A transparent mask and its preparation method and application

Abstract

The invention belongs to the technical field of semiconductor devices, and specifically relates to a transparent mask plate and a preparation method and application thereof, comprising the following steps: S1, punching a circular hole in the center of a copper tape and a heat release tape, and closely attaching the heat release tape and the copper tape to the holes, and then attaching a PET tape to one side of the heat release tape to obtain a sample to be processed; S2, using magnetron sputtering to plate a conductive metal film on the surface of the PET tape in the sample to be processed in S1; S3, using a focused ion beam to perform rough processing on the PET tape in the mask area at the center of the circular hole until the PET tape is cut through to obtain a hole with a preset mask pattern, and then adjusting the beam to perform fine processing on the hole to obtain a PET mask plate; S4, corroding the conductive metal film in the PET mask plate to obtain a transparent mask plate; the invention has an extremely short preparation cycle, a simple method, the mask plate can be reused many times, and the transparent mask plate is very convenient for subsequent mask plate transfer and alignment to prepare semiconductor devices.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor devices, and in particular relates to a transparent mask plate and a preparation method and application thereof. Background Art

[0002] In order to meet the huge demand of the electronics industry, the field of semiconductor devices has achieved rapid development. Among them, the most important step in the preparation of semiconductor devices is the preparation of metal electrodes. At present, the two most commonly used methods for electrode preparation are photolithography and mask method. The preparation steps of photolithography are cumbersome and time-consuming, and the residual photoresist will seriously affect the performance of the device. The mask method can prepare clean and pollution-free metal electrodes, so it has been widely developed.

[0003] The most mature method of the mask method is to use low-stress silicon nitride as the raw material and process the mask shape by etching to achieve the purpose of the mask electrode. However, the preparation of silicon nitride mask plates takes a long time, and because of the low stress of silicon nitride itself, it is very easy to be damaged during use. No matter how the mask plate is attached to the substrate, it will always maintain a certain distance from the substrate, which will cause a certain diffusion effect on the mask shape, thereby affecting the quality of the mask pattern. Another disadvantage is that the mask plate is opaque and it is difficult to align it accurately with the semiconductor material.

[0004] In order to avoid the problems of diffusion and opacity, in recent years, flexible mask methods represented by polymethyl methacrylate (PMMA) and polydimethylsiloxane (PDMS) have also appeared. Due to the viscosity of these masks, the mask pattern does not diffuse and has clear boundaries. However, the success rate of preparing flexible masks is low, the preparation process is extremely complicated, and there are many human factors, which leads to poor process repeatability. In addition, the mask can only be used once and cannot be used multiple times, which has always been a major problem, thereby increasing the preparation cost and time. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a transparent mask plate and a preparation method and application thereof.

[0006] The present invention is specifically achieved through the following technical solutions.

[0007] The first object of the present invention is to provide a method for preparing a transparent mask, which is carried out according to the following steps:

[0008] S1. Punch circular holes in the center of the copper tape and the heat release tape respectively, and stick the heat release tape and the copper tape tightly with the holes facing each other, and then stick a layer of PET tape on one side of the heat release tape to obtain a sample to be processed;

[0009] S2, using magnetron sputtering process to plate a layer of conductive metal film on the surface of the PET tape in the sample to be processed in S1;

[0010] S3, placing the sample processed in S2 in a focused ion beam, first drawing a mask pattern, then rough-machining the PET tape in the central mask area of ​​the circular hole until the PET tape is cut through to obtain a hole of a preset mask pattern, and then adjusting the beam current to fine-machining the hole to obtain a PET mask plate;

[0011] S4, corroding the conductive metal film in the PET mask to obtain a transparent mask.

[0012] Preferably, in S1, the thickness of the copper tape is 1-50 um.

[0013] Preferably, in S1, the thickness of the PET tape is 1-20 um.

[0014] Preferably, in S1, the diameter of the circular hole is 0.5 mm-5 mm, and the diameter of the hole on the copper tape is smaller than or equal to the diameter of the hole on the thermal release tape.

[0015] Preferably, in S3, the mask pattern is drawn by the following steps: placing the sample processed in S2 in a focused ion beam, and under vacuum conditions, when the sample stage is rotated 53°, turning on the Ga ion source, acquiring an image of the sample to be processed, determining the coordinate position of the sample requiring the mask, adjusting the rough processing beam, and drawing the mask pattern on the main operation screen of the focused ion beam according to actual needs.

[0016] Preferably, in S3, the beam current size of the rough machining is 500-90000 pA, and the beam current size of the fine machining is 1-50000 pA, and the beam current of the fine machining is smaller than the beam current of the rough machining.

[0017] Preferably, in S3, the fine processing is to make the edge flatness of the circular hole be 10 to 30 nm.

[0018] Preferably, in S2, the metal in the conductive metal film is gold, silver or copper.

[0019] The second object of the present invention is to provide a transparent mask produced by the above production method.

[0020] The third object of the present invention is to provide an application of the transparent mask plate in the preparation of semiconductor devices, wherein the transparent mask plate is attached to a substrate material, and a metal electrode is sputtered using a magnetron sputtering process to obtain a semiconductor device.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The present invention uses various metal sheets as raw materials, and uses FIB (focused ion beam) to micro-process PET tape to obtain a transparent mask plate with a pre-designed electrode structure, and then the transparent mask plate is attached to a substrate material for metal plating to obtain a preset mask structure; the present invention uses the transparent mask plate prepared by FIB, and for preparing a single semiconductor device, the steps of glue throwing, ultraviolet exposure, and glue removal are omitted in the preparation process, which is shorter in time and more concise in process compared with the existing photolithography preparation method;

[0023] (2) The method for preparing the transparent mask provided by the present invention has a short preparation cycle, a simple method, is transparent, has no diffusion, is not easily damaged during use, and can be used repeatedly. Moreover, the transparent mask obtained by the present invention can be used to prepare a complex metal mask structure on any substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The physical image and SEM image of the transparent template provided in Example 1;

[0025] Figure 2 The graphene electrode CH prepared by using the transparent mask in Example 1 3 NH 3 PbI 3 SEM image of nanowire photodetector device;

[0026] Figure 3 The graphene electrode CH is prepared by using the transparent mask in Example 1 repeatedly for two times. 3 NH 3 PbI 3 SEM image of nanowire photodetector device;

[0027] Figure 4 The graphene electrode CH is prepared by using the transparent mask in Example 1 repeatedly for 10 times. 3 NH 3 PbI 3 SEM image of nanowire photodetector device;

[0028] Figure 5 This is the SEM image of the transparent mask in Example 2;

[0029] Figure 6 The graphene electrode MoS prepared by using the transparent mask in Example 2 2 , CH 3 NH 3 PbI 3 SEM image of the nanowire photodetector device. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention is further described below in conjunction with specific embodiments and drawings, but the embodiments are not intended to limit the present invention.

[0031] The experimental methods and detection methods described in the following embodiments are conventional methods unless otherwise specified; the reagents and materials are commercially available unless otherwise specified.

[0032] Example 1

[0033] A method for preparing a transparent mask is carried out according to the following steps:

[0034] S1. Put a 50um thick copper tape with a 3.5mm diameter hole in the center and a 3mm diameter heat release tape against each other from top to bottom, and then put a layer of 1um thick PET tape under the heat release tape to make a sample to be processed;

[0035] S2, placing the sample to be processed under magnetron sputtering, and sputtering a 100nm thick gold film on the surface of the PET tape;

[0036] S3, then put the sample into FIB and place it in vacuum at 5×10 -4 Pa, turn on the Ga ion source while the sample stage is rotated 53° (tult53°), obtain the image of the sample to be processed, determine the coordinate position of the sample that needs the mask, and adjust the beam size to 3000pA. Draw the following on the main screen of the focused ion beam operation according to actual needs: Figure 1 The mask pattern shown in the SEM image;

[0037] S4, then roughly processing the PET tape in the mask area at the center of the circular hole until the PET tape in the processing area is cut through to obtain a hole of a preset mask shape, and the processing time is about 20 minutes; then adjusting the beam current size to 1000pA, 500pA and 300pA in sequence to finely trim the hole so that the edge flatness of the hole is 10nm, and obtaining a PET mask plate;

[0038] S5. Place the PET mask plate in an iodine potassium iodide solution to etch away the gold film, thereby obtaining a transparent mask plate. Figure 1 As shown by Figure 1 It can be seen that the transparent mask plate was successfully prepared, and the preparation process omitted the steps of spinning glue, ultraviolet exposure, and degumming. Compared with the existing photolithography preparation method, it takes less time and the process is simpler.

[0039] Application Example 1

[0040] The transparent mask in Example 1 is placed on an optical transfer platform and connected to the graphene electrode CH prepared in advance. 3NH 3 PbI 3 The nanowires are aligned and firmly attached, and a gold electrode with a thickness of about 50nm is sputtered by magnetron sputtering to obtain a photoelectric detection device, which proves that the mask can accurately prepare the electrode structure of complex semiconductor devices. The SEM image is shown in Figure 2 shown.

[0041] Application Example 2

[0042] The gold-plated mask in Application Example 1 was washed off the gold on the surface with iodine potassium iodide solution, and then the graphene electrode CH was prepared for the second time according to the method of Application Example 1. 3 NH 3 PbI 3 Nanowire photodetector device, its SEM Figure 3 As shown, it is shown that the mask can be reused.

[0043] Application Example 3

[0044] The graphene electrode CH prepared by repeatedly using the transparent mask prepared in Example 1 for the 10th time 3 NH 3 PbI 3 Nanowire photodetector device, its SEM Figure 4 As shown, the mask can be used repeatedly and is not easily damaged.

[0045] The above application examples 1-3 illustrate that the present invention has a short preparation cycle, a simple method, is transparent, has no diffusion, is not easily damaged during use, and can be used repeatedly.

[0046] Example 2

[0047] A method for preparing a transparent mask is carried out according to the following steps:

[0048] S1. Put a 50um thick copper tape with a 3.5mm diameter hole in the center and a 3mm diameter heat release tape against each other from top to bottom, and then put a layer of 1um thick PET tape under the heat release tape to make a sample to be processed;

[0049] S2, placing the sample to be processed under magnetron sputtering, and sputtering a silver film with a thickness of 100 nm on the surface of the PET tape;

[0050] S3, then put the sample into FIB and place it in vacuum at 5×10 -4 Pa, turn on the Ga ion source while the sample stage is rotated 53° (tult53°), obtain the image of the sample to be processed, determine the coordinate position of the sample that needs the mask, and adjust the beam size to 3000pA. Draw the following on the main screen of the focused ion beam operation according to actual needs: Figure 5 The mask pattern shown in the SEM image;

[0051] S4, then the PET tape in the mask area at the center of the circular hole is roughly processed until the PET tape in the processing area is cut through to obtain a hole of the preset mask shape, and the processing time is about 20 minutes. Then the beam size is adjusted to 1000pA, 500pA and 300pA in sequence to fine-tune the hole so that the edge flatness of the hole is 10nm, and a PET mask is obtained;

[0052] S5, placing the PET mask plate in an iodine potassium iodide solution to corrode the silver, thus obtaining a transparent mask plate, such as Figure 5 shown.

[0053] Application Example 4

[0054] The transparent mask prepared in Example 2 was placed on an optical transfer platform and on the MoS 2 , CH 3 NH 3 PbI 3 The nanosheet heterojunction is aligned and firmly attached, and a gold electrode with a thickness of about 50nm is sputtered by magnetron sputtering to obtain a photoelectric detection device, which proves that the mask template can independently design the mask structure and prepare different types of semiconductor devices. Its SEM image is shown in Figure 6 shown.

[0055] The above embodiments illustrate that the method of the present invention can be used with various types of metal foils, and the prepared transparent mask template can be used to prepare a metal mask structure with a complex structure on any substrate. The preparation process omits the steps of glue throwing, ultraviolet exposure, and glue removal. Compared with the existing photolithography preparation method, it takes less time and has a simpler process. It is transparent, diffusion-free, and not easily damaged during use, and can be used repeatedly.

[0056] It should be noted that when the present invention involves a numerical range, it should be understood that the two endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes a preferred embodiment. Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the attached claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0057] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, they are also intended to be included.

Claims

1. A method for preparing a transparent mask, It is characterized in that The following steps are involved: S1. Punch circular holes in the center of the copper tape and the heat release tape respectively, and stick the heat release tape and the copper tape tightly with the holes facing each other, and then stick a layer of PET tape on one side of the heat release tape to obtain a sample to be processed; S2, using magnetron sputtering process to plate a layer of conductive metal film on the surface of the PET tape in the sample to be processed in S1; S3, placing the sample processed in S2 in a focused ion beam, first drawing a mask pattern, then rough-machining the PET tape in the central mask area of ​​the circular hole until the PET tape is cut through to obtain a hole of a preset mask pattern, and then adjusting the beam current to fine-machining the hole to obtain a PET mask plate; S4, corroding the conductive metal film in the PET mask to obtain a transparent mask.

2. The method for preparing a transparent mask according to claim 1, It is characterized in that In S1, the thickness of the copper tape is 1-50 um.

3. The method for preparing a transparent mask according to claim 1, It is characterized in that In S1, the thickness of the PET tape is 1-20 um.

4. The method for preparing a transparent mask according to claim 1, It is characterized in that In S1, the diameter of the circular hole on the copper tape is 0.5 mm-5 mm, and the diameter of the circular hole on the thermal release tape is 0.5 mm-5 mm.

5. The method for preparing a transparent mask according to claim 1, It is characterized in that In S3, the mask pattern is drawn through the following steps: the sample processed in S2 is placed in a focused ion beam, and under vacuum conditions, when the sample stage is rotated 53°, the Ga ion source is turned on to obtain an image of the sample to be processed, the coordinate position of the sample that requires the mask is determined, the beam current for rough processing is adjusted, and the mask pattern is drawn according to actual needs on the main operation screen of the focused ion beam.

6. The method for preparing a transparent mask according to claim 5, It is characterized in that In S3, the beam current for rough machining is 500-90000 pA, and the beam current for fine machining is 1-50000 pA, and the beam current for fine machining is smaller than the beam current for rough machining.

7. The method for preparing a transparent mask according to claim 1, It is characterized in that In S3, the fine processing is to make the edge flatness of the hole 10-30nm.

8. The method for preparing a transparent mask according to claim 1, It is characterized in that In S2, the metal in the conductive metal film is gold, silver or copper.

9. A transparent mask plate obtained according to the preparation method according to any one of claims 1 to 8.

10. Use of the transparent mask according to claim 9 in the preparation of semiconductor devices, It is characterized in that The transparent mask is attached to the substrate material, and a metal electrode is sputtered by using a magnetron sputtering process to obtain a semiconductor device.

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