CN111477610A

CN111477610A - Alignment structure

Info

Publication number: CN111477610A
Application number: CN202010315379.0A
Authority: CN
Inventors: 陈彦烨; 杨翔甯; 吴志凌; 彭钰雅
Original assignee: Chuangchuang Display Technology Co ltd
Current assignee: Chuangchuang Display Technology Co ltd
Priority date: 2020-04-21
Filing date: 2020-04-21
Publication date: 2020-07-31
Anticipated expiration: 2040-04-21
Also published as: CN111477610B

Abstract

The invention provides an alignment structure, which comprises a substrate, an alignment part and an extension part. The alignment part is arranged on the substrate, the extension part is arranged on the substrate, at least part of the extension part surrounds the alignment part, and a gap is formed between the extension part and the alignment part. Wherein one side of the extension part close to the alignment part and one side of the alignment part close to the extension part are conformal with each other.

Description

Alignment structure

Technical Field

The present invention relates to an alignment structure.

Background

Alignment structures (Alignment structures or Alignment keys) play an important role in processes such as photolithography (photolithography) Alignment, and generally, the Alignment structures are fabricated by directly plating metal or etching a pattern, but after some processes, the metal or the pattern is not visible, or the height difference between the Alignment structure and its peripheral structure causes the photoresist coating on the periphery of the Alignment structure to be thinner, and the uneven coating causes color difference, which causes the misalignment of the identification of the Alignment structure, thereby causing poor yield.

Disclosure of Invention

The invention aims at an alignment structure, and the problem of uneven photoresist coating is avoided by utilizing an extension part.

According to an embodiment of the present invention, an alignment structure is provided, which includes a substrate, an alignment portion, and an extension portion. The alignment part is arranged on the substrate, the extension part is arranged on the substrate, at least part of the extension part surrounds the alignment part, and a gap is formed between the extension part and the alignment part. Wherein a side of the extension portion near the alignment portion and a side of the alignment portion near the extension portion are conformal (conformal) with each other.

Based on the above, compared with the existing alignment structure, the alignment structure provided in the embodiment of the present invention further includes an extension portion, so as to prevent the periphery of the alignment portion for lithography alignment from being thinner, and prevent the occurrence of chromatic aberration at the position from affecting the identification of the alignment portion.

Drawings

FIG. 1A is a plan view of an alignment structure after photoresist coating according to a first embodiment of the present invention.

FIG. 1B is a cross-sectional view taken along the dashed line II-II' of FIG. 1A.

FIG. 1C is a plan view of an alignment structure after photoresist coating according to an embodiment of the invention.

FIG. 1D is a cross-sectional view of an alignment structure after photoresist coating according to one embodiment of the invention.

Fig. 1E is a plan view illustrating an arrangement of the alignment portion and the extension portion according to an embodiment of the invention.

Fig. 2 is a cross-sectional view of an alignment structure according to a second embodiment of the present invention.

Fig. 3 is a cross-sectional view of an alignment structure according to a third embodiment of the present invention.

Description of reference numerals:

100,200,300,400: an alignment structure;

101,201,301,401: a substrate;

205: a light resistance;

102,202,302,402,502,602: an alignment section;

103,203,303,403,503,603: an extension portion;

104,204,304,404: a void;

206: outside the extension portion.

Detailed Description

Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings and the description to refer to the same or like parts.

Referring to fig. 1A and 1B, fig. 1A is a plan view of an alignment structure after coating a photoresist according to a first embodiment of the invention, and fig. 1B is a cross-sectional view taken along a dashed line II-II' of fig. 1A.

According to the first embodiment of the present invention, the alignment structure 200 includes a substrate 201, an alignment portion 202, and an extension portion 203. The alignment portion 202 is disposed on the substrate 201, the extension portion 203 is disposed on the substrate 201, and the extension portion 203 at least partially surrounds the alignment portion 202 and is spaced from the alignment portion 202 by a gap 204. One side of the extending portion 203 close to the aligning portion 202 and one side of the aligning portion 202 close to the extending portion 203 are conformal (conformal), that is, as shown in fig. 1A, one side of the aligning portion 202 close to the extending portion 203 is in a cross shape, and one side of the extending portion 203 close to the aligning portion 202 is also in a cross shape.

Referring to fig. 1B, it can be seen that the photoresist 205 is not thinly coated over the gap 204 between the alignment portion 202 and the extension portion 203, but only the photoresist 205 is thinly coated outside the extension portion 203 (as shown in the dotted line in fig. 1B). In contrast, in the absence of the extension portion 203, the photoresist coating on the outer side of the alignment portion 202 is thin, and when performing photolithography alignment, the coating is thin, which causes color difference, and thus accurate alignment is not possible. Therefore, when the alignment structure 200 provided in this embodiment is viewed in a plan view (fig. 1A), the side of the alignment portion 202 adjacent to the gap 204 and the side of the extension portion 203 do not have color difference, but only have color difference at the extension portion outer side 206 (the extension portion outer side 206 shows color difference in fig. 1A as a black dot), especially in a conformal case, the photoresist coating at the outer side of the alignment portion 202 can be more uniform, and the shape of the alignment portion 202 near the extension portion 203 (i.e. the "outline" of the alignment portion 202 when viewed in a plan view) can be clearly displayed, so that the alignment can be accurately performed. In particular, the substrate 201 may be a temporary substrate, such as a silicon substrate, a plastic substrate, a glass substrate, or a sapphire substrate. The alignment structure 200 provides alignment recognition of a photolithographic process during the fabrication of semiconductor devices. The alignment portion, the extension portion and the substrate may have an adhesive layer therebetween, so that the alignment portion can be accurately aligned with the extension portion as an aid when the alignment portion is not clear due to the adhesive layer.

It should be noted that although the extension 203 in fig. 1A is completely disposed around the alignment portion 202, the present invention is not limited thereto, and the extension may only partially surround the alignment portion, as shown in fig. 1C, the alignment structure 100 includes the substrate 101, the alignment portion 102, and the extension 103 partially surrounds the alignment portion 102, and it can be seen that although a color difference indicated by a black dot occurs at the periphery of the extension 103 and a partial contour of the alignment portion 102, a gap 104 is formed between the contour of the other portion of the alignment portion 102 and the extension 103, so that the contour of the portion is clearly presented without the color difference, and thus, the alignment error can be avoided.

Referring to fig. 1B again, the height of the extension portion 203 in the normal direction of the substrate 201 is equal to the height of the alignment portion 202, but the invention is not limited thereto, and referring to fig. 1D correspondingly, in fig. 1D, the height of the extension portion 503 is greater than the height of the alignment portion 502, the photoresist coating of the alignment portion 502 is more uniform, the color difference is not easy to occur, and the definition of the profile of the alignment portion 502 is better. Preferably, the height ratio of the alignment portion and the extension portion in the normal direction of the substrate falls within the range of 0.5 to 1, the height difference between the alignment portion and the extension portion is less than 1 μm, the height of the extension portion 203 is less than or equal to 20 μm, and a recognition error may occur if the height ratio of the extension portion is greater than 20 um.

Referring to fig. 1B again, the width a of the extension portion 203 in the direction perpendicular to the normal of the substrate 201 is smaller than the width W of the alignment portion 202 in the direction, so as to prevent the extension portion 203 from occupying too much space in the direction and interfering with the alignment operation. Preferably, the width ratio (a/W) of the extension portion 203 to the alignment portion 202 in this direction is 0.2 or more and 10 or less. The effect of photoresist coating uniformity less than 0.2 is not sufficient, and more than 10 takes up too much space. However, in an embodiment not shown, the width a of the extension portion 203 in a direction perpendicular to the normal of the substrate 201 may be larger than the width W of the alignment portion 202 in the direction, and is not limited herein. In addition, in the direction perpendicular to the normal of the substrate 201, the width a of the extension portion 203 and the width B of the void 204 satisfy the following relation, so as to improve the uniformity of the photoresist coating without occupying too much space for the extension portion 203 and the void 204:

5μm≤A；

0.001μm<B<50μm

further, in fig. 1A, the side of the extension portion 203 away from the alignment portion 202 is a quadrangle, not a cross pattern, that is, the side of the extension portion 203 away from the alignment portion 202 and the alignment portion 202 are irregular with each other, which is to avoid that the extension portion 203 is mistaken for the alignment portion 202 when performing the photolithography alignment. However, the present invention is not limited thereto, and referring to fig. 1E, the side of the extension 603 near the alignment part 602 is a quadrangle, instead of a cross pattern like the contour of the alignment part 602, i.e., the side of the extension near the alignment part and the side of the alignment part near the extension part may also be shaped. The shape of the alignment portion is not necessarily a cross, but may be a polygon such as a diamond, a square, etc., which is sufficient for alignment, and the invention is not limited thereto.

According to an embodiment of the present invention, the extension portion may include a semiconductor material, a metal, a dielectric material, an organic material, or a material constituting the alignment portion to simplify the process and increase the yield. Preferably, the alignment portion and the extension portion are formed in the same process.

In fig. 1A and 1B, the void 204 may be filled with a material different from the alignment portion 202 and the extension portion 203, for example, a metal, and in such a case, the characteristic that the material reflectivity in the void 204 is different from the material reflectivity of the alignment portion 202 and the extension portion 203 can be utilized to improve the recognition degree of the profile of the alignment portion 202.

Referring next to fig. 2, a cross-sectional view of an alignment structure 300 according to a second embodiment of the present invention is shown. In the second embodiment, only the portions different from the first embodiment will be described for the convenience of understanding the concept of the present invention, and the portions identical or similar to those of the first embodiment will not be described again.

In fig. 2, the widths of the alignment portion 302 and the extension portion 303 in the direction perpendicular to the normal line of the substrate 301 increase with distance from the substrate 301, and are each formed in an inverted trapezoidal shape, and the width of the void 304 in this direction decreases with distance from the substrate 301.

According to the present embodiment, the ratio of the minimum width B 'and the maximum width E of the gap 304 in the direction perpendicular to the normal of the substrate 301 is greater than or equal to 0.3 and less than 1, because if the minimum width B' of the gap 304 is too small, the photoresist will not be able to stably fill the bottom of the gap 304 when coating the photoresist. According to the present embodiment, the minimum value B' of the width of the gap 304 is greater than 0.001 μm and less than 50 μm, so as to obtain better photoresist coating uniformity and recognition accuracy of the alignment portion 302. According to the present embodiment, the width minimum value a ″ and the width maximum value a' of the extension portion 303 in the direction perpendicular to the normal line of the substrate 301 satisfy the following conditional expressions:

5μm≤A’；

0.001 μm.ltoreq.A "< A'; and is

0.3≤A”/A’≤1

According to the present embodiment, the angle D between the inverted trapezoid structure of the alignment portion 302 and the substrate 301 satisfies the relation 30 ° < D <90 °, so as to prevent the photoresist from being unable to stably and completely fill the bottom of the gap 304 due to the excessively small angle D.

Referring next to fig. 3, a cross-sectional view of an alignment structure 400 according to a third embodiment of the invention is shown. In fig. 3, the widths of the alignment portion 402 and the extension portion 403 in the direction perpendicular to the normal line of the substrate 401 decrease with distance from the substrate 401, and are each formed in a trapezoidal shape, and the width of the void 404 in this direction increases with distance from the substrate 401.

According to the embodiment, the ratio of the minimum width B ″ of the gap 404 in the direction perpendicular to the normal of the substrate 401 to the maximum width E' is greater than or equal to 0.3 and less than 1, because if the minimum width B ″ of the gap 404 is too small, the effect of improving the photoresist coating uniformity is not sufficient. According to the embodiment, the maximum width E 'of the gap 404 is greater than 0.001 μm and less than 50 μm, and the minimum width B ″ of the gap 404 is greater than 0.001 μm and less than the maximum width E' for better photoresist coating uniformity and recognition accuracy of the alignment part 402. According to the present embodiment, the width minimum value F ″ and the width maximum value F' of the extension portion 403 in the direction perpendicular to the normal line of the substrate 401 satisfy the following conditional expressions:

5μm≤F’；

0.001 μm ≦ F "< F'; and is

0.3≤F”/F’≤1

According to the embodiment, the angle D 'between the trapezoid structure of the alignment portion 402 and the substrate 401 is in accordance with the relation 90 ° < D' ≦ 150 °, so as to avoid the insufficient effect of improving the photoresist coating uniformity due to the excessive angle D.

In summary, compared with the prior art, the alignment structure provided in the embodiment of the present invention further includes an extension portion, and the extension portion is disposed to make the photoresist coating more uniform, thereby improving the accuracy of identifying the alignment portion.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An alignment structure, comprising:

a substrate;

an alignment portion disposed on the substrate; and

the extension part is arranged on the base plate, at least partially surrounds the alignment part, and is spaced from the alignment part by a gap.

2. The alignment structure of claim 1, wherein a height of the extension portion in a first direction is equal to or greater than a height of the alignment portion in the first direction, the first direction being parallel to a normal direction of the substrate.

3. The alignment structure of claim 2, wherein a height ratio of the alignment portion and the extension portion in the first direction falls within a range of 0.5 to 1.

4. The alignment structure according to claim 1, wherein a width ratio of the extension portion to the alignment portion in the second direction is greater than or equal to 0.2 and less than or equal to 10, and the second direction is perpendicular to a normal direction of the substrate.

5. The alignment structure of claim 1, wherein the widths of the alignment portion and the extension portion in the second direction increase with distance from the substrate, the width of the gap in the second direction decreases, and the second direction is perpendicular to a normal direction of the substrate.

6. The alignment structure of claim 1, wherein widths of the alignment portion and the extension portion in a second direction decrease with distance from the substrate, a width of the gap in the second direction increases, and the second direction is perpendicular to a normal direction of the substrate.

7. The alignment structure according to claim 1, wherein a ratio of a minimum value to a maximum value of a width of the void in the second direction is 0.3 or more and 1 or less, and the second direction is perpendicular to a normal direction of the substrate.

8. The alignment structure of claim 7, wherein the minimum value of the void is greater than 0.001 microns and less than 50 microns.

9. The alignment structure of claim 1, wherein a side of the extension portion distal from the alignment portion and a side of the alignment portion proximal to the extension portion are shaped with respect to each other.

10. The alignment structure of claim 1, wherein a side of the extension portion adjacent to the alignment portion and a side of the alignment portion adjacent to the extension portion are conformal with each other.