical Layout.................................29
3.5 Measurement Result..................................32
3.5.1 Implementation..................................32
3.5.2 Measurement Environment.........................32
3.5.3 Measurement Result..............................33
3.6 Summary.............................................33

4 Image Processing Unit using a-Si TFT process 37
4.1 Hardware System Overview............................37
4.2 Instruction Sets and Operation Mode Switching.......39
4.2.1 Instruction Sets................................39
4.2.2 Operation Mode..................................39
4.3 Architecture Overview...............................44
4.3.1 Image Control Unit Core.........................44
4.3.2 DSP Core Architecture...........................44
4.3.3 Self Checking Design............................48
4.4 Experimental results................................49
4.5 Implementation......................................49
4.5.1 Cell Library For Digital a-Si TFTs Circuit Design....................................................49
4.5.2 Clock Tree Synthesis............................51
4.5.3 Simulation and Test Consideration...............54
4.5.4 Chip Layout and Specification...................55
4.5.5 Design Flow.....................................57
4.5.6 Comparison .....................................57
4.6 Summary.............................................59

5 Conclusions 61

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