Nanoimprint mold, manufacturing method and manufacturing process of fingerprint recognition chip

Abstract

The present invention provides a nanoimprint mold, a manufacturing method thereof, and a manufacturing process of a fingerprint recognition chip. Among them, the manufacturing method of the nanoimprint mold includes: sequentially forming multiple semiconductor films with controllable thicknesses on a semiconductor substrate, and performing high-precision patterning on at least one of the semiconductor films, so as to form the three-dimensional nanoimprint mold through the combination of these patterned semiconductor films. The shape of the nanoimprint mold can be precisely controlled by the patterned semiconductor films to achieve a high-precision controllable shape. It can be used to match micro-lenses of any fingerprint recognition chip and micro-lenses of other CMOS image sensors.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly to a semiconductor nanoimprint mold, a manufacturing method thereof, and a manufacturing process of a fingerprint recognition chip. Background Art

[0002] Nanoimprint lithography technology essentially applies the traditional mold replication principle to the microfabrication field.

[0003] The transfer of the NIL pattern is achieved by the mold pressing down, causing the resist to flow and fill into the surface feature pattern of the mold; subsequently, the pressing load of the mold is increased, resulting in the thinning of the resist. During the thinning process of the resist, the pressing load remains constant; when the resist is thinned to within the range allowed by subsequent processes (the set remaining film thickness), the mold pressing is stopped and the resist is cured.

[0004] Compared with the traditional lithography process, it does not achieve the patterning of the resist by changing the chemical properties of the resist, but by the force-induced deformation of the resist.

[0005] According to the imprint area, imprint lithography technology can be divided into step imprint lithography (SIL) and full-wafer imprint; according to whether the resist needs to be heated during the imprint process, it can be divided into hot embossing lithography and room-temperature imprint lithography (UV-NIL); according to the hardness of the imprint mold, it can be divided into soft imprint lithography and hard imprint lithography.

[0006] As the initial carrier of the imprint features, the mold directly determines the quality of the imprint features. To achieve high-quality imprint replication, a high-quality imprint mold is necessary. Different from the mask (4X) used in traditional optical lithography, the 1X template used in nanoimprint lithography faces greater challenges in mold manufacturing, inspection, and repair technologies.

[0007] Currently, the manufacturing of the mold has become the biggest technical bottleneck of NIL. Moreover, with the increasing in-depth research of nanoimprint lithography and the continuous expansion of the application fields, the manufacturing of NIL molds will become more and more important and face more severe challenges.

[0008] According to the latest research progress of various nanoimprint lithography mold manufacturing technologies at home and abroad, the main challenges faced by current NIL molds are: the manufacturing of three-dimensional molds, large-area molds, and high-resolution molds, and the inspection and repair of mold defects. These will be the most urgent problems to be solved and the main research hotspots in the current and next few years. In addition, compared with hard molds, soft molds can well adapt to the flatness tolerance and parallelism error problems between the mold and the substrate, increase the imprint area, have the ability to imprint on the entire silicon wafer, have a small imprint force, are easy to form and demold, and can overcome resist particle defects and other advantages.

[0009] Better soft mold manufacturing processes are also a key research direction at present. With the continuous improvement and enhancement of mold manufacturing technologies, the application of nanoimprint lithography will also become more and more extensive.

[0010] With the rapid development of the terminal industry, biometric recognition technologies have attracted increasing attention. Currently, fingerprint recognition devices are installed in mobile terminals for various operations such as unlocking and password setting through fingerprint recognition. The practical application of more convenient biometric recognition technologies, such as fingerprint recognition technology, has become a necessity for the public.

[0011] Among them, the optical fingerprint recognition device adopts the imaging principle of CIS (CMOS image sensor) to collect signals from biometric fingerprint images and finally form images; then, the collected image information is compared with the pre-stored fingerprint image information to identify information related to biometric fingerprints.

[0012] In traditional technologies, the light-blocking layer is formed by depositing semiconductor materials or metal layers + photolithography + etching, which requires multiple steps; and the method for preparing micro-lenses is: first, the chip circuit is fabricated and a passivation layer is added; then, additional processes are used to prepare a planarization layer and micro-lenses using organic materials. Overall, using additional processes and materials will increase product costs, extend the production cycle, and the quality of the fabricated products will also be affected by more uncontrollable factors and cannot be better guaranteed. Summary of the Invention

[0013] The purpose of the present invention is to provide a manufacturing process for semiconductor nanoimprint molds and fingerprint recognition chips, so as to solve the technical problem of the complex manufacturing process of optical fingerprint recognition devices in traditional technologies.

[0014] To solve the above technical problems, the present invention provides a method for manufacturing a nanoimprint mold, including:

[0015] Successively form multiple semiconductor films with controllable thicknesses on a semiconductor substrate, and perform high-precision patterning on at least one of the semiconductor films, so as to form the three-dimensional nanoimprint mold through the combination of these patterned semiconductor films.

[0016] Preferably, provide a semiconductor substrate;

[0017] Successively form the nth semiconductor film on the semiconductor substrate by CVD;

[0018] Successively form the nth semiconductor pattern in the nth semiconductor film by photolithography and etching;

[0019] The semiconductor substrate and all semiconductor patterns form a groove or a protrusion to form the nanoimprint mold; wherein, n is a natural number.

[0020] Preferably, the semiconductor film is silicon dioxide, glass or silicon.

[0021] Preferably, the semiconductor pattern is a round hole or a round wafer.

[0022] Preferably, the formed groove or protrusion is a semi-spherical groove or a semi-spherical protrusion.

[0023] Preferably, the maximum circumferential diameter of the semi-spherical groove or the semi-spherical protrusion is 46 μm, and the depth is 7.5 μm.

[0024] Preferably, the edge of the nth layer semiconductor pattern covers the edge of the (n - 1)th layer semiconductor pattern or the edge of the (n - 1)th layer semiconductor pattern exceeds the edge of the nth layer semiconductor pattern.

[0025] Preferably, the thickness of the semiconductor pattern is 200 Å - 250 Å.

[0026] Preferably, the value range of n is: 30 ≤ n ≤ 40.

[0027] Preferably, the alignment accuracy range of the photolithography and etching is 0.005 μm - 0.05 μm.

[0028] Preferably, after the nth layer semiconductor film is sequentially formed on the semiconductor substrate by CVD, before the nth layer semiconductor pattern is sequentially formed in the nth layer semiconductor film by using photolithography and etching, a step of chemical mechanical polishing of the nth layer semiconductor film is further included.

[0029] The technical solution of the present invention further provides a semiconductor nanoimprint mold, including: a semiconductor substrate, n layers of semiconductor films formed on the semiconductor substrate, semiconductor patterns included in the semiconductor films, and the semiconductor substrate and all semiconductor patterns form a groove or a protrusion to form the nanoimprint mold; wherein, n is a natural number.

[0030] Preferably, it includes: the semiconductor film is silicon dioxide.

[0031] Preferably, the semiconductor pattern is a round hole or a round wafer.

[0032] Preferably, the groove or the protrusion is a semi-spherical groove or a semi-spherical protrusion.

[0033] Preferably, the maximum circumferential diameter of the semi-spherical groove or the semi-spherical protrusion is 46 μm, and the depth is 7.5 μm.

[0034] Preferably, the edge of the nth layer semiconductor pattern covers the edge of the (n - 1)th layer semiconductor pattern or the edge of the (n - 1)th layer semiconductor pattern exceeds the edge of the nth layer semiconductor pattern.

[0035] Preferably, the thickness of the semiconductor pattern is 200 Å to 250 Å.

[0036] Preferably, the value range of n is: 30 ≤ n ≤ 40.

[0037] The technical solution of the present invention also provides a manufacturing process for a fingerprint recognition chip, including:

[0038] Providing a semiconductor nanoimprint mold formed by the manufacturing method as described above;

[0039] Covering a semiconductor material layer on the surface of the image sensor chip, and using the semiconductor nanoimprint mold to imprint to form the microlens of the fingerprint recognition chip.

[0040] Preferably, the semiconductor material layer is an epoxy resin material or an acrylic material.

[0041] Compared with the prior art, the semiconductor nanoimprint mold and the fingerprint recognition chip of the present invention have the following beneficial effects:

[0042] In the present invention, in the manufacturing method of the provided semiconductor nanoimprint mold, multiple semiconductor films with controllable thicknesses are sequentially formed on a semiconductor substrate, and at least one of the semiconductor films is patterned with high precision. Through the combination of these patterned semiconductor films, the three-dimensional nanoimprint mold is formed. In this process, the material, thickness, pattern, etching rate, etc. of each layer of film can be controlled and adjusted through semiconductor process parameters. Furthermore, grooves with arbitrary morphologies can be formed through these parameters to match the microlenses of any fingerprint recognition chip and other CMOS image sensors.

[0043] In the present invention, the semiconductor nanoimprint mold formed by the above manufacturing method can directly imprint the semiconductor material layer covered on the surface of the image sensor chip to form the microlens of the fingerprint recognition chip by means of nanoimprinting. Such a process is simple and efficient, saving process steps and costs. Description of the Drawings

[0044] Figure 1 It is a flowchart of the manufacturing method of the semiconductor nanoimprint mold provided in an embodiment of the present invention;

[0045] Figure 2 It is a cross-sectional view of the semiconductor nanoimprint mold provided in an embodiment of the present invention. Detailed Embodiments

[0046] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the spirit of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0047] Secondly, the present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of illustration, the schematic diagrams are only examples and should not limit the scope of protection of the present invention herein.

[0048] The method for manufacturing an imprint mold provided by the present invention is to grow / deposit multiple semiconductor films with controllable thicknesses on a semiconductor substrate in sequence by processes such as chemical vapor deposition or physical vapor deposition. At the same time, lithography, etching, chemical mechanical polishing, etc. are used to perform high-precision patterning on each layer or some of the semiconductor films, and through the superposition and combination of these patterned semiconductor films and subsequent processing, grooves or protrusions are formed to obtain the nanoimprint mold.

[0049] The nanoimprint mold can be applied to the production of micro-lenses for fingerprint recognition chips and micro-lenses of other CMOS image sensors.

[0050] Since each process of the present invention is precisely controllable and adjustable, the morphology of the prepared mold is controllable and can meet the requirements of any product.

[0051] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following describes in detail the manufacturing process of the semiconductor nanoimprint mold and fingerprint recognition chip of the present invention with reference to the accompanying drawings.

[0052] The present invention provides a method for manufacturing a nanoimprint mold, including:

[0053] Form multiple semiconductor films with controllable thicknesses on a semiconductor substrate in sequence, and perform high-precision patterning on at least one of the semiconductor films, so as to form the three-dimensional nanoimprint mold through the combination of these patterned semiconductor films.

[0054] Refer to Figure 1 As shown, in a specific embodiment, the method for manufacturing the nanoimprint mold includes:

[0055] Step S100: Provide a semiconductor substrate;

[0056] In this embodiment, the semiconductor substrate is a silicon wafer substrate. It may also include an epitaxial layer on the surface of the silicon substrate.

[0057] In other embodiments, the semiconductor substrate may also be a germanium substrate, a GaAs substrate, a GaN substrate, or a SiC substrate, or a substrate of other semiconductor materials.

[0058] Step S200: Sequentially form an nth layer semiconductor film on the semiconductor substrate by CVD;

[0059] In this embodiment, the material of the nth layer semiconductor film is silicon dioxide, glass, or silicon.

[0060] Preferably, in this step, the thickness of the nth layer semiconductor film formed by CVD is greater than 250 Å.

[0061] Step S300: Sequentially form an nth layer semiconductor pattern in the nth layer semiconductor film by lithography and etching;

[0062] Specifically, in this embodiment, the alignment accuracy range of the lithography and etching is 0.005 μm to 0.05 μm.

[0063] Specifically, in this embodiment, after sequentially forming the nth layer semiconductor film on the semiconductor substrate by CVD, before sequentially forming the nth layer semiconductor pattern in the nth layer semiconductor film by lithography and etching, it further includes a step of chemically mechanical polishing the nth layer semiconductor film.

[0064] Specifically, in this embodiment, the thickness of each layer of the semiconductor pattern is 200 Å to 250 Å.

[0065] Step S400: The semiconductor substrate and all semiconductor patterns form a groove or a protrusion to form the nanoimprint mold; where n is a natural number.

[0066] Specifically, in this embodiment, the formed semiconductor pattern is a round hole or a round wafer. The edge of the nth layer semiconductor pattern covers the edge of the (n - 1)th layer semiconductor pattern or the edge of the (n - 1)th layer semiconductor pattern exceeds the edge of the nth layer semiconductor pattern.

[0067] Preferably, the n layer semiconductor patterns are stacked to form a groove or a protrusion, and the groove or the protrusion is a semi-spherical groove or a semi-spherical protrusion.

[0068] Specifically, in this embodiment, the maximum circumferential diameter of the semi-spherical groove or the semi-spherical protrusion is 46 μm, and the depth is 7.5 μm.

[0069] Specifically, the following combines Figure 1 , with reference to Figure 2 shown, a specific example is used to specifically illustrate the present invention.

[0070] FIG. 1 is a schematic structural diagram of an imprinting mold according to an embodiment of the present invention. Among them, 100 is a semiconductor substrate, which may also include a semiconductor substrate and an epitaxial layer disposed thereon. 101 is a silicon oxide layer, 102 is a silicon nitride layer, and 103, 104, …, 109 are respectively the first to seventh semiconductor films deposited and patterned subsequently. These 7 semiconductor films together form a groove (110), and these grooves can be used as a mold for nanoimprinting, and are used for producing microlenses for fingerprint recognition chips and microlenses for other CMOS image sensors.

[0071] The specific process steps are as follows:

[0072] First, a SiO2 layer 101 and a SiN layer 102 are deposited on the semiconductor substrate 100 by CVD as the base of the imprinting mold;

[0073] Subsequently, on the above basis, the first semiconductor film 103 made of SiO2 is deposited by CVD, and then patterned by high-precision lithography and etching to form the pattern of 103;

[0074] Subsequently, on the above basis, a SiO2 layer 104 is continuously deposited by CVD, and patterned by lithography and etching to form a semiconductor pattern in the SiO2 layer 104. The SiO2 layer 104 needs to shrink inward based on the first semiconductor film 103;

[0075] Subsequently, on the above basis, the relevant processes are repeated in sequence to form semiconductor film coatings 105, 106, …, 109, etc. The pattern of the latter layer needs to shrink inward based on the pattern of the previous layer, and this shrinkage amount depends on the morphology of the microlens and the process deviation;

[0076] After all the above semiconductor processes, the groove is basically formed. However, since the etching processes of the semiconductor film layers 103 to 109 will inevitably cause some uneven morphology, a thin silicon oxide needs to be deposited by CVD afterwards. This silicon oxide can appropriately smooth the groove surface and optimize the morphology.

[0077] Throughout the process, the material, thickness, pattern, etching rate, etc. of each layer of film are controllable and adjustable. Grooves with arbitrary morphologies can be formed through these parameters to match microlenses for any fingerprint recognition chips and microlenses for other CMOS image sensors.

[0078] This embodiment also provides a semiconductor nanoimprinting mold, including: a semiconductor substrate, n semiconductor films formed on the semiconductor substrate, the semiconductor films including semiconductor patterns, and the semiconductor substrate and all semiconductor patterns form grooves or protrusions to form the nanoimprinting mold; where n is a natural number.

[0079] In this embodiment, the semiconductor film is silicon dioxide.

[0080] In this embodiment, the semiconductor pattern is a round hole or a round wafer.

[0081] In this embodiment, the groove or protrusion is a semi-spherical groove or a semi-spherical protrusion.

[0082] In this embodiment, the maximum circumferential diameter of the semi-spherical groove or semi-spherical protrusion is 46 μm, and the depth is 7.5 μm.

[0083] In this embodiment, the edge of the nth layer semiconductor pattern covers the edge of the (n - 1)th layer semiconductor pattern or the edge of the (n - 1)th layer semiconductor pattern exceeds the edge of the nth layer semiconductor pattern.

[0084] In this embodiment, the thickness of the semiconductor pattern is 200 Å - 250 Å.

[0085] In this embodiment, the value range of n is: 30 ≤ n ≤ 40.

[0086] In addition, this embodiment also provides a manufacturing process for a fingerprint recognition chip, including:

[0087] Providing a semiconductor nanoimprint mold formed by the manufacturing method as described above;

[0088] Covering a semiconductor material layer on the surface of the image sensor chip, and using the semiconductor nanoimprint mold to imprint and form the microlens of the fingerprint recognition chip.

[0089] In this embodiment, the semiconductor material layer is an epoxy resin material or an acrylic material.

[0090] Although the present invention has been disclosed above with preferred embodiments, it is not used to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention without departing from the spirit and scope of the present invention. Therefore, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for fabricating a nanoimprint mold, characterized in that, Including: Forming multiple semiconductor films with controllable thicknesses in sequence on a semiconductor substrate, and performing high-precision patterning on at least one of the semiconductor films, so as to form the three-dimensional nanoimprint mold through the combination of these patterned semiconductor films; The edge of the nth layer semiconductor pattern covers the edge of the (n - 1)th layer semiconductor pattern or the edge of the (n - 1)th layer semiconductor pattern exceeds the edge of the nth layer semiconductor pattern.

2. The method for fabricating a nanoimprint mold according to claim 1, characterized in that, Providing a semiconductor substrate; Sequentially forming the nth layer semiconductor film on the semiconductor substrate by CVD; Sequentially forming the nth layer semiconductor pattern in the nth layer semiconductor film by using photolithography and etching; The semiconductor substrate and all semiconductor patterns form a groove or a protrusion to form the nanoimprint mold; wherein, n is a natural number.

3. The method for fabricating a nanoimprint mold according to claim 1, characterized in that, The semiconductor film is silicon dioxide, glass or silicon.

4. The method for fabricating a nanoimprint mold according to claim 1, characterized in that, The semiconductor pattern is a round hole or a round wafer.

5. The method for fabricating a nanoimprint mold according to claim 2 or 4, characterized in that, The formed groove or protrusion is a semi-spherical groove or a semi-spherical protrusion.

6. The method for fabricating a nanoimprint mold according to claim 5, characterized in that, The maximum circumferential diameter of the semi-spherical groove or the semi-spherical protrusion is 46 μm, and the depth is 7.5 μm.

7. The method for fabricating a nanoimprint mold according to claim 1, characterized in that, The thickness of the semiconductor pattern is 200 Å - 250 Å.

8. The method for fabricating a nanoimprint mold according to claim 1, characterized in that, The value range of n is: 30 ≤ n ≤ 40.

9. The method for fabricating a nanoimprint mold according to claim 1, characterized in that, The alignment accuracy range of the photolithography and etching is 0.005 μm - 0.05 μm.

10. The method for fabricating a nanoimprint mold according to claim 1, characterized in that, After sequentially forming the nth layer semiconductor film on the semiconductor substrate by CVD, and before sequentially forming the nth layer semiconductor pattern in the nth layer semiconductor film by using photolithography and etching, it further includes the step of chemically mechanical polishing the nth layer semiconductor film.

11. A semiconductor nanoimprint mold, characterized in that, Including: A semiconductor substrate, n semiconductor films formed on the semiconductor substrate, the semiconductor films include semiconductor patterns, and the semiconductor substrate and all semiconductor patterns form a groove or a protrusion to form the nanoimprint mold; wherein, n is a natural number; The edge of the nth layer semiconductor pattern covers the edge of the (n - 1)th layer semiconductor pattern or the edge of the (n - 1)th layer semiconductor pattern exceeds the edge of the nth layer semiconductor pattern.

12. The semiconductor nanoimprint mold according to claim 11, characterized in that, Including: The semiconductor film is silicon dioxide.

13. The semiconductor nanoimprint mold according to claim 11, characterized in that, The semiconductor pattern is a round hole or a round wafer.

14. The semiconductor nanoimprint mold according to claim 11 or 13, characterized in that, The groove or the protrusion is a semi-spherical groove or a semi-spherical protrusion.

15. The semiconductor nanoimprint mold according to claim 11, characterized in that, The maximum circumferential diameter of the semi-spherical groove or the semi-spherical protrusion is 46 μm, and the depth is 7.5 μm.

16. The semiconductor nanoimprint mold according to claim 11, wherein The thickness of the semiconductor pattern is 200 Å - 250 Å.

17. The semiconductor nanoimprint mold according to claim 11, wherein The value range of n is: 30 ≤ n ≤ 40.

18. A manufacturing process of a fingerprint recognition chip, wherein Including: Providing a semiconductor nanoimprint mold formed by the manufacturing method as claimed in claim 1; Covering a semiconductor material layer on the surface of an image sensor chip, and using the semiconductor nanoimprint mold to imprint and form the microlens of the fingerprint recognition chip.

19. The manufacturing process of the fingerprint recognition chip according to claim 18, wherein The semiconductor material layer is an epoxy resin material or an acrylic material.

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