A method for detecting pattern deviation after epitaxial growth

Abstract

The present invention provides a method for detecting pattern shift after epitaxial growth, comprising forming multiple current-layer patterns on a wafer; performing epitaxial growth on the multiple current-layer patterns on the wafer, and forming two types of marks on the current-layer patterns after epitaxy, one of which is named A alignment mark and the other is named B alignment mark; using a visual imaging alignment lithography machine to form A overlay marks corresponding to the A alignment marks; using a high-order diffraction alignment lithography machine to form B overlay marks corresponding to the B alignment marks; respectively measuring the A overlay accuracy between the A alignment mark and the A overlay mark, and the B overlay accuracy between the B alignment mark and the B overlay mark; and performing a differential comparison between the A overlay accuracy and the B overlay accuracy. The method of the present invention detects whether the pattern on the wafer has shifted in position by measuring the vector diagrams of the overlay marks after exposure by two different alignment systems, and can be used to detect the direction and degree of pattern shift after epitaxial growth.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, in particular to a method for detecting pattern deviation after epitaxial growth. Background Art

[0002] The epitaxial growth process is widely used in the field of multifunctional semiconductors, such as BCD and power semiconductors, to improve the high-voltage performance of the products. During the epitaxial growth process, the pattern will drift along the crystal direction. To ensure the stability of the epitaxial product, monitoring the stability of the pattern drift after epitaxy plays a key role.

[0003] Currently, the drift of graphics is mainly judged by slicing and staining, and it is difficult to detect the drift of graphics after epitaxy in an intuitive way.

[0004] Therefore, a new method needs to be proposed to solve the above problems. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a method for detecting pattern shift after epitaxial growth, so as to solve the problem in the prior art that pattern drift after epitaxial growth cannot be accurately detected.

[0006] To achieve the above and other related objectives, the present invention provides a method for detecting pattern deviation after epitaxial growth, comprising at least:

[0007] Step 1: providing a wafer, and forming a plurality of layer patterns on the wafer;

[0008] Step 2: epitaxially growing the plurality of current layer patterns on the wafer, and forming two types of marks on the current layer patterns after epitaxy, one type of which is named A alignment mark and the other type of which is named B alignment mark;

[0009] Step 3: using a visual imaging alignment lithography machine to form an A overlay mark corresponding to the A alignment mark; using a high-order diffraction alignment lithography machine to form a B overlay mark corresponding to the B alignment mark;

[0010] Step 4, measuring the A overlay accuracy between the A alignment mark and the A overlay mark, and the B overlay accuracy between the B alignment mark and the B overlay mark;

[0011] Step 5: Perform differential comparison between the A overlay accuracy and the B overlay accuracy.

[0012] Preferably, the A alignment mark and the B alignment mark formed in step 2 are both located on the dicing street of the wafer.

[0013] Preferably, the multiple current layer patterns in step 1 are formed by exposure using the same photolithography machine, and the multiple current layer patterns have the same size and shape.

[0014] Preferably, the thickness of the epitaxial layer in the A alignment mark and the B alignment mark formed after epitaxy in step 2 is the same.

[0015] Preferably, the A overlay mark in step three is a photoresist pattern superimposed on the A alignment mark.

[0016] Preferably, in step three, the A overlay mark is formed by exposure and alignment using the visual imaging alignment lithography machine.

[0017] Preferably, the alignment method of the visual imaging alignment lithography machine in step three is a field of view imaging alignment method.

[0018] Preferably, the B overlay mark in step three is a photoresist pattern superimposed on the B alignment mark.

[0019] Preferably, in step three, the B overlay mark is formed by exposure and alignment using the high-order diffraction alignment lithography machine.

[0020] Preferably, the alignment method of the high-order diffraction alignment lithography machine in step three is a diffraction imaging alignment method.

[0021] As described above, the method of detecting pattern offset after epitaxial growth of the present invention has the following beneficial effects: the method of the present invention detects whether the pattern on the wafer has position drift by measuring the vector diagram of the overlay mark after exposure by two different alignment systems, and can be used to detect the direction and degree of pattern offset after epitaxial growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Displayed is an image of the alignment mark after alignment of the lithography machine using the visual imaging method in the present invention;

[0023] Figure 2 Displayed is an image of the alignment mark after alignment using the high-order diffraction alignment lithography machine in the present invention;

[0024] Figure 3 Displayed is the overlay measurement vector diagram after alignment of the visual imaging alignment lithography machine in the present invention;

[0025] Figure 4 Shown is the overlay measurement vector diagram after alignment of the high-order diffraction alignment lithography machine in the present invention. DETAILED DESCRIPTION

[0026] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0027] See also Figures 1 to 4 It should be noted that the diagrams provided in this embodiment are merely schematic illustrations of the basic concept of the present invention. Therefore, the diagrams only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0028] The present invention provides a method for detecting pattern deviation after epitaxial growth, which at least comprises:

[0029] Step 1: providing a wafer, and forming a plurality of layer patterns on the wafer;

[0030] Furthermore, in the present invention, the plurality of layer patterns in step 1 of this embodiment are formed by exposure using the same photolithography machine, and the plurality of layer patterns are of the same size and shape. In other words, the plurality of layer patterns have the same pattern structure.

[0031] Step 2: Epitaxially grow the multiple current-layer patterns on the wafer, and the current-layer patterns after epitaxy form two types of marks, one of which is named A alignment mark and the other is named B alignment mark; that is, the patterns named A alignment mark and B alignment mark are formed after the current-layer patterns are epitaxially grown, and the two are essentially graphic structures with the same shape, size and thickness of the grown epitaxial layer.

[0032] The present invention further provides that the alignment marks A and B formed in step 2 of this embodiment are both located on the dicing streets of the wafer. The alignment marks A and B are graphic objects used for subsequent alignment and exposure using a visual imaging alignment lithography machine and a high-order diffraction alignment lithography machine, respectively.

[0033] Furthermore, in the present invention, the thickness of the epitaxial layer in the A alignment mark and the B alignment mark formed after epitaxy in step 2 of this embodiment is the same.

[0034] Step 3: using a visual imaging alignment lithography machine to form an A overlay mark corresponding to the A alignment mark; using a high-order diffraction alignment lithography machine to form a B overlay mark corresponding to the B alignment mark;

[0035] Furthermore, in the present invention, the A overlay mark in step three of this embodiment is a photoresist pattern superimposed on the A alignment mark.

[0036] Furthermore, in step three of this embodiment, the visual imaging alignment lithography machine is used to form the A overlay mark through exposure and alignment.

[0037] The present invention further states that the alignment method of the visual imaging alignment lithography machine in step 3 of this embodiment is a field of view imaging alignment method. Figure 1 As shown, Figure 1 The image shown is an image of the alignment mark after alignment using the visual imaging alignment lithography machine in the present invention. That is, the alignment system of the visual imaging alignment lithography machine directly aligns and obtains alignment signals.

[0038] The present invention further states that the B overlay mark in step 3 of this embodiment is a photoresist pattern superimposed on the B alignment mark. Figure 3 As shown, Figure 3 The image shown is an image of the overlay mark superimposed on the alignment mark in the present invention. That is, the outer frame is the overlay mark after extension, and the inner frame is the alignment mark.

[0039] Furthermore, in step three of this embodiment, the high-order diffraction alignment lithography machine is used to form the B overlay mark through exposure and alignment.

[0040] Furthermore, the present invention further provides that the alignment method of the high-order diffraction alignment lithography machine in step 3 of this embodiment is a diffraction imaging alignment method. Figure 2 As shown, Figure 2 The image shows the alignment marks after alignment using the high-order diffraction alignment lithography machine in the present invention. In other words, the alignment system of the high-order diffraction alignment lithography machine is a high-order alignment system.

[0041] Step 4: respectively measure the A overlay accuracy between the A alignment mark and the A overlay mark and the B overlay accuracy between the B alignment mark and the B overlay mark; Figure 3 and Figure 4 As shown, Figure 3 Displayed is the overlay measurement vector diagram after alignment of the visual imaging alignment lithography machine in the present invention; Figure 4 Shown is the overlay measurement vector diagram after alignment of the high-order diffraction alignment lithography machine in the present invention.

[0042] Step 5: Compare the A overlay accuracy with the B overlay accuracy. The overlay mark measurement process (KLA) uses visual imaging to analyze the brightness of the image and convert it into a signal for measurement. This method is closer to the A alignment system. Therefore, theoretically, the overlay accuracy measurement vector value after A alignment will be smaller. In fact, from the final vector diagram results, the deviation of the measurement result after A alignment is smaller than that of the B diffraction alignment method, and by comparing the vector diagrams of the two, it can be judged that the pattern has a large drift mainly in the horizontal direction. Therefore, this method can be used to detect the direction and degree of pattern offset after epitaxial growth.

[0043] In summary, the method of the present invention detects positional drift of patterns on a wafer by measuring the vector diagrams of overlay marks after exposure using two different alignment systems. This can be used to determine the direction and extent of pattern shift after epitaxial growth. Therefore, the present invention effectively overcomes the shortcomings of existing technologies and possesses high industrial applicability.

[0044] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A method for detecting pattern deviation after epitaxial growth, characterized in that: At least: Step 1: providing a wafer, and forming a plurality of layer patterns on the wafer; the plurality of layer patterns have the same pattern structure; Step 2: epitaxially growing the plurality of current layer patterns on the wafer, wherein the current layer patterns after epitaxial growth respectively form two types of marks, one type of which is named A alignment mark and the other type of which is named B alignment mark; the A alignment mark and the B alignment mark are graphic structures with the same shape, size and thickness of the grown epitaxial layer; Step 3: using a visual imaging alignment lithography machine to form an A overlay mark corresponding to the A alignment mark; using a high-order diffraction alignment lithography machine to form a B overlay mark corresponding to the B alignment mark; Step 4, measuring the A overlay accuracy between the A alignment mark and the A overlay mark, and the B overlay accuracy between the B alignment mark and the B overlay mark; Step 5: Perform differential comparison between the A overlay accuracy and the B overlay accuracy.

2. The method for detecting pattern deviation after epitaxial growth according to claim 1, wherein: The A alignment mark and the B alignment mark formed in step 2 are both located on the dicing street of the wafer.

3. The method for detecting pattern deviation after epitaxial growth according to claim 1, wherein: The multiple current layer patterns in step 1 are formed by exposure using the same photolithography machine.

4. The method for detecting pattern deviation after epitaxial growth according to claim 1, wherein: The A overlay mark in step three is a photoresist pattern superimposed on the A alignment mark.

5. The method for detecting pattern deviation after epitaxial growth according to claim 4, wherein: In step three, the visual imaging alignment lithography machine is used to form the A overlay mark through exposure and alignment.

6. The method for detecting pattern deviation after epitaxial growth according to claim 5, wherein: The alignment method of the visual imaging alignment lithography machine described in step three is a field of view imaging alignment method.

7. The method for detecting pattern deviation after epitaxial growth according to claim 1, wherein: The B overlay mark in step three is a photoresist pattern superimposed on the B alignment mark.

8. The method for detecting pattern deviation after epitaxial growth according to claim 7, wherein: In step three, the B overlay mark is formed by exposure and alignment using the high-order diffraction alignment lithography machine.

9. The method for detecting pattern deviation after epitaxial growth according to claim 8, wherein: The alignment method of the high-order diffraction alignment lithography machine described in step three is a diffraction imaging alignment method.

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