CN-122018246-A - Method for solving abnormal photoetching morphology

CN122018246ACN 122018246 ACN122018246 ACN 122018246ACN-122018246-A

Abstract

A method for solving the problem of abnormal photoetching morphology comprises the steps of S1 providing a product piece, S2 gluing, exposing and developing, S3 observing morphology, S4 indicating abnormal photoetching morphology if observed line white edges are larger than specified values compared with line white edges under the same normal imaging focal length of a standard card, S5 corresponding the observed line white edges to line white edges under the larger normal imaging focal length of the standard card and determining the larger normal imaging focal length F ́, S6 subtracting the normal imaging focal length F of the step S2 from the larger normal imaging focal length F ́ to obtain a normal imaging focal length difference value, wherein the negative number of the normal imaging focal length difference value is the complement value of the imaging focal length, S7 complementing the complement value of the imaging focal length into an exposed machine table, S8 providing another product piece, S9 gluing, exposing and developing, wherein the exposed machine table is complemented with the normal imaging focal length based on the step S7, S10 observing morphology, and recovering the photoetching morphology.

Inventors

WANG YUE
SUN SHANSHAN
ZHOU HONGYU
LI HAITAO

Assignees

安徽晶微科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260313

Claims (10)

1. The method for solving the problem of the abnormal photoetching morphology is characterized by comprising the following steps: s1, providing a product piece before photoetching; S2, gluing, exposing and developing the product piece, wherein during exposure, crystal grains distributed in a two-dimensional array along the X direction and the Y direction are adopted to form a layout of the product piece, FEM data is adopted for exposure, in the FEM data, exposure dose is constant, an imaging focal length is taken as a normal imaging focal length F along the X direction or the Y direction by taking the crystal grain at the center of the product piece as a normal imaging focal length F and is changed along with the crystal grain to make a fixed step length delta F, the imaging focal length is increased from left to right when the imaging focal length is changed in the X direction, and the imaging focal length is increased from top to bottom when the imaging focal length is changed in the Y direction; S3, observing the appearance of the developed graph of the product piece; S4, based on the same part of the crystal grain at the same position of the product sheet, comparing the observed appearance with the appearance under the same normal imaging focal length of the standard card, if the observed line white edge is larger than a specified value compared with the line white edge under the same normal imaging focal length of the standard card, indicating that the photoetching appearance is abnormal, otherwise, the photoetching appearance is normal, and the technological parameters of gluing, exposure and development in the step S2 are used for subsequent production; s5, under the condition that the photoetching appearance is judged to be abnormal in the step S4, the observed line white edge is corresponding to the line white edge of the standard card under a larger normal imaging focal length, and the larger normal imaging focal length F ́ is determined; S6, subtracting the normal imaging focal length F in the step S2 from the larger normal imaging focal length F ́ to obtain a normal imaging focal length difference value, wherein the negative number of the normal imaging focal length difference value is the complement value of the imaging focal length; S7, supplementing the complement value of the imaging focal length into the exposed machine table, so that the actual normal imaging focal length of the machine table after supplementing the complement value is the sum of the normal imaging focal length F and the complement value of the imaging focal length in the step S2; S8, providing another product piece before photoetching; s9, gluing, exposing and developing the other product piece, wherein the exposed machine is based on the actual normal imaging focal length of the machine after the complementary value of the crystal grain in the center of the product piece is the complementary value in the normal imaging focal length in the step S7; S10, observing the appearance of the graph of the another product piece after development; S11, based on the same part of the crystal grain at the same position of the other product piece, comparing the observed appearance with the appearance under the normal imaging focal length which is the same as the actual normal imaging focal length of the standard card, if the observed line white edge is still larger than a specified value compared with the line white edge under the normal imaging focal length which is the same as the actual normal imaging focal length of the standard card, the photoetching appearance is still abnormal, the solving method of the photoetching appearance abnormality fails, the solving of the photoetching appearance abnormality is needed to be solved from other aspects of the photoetching process, otherwise, the photoetching appearance is restored to be normal, and the technological parameters of gluing, exposure and development in the step S9 are used for subsequent production.
2. The method of claim 1, wherein the step of determining the pattern of the defects in the wafer, In step S1 and step S8, The product piece is a wafer with the diameter of 8 inches and the surface being plated with a 150A thick SIN film layer.
3. The method of claim 1, wherein the step of determining the pattern of the defects in the wafer, In step S2 and step S9, The gluing comprises the following substeps: sa, forming an HMDS film, and forming the HMDS film on the surface of the product sheet in a gas phase mode; Sb, cooling before spin coating, and cooling the product sheet with the HMDS film formed on the surface to the temperature required by spin coating in a cooling tank; Sc, coating, namely spin coating the product sheet with spin coating glue in a glue coating process groove; And Sd, pre-baking, namely pre-baking the product sheet subjected to spin coating and glue homogenizing in a pre-baking process tank.
4. A method for solving a lithographic topography anomaly as claimed in claim 3, In the sub-step Sa, The operation of forming the HMDS film in a gas phase mode comprises the steps of placing a product sheet on a carrying table of a vacuum chamber, heating the carrying table to 110 ℃, taking nitrogen as carrier gas, introducing HMDS steam carried by the nitrogen at the pressure of 25kPa, keeping the pressure of the vacuum chamber at 20Pa, introducing the HMDS steam carried by the nitrogen for 60 seconds, and forming the HMDS film with the thickness of 6A.
5. A method for solving a lithographic topography anomaly as claimed in claim 3, In sub-step Sb, the temperature required for spin coating is 23 ℃.
6. A method for solving a lithographic topography anomaly as claimed in claim 3, In the substep Sc, the spin coating and gluing process comprises the steps of dripping 1.5mL of glue solution to the central position of a 2050rmp dynamic product sheet, rotating the product sheet for 30s at 3180rpm after the glue solution is dripped for 1.5s, and finally obtaining the glue coating thickness of 5350A; in the substep Sc, the glue model is AR80-4CP; In sub-step Sd, the pre-bake temperature is 90 ℃ for 60s.
7. The method of claim 1, wherein the step of determining the pattern of the defects in the wafer, In step S7, the normal imaging focal length F and the complement of the normal imaging focal length are performed by adjusting the offset (offset) and offset calibration (AIS) input fields in the wafer focus (Wafer Focusing) in the tool parameter window (ADJUST MACHINE PARAMETERS) in the control interface of the exposure tool.
8. A method for solving a lithographic topography anomaly as claimed in claim 3, In step S2 and step S9, The exposure includes the sub-steps of: si, cooling before exposure, and cooling the glued pre-baked product sheet in a cooling tank to the temperature of 23 ℃ required by exposure; Sii, exposing, namely performing step exposure by using a mask VOT612-005-BA and a Nikon SF120 machine, wherein the step X direction is 12949 mu m, the step Y direction is 250389 mu m, the exposure dose of each step exposure is 500mj/cm 2 and the NA value is 0.62, and the normal imaging focal length is the actual normal imaging focal length determined by 1.2 mu m in the step S2 or the complement value of the step S9 to-0.3 mu m; siii, post-exposure baking, wherein the post-exposure baking is performed in a post-exposure baking process tank, and the temperature of the post-exposure baking is 110 ℃ and the time is 120 seconds.
9. The method of claim 8, wherein the step of determining the pattern of the defects in the wafer, In step S2 and step S9, The development includes the sub-steps of: SI, cooling before development, cooling the post-exposure baked product pieces in a cooling tank to a temperature of 23 ℃ required for development; SII, developing, namely placing a product sheet cooled before developing on a rotary table of a developing machine, dripping developing solution to the center of the product sheet while rotating, and flushing while rotating, wherein the rotation is unidirectional rotation, the rotating speed is 2000rpm, positive photoresist developing solution is adopted, the model of the developing solution is ZX-238 type, the developing time is 60s, and the flushing time is 30s; SIII, post-baking in a post-baking process tank, wherein the post-baking temperature is 110 ℃ and the post-baking time is 90s.
10. The method of claim 1, wherein the step of determining the pattern of the defects in the wafer, In step S3 and step S10, the observation morphology is performed under a line width scanning electron microscope.

Description

Method for solving abnormal photoetching morphology Technical Field The present disclosure relates to the field of semiconductors, and more particularly to a method of solving a lithographic topography anomaly. Background In semiconductor manufacturing, photolithography is one of the key technologies for integrated circuits. Photolithography generally involves gumming, exposure and development. After development is completed, the photoetching result, particularly the photoetching morphology, which refers to the three-dimensional contour feature of the graph formed by photoetching, is usually observed under a scanning electron microscope, the line white edge of the three-dimensional contour is one of the morphology features, the line white edge represents the verticality of the side wall or the flatness of the side wall of the line in the vertical direction, and the reduction of the line white edge is the key for improving the three-dimensional contour precision and yield of the photoetching graph. In production, the large line white edge is considered as abnormal photoetching morphology, and is derived from several main aspects of environment, equipment, materials, process parameters and the like, so that further intensive research is needed to provide a solution for production. Disclosure of Invention In view of the problems in the background art, an object of the present disclosure is to provide a method for solving a lithography morphology anomaly, which can provide a solution for the lithography morphology anomaly with a large line white edge. It is another object of the present disclosure to provide a solution to the lithographic topography anomalies that can be more efficient and less costly to resolve. Thus, a method for solving the problem of abnormal photoetching morphology comprises the following steps: S1, providing a product piece before photoetching; S2, gluing, exposing and developing the product piece, wherein crystal grains distributed in a two-dimensional array along the X direction and the Y direction form a layout of the product piece, FEM data is adopted for exposure, in FEM data, exposure dose is constant, an imaging focal length takes the crystal grain at the center of the product piece as a normal imaging focal length F along the X direction or the Y direction and changes along with the crystal grain by a fixed step length delta F, the imaging focal length increases from left to right when the imaging focal length changes in the X direction, and the imaging focal length increases from top to bottom when the imaging focal length changes in the Y direction; S3, observing the pattern of the developed product piece, S4, comparing the observed pattern with the pattern of the standard card under the same normal imaging focal length based on the same part of the crystal grain at the same position of the product piece, if the observed line white edge is larger than a specified value compared with the line white edge of the standard card under the same normal imaging focal length, indicating that the photoetching pattern is abnormal, otherwise, the photoetching pattern is normal, and the gluing, exposure and developing process parameters of the step S2 are used for subsequent production, S5, under the condition that the photoetching pattern is judged to be abnormal in the step S4, corresponding the observed line white edge to the line white edge of the standard card under the larger normal imaging focal length and determining the larger normal imaging focal length F ́, S6, subtracting the normal imaging focal length F of the step S2 from the larger normal imaging focal length F ́ to obtain a normal imaging focal length difference value, wherein the negative number of the normal imaging focal length difference is the complement value of the imaging focal length, S7, adding the complement value of the imaging focal length to an exposure machine, the method comprises the steps of S2, S8, providing another product piece before photoetching, S9, gluing, exposing and developing the another product piece, wherein the exposed machine is based on the step S7, the normal imaging focal length of the machine is the sum of the normal imaging focal length F and the complementary value of the imaging focal length, S10, observing the morphology of the graph of the another product piece after development, S11, comparing the observed morphology with the morphology of the standard card under the normal imaging focal length identical to the normal imaging focal length of the standard card, if the observed line white edge is still larger than a specified value compared with the line white edge of the standard card under the normal imaging focal length identical to the normal imaging focal length of the standard card, indicating that the photoetching is still abnormal, failing to solve the problem of the abnormal morphology, and needing to restore the morphology from other aspects of the photoetching process, and c