Alignment mark structure

1. A semiconductor substrate having an upper layer and an alignment mark structure formed on a surface region of the upper layer, the surface region defined by opposite first and second parallel sides extending along the upper layer, wherein the alignment mark structure comprises:

a first outer side wall extending upwardly from the upper layer and extending lengthwise along the first side of the surface region, wherein the first outer side wall is defined lengthwise by alternating first and second wall portions, wherein each of the first wall portions is spaced farther from the first side of the surface region than each of the second wall portions;

a second outer side wall extending upwardly from the upper layer and extending lengthwise along the second side of the surface region, wherein the second outer side wall is defined lengthwise by alternating third and fourth wall portions, wherein each of the third wall portions is spaced farther from the second side of the surface region than each of the fourth wall portions; and

an alignment pattern defined by openings in the alignment mark structure located between the first and second outer side walls,

wherein the alignment mark structure has a continuous periphery.

2. The semiconductor substrate as claimed in claim 1 , wherein the alignment pattern is defined by plural sub-patterns, wherein each sub-pattern includes plural regularly spaced and elongate openings extending lengthwise in a direction parallel to each other.

3. The semiconductor substrate as claimed in claim 2 , wherein the plural sub-patterns are spaced apart and aligned between the first and second outer side walls.

4. The semiconductor substrate as claimed in claim 3 , wherein plural openings of each sub-pattern extend lengthwise at a right angle relative to the plural openings of each adjacent sub-pattern.

5. The semiconductor substrate as claimed in claim 4 , wherein the plural openings of each sub-pattern extend either parallel to or perpendicular to the first and second sides of the surface region of the semiconductor substrate.

6. The semiconductor substrate as claimed in claim 1 , wherein the surface region of the upper layer is located within a grid line formed in a surface of the semiconductor substrate.

7. A semiconductor substrate having an upper layer and an alignment mark structure formed on a surface region of the upper layer, the surface region defined by opposite first and second parallel sides extending along the upper layer, wherein the alignment mark structure comprises:

a first outer side wall extending upwardly from the upper layer and extending lengthwise along the first side of the surface region;

a second outer side wall extending upwardly from the upper layer and extending lengthwise along the second side of the surface region; and

an alignment pattern defined by openings in the alignment mark structure located between the first and second outer side walls, wherein at least one of the openings is an elongate opening extending lengthwise in a first direction parallel to the first and second sides of the surface region of the upper layer,

wherein the first outer side wall is configured such that a first distance in a second direction between a first elongate portion of the elongate opening and the first outer side wall is smaller than a second distance in the second direction between a remaining second elongate portion of the elongate opening and the first outer side wall,

wherein the alignment mark structure has a continuous periphery.

8. The semiconductor substrate as claimed in claim 7 , wherein a difference between the first and second distances is within a range of 5 μm to 10 μm.

9. The semiconductor substrate as claimed in claim 7 , wherein the alignment pattern is defined by plural sub-patterns, wherein each sub-pattern includes plural regularly spaced and elongate openings extending lengthwise in a direction parallel to each other.

10. The semiconductor substrate as claimed in claim 9 , wherein the plural sub-patterns are spaced apart and aligned between the first and second outer side walls.

11. The semiconductor substrate as claimed in claim 10 , wherein plural openings of each sub-pattern extend lengthwise at a right angle relative to the plural openings of each adjacent sub-pattern.

12. The semiconductor substrate as claimed in claim 11 , wherein the plural openings of each sub-pattern extend either parallel to or perpendicular to the first and second sides of the surface region of the semiconductor substrate.

13. The semiconductor substrate as claimed in claim 7 , wherein the surface region of the upper layer is located within a grid line formed in a surface of the semiconductor substrate.