Semiconductor device and fabrication method thereof

• US 7,569,854 B2
• Filed: 06/18/2004
• Issued: 08/04/2009
• Est. Priority Date: 07/06/1999
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Arai, Yasuyuki, Koyama, Jun, Yamazaki, Shunpei
• Primary Examiner(s): Jackson; Jerome
• Assistant Examiner(s): Diaz; Jose R
• Application Number:
  US10/871,621
• Publication Number:
  US 20040222467A1
• Time in Patent Office: 1,873 Days
• Field of Search: 257/59
• US Class Current: 257/59
• CPC Class Codes: G02F 1/13306 Circuit arrangements or driving methods for the control of single liquid crystal cells G02F1/132, G02F1/133382 take precedence
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/13394 spacers regularly patterned on the cell subtrate, e.g. walls, pillars G02F1/133377 takes precedence
• CPC Class Codes: G02F 1/13396 Spacers having different sizes
• CPC Class Codes: G02F 1/13398 Spacer materials; Spacer properties
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/13454 Drivers integrated on the active matrix substrate G02F1/136277 takes precedence
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer
• CPC Class Codes: G02F 1/13624 having more than one switching element per pixel
• CPC Class Codes: G02F 1/136245 having complementary transistors
• CPC Class Codes: G02F 1/136277 formed on a semiconductor substrate, e.g. of silicon
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: H01L 21/0214 the material being a silicon oxynitride, e.g. SiON or SiON:H
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/02208 the precursor containing a compound comprising Si
• CPC Class Codes: H01L 21/02266 deposition by physical ablation of a target, e.g. sputtering, reactive sputtering, physical vapour deposition or pulsed laser deposition
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/02532 : Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02592 : amorphous
• CPC Class Codes: H01L 21/0262 : Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 21/02631 : Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
• CPC Class Codes: H01L 21/02667 : Crystallisation or recrystallisation of non-monocrystalline semiconductor materials, e.g. regrowth
• CPC Class Codes: H01L 21/0273 : characterised by the treatment of photoresist layers
• CPC Class Codes: H01L 21/3065 : Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/3081 : characterised by their composition, e.g. multilayer masks, materials
• CPC Class Codes: H01L 27/12 : the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H01L 27/1214 : comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1218 : with a particular composition or structure of the substrate
• CPC Class Codes: H01L 27/1248 : with a particular composition or shape of the interlayer dielectric specially adapted to the circuit arrangement
• CPC Class Codes: H01L 27/1251 : comprising TFTs having a different architecture, e.g. top- and bottom gate TFTs
• CPC Class Codes: H01L 27/1274 : using crystallisation of amorphous semiconductor or recrystallisation of crystalline semiconductor
• CPC Class Codes: H01L 27/1288 : employing particular masking sequences or specially adapted masks, e.g. half-tone mask
• CPC Class Codes: H01L 29/167 : further characterised by the doping material H01L29/1604 takes precedence
• CPC Class Codes: H01L 29/66742 : Thin film unipolar transistors
• CPC Class Codes: H01L 29/66757 : Lateral single gate single channel transistors with non-inverted structure, i.e. the channel layer is formed before the gate
• CPC Class Codes: H01L 29/7833 : with lightly doped drain or source extension, e.g. LDD MOSFET's; DDD MOSFET's for thin film transistors H01L29/78618
• CPC Class Codes: H01L 29/78621 : with LDD structure or an extension or an offset region or characterised by the doping profile
• CPC Class Codes: H01L 29/78672 : Polycrystalline or microcrystalline silicon transistor
• CPC Class Codes: H01L 29/78675 : with normal-type structure, e.g. with top gate
• CPC Class Codes: Y10S 438/919 : Compensation doping

Abstract

A p channel TFT of a driving circuit has a single drain structure and its n channel TFT, an LDD structure. A pixel TFT has the LDD structure. A pixel electrode disposed in a pixel unit is connected to the pixel TFT through a hole bored in at least a protective insulation film formed of an inorganic insulating material and formed above a gate electrode of the pixel TFT, and in an inter-layer insulation film disposed on the insulation film in close contact therewith. These process steps use 6 to 8 photo-masks.

Claims

1. A semiconductor device comprising:

a pixel TFT provided over a substrate and comprising a channel formation region, an n type impurity region having a first concentration, disposed in contact with the channel formation region and forming an LDD region, and an n type impurity region for forming a source region or a drain region, having a second concentration and disposed outside the n type impurity region having the first concentration;

a p channel type TFT of a driving circuit provided over the substrate and comprising a channel formation region and a p type impurity region having a third concentration, for forming a source region or a drain region;

an n channel type TFT of the driving circuit provided over the substrate and comprising a channel formation region, an n type impurity region having the first concentration, disposed in contact with the channel formation region and forming an LDD region, and an n type impurity region for forming a source region or a drain region, having the second concentration and disposed outside the n type impurity region having the first concentration;

a protective insulation film provided over a gate electrode of the pixel TFT;

an inter-layer insulation film provided over the protective insulation film and comprising an organic resin to provide a level surface over the pixel TFT; and

a pixel electrode having a light reflecting surface and provided over the inter-layer insulation film and connected to the pixel TFT through a first hole bored in at least the protective insulation film and the inter-layer insulation film,

wherein the p channel type TFT of the driving circuit has an offset region formed between the channel formation region and the p type impurity region having the third concentration, for forming the source region or the drain region, and

wherein a columnar spacer is formed over a second hole bored in at least the protective insulation film and the inter-layer insulation film in the driving circuit.

2. A semiconductor device according to claim 1, wherein a gate electrode of each of the pixel TFT and the n-channel type TFT and the p channel type TFT of the driving circuit comprises a heat-resistant conductive material, and a gate lead wire extending from the driving circuit and connected to the gate electrode is formed of a low resistance conductive material.

3. A semiconductor device according to claim 2, wherein the heat-resistant conductive material is an element selected from tantalum (Ta), titanium (Ti), molybdenum (Mo) and tungsten (W), or a compound consisting of the element as the principal component, or a compound comprising the combination of elements, or a nitride consisting of the element as a component or a silicide consisting of the element as a component.

4. An electronic apparatus according to claim 1, wherein the semiconductor device is one selected from the group consisting of a personal computer, a video camera, a portable information terminal a digital camera, a digital video disk player, an electronic game machine and a projector.

5. A semiconductor device according to claim 1, wherein the p channel type TFT of the driving circuit is used as at least an analog switch.

6. A semiconductor device according to claim 1, wherein the protective insulation film comprises a silicon oxide nitride.

7. A semiconductor device according to claim 1, wherein the columnar spacer is formed over at least one of the p channel type TFT and the n channel type TFT of the driving circuit.

8. A semiconductor device according to claim 1, wherein the columnar spacer is so formed as to cover at least one of a source lead wire and a drain lead wire of at least one of the p channel type TFT and the n channel type TFT of the driving circuit.

9. A semiconductor device having a liquid crystal sandwiched between a pair of substrates, wherein:

one of the substrates has a pixel TFT of a pixel unit and a p channel type TFT and an n channel type TFT of a driving circuit;

the p channel type TFT of the driving circuit has a channel formation region and a p type impurity region having a third concentration, for forming a source region or a drain region;

each of the n channel type TFT of the driving circuit and the pixel TFT has a channel formation region, an n type impurity region having a first concentration, disposed in contact with the channel formation region and forming an LDD region, and an n type impurity region for forming a source region or a drain region, having a second concentration and disposed outside the n type impurity region having the first concentration;

each of pixel electrodes disposed in the pixel unit has a light reflecting surface and is formed on an inter-layer insulation film comprising an organic insulating material and is connected to the pixel TFT through a hole bored in at least a protective insulation film comprising an inorganic insulating material and disposed above a gate electrode of the pixel TFT and the inter-layer insulation film formed on the protective insulation film;

the one substrate is bonded to the other of the substrates having a transparent conductor film formed thereover through at least one columnar spacer formed to be in superposition with the hole; and

the p channel type TFT of the driving circuit has an offset region formed between the channel formation region and the p type impurity region having the third concentration, for forming the source region or the drain region.

10. A semiconductor device according to claim 9, wherein the gate of each of the pixel TFT and the n-channel type TFT and the p channel type TFT of the driving circuit is formed of a heat-resistant conductive material, and a gate lead wire extending from the driving circuit and connected to the gate electrode is formed of a low resistance conductive material.

11. A semiconductor device according to claim 10, wherein the heat-resistant conductive material is an element selected from tantalum (Ta), titanium (Ti), molybdenum (Mo) and tungsten (W), or a compound consisting of the element as the principal component, or a compound comprising the combination of the elements, or a nitride consisting of the element as a component or a silicide consisting of the element as a component.

12. A semiconductor device according to claim 9, further comprising a columnar spacer formed over at least one of the p channel type TFT and the n channel type TFT of the driving circuit.

13. A semiconductor device according to claim 9, further comprising a columnar spacer formed as to cover at least one of a source lead wire and a drain lead wire of at least one of the p channel type TFT and the n channel type TFT of the driving circuit.

14. An electronic apparatus according to claim 9, wherein the semiconductor device is one selected from the group consisting of a personal computer, a video camera, a portable information terminal, a digital camera, a digital video disk player, an electronic game machine and a projector.

15. A semiconductor device according to claim 9, wherein the p channel type TFT of the driving circuit is used as at least an analog switch.