1. A fast-search adaptive motion accuracy search method for estimating motion vectors in motion-compensated video coding by finding a best motion vector for a macroblock, said method comprising the steps of:
(a) searching a first set of motion vector candidates in a grid of sub-pixel resolution of a predetermined square radius centered on V1 to find a best motion vector V2 using a first criteria;
(b) searching a second set of motion vector candidates in a grid of sub-pixel resolution of a predetermined square radius centered on V2 to find a best motion vector V3 using a second criteria;
(c) searching a third set of motion vector candidates in a grid of sub-pixel resolution of a predetermined square radius centered on V3 to find said best motion vector of said macroblock using a third criteria; and
(d) wherein at least one of said first criteria, said second criteria, and said third criteria is a rate-distortion criteria.
2. The method of claim 1, said step of searching a first set of motion vector candidates in a grid of sub-pixel resolution of a predetermined square radius centered on V1 to find a best motion vector V2 further comprising the step of searching a first set of eight motion vector candidates in a grid of \xbd-pixel resolution of square radius 1 centered on V1 to find a best motion vector V2.
3. The method of claim 1, said step of searching a second set of motion vector candidates in a grid of sub-pixel resolution of a predetermined square radius centered on V2 to find a best motion vector V3 further comprising the step of searching a second set of eight motion vector candidates in a grid of \u2159-pixel resolution of square radius 1 centered on V2 to find a best motion vector V3.
4. The method of claim 1 further comprising the steps of using V2 as the motion vector for the macroblock if V2 has the smallest rate-distortion cost and skipping step (c) of claim 1.
5. The method of claim 1, said step of searching a third set of motion vector candidates in a grid of sub-pixel resolution of a predetermined square radius centered on V3 to find said best motion vector of said macroblock further comprising the step of searching a third set of eight motion vector candidates in a grid of \u2159-pixel resolution of square radius 1 centered on V3 to find said best motion vector of said macroblock.
6. The method of claim 1, said step of searching a third set of motion vector candidates in a grid of sub-pixel resolution of a predetermined square radius centered on V3 to find said best motion vector of said macroblock further comprising the step of skipping motion vector candidates of said third set of motion vector candidates that have already been tested.
7. The method of claim 1 further wherein said step of searching said first set of motion vector candidates further comprises the step of searching said first set of motion vector candidates using a first filter to do a first interpolation, said step of searching said second set of motion vector candidates further comprises the step of searching said second set of motion vector candidates using a second filter to do a second interpolation, and said step of searching said third set of motion vector candidates further comprises the step of searching said third set of motion vector candidates using a third filter to do a third interpolation.
8. The method of claim 1, said step of searching a second set of motion vector candidates in a grid of sub-pixel resolution of a predetermined square radius centered on V2 to find a best motion vector V3 further comprising the steps of:
(a) searching three candidates of \u2153-pel accuracy V2 and a \xbd-pel location with the next lowest rate-distortion cost if V2 is at the center;
(b) searching four vector candidates of \u2153-pel accuracy that are closest to V2 if V2 is a corner vector; and
(c) determining which of two corners has lower rate-distortion cost and searching four vector candidates of \u2153-pel accuracy that are closest to a line between said corner with lower rate-distortion cost, if V2 is between two corners vectors.
9. An adaptive motion accuracy search method for estimating motion vectors in motion-compensated video coding by finding a best motion vector for a macroblock, said method comprising the steps of:
(a) searching a first set of motion vector candidates in a grid centered on V1 using a first criteria to find a best motion vector V2 using a first filter to do a first interpolation;
(b) searching a second set of motion vector candidates in a grid centered on V2 using a second criteria to find a best motion vector V3 using a second filter to do a second interpolation; and
(c) searching a third set of motion vector candidates in a grid centered on V3 using a third criteria to find said best motion vector of said macroblock using a third filter to do a third interpolation;
(d) wherein at least one of said first criteria, said second criteria, and said third criteria is a rate-distortion criteria.
10. The method of claim 9 wherein said step of searching using a first filter to do a first interpolation further comprises using a simple filter to do a coarse interpolation.
11. The method of claim 9 wherein said step of searching using a first filter to do a first interpolation further comprises using a simple filter to do a coarse interpolation and said step of searching using a second filter to do a second interpolation further comprises using a complex filter to do a fine interpolation.
12. The method of claim 11 wherein said step of searching using a third filter to do a third interpolation further comprises using a complex filter to do a fine interpolation.
13. The method of claim 9 wherein said step of searching using a first filter to do a first interpolation further comprises using a bilinear filter to interpolate the reference frame by 2\xd72.
14. The method of claim 9 wherein said step of searching using a first filter to do a first interpolation further comprises using a bilinear filter to interpolate the reference frame by 2\xd72 and said step of searching using a second filter to do a second interpolation further comprises using a cubic filter to do a fine interpolation.
15. The method of claim 14 wherein said step of searching using a third filter to do a third interpolation further comprises using a cubic filter to do a fine interpolation.
16. An adaptive motion accuracy search method for estimating motion vectors in motion-compensated video coding by finding a best motion vector for a macroblock, said method comprising the steps of:
(a) searching at a first motion accuracy for a first best motion vector of said macroblock;
(b) encoding said first best motion vector and said first motion accuracy;
(c) searching for at least one second best motion vector of said macroblock at an at least one second motion accuracy;
(d) encoding said at least one second best motion vector and said at least one second motion accuracy; and
(e) selecting the best motion vector of said first and at least one second best motion vectors using rate-distortion criteria.
17. The method of claim 16 wherein said step of selecting the best motion vector using rate-distortion criteria further comprises the step of said rate-distortion criteria adapting according to the different motion accuracies to determine both the best motion vectors and the best motion accuracies.
18. The method of claim 16, said step of searching for at least one second best motion vector at an at least one second motion accuracy further comprising the step of searching for at least one second best motion vector of said macroblock at an at least one second motion accuracy that is finer than said first motion accuracy.
19. The method of claim 16 wherein said step of selecting the best motion vector using rate-distortion criteria further comprises the step of using rate-distortion criteria of the type \u201cdistortion+L*Bits\u201d to select the best motion vector.
20. An adaptive motion accuracy search method for estimating motion vectors in motion-compensated video coding by finding a best motion vector for a macroblock, said method comprising the steps of:
(a) searching at a motion accuracy for a best motion vector of said macroblock using rate-distortion criteria;
(b) encoding said motion accuracy using a code from a VLC table that is interpreted differently at different coding units according to the associated motion vector accuracy; and
(c) encoding said best motion vector in the respective accuracy space.
21. A system for estimating motion vectors in motion-compensated video coding by finding a best motion vector for a macroblock, said system comprising:
(a) a first encoder for searching a first set of motion vector candidates in a grid of sub-pixel resolution of a predetermined square radius centered on V1 using a first criteria to find a best motion vector V2;
(b) a second encoder for searching a second set of motion vector candidates in a grid of sub-pixel resolution of a predetermined square radius centered on V2 using a second criteria to find a best motion vector V3; and
(c) a third encoder for searching a third set of motion vector candidates in a grid of sub-pixel resolution of a predetermined square radius centered on V3 using a third criteria to find said best motion vector of said macroblock;
(d) wherein at least one of said first criteria, said second criteria, and said third criteria is a rate-distortion criteria.
22. The system of claim 21 wherein said first, second, and third encoders are a single encoder.
23. A fast-search adaptive motion accuracy search method for estimating motion vectors in motion-compensated video coding by finding a best motion vector for a macroblock, said method comprising the steps of:
(a) searching a first set of motion vector candidates in a grid of sub-pixel resolution of a predetermined square radius centered on V1 to find a best motion vector V2;
(b) searching a second set of motion vector candidates in a grid of sub-pixel resolution of a predetermined square radius centered on V2 to find a best motion vector V3;
(c) searching a third set of motion vector candidates in a grid of sub-pixel resolution of a predetermined square radius centered on V3 to find said best motion vector of said macroblock, and
(d) using V2 as the motion vector for the macroblock if V2 has the smallest rate-distortion cost and skipping step (c).
24. The method of claim 1, wherein said first criteria, said second criteria, and said third criteria are all rate-distortion criteria.
25. The method of claim 9, wherein said first criteria, said second criteria, and said third criteria are all rate-distortion criteria.
26. The system of claim 21, wherein said first criteria, said second criteria, and said third criteria are all rate-distortion criteria.
27. A motion compensated video coding apparatus comprising:
a motion compensation means for compensating a motion, block by block, using the motion vector, that represents an amount of movement from a corresponding position of a reference frame to an objective current block, for each of the blocks divided from a frame of an input image, with two or more fractional accuracy levels expressed by 1N pel (N is an arbitrary integer); and
an encoding means for encoding the fractional accuracy level and the motion vector, wherein
encoding the fractional accuracy level is performed separately from encoding the motion vector,
encoding the motion vector for each block is performed block by block,
the motion compensation is performed by interpolation with a first filter which is selected among a plurality of different interpolation filters corresponding to a first fractional accuracy level of the two or more fractional accuracy levels,
the motion compensation is performed by interpolation with a second filter that requires more complicated calculation than that for the first filter and is selected among the plurality of different interpolation filters corresponding to a second fractional accuracy level that is more accurate than the first fractional accuracy level of the two or more fractional accuracy levels, and
the fractional accuracy level can be set frame by frame and is fixed for every motion vector within a frame but can be different from the fractional accuracy level used for a different frame.
28. A motion compensated video decoding apparatus comprising:
a decoding means for decoding a motion vector that represents an amount of movement from a corresponding position of a reference frame in an objective current block for each of the blocks included in the coded data obtained by encoding an image frame block by block;
a decoding means for decoding a fractional accuracy level of a motion vector with two or more fractional accuracy levels expressed by 1N pel (N is an arbitrary integer); and
a motion compensation means for compensating a motion using the decoded fractional accuracy level and the decoded motion vectors, wherein
decoding the fractional accuracy level is performed separately from decoding the motion vector,
decoding the motion vector for each block is performed block by block,
the motion compensation is performed by interpolation with a first filter which is selected from among a plurality of different interpolation filters corresponding to a first fractional accuracy level of the two or more fractional accuracy levels,
the motion compensation is performed by interpolation with a second filter that requires more complicated calculation than that for the first filter and is selected among the plurality of different interpolation filters corresponding to a second fraction accuracy level that is more accurate than the first fractional accuracy level of the two or more fraction accuracy levels, and
the fractional accuracy level can be set frame by frame and is fixed for every motion vector within a frame but can be different from the fractional accuracy level used for a different frame.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for fabricating a semiconductor device, comprising:
etching a substrate to form trenches that separate active regions;
forming an insulation layer having an opening to open a portion of a sidewall of each active region;
forming a silicon layer pattern to gap-fill a portion of each trench and cover the opening in the insulation layer;
forming a metal layer over the silicon layer pattern; and
forming a metal silicide layer as buried bit lines, wherein the metal silicide layer is formed when the metal layer reacts with the silicon layer pattern.
2. The method of claim 1, wherein the forming of the silicon layer pattern comprises:
forming a silicon layer over the insulation layer to gap-fill the trenches; and
etching the silicon layer, wherein the etched silicon layer covers the opening.
3. The method of claim 1, wherein the forming of the silicon layer pattern comprises:
forming a silicon layer having a seam within the silicon layer, wherein the silicon layer gap-fills the trenches; and
etching the silicon layer to etch an upper portion of the seam, wherein the etched silicon layer covers the opening.
4. The method of claim 3, wherein the silicon layer is deposited at a temperature ranging from 600\xb0 C. to 900\xb0 C.
5. The method of claim 1, wherein the forming of the silicon layer pattern comprises:
forming a silicon layer over the insulation layer to gap-fill the trenches;
performing a primary etch process on the silicon layer;
forming spacers on sidewalls of the insulation layer after the primary etch process; and
performing a secondary etch process on the silicon layer by using the spacers as an etch barrier.
6. The method of claim 5, wherein the silicon layer pattern has a U-shaped cavity after the secondary etch process.
7. The method of claim 1, wherein the forming of the silicon layer pattern comprises:
depositing a silicon layer through an atomic layer deposition (ALD) process or a chemical vapor deposition (CVD) process; and
etching the silicon layer.
8. The method of claim 1, wherein the silicon layer pattern includes a polysilicon layer.
9. The method of claim 1, wherein the metal layer includes one selected from the group consisting of cobalt (Co), titanium (Ti), tantalum (Ta), nickel (Ni), tungsten (W), platinum (Pt), and palladium (Pd).
10. The method of claim 1, wherein the forming of the metal silicide layer is performed using a rapid thermal annealing (RTA) method.
11. The method of claim 1, further comprising removing a remained portion of the metal layer, which is not reacted with the silicon layer pattern, after the forming of the metal silicide layer.
12. A method for fabricating a semiconductor device, comprising:
etching a substrate to form trenches that separate active regions;
forming an insulation layer having an opening to open a portion of a sidewall of each active region;
forming a silicon layer over the insulation layer to gap-fill a portion of each trench and cover the opening in the insulation layer;
forming spacers on portions of sidewalls of the insulation layer;
etching the silicon layer by using the spacers as an etch barrier;
forming a metal layer over the etched silicon layer; and
forming a metal silicide layer as buried bit lines, wherein the metal silicide layer is formed when the metal layer reacts with the silicon layer.
13. The method of claim 12, wherein the forming of the spacers comprises:
forming a spacer layer to be used as the spacers over the portions of the sidewalls of the insulation layer; and
performing an etch-back process on the spacer layer.
14. The method of claim 12, wherein the spacers comprise one selected from the group consisting of an insulation layer, a metal layer, and a metal nitride layer.
15. The method of claim 12, wherein the spacers comprise one selected from the group consisting of a silicon layer, a silicon oxide layer, a silicon nitride layer, TiN, TiAlN, TiW, TiO2, WSi2, WN, TaN, TaW and Ta2O5.
16. The method of claim 12, wherein in the forming of the silicon layer, the silicon layer comprises a polysilicon layer.
17. The method of claim 12, wherein the silicon layer is deposited through an atomic layer deposition (ALD) process or a chemical vapor deposition (CVD) process.
18. The method of claim 12, wherein the metal layer comprises one selected from the group consisting of cobalt (Co), titanium (Ti), tantalum (Ta), nickel (Ni), tungsten (W), platinum (Pt), and palladium (Pd).
19. The method of claim 12, wherein the forming of the metal silicide layer comprises:
performing a primary annealing process to react the metal layer with the silicon layer;
removing a remained portion of the metal layer, which is not reacted with the silicon layer; and
performing a secondary annealing process.
20. The method of claim 12, wherein the metal silicide layer comprises a cobalt silicide layer.
21. The method of claim 12, wherein the forming of the metal silicide layer is performed using a rapid thermal annealing (RTA) method.
22. The method of claim 12, wherein the forming of the metal silicide layer comprises:
performing an annealing process to react the metal layer with the silicon layer; and
removing the metal layer.
23. The method of claim 12, further comprising:
removing the spacers after the forming of the metal silicide layer.
24. The method of claim 12, wherein after the etching of the silicon layer by using the spacers as the etch barrier,
the silicon layer remains on the bottom and sidewalls of each trench and fills the opening.
25. The method of claim 12, wherein after the etching of the silicon layer by using the spacers as the etch barrier,
the silicon layer remains on sidewalls of each trench and fills the opening.
26. The method of claim 12, wherein after the etching of the silicon layer by using the spacers as the etch barrier, the etched silicon layer has a cavity.