Thin-film transistor circuit, design method for thin-film transistor, design program for thin-film transistor circuit, design program recording medium, design library database, and display device

1. A design method for a thin-film transistor circuit using a crystallized semiconductor thin film which contains crystal grains regularly grown in a lateral direction by crystallization and larger than a predetermined transistor channel size, the method comprising the steps of:

defining in a computer a crystallization array-pattern representing the arrangement of crystal-grain-defining areas which are arrayed for two dimensional partitioning of the crystallized semiconductor thin film and each of which accommodates one of the crystal grains; and

causing the computer to, on the basis of the crystallization array-pattern, create a device pattern of thin-film transistors each of which has a channel region placed at a position fixed in a corresponding one of the crystal-grain-defining areas and a wiring pattern of wirings which interconnect the thin-film transistors.

2. The design method according to claim 1 , wherein the crystallization array-pattern is configured such that the crystal-grain-defining areas are arrayed in a matrix form and accommodate crystal grains each of which is nearly rectangular in shape.

3. The design method according to claim 2 , further comprising the steps of:

constructing in the computer a library database containing standard cells which represent various logic gate circuits each of which includes two or more thin-film transistors whose channel region is placed at a position fixed in one of the crystal-grain-defining areas, and wirings which interconnect the two or more thin-film transistors; and

causing the computer to refer to the library database on the basis of circuit information input externally, to create the device pattern and the wiring pattern.

4. A design method for a thin-film transistor circuit using a crystallized semiconductor, thin film, the method comprising the steps of;

defining in a computer a crystallization array-pattern representing the arrangement of crystal-grain-defining areas which are arrayed for two-dimensional partitioning of the crystallized semiconductor thin film and each of which accommodates a crystal grain larger than a predetermined size;

causing the computer to, on the basis of the crystallization array-pattern, create a device pattern of thin-film transistors each of which has a channel region placed at a position fixed in a corresponding one of the crystal-grain-defining areas and a wiring pattern of wirings which interconnect the thin-film transistors;

wherein the crystallization array-pattern is configured such that the crystal-grain-defining areas are arrayed in a matrix form and accommodate crystal grains each of which is nearly rectangular in shape;

constructing in the computer a library database containing standard cells which represent various logic gate circuits each of which includes two or more thin-film transistors whose channel region is placed at a position fixed in one of the crystal-grain-defining areas, and wirings which interconnect the two or more thin-film transistor;

causing the computer to refer to the library database on the basis of circuit information input externally, to create the device pattern and the wiring pattern; and

wherein the library database further contains macrocells each of which represents a combination of some of the logic gate circuits.

5. A design method for a thin-film transistor circuit using a crystallized semiconductor thin film, the method comprising the steps of:

defining in a computer a crystallization array pattern representing the arrangement of crystal-grain-defining areas which are arrayed for two dimensional partitioning of the crystallized semiconductor thin film and each of which accommodates a crystal grain larger than a predetermined size;

causing the computer to, on the basis of the crystallization array-pattern, create a device pattern of thin-film transistors each of which has a channel region placed at a position fixed in a corresponding one of the crystal-grain-defining areas and a wiring pattern of wirings which interconnect the thin-film transistors;

wherein the crystallization array-pattern is configured such that the crystal-grain-defining areas are arrayed in a matrix form and accommodate crystal grains each of which is nearly rectangular in shape; and

wherein the thin-film transistors are determined in the device pattern to have a channel length and channel width not exceeding the length of one side of each crystal-grain-defining area.

6. A design method for a thin-film transistor circuit using a crystallized semiconductor thin film, the method comprising the steps of:

defining in a computer a crystallization array pattern representing the arrangement of crystal-grain-defining areas which are arrayed for two dimensional partitioning of the crystallized semiconductor thin film and each of which accommodates a crystal grain larger than a predetermined size;

causing the computer to, on the basis of the crystallization array-pattern, create a device pattern of thin-film transistors each of which has a channel region placed at a position fixed in a corresponding one of the crystal-grain-defining areas and a wiring pattern of wirings which interconnect the thin-film transistors;

wherein the crystallization array-pattern is configured such that the crystal-grain-defining areas are arrayed in a matrix form and accommodate crystal grains each of which is nearly rectangular in shape; and

wherein the thin-film transistors are arranged at intervals of integral multiples of the length of one side of each crystal-grain-defining area.

7. A design method for a thin-film transistor circuit using a crystallized semiconductor thin film, the method comprising the steps of:

defining in a computer a crystallization array pattern representing the arrangement of crystal grain-defining areas which are arrayed for two dimensional partitioning of the crystallized semiconductor thin film and each of which accommodates a crystal grain larger than a predetermined size;

causing the computer to, on the basis of the crystallization array-pattern, create a device pattern of thin-film transistors each of which has a channel region placed at a position fixed in a corresponding one of the crystal-grain-defining areas and a wiring pattern of wirings which interconnect the thin-film transistors;

wherein the crystallization array-pattern is configured such that the crystal-grain-defining areas are arrayed in a matrix form and accommodate crystal grains each of which is nearly rectangular in shape; and

wherein the length, LC, of one side of each crystal-grain-defining area, the dimension, LG, of the larger one of the channel length and channel width of each thin-film transistor, and the alignment tolerance, LA, between the crystallization array-pattern and the device pattern are set so as to satisfy a relationship LC≧(LG+2×LA).

8. A design program for a thin-film transistor circuit using a crystallized semiconductor thin film which contains crystal grains regularly grown in a lateral direction by crystallization and larger than predetermined transistor channel size the program which causes a computer to carry out the processes of:

defining a crystallization array-pattern representing the arrangement of crystal-grain-defining areas which are arrayed for two-dimensional partitioning of the crystallized semiconductor thin film and each of which accommodates one of the crystal grains; and

on the basis of the crystallization array-pattern, creating a device pattern of thin-film transistors each of which has a channel region placed at a position fixed in a corresponding one of the crystal-grain-defining areas and a wiring pattern of wirings which interconnect the thin-film transistors.

9. The design program according to claim 8 , wherein the crystallization array-pattern is configured such that the crystal-grain-defining areas are arrayed in a matrix form and accommodate crystal grains each of which is nearly rectangular in shape.

10. The design program according to claim 8 , which further causes the computer to carry out the processes of:

constructing a library database containing standard cells which represent various logic gate circuits each of which includes two or more thin-film transistors whose channel region is placed at a position fixed in one of the crystal-grain-defining areas, and wirings which interconnect the two or more thin-film transistors; and

referring to the library database on the basis of circuit information input externally, to create the device pattern and the wiring pattern.

11. The design program according to claim 10 , wherein the library database further contains macrocells each representing a combination of some of the logic gate circuits.

12. A recording medium recorded with a design program for a thin-film transistor circuit using a crystallized semiconductor which contains crystal grains regularly grown in a lateral direction by crystallization and larger than a predetermined transistor channel size, and which causes a computer to carry out the processes of:

defining a crystallization array-pattern representing the arrangement of crystal-grain-defining areas which are arrayed for two-dimensional partitioning of the crystallized semiconductor thin film and each of which accommodates a crystal grain larger than a predetermined size; and

on the basis of the crystallization array-pattern, creating a device pattern of thin-film transistors each of which has a channel region placed at a fixed position within a corresponding one of the crystal-grain-defining areas and a wiring pattern of wirings which interconnect the thin-film transistors.

13. The recording medium according to claim 12 , wherein the crystallization array-pattern is configured such that the crystal-grain-defining areas are arrayed in a matrix form and accommodate crystal grains each of which is nearly rectangular in shape.

14. The recording medium according to claim 13 ,

wherein the design program further causes the computer to carry out the processes of:

constructing a library database containing standard cells which represent various logic gate circuits each of which includes two or more thin-film transistors whose channel region is placed at a position fixed in one of the crystal-grain-defining areas, and wirings which interconnect the two or more thin-film transistors; and

referring to the library database on the basis of circuit information input externally, to create the device pattern and the wiring pattern.

15. The recording medium according to claim 14 , wherein the library database further contains macrocells each representing a combination of some of the logic gate circuits.

16. A thin-film transistor circuit comprising:

a crystallized semiconductor thin film which contains crystal grains regularly grown in a lateral direction by crystallization and larger than a predetermined transistor channel size and is two-dimensionally partitioned into crystal-grain-defining areas each of which accommodates one of the crystal grains;

thin-film transistors each of which has a channel region placed at a position fixed in a corresponding one of the crystal-grain-defining areas; and

wirings which interconnect the thin-film transistors.

17. The thin-film transistor circuit according to claim 16 , wherein the thin-film transistors and the wirings form logic gate circuits each of which has a common structure occupying a predetermined number of crystal-grain-defining areas.

18. The thin-film transistor circuit according to claim 16 , wherein the crystal-grain-defining areas are arrayed in a matrix form and accommodate crystal grains each of which is nearly rectangular in shape.

19. A thin-film transistor circuit comprising: p 1 a crystallized semiconductor thin film two-dimensionally partitioned into crystal-grain-defining areas each of which accommodates a crystal grain larger than a predetermined size;

thin-film transistors each of which has a channel region placed at a position fixed in a corresponding one of the crystal-grain-defining areas;

wirings which interconnect the thin-film transistors; and

wherein at least one of the thin-film transistors includes a pair of sub-transistors which have channel regions formed in the surface of crystal grains having identical crystal plane indexes, and are connected in such a way as to have main current directions identical to each other.

20. A display device comprising:

an active-matrix circuit having pixels arrayed in a matrix form;

a drive control circuit connected to the active-matrix circuit; and

a thin-film semiconductor substrate which supports the active-matrix circuit and the drive control circuit;

wherein the drive control circuit includes a thin film transistor circuit comprising a crystallized semiconductor thin film which contains crystal grains regularly grown in a lateral direction by crystallization and larger than a predetermined transistor channel size and is two-dimensionally partitioned into crystal-grain-defining areas each of which accommodates one of the crystal grains; thin-film transistors each of which has a channel region placed at a position fixed in a corresponding one of the crystal-grain-defining areas; and wirings which interconnect the thin-film transistors.