Method for early acquisition of the value of a reticle

Abstract

The application provides a method for obtaining overlay yield in advance, comprising: performing photolithography on epitaxial layers with different thicknesses respectively; measuring the epitaxial layers after photolithography to obtain a plurality of sets of overlay deviation data; establishing a plurality of fitting functions according to the thicknesses of the epitaxial layers and the overlay deviation data; and obtaining the overlay yield of an epitaxial layer to be photolithographed according to the fitting functions and the thickness of the epitaxial layer to be photolithographed. The application performs photolithography on epitaxial layers with different thicknesses, obtains a plurality of sets of overlay deviation data, establishes fitting functions by using the overlay deviation data, and finally obtains the overlay yield of an epitaxial layer to be photolithographed by using the fitting functions, thereby improving the overlay precision of the epitaxial layer, ensuring the accuracy of overlay, and avoiding the situation that the epitaxial layer needs to be photolithographed due to overlay abnormality.

Description

Technical Field

[0001] This application relates to the field of photolithography technology, specifically to a method for obtaining the value of overlayed goods in advance. Background Technology

[0002] Epitaxial growth technology is widely used in the manufacturing of multifunctional semiconductor devices, such as BCD (bipolar-CMOS-DMOS) devices and power semiconductor devices. The epitaxial layer is used to improve the high voltage resistance of the product.

[0003] Epitaxial growth utilizes the characteristic of silicon atoms or other atoms growing along the crystal phase. Therefore, epitaxial growth is directional, and the pattern will drift during the epitaxial process. The degree of drift varies for epitaxial layers of different thicknesses. For photolithography, the overlay deviation is relatively large. In addition, due to the abnormal overlay of the epitaxial layer, the number of photolithography reworks is increased, wasting human and material resources. Summary of the Invention

[0004] This application provides a method for obtaining the value of overlay in advance, which can solve at least one of the problems in photolithography, such as large overlay deviation of epitaxial layer and many rework times due to abnormal overlay of epitaxial layer.

[0005] On one hand, embodiments of this application provide a method for obtaining the value of overprinted goods in advance, including:

[0006] Photolithography was performed on multiple epitaxial layers of different thicknesses.

[0007] The epitaxial layer after photolithography is measured to obtain multiple sets of overlay deviation data;

[0008] Based on the thickness of the epitaxial layer and the overlay deviation data, multiple fitting functions are established;

[0009] Based on the fitting function and the thickness of the epitaxial layer to be photolithographically etched, the overlay value of the epitaxial layer to be photolithographically etched is obtained.

[0010] Optionally, in the method for obtaining the value of the overlay in advance, the step of performing photolithography on multiple epitaxial layers of different thicknesses includes:

[0011] Photolithography is performed on multiple epitaxial layers at certain thickness intervals.

[0012] Optionally, in the method for obtaining the value of the overlay in advance, the thickness interval is 0.2 μm.

[0013] Optionally, in the method for obtaining the value of the overlay in advance, photolithography is performed on each of the epitaxial layers with a thickness in the range of 3.7 μm to 4.5 μm.

[0014] Optionally, in the method for obtaining the value of the overprinted goods in advance, each group of overprinting deviation data includes: the maximum overprinting offset, the minimum overprinting offset, and multiple intermediate overprinting offsets.

[0015] Optionally, in the method for obtaining the value of the overlay in advance, the step of establishing multiple fitting functions based on the thickness of the epitaxial layer and the overlay deviation data includes:

[0016] A first fitting function is established based on the thickness of the epitaxial layer and the maximum overlay offset;

[0017] A second fitting function is established based on the thickness of the epitaxial layer and the minimum overlay offset.

[0018] Optionally, in the method for obtaining the overlay value in advance, the step of obtaining the overlay value of the epitaxial layer to be photolithographically lithographically oriented based on the fitting function and the thickness of the epitaxial layer to be photolithographically oriented includes:

[0019] Based on the first fitting function and the thickness of the epitaxial layer to be photolithographically etched, the first set of etching values ​​for the epitaxial layer to be photolithographically etched is obtained.

[0020] Based on the second fitting function and the thickness of the epitaxial layer to be photolithographically etched, the second set of etching values ​​for the epitaxial layer to be photolithographically etched is obtained;

[0021] Based on the first set of etched values ​​and the second set of etched values, the final set of etched values ​​for the epitaxial layer that needs to be photolithographically etched is obtained.

[0022] Optionally, in the method of obtaining the value of the overlay in advance, the average value of the first overlay and the second overlay are calculated, and the average value is used as the final overlay value of the epitaxial layer that needs to be photolithographically etched.

[0023] Optionally, in the method for obtaining the value of the embedded goods in advance, the material of the epitaxial layer is silicon, silicon germanium, or gallium nitride.

[0024] Optionally, in the method for obtaining the value of the overlay in advance, the epitaxial layer is located on a substrate, and the substrate is made of silicon, silicon germanium, or gallium nitride.

[0025] The technical solution of this application has at least the following advantages:

[0026] This application first performs photolithography on multiple epitaxial layers of different thicknesses; then measures the photolithographically ... Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a flowchart of a method for obtaining the value of a packaged item in advance, according to an embodiment of the present invention.

[0029] Figure 2 This is a schematic diagram of the first and second fitting curves according to an embodiment of the present invention. Detailed Implementation

[0030] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0033] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0034] This application provides a method for obtaining the value of overprinted goods in advance, referring to... Figure 1 , Figure 1 This is a flowchart of a method for obtaining the value of overprinted goods in advance according to an embodiment of the present invention. The method for obtaining the value of overprinted goods in advance includes:

[0035] Step S10: Perform photolithography on multiple epitaxial layers of different thicknesses. Specifically, the material of the epitaxial layers includes, but is not limited to, silicon, germanium-silicon, or gallium nitride. The epitaxial layers are deposited on a substrate, and the material of the substrate includes, but is not limited to, silicon, germanium-silicon, or gallium nitride.

[0036] In this embodiment, photolithography is performed on each of the multiple epitaxial layers at certain thickness intervals.

[0037] Preferably, the thickness interval can be 0.2 μm.

[0038] Preferably, photolithography is performed on each of the epitaxial layers with a thickness in the range of 3.7 μm to 4.5 μm. For example, epitaxial layers with thicknesses of 3.7 μm, 3.9 μm, 4.1 μm, 4.3 μm, and 4.5 μm are selected for photolithography.

[0039] Step S20: Measure the epitaxial layer after photolithography to obtain multiple sets of overlay deviation data;

[0040] Preferably, the overprinting deviation data in each group includes: maximum overprinting offset, minimum overprinting offset, and multiple intermediate overprinting offsets. The maximum overprinting offset, minimum overprinting offset, and multiple intermediate overprinting offsets can all include overprinting offsets in the X direction (lateral) and Y direction (vertical).

[0041] Step S30: Based on the thickness of the epitaxial layer and the overlay deviation data, establish at least two fitting functions;

[0042] In this embodiment, reference Figure 2 , Figure 2 This is a schematic diagram of the first and second fitting curves according to an embodiment of the present invention. The step of establishing multiple fitting functions based on the thickness of the epitaxial layer and the overlay deviation data may specifically include:

[0043] Based on the thickness of the epitaxial layer and the maximum overlay offset, a first fitting curve is obtained, and a first fitting function is established based on the first fitting curve.

[0044] A second fitting curve is obtained based on the thickness of the epitaxial layer and the minimum overlay offset, and a second fitting function is established based on the second fitting curve.

[0045] Step S40: Based on the fitting function and the thickness of the epitaxial layer to be photolithographically lithographically etched, obtain the overlay value of the epitaxial layer to be photolithographically lithographically etched.

[0046] In this embodiment, the step of obtaining the overlay value of the epitaxial layer to be photolithographically lithographically oriented based on the fitting function and the thickness of the epitaxial layer to be photolithographically oriented may specifically include:

[0047] Based on the first fitting function and the thickness of the epitaxial layer to be photolithographically etched, the first set of etching values ​​for the epitaxial layer to be photolithographically etched is obtained.

[0048] Based on the second fitting function and the thickness of the epitaxial layer to be photolithographically etched, the second set of etching values ​​for the epitaxial layer to be photolithographically etched is obtained;

[0049] Based on the first set of etched values ​​and the second set of etched values, the final set of etched values ​​for the epitaxial layer that needs to be photolithographically etched is obtained.

[0050] Furthermore, in this embodiment, the average value of the first set of etched goods and the second set of etched goods can be calculated, and the average value of the first set of etched goods and the second set of etched goods can be used as the final set of etched goods value of the epitaxial layer that needs to be photolithographically etched.

[0051] In this application, photolithography is first performed on multiple epitaxial layers of different thicknesses; then, the photolithographically ...

[0052] In another embodiment, multiple new fitting curves can be obtained based on the thickness of the epitaxial layer and multiple intermediate overlay offsets between the maximum and minimum overlay offsets. Then, multiple overlay values ​​are obtained based on the new fitting curves and the thickness of the epitaxial layer to be lithographically etched. Finally, the average of the first overlay value, the second overlay value, and the multiple overlay values ​​is calculated, and this average is used as the final overlay value of the epitaxial layer to be lithographically etched, further ensuring the accuracy of overlay.

[0053] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.

Claims

1. A method of early acquisition of value for overlay, characterized by, The method comprises the following steps: photolithography is performed on a plurality of epitaxial layers with different thicknesses respectively; measurement is performed on the epitaxial layers after photolithography to obtain a plurality of sets of overlay error data, wherein each set of the overlay error data comprises a maximum overlay offset, a minimum overlay offset and a plurality of intermediate overlay offsets; a plurality of fitting functions are established according to the thicknesses of the epitaxial layers and the overlay error data; an overlay yield value of an epitaxial layer to be subjected to photolithography is obtained according to the fitting functions and the thickness of the epitaxial layer to be subjected to photolithography; the step of establishing a plurality of fitting functions according to the thicknesses of the epitaxial layers and the overlay error data comprises: a first fitting function is established according to the thicknesses of the epitaxial layers and the maximum overlay offset; a second fitting function is established according to the thicknesses of the epitaxial layers and the minimum overlay offset.

2. The method of Claim 1, wherein, The step of performing photolithography on a plurality of epitaxial layers with different thicknesses respectively comprises: photolithography is performed on a plurality of the epitaxial layers with a certain thickness interval.

3. The method of claim 2, wherein, The thickness interval is 0.2 μm.

4. The method of Claim 1 or 2, wherein, Photolithography is performed on a plurality of epitaxial layers with thicknesses in the range of 3.7 μm to 4.5 μm respectively.

5. The method of claim 1, wherein, The step of obtaining an overlay yield value of an epitaxial layer to be subjected to photolithography according to the fitting functions and the thickness of the epitaxial layer to be subjected to photolithography comprises: a first overlay yield value of the epitaxial layer to be subjected to photolithography is obtained according to the first fitting function and the thickness of the epitaxial layer to be subjected to photolithography; a second overlay yield value of the epitaxial layer to be subjected to photolithography is obtained according to the second fitting function and the thickness of the epitaxial layer to be subjected to photolithography; a final overlay yield value of the epitaxial layer to be subjected to photolithography is obtained according to the first overlay yield value and the second overlay yield value.

6. The method of claim 5, wherein, An average value of the first overlay yield value and the second overlay yield value is calculated, and the average value is taken as the final overlay yield value of the epitaxial layer to be subjected to photolithography.

7. The method of Claim 1, wherein, The material of the epitaxial layer is silicon, silicon germanium or gallium nitride.

8. The method of claim 1, wherein, The epitaxial layer is located on a substrate, and the material of the substrate is silicon, silicon germanium or gallium nitride.

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