Multi-pattern shadow mask system and method for laser annealing

• US 6,727,125 B2
• Filed: 04/17/2002
• Issued: 04/27/2004
• Est. Priority Date: 04/17/2002
• Status: Active Grant

• Current Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Voutsas, Apostolos T., Adachi, Masahiro
• Primary Examiner(s): Whitehead, Jr., Carl
• Assistant Examiner(s): MENZ, LAURA MARY
• Application Number:
  US10/124,853
• Publication Number:
  US 20030199176A1
• Time in Patent Office: 741 Days
• Field of Search: 438/480, 438/53, 438/345, 438/446, 438/386, 438/166, 438/413, 438/585, 438/52, 438/905, 445/3, 445/30, 219/121.62, 219/121.83, 219/121.61, 219/121.65, 427/282, 427/58, 427/96
• US Class Current: 438/166
• CPC Class Codes: B23K 26/066 by using masks
• CPC Class Codes: H01L 21/268 using electromagnetic radiation, e.g. laser radiation
• CPC Class Codes: H01L 21/324 Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering H01L21/20 - H01L21/288 and H01L21/302 - H01L21/322 take precedence
• CPC Class Codes: H01L 27/1285 using control of the annealing or irradiation parameters, e.g. using different scanning direction or intensity for different transistors
• CPC Class Codes: H01L 29/6675 Amorphous silicon or polysilicon transistors

Abstract

A multi-pattern shadow mask, shadow mask laser annealing system, and a multi-pattern shadow mask method for laser annealing are provided. The method comprises: supplying a silicon substrate; supplying a multi-pattern shadow mask with a plurality of aperture patterns; creating substrate alignment marks; with respect to the alignment marks, laser annealing a substrate region in a plurality of aperture patterns; forming a corresponding plurality of polysilicon regions; and, forming a corresponding plurality of transistor channel regions in the plurality of polysilicon regions. Typically, the shadow mask includes a plurality of sections, with each section having at least one aperture pattern. A shadow mask section can be selected to create a corresponding aperture pattern. If the mask section includes a plurality of aperture patterns, the selection of a section creates all the corresponding aperture patterns in the selected section.

Claims

1. A multi-pattern shadow mask method for laser annealing, the method comprising:

creating substrate alignment marks;

with respect to the alignment marks, laser annealing a substrate region in a plurality of aperture patterns, which includes,

laser annealing a first area of a first substrate region with a first aperture pattern;

step-and-repeat laser annealing in a second area, adjacent the first area, in the substrate region; and

,

forming a corresponding plurality of polycrystalline regions which includes laterally growing crystals in response to the step-and repeat laser annealing process.

2. The method of claim 1 further comprising:

forming a corresponding plurality of transistor channel regions in the plurality of polycrystalline regions.

3. The method of claim 1 further comprising:

supplying a silicon substrate; and

,

wherein forming a corresponding plurality of polycrystalline regions includes forming polysilicon regions.

4. The method of claim 3 wherein creating substrate alignment marks includes forming a rectangular substrate region with alignment marks in at least two corners of the substrate region.

5. The method of claim 4 wherein laser annealing in a plurality of aperture patterns includes:

laser annealing a first substrate region with a first aperture pattern; and

,

laser annealing a second substrate region with a second aperture pattern.

6. The method of claim 5 further comprising:

supplying a multi-pattern shadow mask with a plurality of aperture patterns; and

,

wherein laser annealing in a plurality of aperture patterns includes using the shadow mask to create the plurality of aperture patterns.

7. The method of claim 6 wherein supplying a multi-pattern shadow mask with a plurality of aperture patterns includes supplying a shadow mask with a plurality of sections, each section having at least one aperture pattern;

and,

wherein using the shadow mask to create the plurality of aperture patterns includes selecting a shadow mask section to create a corresponding aperture pattern in the substrate.

8. The method of claim 7 wherein supplying a shadow mask with a plurality of sections, each section having at least one aperture pattern, includes supplying a shadow mask with a first section having a first aperture pattern and a second section having a second aperture pattern;

and,

wherein using the shadow mask to create the plurality of aperture patterns includes;

laser annealing with a first aperture pattern in response to using the shadow mask first section; and

,

laser annealing with a second aperture pattern in response to using the shadow mask second section.

9. The method of claim 8 wherein supplying a shadow mask with a plurality of sections, each section having at least one aperture pattern, includes each shadow mask section having a plurality of aperture patterns;

and,

wherein using the shadow mask to create the plurality of aperture patterns includes creating a plurality of aperture patterns in response to using each shadow mask section.

10. The method of claim 9 wherein using the shadow mask to create the plurality of aperture patterns includes:

selecting a first mask section with a plurality of aperture patterns;

using the alignment marks, aligning a substrate region with the first mask;

using the first mask section to step-and-repeat laser anneal regions in the substrate with the plurality of aperture patterns;

selecting a second mask section with a plurality of aperture patterns;

using the alignment marks, aligning a substrate region with the second mask;

using the second mask section to step-and repeat laser anneal regions in the substrate with the plurality of aperture patterns; and

,

wherein forming polycrystalline regions in a plurality of patterns includes;

forming a plurality of polycrystalline patterns in response to laser annealing with the first mask section; and

,

forming a plurality of polycrystalline patterns in response to laser annealing with the second mask section.

11. The method of claim 10 wherein forming a corresponding plurality of transistor channel regions in the plurality of polycrystalline regions includes forming a liquid crystal display (LCD) panel with regions selected from the group including pixel regions, gate driver regions, source driver regions, digital-to-analog converter regions, analog amplifier regions, shift register regions, memory regions, and microprocessor regions.

12. The method of claim 7 wherein supplying a shadow mask with a plurality of sections, each section having at least one aperture pattern, includes supplying a shadow mask with a first section having a first aperture pattern and a second section having a second aperture pattern;

and,

wherein using the shadow mask to create the plurality of aperture patterns includes;

step-and-repeat laser annealing in a first direction on the substrate using the first aperture pattern of the shadow mask first section; and

,

step-and-repeat laser annealing in a second direction, transverse to the first direction, on the substrate using a second aperture of the shadow mask second section.

13. The method of claim 12 further comprising:

supplying a transverse orienting laser beam;

wherein laser annealing in the first direction includes orienting the laser beam in a first orientation; and

,

wherein laser annealing in the second direction includes orienting the laser beam in a second orientation, transverse to the first orientation.

14. A multi-pattern shadow mask method for laser annealing, the method comprising:

supplying a silicon substrate;

supplying a multi-pattern shadow mask with a first section having a plurality of aperture patterns and a second section having a plurality of aperture patterns;

forming rectangular substrate regions with alignment marks in at least two corners of each substrate region;

using the alignment marks, aligning a first substrate region with the shadow mask first section;

with respect to the alignment marks, laser annealing a first plurality of areas in the first substrate region with the shadow mask first section;

step-and-repeat laser annealing in a second plurality of areas, adjacent the first plurality of areas, in the first substrate region;

using the alignment marks, aligning a second substrate region with the shadow mask second section;

laser annealing the second substrate region with the shadow mask second section;

step-and-repeat laser annealing in a second plurality of areas, adjacent the first plurality of areas, in the second substrate region; and

,

forming a plurality of polysilicon patterns in the first and second substrate regions by laterally growing crystals in response to the step-and-repeat laser annealing process.