Preprocessing method of chip
By using dilute hydrofluoric acid treatment solution to the chip cross-section and cleaning the ultra-pure water, the problem of poor image rendering effect of different material layers of the chip cross-section in the prior art is solved, and a clearer effect is achieved The chip cross-sectional morphology and a more controllable pre-processing process.
Patent Information
- Application Number
- CN202410655546.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-08-10
- Filing Date
- 2024-05-24
- Publication Date
- 2025-02-18
AI Technical Summary
In the existing chip pretreatment methods, the preparation of buffer oxide etching liquid is complicated, and the silicate crystals produced by the reaction are difficult to dissolve, which is easy to remain on the chip cross-section, affecting the observation effect; the reaction ion etching machine is complex in operation, time-consuming, and equipment cost. high.
The chip cross-section is micro-etched with dilute hydrofluoric acid treatment solution, and then the first cleaning process is performed using ultrapure water to remove the remaining dilute hydrofluoric acid liquid and obtain the cross-section to be detected.
It significantly improves the boundary line of the silicon oxide layer, improves the chip cross-section morphology quality, simplifies the pre-processing process, and reduces equipment costs and operational complexity.
Smart Images
Figure CN119480663A_ABST
Abstract
Description
[0001] This application claims the priority of Chinese patent application 2023110080552 filed on August 10, 2023, and incorporates the entire contents of the patent application by introduction. Technical Field
[0002] The present invention relates to the technical field of chip cleaning technology, and in particular to a chip pre-treatment method. Background Art
[0003] The chip cross section needs to be pre-treated before microscopic observation. Existing pre-treatment methods include using a buffered oxide etchant or a reactive ion etcher to pre-treat the chip cross section. Buffered oxide etchant (BOE) is a mixture of hydrofluoric acid (49%) and water or ammonium fluoride and water. BOE is a mixture and has a complicated preparation process. The concentration and time required for pre-treatment of the chip cross section need to be optimized. At the same time, the silicate crystals produced by the reaction will adhere to the chip cross section because they are insoluble substances, thereby affecting the morphological quality of the observed chip cross section. The selection of reactive ion etcher is more complicated than usual, and an adapted fixture is required to clamp the chip cross section. The operation is complicated, relatively time-consuming, and the equipment cost is high.
[0004] Therefore, it is necessary to develop a chip pre-processing method to solve the above problems existing in the prior art. Summary of the invention
[0005] The object of the present invention is to provide a chip pre-processing method, which solves the problem of poor imaging effect of boundary lines of different material layers on the chip cross section in the prior art.
[0006] To achieve the above object, the present invention provides a chip pre-treatment method, wherein the chip treated by the pre-treatment method is used for microscopic observation, and the chip pre-treatment method comprises the following steps:
[0007] S0: Provide chip cross section;
[0008] S1: placing the chip cross section in a dilute hydrofluoric acid treatment solution for micro-etching to obtain a micro-etched chip cross section;
[0009] S2: using ultrapure water to perform a first cleaning treatment on the micro-etched chip cross section to remove the dilute hydrofluoric acid treatment solution remaining on the micro-etched chip cross section to obtain a chip cross section to be tested.
[0010] The chip pretreatment method of the present invention has the following beneficial effects: the preparation process of the dilute hydrofluoric acid treatment solution used in the present invention is simple, the effect of selective micro-etching can be achieved on the chip cross section containing silicon oxide, and the boundary of the silicon oxide layer can be significantly improved. At the same time, the use of the dilute hydrofluoric acid treatment solution to perform micro-etching treatment on the chip cross section can make the pretreatment process more controllable and easy to operate, and there is no obvious damage to the film layer morphology of the chip cross section, and the measurement of the film layer thickness is not affected. The present invention solves the problem of poor imaging effect of the boundary lines of different material layers on the chip cross section in the prior art.
[0011] Optionally, the concentration of the dilute hydrofluoric acid treatment solution is 1%-10%.
[0012] Optionally, the temperature of the micro-etching treatment is 20-25 degrees Celsius, and the time of the micro-etching treatment is 2-20 seconds.
[0013] Optionally, the temperature of the first cleaning treatment is 20-25 degrees Celsius, and the time of the first cleaning treatment is 10-30 seconds.
[0014] Optionally, the chip pre-treatment method further includes the following steps: S3: performing gold plating on the chip cross section to be detected, and performing microscopic observation on the gold-plated chip cross section to be detected.
[0015] Optionally, between step S2 and step S3, the following steps are further included: ultrasonically cleaning the cross section of the chip to be detected, then using ultrapure water to perform a second cleaning treatment on the cross section of the chip to be detected after the ultrasonic cleaning, and finally drying the cross section of the chip to be detected after the second cleaning treatment. The beneficial effect is that the use of ultrasonic cleaning can conveniently and effectively improve the cleanliness of the chip cross section, which is conducive to microscopic observation, and the equipment cost required for ultrasonic cleaning is relatively low.
[0016] Optionally, in step S0, the step of providing a chip cross section further includes:
[0017] S01: Processing micro grooves on the chip;
[0018] S02: applying pressure to the back side of the chip with the micro groove so that the chip is broken along the direction of the micro groove under the action of the pressure, and the broken cross section is the cross section of the chip.
[0019] Optionally, the temperature of the ultrasonic cleaning is 20-25 degrees Celsius, and the time of the ultrasonic cleaning is 30-60 seconds.
[0020] Optionally, the gas used in the drying process is nitrogen or dry compressed air.
[0021] Optionally, the instrument used for the microscopic observation is a scanning electron microscope.
[0022] The beneficial effects of this application are:
[0023] 1. Use dilute hydrofluoric acid treatment solution as the pretreatment solution. The dilute hydrofluoric acid treatment solution has a single component, is easy to prepare and obtain, and has high selectivity for micro-etching of different materials.
[0024] 2. Using dilute hydrofluoric acid treatment solution can effectively reveal the film boundary of the chip cross section containing the silicon oxide layer, which is more conducive to the measurement of the film thickness.
[0025] 3. The optimized treatment conditions of the dilute hydrofluoric acid treatment solution make the micro-etching process more controllable, easy to operate, short time consumption, and low equipment and material costs.
[0026] 4. Use ultrasonic cleaning to remove contaminants from the chip cross section, and use a scanning electron microscope to significantly improve the quality of chip cross section observation. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 A schematic flow chart of a chip pre-processing method according to an embodiment of the present invention;
[0028] Figure 2 A schematic structural diagram of a chip cross section according to an embodiment of the present invention;
[0029] Figure 3 A schematic diagram of the structure of a chip subjected to micro-etching processing according to an embodiment of the present invention;
[0030] Figure 4 A schematic structural diagram of a chip cross section to be detected according to an embodiment of the present invention;
[0031] Figure 5 A schematic diagram of a structure for cleaning a chip according to an embodiment of the present invention;
[0032] Figure 6 A schematic diagram of scanning electron microscope scanning results of a chip cross section according to an embodiment of the present invention;
[0033] Figure 7 It is a schematic diagram of scanning electron microscope scanning results of a chip cross section to be inspected according to an embodiment of the present invention. DETAILED DESCRIPTION
[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be understood by people with general skills in the field to which the present invention belongs. "Including" and similar words used in this article mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.
[0035] The chip cross section contains structures with poor conductivity such as silicon oxide. When observing under a microscope, the emitted electrons will accumulate on the oxide surface, resulting in a charging effect that makes it impossible to obtain a clear cross-sectional structure of the chip. When actually breaking and obtaining the chip cross section, especially when breaking the chip by hand to obtain the cross section, the chip cross section is prone to adsorbing foreign impurity particles, causing the chip cross section to be contaminated, making it difficult to obtain a clean cross-sectional morphology during microscopic observation.
[0036] Figure 1 A schematic flow chart of a chip pre-processing method according to an embodiment of the present invention; Figure 2 A schematic structural diagram of a chip cross section according to an embodiment of the present invention; Figure 3 A schematic diagram of the structure of a chip subjected to micro-etching processing according to an embodiment of the present invention; Figure 4 A schematic structural diagram of a chip cross section to be detected according to an embodiment of the present invention; Figure 5 A schematic diagram of a structure for cleaning a chip according to an embodiment of the present invention; Figure 6 A schematic diagram of scanning electron microscope scanning results of a chip cross section according to an embodiment of the present invention; Figure 7 It is a schematic diagram of scanning electron microscope scanning results of a chip cross section to be inspected according to an embodiment of the present invention.
[0037] Some embodiments of the present invention refer to Figure 1 , a chip pre-treatment method is provided, the chip treated by the pre-treatment method is used for microscopic observation, the chip pre-treatment method comprises the following steps:
[0038] S0: Provide chip cross section;
[0039] S1: placing the chip cross section in a dilute hydrofluoric acid treatment solution for micro-etching to obtain a micro-etched chip cross section;
[0040] S2: performing a first cleaning treatment on the micro-etched chip cross section using ultrapure water to remove the dilute hydrofluoric acid treatment solution remaining on the micro-etched chip cross section, thereby obtaining a chip cross section to be tested;
[0041] S3: performing gold plating on the chip cross section to be inspected, and performing microscopic observation on the gold-plated chip cross section to be inspected.
[0042] Specifically, the preparation process of the dilute hydrofluoric acid treatment solution used in the present invention is simple, and the effect of selective micro-etching can be achieved on the cross section of the chip containing silicon oxide, which can significantly improve the boundary of the silicon oxide layer. At the same time, the use of the dilute hydrofluoric acid treatment solution to perform micro-etching on the cross section of the chip can make the pre-treatment process more controllable and easy to operate, and there is no obvious damage to the film layer morphology of the cross section of the chip, and it does not affect the measurement of the film layer thickness. The present invention solves the problem of poor imaging effect of the boundary line of different material layers on the cross section of the chip in the prior art.
[0043] In some embodiments of the present invention, the step of performing gold plating on the chip cross section to be inspected includes the following steps: placing the chip cross section to be inspected in a gold plating machine equipped with a scanning electron microscope to perform gold plating on the chip cross section to be inspected.
[0044] In some embodiments of the present invention, the concentration of the dilute hydrofluoric acid treatment solution is 1%-10%. In some specific embodiments, the concentration of the dilute hydrofluoric acid treatment solution is any one of 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% and 10%. In other specific embodiments, the concentration of the dilute hydrofluoric acid treatment solution is 3%-7%. In some other specific embodiments, the concentration of the dilute hydrofluoric acid treatment solution is a mass percentage concentration.
[0045] In some embodiments of the present invention, the temperature of the micro-etching process is 20-25 degrees Celsius, and the time of the micro-etching process is 2-20 seconds.
[0046] Some embodiments of the present invention refer to Figure 2 , step S0, the step of providing a chip cross section further comprises:
[0047] S01: processing micro grooves on chip 1;
[0048] S02: applying pressure on the back side of the chip 1 at the micro groove so that the chip 1 is broken along the direction of the micro groove under the action of the pressure, and the broken section is the chip cross section 11.
[0049] Some embodiments of the present invention refer to Figure 2 , the direction of the micro groove is the direction indicated by A, and the number of the micro groove is one.
[0050] Some embodiments of the present invention refer to Figure 3 and Figure 4 The micro-etching treatment is carried out in the container 2, the chip 1 and the chip cross section 11 are completely immersed in the dilute hydrofluoric acid treatment solution 21, and the micro-etching treatment is performed for 2-20 seconds at room temperature to obtain the chip cross section 12 to be detected.
[0051] In some embodiments of the present invention, the temperature of the first cleaning treatment is 20-25 degrees Celsius, and the time of the first cleaning treatment is 10-30 seconds.
[0052] Some embodiments of the present invention further include the following steps between step S2 and step S3: ultrasonically cleaning the cross section of the chip to be detected, then using ultrapure water to perform a second cleaning treatment on the cross section of the chip to be detected after the ultrasonic cleaning, and finally drying the cross section of the chip to be detected after the second cleaning treatment. Ultrasonic cleaning can conveniently and effectively improve the cleanliness of the chip cross section, facilitate microscopic observation, and the equipment cost required for ultrasonic cleaning is relatively low.
[0053] In some embodiments of the present invention, the specific step of finally drying the chip cross section to be inspected after the second cleaning treatment comprises: using a nitrogen gun to fully purge the chip cross section to be inspected after the second cleaning treatment to complete the drying treatment.
[0054] In some embodiments of the present invention, the temperature of the ultrasonic cleaning is 20-25 degrees Celsius, and the time of the ultrasonic cleaning is 30-60 seconds.
[0055] Some embodiments of the present invention refer to Figure 4 and Figure 5 The ultrasonic cleaning is performed in an ultrasonic cleaning machine 3, the chip 1 and the chip section to be tested 12 are completely immersed in the ultrapure water 31, and ultrasonic cleaning is performed for 30-60 seconds at room temperature.
[0056] In some embodiments of the present invention, the gas used in the drying process is nitrogen or dry compressed air.
[0057] In some embodiments of the present invention, the instrument used for the microscopic observation is a scanning electron microscope.
[0058] In some embodiments of the present invention, a scanning electron microscope is used to detect the cross section of the gold-plated chip, and the detection results are referred to Figure 6 The cross section of the chip to be tested after the gold plating treatment was tested using a scanning electron microscope, and the test results were referred to Figure 7 . Reference Figure 6 and Figure 7Compared with the chip cross section, the chip cross section to be tested obtained after the chip pretreatment method provided by the present application has better cleanliness, which is conducive to microscopic observation of the chip cross section, and the film layer morphology of the chip cross section has no obvious damage, which will not affect the measurement of the film layer thickness.
[0059] Figure 6 The cross section of the chip is not subjected to the pretreatment method provided by the present invention, that is, no dilute hydrofluoric acid treatment solution and ultrasonic cleaning are used. Figure 6 The chip cross section in is the chip cross section described in step S0; Figure 7 The chip cross section to be tested is obtained after being treated by the chip pre-treatment method provided by the present invention, that is, using a dilute hydrofluoric acid treatment solution and ultrasonic cleaning. Figure 6 The chip cross section and Figure 7 The cross-sections of the chips to be tested have been gold-plated, which is a necessary operation for observing cross-section samples using a scanning electron microscope.
[0060] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.
Claims
1. A chip pre-processing method, characterized in that: The chip treated by the pre-treatment method is used for microscopic observation, and the chip pre-treatment method comprises the following steps: S0: Provide chip cross section; S1: placing the chip cross section in a dilute hydrofluoric acid treatment solution for micro-etching to obtain a micro-etched chip cross section; S2: using ultrapure water to perform a first cleaning treatment on the micro-etched chip cross section to remove the dilute hydrofluoric acid treatment solution remaining on the micro-etched chip cross section to obtain a chip cross section to be tested.
2. The chip pre-processing method according to claim 1, characterized in that: The concentration of the dilute hydrofluoric acid treatment solution is 1%-10%.
3. The chip pre-processing method according to claim 1, characterized in that: The temperature of the micro-etching treatment is 20-25 degrees Celsius, and the time of the micro-etching treatment is 2-20 seconds.
4. The chip pre-processing method according to claim 1, characterized in that: The temperature of the first cleaning process is 20-25 degrees Celsius, and the time of the first cleaning process is 10-30 seconds.
5. The chip pre-processing method according to claim 1, characterized in that: The following steps are also included: S3: performing gold plating on the chip cross section to be inspected, and performing microscopic observation on the gold-plated chip cross section to be inspected.
6. The chip pre-processing method according to claim 5, characterized in that: The following steps are also included between step S2 and step S3: The chip section to be detected is ultrasonically cleaned, and then the chip section to be detected that has been ultrasonically cleaned is subjected to a second cleaning treatment using ultrapure water. Finally, the chip section to be detected that has been subjected to the second cleaning treatment is dried.
7. The chip pre-processing method according to claim 1, characterized in that: Step S0, the step of providing a chip cross section further includes: S01: Processing micro grooves on the chip; S02: applying pressure to the back side of the chip with the micro groove so that the chip is broken along the direction of the micro groove under the action of the pressure, and the broken cross section is the cross section of the chip.
8. The chip pre-processing method according to claim 6, characterized in that: The temperature of the ultrasonic cleaning is 20-25 degrees Celsius, and the time of the ultrasonic cleaning is 30-60 seconds.
9. The chip pre-processing method according to claim 6, characterized in that: The gas used in the drying process is nitrogen or dry compressed air.
10. The chip pre-processing method according to claim 1, characterized in that: The instrument used for the microscopic observation is a scanning electron microscope.