CN106597810A - Wafer patterning process - Google Patents

Abstract

The invention provides a wafer patterning process, which comprises the following steps: providing a wafer with a plurality of notches, wherein the notches are respectively positioned at the edge of the wafer; using an exposure machine, and performing a first exposure operation according to a first nick in the nicks as a reference point; determining a rotation angle according to the first exposure result and executing a rotation operation; and performing a second exposure operation on the wafer. Therefore, the invention can achieve the simplicity of the process on the wafer layout, and can also reduce the cost of the process and increase the process latitude.

Description

Wafer Patterning Process

technical field

The invention relates to a semiconductor manufacturing process, in particular to a wafer patterning manufacturing process which simplifies the exposure operation.

Background technique

For advanced semiconductor manufacturing processes, due to design rule (design rule) and critical dimension (critical dimension) scaling, especially dynamic random access memory (dynamic random access memory, DRAM) integrated circuit combination with a large-area array structure, often for scaling storage At the same time, the unit area avoids the barrier layer or increases the contact area with the underlying silicon (Sicon contact area), and some layers need special tilt angle (tilt) or bending (wiggle shape) design.

However, pattern lithography (lithograohy) imaging at a specific oblique angle will increase many difficulties and process window considerations. First of all, lighting requires a special lighting mode design, or the exposure machine needs to be equipped with a high-end lighting module. Next, for the part processed by optical proximity correction (OPC), the unit processing time is relatively long and the difficulty is relatively high, and the array edge needs multiple optimization adjustments and special processing. Furthermore, in mask manufacturing, mask manufacturing costs remain high and mask critical dimension uniformity (CDU) control is difficult due to a substantial increase in mask read and write time. Finally, it leads to problems such as poor process tolerance and rough borders of linear patterns. Therefore, how to simplify the process problems that may be caused by such special exposure patterns is an important issue for the lithography process.

Contents of the invention

The present invention proposes a wafer patterning process, which mainly adopts different masks, and realizes the exposure application at a special angle by controlling the rotation angle of the wafer or the mask. On the wafer layout (layout), it can simultaneously achieve The simplicity of the manufacturing process can also reduce the cost of the manufacturing process and increase the tolerance of the manufacturing process.

The present invention provides a wafer patterning process, comprising: providing a wafer with a plurality of scribes respectively located on the edge of the wafer; using an exposure machine, and The notch is used as a reference point to perform the first exposure operation; a rotation angle is determined according to the first notch, and a rotation operation is performed; and a second exposure operation is performed on the wafer.

In an embodiment of the present invention, the first notch of the above-mentioned notches is a reference point, so that the step of performing the first exposure operation includes determining a fixed angle according to the first notch of the wafer.

In an embodiment of the present invention, the step of determining the rotation angle according to the first exposure result to perform a rotation operation includes rotating the wafer by the rotation angle based on the fixed angle.

In an embodiment of the present invention, the rotation angle is clockwise rotation or counterclockwise rotation.

In an embodiment of the present invention, the step of determining the rotation angle according to the first exposure result to perform a rotation operation includes rotating a mask of the exposure machine by the fixed angle as a reference to rotate the rotation angle.

In an embodiment of the present invention, the rotation angle is clockwise rotation or counterclockwise rotation.

In an embodiment of the present invention, the above-mentioned mask includes at least one pattern, and the at least one pattern includes a square, a rectangle, a line, or a combination thereof.

In an embodiment of the present invention, after performing the above-mentioned first exposure step, a developing operation is further included.

In an embodiment of the present invention, after performing the above-mentioned developing operation step, an etching operation is further included.

Based on the above, a wafer patterning process proposed by the present invention uses different masks and controls the rotation angle of the wafer or mask to realize the application of exposure at a special angle, thereby achieving the simplicity of the process and also Reduce the cost of the process and increase the tolerance of the process.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail with reference to the accompanying drawings.

Description of drawings

1 is a flowchart of a wafer patterning process according to the present invention;

2 is a schematic diagram of a wafer rotation operation according to an embodiment of the present invention;

FIG. 3 is a schematic diagram illustrating the operation of a wafer patterning process according to an embodiment of the present invention.

Explanation of reference signs:

50: block;

51, 53: linear pattern;

70, 90: notch;

100: wafer;

S110-S140: steps of wafer patterning process;

θ ₁ : included angle;

θ, θ ₂ : rotation angle.

detailed description

Reference will now be made in detail to the exemplary embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. In addition, wherever possible, elements/components/symbols with the same reference numerals are used in the drawings and embodiments to represent the same or similar parts.

Generally speaking, the so-called patterning lithography is to completely and accurately copy the designed circuit pattern on the wafer, and the semiconductor factory usually needs to make the designed pattern into a mask and apply optical imaging The principle of projecting a pattern onto a wafer. Only the part of the light emitted by the light source that passes through the transparent area of the mask can continue to pass through the lens and appear as an image on the wafer surface.

In detail, when pattern lithography is usually performed, firstly, the surface of the wafer is cleaned in advance, and then a photosensitive chemical substance similar to a film function is applied, which is called photoresist. Then, the light passing through the mask and lens will react with the photoresist (this step is usually called exposure operation). The exposed wafer needs to be developed again, and the exposed and unexposed photoresist on the wafer is chemically processed, so that the pattern on the mask can be completely transferred to the mask. Then, the etching operation is continued.

In order to explain more clearly, the following is the flow chart of the wafer patterning process in FIG. 1 and the operation schematic diagrams of the wafer patterning process in FIGS. 2 and 3 below to illustrate the specific exposure operation of the wafer 100 of the present invention. process.

FIG. 1 is a flowchart of a wafer patterning process according to the present invention. In this embodiment, the wafer patterning process is described by using a double exposure operation, but it is not limited thereto. Referring to FIG. 1 , firstly, a wafer is provided, which has a plurality of notches, and the notches are respectively located on the edge of the wafer (step S110 ). Next, an exposure machine is used to perform a first exposure operation based on one of the notches on the wafer as a reference point (step S120 ). Next, a rotation angle is determined according to the first exposure result, and a rotation operation is performed (step S130). Finally, a second exposure operation is performed on the wafer (step S140). It should be noted that the above-mentioned rotation angle is determined by a specific oblique angle in the pre-exposed pattern (this part will be described in detail later with FIG. 2 ).

FIG. 2 is a schematic diagram of a wafer spinning operation according to an embodiment of the present invention. Please refer to FIG. 2 , there are multiple notches on the outer edge of the wafer 100 , based on the principle of concise description, only the notches 70 and 90 are shown, but not limited thereto. In this embodiment, the angle between the two notches 70, 90 (that is, the rotation angle θ ₂ ) is determined by the linear pattern (ie, the pattern on the mask) and the horizontal line of the pre-executed exposure operation on the wafer 100 The included angle θ ₁ between them, in other words, the included angle θ ₁ is equal to the rotation angle θ ₂ , as shown in FIG. 2 .

More specifically, when the angle θ ₁ between the linear pattern 51 in the block 50 on the wafer 100 and the horizontal line is pre-executed, in the exposure operation, since the angle θ ₁ is equal to the rotation angle θ ₂ , so in the rotation operation, the wafer 100 will be rotated by the corresponding rotation angle θ2 to the position of the notch 90 based _on the notch 70 . At this time, after the exposure operation is performed, it can appear as a linear pattern 53 in the block 50 , as shown in FIG. 2 . In other embodiments, the mask (not shown) may also be rotated by the corresponding rotation angle θ ₂ , so that the wafer 100 appears as the linear pattern 53 under the exposure operation. In addition, the rotation operation of the wafer 100 or the mask can be rotated clockwise or counterclockwise according to the notches on the outer edge of the wafer 100. In this embodiment, the wafer 100 is rotated counterclockwise. , for exposure operations, but not as a limitation.

FIG. 3 is a schematic diagram illustrating the operation of a wafer patterning process according to an embodiment of the present invention. Referring to FIG. 3 , firstly, the wafer 100 is subjected to a first exposure operation using a mask in the wafer patterning process to complete the first type of patterning. In detail, one of the notches on the outer edge of the wafer 100 is used as a reference point, and a fixed angle is determined as a starting position according to the notch to perform the first exposure operation. In this embodiment, the fixed angle of the initial position is 0 degree, but it is not limited thereto.

Next, the rotation angle θ required for the formation of the first type of pattern is determined according to the first exposure result, so as to control the rotation angle θ required for the mask (not shown) or the wafer 100 to be rotated for the formation of the first type of pattern. In this embodiment, if the mask has multiple types of patterns, such as squares, rectangles, lines or combinations thereof, repeat the above second type of pattern making to complete.

Please continue to refer to FIG. 3 , finally, using the first type of pattern as a reference point, the mask or the wafer is rotated by a rotation angle θ, and then the exposure operation of the second type of pattern is performed. In addition, it is worth mentioning that the rotation operation of the above-mentioned wafer as a mask can be rotated clockwise or counterclockwise according to the notch on the outer edge of the wafer. In this embodiment, the wafer 100 adopts reverse Rotate clockwise to perform exposure operations of different types of patterns, but not limited thereto. In this way, the above-mentioned rotating operation causes the exposed patterns of the wafer 100 to be performed at any angle according to design requirements.

To sum up, a wafer patterning process proposed by the present invention implements exposure applications at special angles (such as oblique angles) by using different masks and controlling the rotation angle of the wafer or mask, thereby greatly reducing The roughness on the boundary of the linear graph can also simplify the complexity of the exposure operation, thereby reducing the cost of the manufacturing process and increasing the tolerance of the manufacturing process.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (9)

1. A wafer patterning process for transferring a pattern on a mask to a wafer, characterized in that it comprises: providing a wafer with a plurality of notches, the plurality of notches are respectively located at the edge of the wafer; using an exposure machine to perform a first exposure operation based on the first notch of the plurality of notches as a reference point; determining a rotation angle according to a first exposure result, and performing a rotation operation; and A second exposure operation is performed on the wafer. 2. The wafer patterning process according to claim 1, wherein, according to the first notch in the plurality of notches as a reference point, the step of performing the first exposure operation comprises: A fixed angle is determined according to the first notch of the wafer. 3. The wafer patterning process according to claim 2, wherein the step of determining the rotation angle according to the first exposure result to perform a rotation operation comprises: The wafer is rotated by the rotation angle based on the fixed angle. 4. The wafer patterning process according to claim 3, wherein the rotation angle is clockwise rotation or counterclockwise rotation. 5. The wafer patterning process according to claim 2, wherein the step of determining the rotation angle according to the first exposure result to perform a rotation operation comprises: The mask is rotated by the rotation angle based on the fixed angle. 6 . The wafer patterning process according to claim 5 , wherein the rotation angle is clockwise rotation or counterclockwise rotation. 7. The wafer patterning process according to claim 5, wherein the mask comprises at least one pattern, and the at least one pattern comprises a square, a rectangle, a line or a combination thereof. 8. The wafer patterning process according to claim 1, further comprising: A developing operation is performed. 9. The wafer patterning process according to claim 8, further comprising: An etching operation is performed.