Method for evaluating negative photoresist shrinkage

Abstract

The application provides a method for evaluating negative photoresist shrinkage, forming an opening pattern, the depth of the opening pattern is a target multiple of the thickness of the negative photoresist to be verified, and the thickness of the negative photoresist to be verified is the thickness of the negative photoresist higher than the opening pattern; forming the negative photoresist covering the opening pattern, and patterning the negative photoresist by using a photolithography process; obtaining the filling condition of the negative photoresist in the opening pattern; judging whether the negative photoresist has cracks according to the filling condition; if yes, it is judged that the negative photoresist has excessive shrinkage; and if no, it is judged that the negative photoresist does not have excessive shrinkage. The application can more accurately and directly judge whether the negative photoresist has excessive shrinkage; the method of the application is simple, does not involve new mask making and machine modification, improves the verification efficiency and accuracy of the negative photoresist, and saves the cost.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a method for evaluating the shrinkage of negative photoresist. Background Technology

[0002] Photolithography includes two basic process types: negative photolithography and positive photolithography. In negative photolithography, after exposure, the photoresist becomes insoluble due to cross-linking and hardens. Once hardened, the cross-linked photoresist cannot be washed away from the solvent, allowing a pattern that is the opposite of the pattern on the photomask to be copied onto the silicon wafer surface.

[0003] In advanced manufacturing processes, negative photoresist, while lacking high resolution, possesses excellent solubility and is therefore largely used for trench or deep hole filling. However, the pattern of negative photoresist shrinks after exposure and development. Excessive shrinkage can affect the final film retention rate, making it crucial to verify photoresist shrinkage when evaluating its performance.

[0004] Please see Figure 1 Existing methods for assessing negative photoresist shrinkage include:

[0005] 1. Determine the required dimensions of the graphic based on the thickness of the negative adhesive;

[0006] 2. Select a photomask containing the dimensions of the measured pattern, and perform adhesive application, exposure, and development;

[0007] 3. Measure whether the key dimensions at the cross-section of the adhesive block have changed;

[0008] 4. Determine whether the glue has shrunk by comparing A, B, C...

[0009] The common method for verifying adhesive shrinkage is to measure the key dimensions of the block pattern to determine whether the adhesive has shrunk. This method is performed on a bare wafer and cannot characterize the photoresist situation inside trenches or deep holes.

[0010] To address the above issues, a novel method for evaluating negative photoresist shrinkage is needed. Summary of the Invention

[0011] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method for evaluating negative photoresist shrinkage, which solves the problem that the existing method for verifying photoresist shrinkage is to determine whether the photoresist has shrunk by measuring the key dimensions of the block pattern. This method is performed on a bare wafer and cannot characterize the photoresist situation inside trenches or deep holes.

[0012] To achieve the above and other related objectives, the present invention provides a method for evaluating the shrinkage of negative photoresist, comprising:

[0013] Step 1: Form an opening pattern. The depth of the opening pattern is a target multiple of the thickness of the negative photoresist to be verified. The thickness of the negative photoresist to be verified is greater than the thickness of the opening pattern.

[0014] Step 2: Form a negative photoresist covering the opening pattern, and pattern the negative photoresist using photolithography;

[0015] Step 3: Obtain the filling status of the negative photoresist in the opening pattern;

[0016] Step 4: Determine whether the negative photoresist has cracks based on the filling condition; if so, the negative photoresist has undergone excessive shrinkage; if not, the negative photoresist has not undergone excessive shrinkage.

[0017] Preferably, the opening pattern in step one is on a semiconductor material layer.

[0018] Preferably, the semiconductor material layer is a nitride layer or an oxide layer.

[0019] Preferably, the semiconductor material layer in step one is formed on a substrate.

[0020] Preferably, the substrate in step one comprises a bulk semiconductor substrate or a silicon-on-insulator (SOI) substrate.

[0021] Preferably, the opening pattern in step one is a groove.

[0022] Preferably, the opening pattern in step one is a through hole.

[0023] Preferably, the depth of the opening pattern in step one is greater than twice the thickness of the negative photoresist to be verified.

[0024] Preferably, in step three, the filling status of the negative photoresist in the opening pattern is obtained using a dark-field scanning method.

[0025] Preferably, in step three, the filling status of the negative photoresist in the opening pattern is obtained using an optical analysis slicing method.

[0026] As described above, the method for evaluating negative photoresist shrinkage of the present invention has the following beneficial effects:

[0027] This invention can more accurately and intuitively determine whether negative photoresist has undergone excessive shrinkage. The method of this invention is simple and does not involve new pattern making or equipment modification, which improves the efficiency and accuracy of negative photoresist verification and saves costs. Attached Figure Description

[0028] Figure 1This diagram illustrates a prior art method for evaluating negative photoresist shrinkage.

[0029] Figure 2 The diagram shows a method for evaluating negative photoresist shrinkage according to the present invention.

[0030] Figure 3 The diagram shows a cross-sectional view of the structure used to evaluate the shrinkage of negative photoresist according to the present invention.

[0031] Figure 4 This is a schematic diagram showing the filling of the opening pattern by the negative photoresist in the first embodiment;

[0032] Figure 5 This is a schematic diagram showing the filling of the opening pattern by the negative photoresist in the second embodiment;

[0033] Figure 6 This diagram illustrates the filling of the opening pattern by the negative photoresist in the third embodiment. Detailed Implementation

[0034] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0035] Please see Figure 1 The present invention provides a method for evaluating the shrinkage of negative photoresist, comprising:

[0036] Step 1, please refer to Figure 3 An opening pattern is formed, the depth of which is a target multiple of the thickness of the negative photoresist to be verified, and the thickness of the negative photoresist to be verified is greater than the thickness of the opening pattern.

[0037] In some embodiments, the opening pattern in step one is on a semiconductor material layer.

[0038] In some embodiments, the semiconductor material layer is a nitride layer or an oxide layer. For example, a silicon nitride layer and a silicon dioxide layer.

[0039] In some embodiments, the semiconductor material layer in step one is formed on the substrate.

[0040] In some embodiments, the substrate in step one comprises a bulk semiconductor substrate or a silicon-on-insulator (SOI) substrate. The SOI substrate includes an insulating layer beneath a thin semiconductor layer serving as the active layer. The semiconductor in the active layer and the bulk semiconductor typically comprise the crystalline semiconductor material silicon, but may also include one or more other semiconductor materials, such as germanium, silicon-germanium alloys, compound semiconductors (e.g., GaAs, AlAs, InAs, GaN, AlN, etc.) or alloys thereof (e.g., GaxAl1-xAs, GaxAl1-xN, InxGa1-xAs, etc.), oxide semiconductors (e.g., ZnO, SnO2, TiO2, Ga2O3, etc.), or combinations thereof. The semiconductor material may be doped or undoped. Other substrates that may be used include multilayer substrates, gradient substrates, or mixed-orientation substrates.

[0041] In some embodiments, the opening pattern in step one is a groove.

[0042] In some embodiments, the opening pattern in step one is a through hole.

[0043] In some embodiments, the depth of the opening pattern in step one is greater than twice the thickness of the negative photoresist to be verified.

[0044] Step 2: Form a negative photoresist covering the opening pattern, and use photolithography to pattern the negative photoresist;

[0045] Step 3: Obtain the filling status of the negative photoresist in the opening pattern;

[0046] In some embodiments, step three uses dark-field scanning to obtain the filling status of the negative photoresist in the opening pattern.

[0047] In some embodiments, step three utilizes an optical analysis slicing method to obtain the filling status of the negative photoresist in the opening pattern.

[0048] Step 4: Determine whether cracks have appeared in the negative photoresist based on the filling situation; if so, the negative photoresist has undergone excessive shrinkage; if not, the negative photoresist has not undergone excessive shrinkage.

[0049] This invention can more accurately and intuitively determine whether negative photoresist has undergone excessive shrinkage. The method of this invention is simple and does not involve new pattern making or equipment modification, which improves the efficiency and accuracy of negative photoresist verification and saves costs.

[0050] Please see Figure 4 The absence of cracks in the filling of the opening pattern by the negative photoresist indicates that excessive shrinkage of the negative photoresist has not occurred; please refer to the figure. Figure 5 and Figure 6The appearance of cracks in the filling of the opening pattern by the negative photoresist indicates that the negative photoresist has shrunk excessively.

[0051] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0052] In summary, this invention provides a more accurate and intuitive way to determine whether excessive shrinkage of negative photoresist has occurred. The method is simple, requiring no new PCB layout or equipment modifications, thus improving both the efficiency and accuracy of negative photoresist verification while saving costs. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and possesses high industrial applicability.

[0053] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can 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 those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method of assessing negative photoresist shrinkage, characterized by, At least including: Step 1: Form an opening pattern. The depth of the opening pattern is a target multiple of the thickness of the negative photoresist to be verified. The thickness of the negative photoresist to be verified is greater than the thickness of the opening pattern. Step 2: Form a negative photoresist covering the opening pattern, and pattern the negative photoresist using photolithography; Step 3: Obtain the filling status of the negative photoresist in the opening pattern; Step 4: Determine whether the negative photoresist has cracks based on the filling condition; if so, determine that the negative photoresist has shrunk excessively; if not, determine that the negative photoresist has not shrunk excessively.

2. The method of claim 1, wherein: The opening pattern described in step one is on a semiconductor material layer.

3. The method of assessing negative photoresist shrink according to claim 2, wherein: The semiconductor material layer in step one is formed on the substrate.

4. The method of assessing negative photoresist shrink according to claim 3, wherein: The substrate in step one includes a bulk semiconductor substrate or a silicon-on-insulator (SOI) substrate.

5. The method of claim 2, wherein: The semiconductor material layer is a nitride layer or an oxide layer.

6. The method of claim 1, wherein: The opening pattern mentioned in step one is a groove.

7. The method of claim 1, wherein: The opening pattern mentioned in step one is a through hole.

8. The method of claim 1, wherein: The depth of the opening pattern in step one is greater than twice the thickness of the negative photoresist to be verified.

9. The method of claim 1, wherein: In step three, the filling status of the negative photoresist in the opening pattern is obtained using a dark-field scanning method.

10. The method of claim 1, wherein: In step three, the filling status of the negative photoresist in the opening pattern is obtained by using an optical analysis slicing method.

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