Method for manufacturing a device structure based on a laser etching process

Abstract

The application provides a device structure preparation method based on a laser etching process, comprising the following steps: 1) focusing a plurality of laser mother light beams respectively, and then equally dividing the plurality of laser mother light beams into a plurality of laser sub-light beams, and arranging the plurality of laser sub-light beams at equal distances; 2) providing a control module, the control module can independently control each laser sub-light beam; 3) acquiring the actual positions of the laser sub-light beams through a laser marking alignment method, so as to establish a coordinate layer corresponding to the actual positions of each laser sub-light beam in the control module; and 4) based on the coordinate layer, controlling each laser sub-light beam to perform laser etching on a target substrate through the control module, so as to form a required device structure. The application can achieve the purpose of precise etching of light waveguides with different positions and different shapes in a mask-free state through control of a plurality of laser beams, can greatly reduce the cost and improve the etching rate, and can realize precise etching of light waveguides with different depths by changing the types and energy of the laser.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor integrated circuit design and manufacturing, and in particular relates to a method for fabricating device structures based on laser etching technology. Background Technology

[0002] In integrated optical circuits, the optical waveguide is the most fundamental component. Commonly used etching methods for optical waveguides include photolithography, plasma etching, electron beam etching, and laser etching. Among these, laser etching possesses superior characteristics such as non-contact operation, high flexibility, fast processing speed, small heat-affected zone, and the ability to focus to extremely small spot sizes at the laser wavelength level. It can achieve excellent dimensional accuracy and processing quality, and is widely used in fields such as solar cells and electronic semiconductor materials where high processing precision and process control are required. Consequently, the market demand for related processing equipment is growing rapidly.

[0003] Silicon photonics chips feature high processing speed, low power consumption, and low latency. Due to the unique physical properties of light, the structural requirements for photonic chips are not as stringent as those for electronic chips. Therefore, photonic chips do not require high-precision process lines of 28nm or even 7nm. However, the requirements for process stability and consistency are much more stringent. With the development of silicon photonics technology, traditional photolithography processes can no longer meet the requirements of etching processes for sidewall roughness, steepness, and high aspect ratio. Furthermore, with the advancement of technology, the number of photomasks required increases exponentially, leading to ever-increasing process costs.

[0004] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method for fabricating device structures based on laser etching technology, which solves the problems of rough sidewalls and high cost in the etching of semiconductor devices in the prior art.

[0006] To achieve the above and other related objectives, the present invention provides a method for fabricating a device structure based on laser etching technology. The method includes: 1) focusing multiple laser master beams and then dividing each laser master beam into multiple laser sub-beams, and arranging the multiple laser sub-beams at equal intervals; 2) providing a control module for independently controlling each laser sub-beam; 3) obtaining the actual position of each laser sub-beam using a laser marking alignment method, and transmitting the actual position to the control module to establish a coordinate layer in the control module that corresponds one-to-one with the actual position of each laser sub-beam; 4) based on the coordinate layer, controlling each sub-laser to perform laser etching on a target substrate through the control module to form the desired device structure on the target substrate.

[0007] Optionally, the laser mentioned in step 1) includes one or more of femtosecond lasers, pulsed lasers, laser plasmas, and excimer lasers.

[0008] Optionally, in step 1), the laser master beam is divided into multiple equally spaced laser sub-beams by a laser beam splitter. Each laser sub-beam has a switch in its channel, and the switch is connected to and controlled by the control module.

[0009] Optionally, the diameter of the laser sub-beam after equal division in step 1) is 10 to 50 nanometers.

[0010] Optionally, in step 1), the spacing between the laser sub-beams arranged at equal intervals is 60–100 nanometers.

[0011] Optionally, in step 1), the overall arrangement size of the multiple laser sub-beams has a diameter greater than or equal to the size of the area to be etched on the target substrate.

[0012] Optionally, the parameters that can be independently controlled for each laser sub-beam in step 2) include laser switch, laser energy level, and laser irradiation time.

[0013] Optionally, in step 4), the laser energy and laser irradiation time in a vacuum environment are adjusted by the control module to control the etching size and depth of the laser etching, thereby forming the desired device structure on the target substrate.

[0014] Optionally, the independent control of each laser sub-beam in step 2) is achieved through a system-on-a-chip or a computer program.

[0015] Optionally, the laser marking alignment method in step 3) includes: providing a feedback structure, and after each of the laser sub-beams is turned on and a mark is formed on the feedback structure, feeding back the position of each mark to the control module, so as to establish a coordinate layer in the control module that corresponds one-to-one with the actual position of each of the laser sub-beams.

[0016] Optionally, the target substrate in step 4) includes a stack of one or more of silicon dioxide, silicon nitride, monocrystalline silicon, polycrystalline silicon, and polymers.

[0017] Optionally, in step 4), after each laser sub-beam is precisely aligned with the target substrate by the alignment mechanism, the stepping array is controlled by the control module, thereby controlling the laser etching of the entire device structure on the target substrate.

[0018] Optionally, the minimum critical dimension of the device structure formed by laser etching in step 4) is greater than or equal to 200 nanometers.

[0019] Optionally, the process may also include step 5), cleaning the target substrate to remove impurities formed by laser etching, wherein the cleaning process includes one or a combination of wet cleaning and dry cleaning processes.

[0020] Optionally, the device structure includes either an optical waveguide structure or a MEMS device structure.

[0021] As described above, the method for fabricating device structures based on laser etching technology of the present invention has the following beneficial effects:

[0022] This invention provides a method for fabricating device structures based on laser etching technology. By controlling multiple laser beams, it enables precise etching of optical waveguides of different positions and shapes without a mask, significantly reducing costs and increasing etching rates. By changing the type and energy of the laser, precise etching of optical waveguides at different depths can be achieved. This method has wide applications in optical waveguide etching, photolithography, and silicon photonics back-end metal etching. Furthermore, this invention can be extended to the development of photolithography for integrated optical paths and back-end metal etching processes for MEMS products. Attached Figure Description

[0023] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the embodiments of this application and to illustrate the implementation of this application, together with the textual description, to explain the principles of this application. Obviously, the drawings described below are merely some embodiments of this application.

[0024] Figure 1 The diagram shows a step flow diagram of a device structure fabrication method based on laser etching process according to an embodiment of the present invention.

[0025] Figure 2 The diagram shows a laser sub-beam arrangement in a method for fabricating a device structure based on laser etching technology, as described in an embodiment of the present invention.

[0026] Component designation explanation

[0027] 101 laser sub-beams

[0028] S11~S15 Step 1)~Step 5) Detailed Implementation

[0029] 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.

[0030] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components.

[0031] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0032] In the detailed description of embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged and not to scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0033] For ease of description, spatial relation terms such as “below,” “under,” “lower than,” “below,” “above,” and “upper” may be used herein to describe the relationship between one element or feature shown in the accompanying drawings and other elements or features. It will be understood that these spatial relation terms are intended to include directions other than those depicted in the drawings for devices in use or operation. Furthermore, when a layer is referred to as being “between” two layers, it may be the only layer between the two layers, or there may be one or more layers in between.

[0034] In the context of this application, the structure described above the first feature may include embodiments in which the first and second features are formed in direct contact, or embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0035] 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 illustrations 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.

[0036] like Figures 1-2 As shown, this embodiment provides a method for fabricating a device structure based on laser etching technology, the method comprising:

[0037] like Figures 1-2 As shown, firstly, step 1) S11 is performed, where multiple laser master beams are focused and then each laser master beam is equally divided into multiple laser sub-beams 101, and the multiple laser sub-beams 101 are arranged at equal intervals.

[0038] In one embodiment, the laser mentioned in step 1) includes one or more of femtosecond lasers, pulsed lasers, laser plasmas, and excimer lasers. In this embodiment, the laser selected is a femtosecond laser.

[0039] In one embodiment, such as Figure 2 As shown, in step 1), the laser master beam is divided into multiple equally spaced laser sub-beams 101 by a laser beam splitter. Each laser sub-beam 101 has a switch within its channel, and the switch is connected to and controlled by the control module. The laser beam splitter can be either a refractive laser beam splitter or a diffractive laser beam splitter. The refractive laser beam splitter can be a microlens laser beam splitter, a microprism laser beam splitter, or a refractive beam splitter with Gaussian beam input, etc. The diffractive laser beam splitter can be an amplitude-type laser beam splitter, a pure phase-type laser beam splitter, or a complex amplitude laser beam splitter, etc.

[0040] In one embodiment, the diameter of the laser sub-beam 101 after the equal division process in step 1) is 10 to 50 nanometers. For example, the diameter of the laser sub-beam 101 can be 10 nanometers, 20 nanometers, 30 nanometers, 50 nanometers, etc., and is not limited to the examples listed above.

[0041] In one embodiment, the spacing between the laser sub-beams 101 arranged at equal intervals in step 1) is 60 to 100 nanometers. For example, the spacing between the laser sub-beams 101 can be 60 nanometers, 70 nanometers, 80 nanometers, 90 nanometers, 100 nanometers, etc., and is not limited to the examples listed above.

[0042] In one embodiment, the overall diameter of the arrangement of the multiple laser sub-beams 101 in step 1) is greater than or equal to the size of the area to be etched on the target substrate. For example, for a 12-inch wafer, the diameter of the area to be etched is 11.5 inches. The overall diameter of the arrangement of the multiple laser sub-beams 101 can be 11.5 inches or 12 inches, etc., to cover the area to be etched at once and improve the efficiency of subsequent etching.

[0043] like Figure 1 As shown, then step 2) S12 is performed, providing a control module, which is connected to each of the laser sub-beams 101, so that each laser sub-beam 101 can be controlled independently.

[0044] In one embodiment, the parameters that can be independently controlled by each laser sub-beam 101 in step 2) include laser switch, laser energy level, and laser irradiation time, wherein the laser irradiation time can be controlled by the time the laser is turned on and off.

[0045] In one embodiment, the independent control of each laser sub-beam 101 in step 2) is achieved through a system-on-a-chip or a computer program.

[0046] like Figure 1 As shown, step 3) S13 is then performed, in which the control module obtains the actual position of the laser sub-beam 101 by means of the laser marking alignment method, so as to establish a coordinate layer in the control module that corresponds one-to-one with the actual position of each laser sub-beam 101.

[0047] In one embodiment, the laser marking alignment method in step 3) includes: providing a feedback structure, and after each of the laser sub-beams 101 is turned on and a mark is formed on the feedback structure, feeding back the position of each mark to the control module, so that the control module establishes a coordinate layer that corresponds one-to-one with the actual position of each of the laser sub-beams 101. Specifically, the coordinate layer has a one-to-one correspondence with the position of each of the laser sub-beams 101. The coordinate layer can accurately characterize the actual position of the laser sub-beams 101. At the same time, the control module converts the programming operation of the laser sub-beam points on the coordinate layer into operation signals to control the actual operation of the laser sub-beams 101, and can display the operation through a display screen, etc., so as to facilitate the operator's programming operation of laser etching.

[0048] like Figure 1 As shown, then step 4) S14 is performed, based on the coordinate layer, the control module controls each sub-laser to perform laser etching on the target substrate to form the desired device structure on the target substrate.

[0049] In one embodiment, step 4) involves adjusting the laser energy and irradiation time in a vacuum environment via the control module to control the etching size and depth, thereby forming the desired device structure on the target substrate. For example, for the same laser energy, a longer irradiation time results in a greater etching depth, and vice versa. Similarly, for the same laser irradiation time, a higher laser energy results in a larger etching size and depth, and vice versa. Based on these principles, the final laser etching size and depth can be precisely controlled.

[0050] In one embodiment, the target substrate can be etched by turning on the pulsed laser sub-beam 101 of the patterned area to be etched in a vacuum environment, turning off the pulsed laser sub-beam 101 of the non-patterned area to be etched, and adjusting the energy and irradiation time of the patterned area pulsed laser sub-beam 101.

[0051] In one embodiment, the target substrate in step 4) comprises a stack of one or more of silicon dioxide, silicon nitride, monocrystalline silicon, polycrystalline silicon, and polymers. For example, the target substrate can be an SOI substrate, which is formed by depositing a buried oxide layer and a top silicon layer on a silicon substrate, respectively. The thickness of the buried oxide layer can be 2 micrometers, and the thickness of the top silicon layer can be 220 nanometers.

[0052] In one embodiment, in step 4), after the alignment mechanism precisely aligns each laser sub-beam 101 with the target substrate, the control module controls the stepping array to control the laser etching of the entire device structure on the target substrate. For example, the stepping array can be positioned at the bottom of the target substrate to control its stepping movement, or it can be positioned above the laser sub-beams 101 to control their stepping movement. Simultaneously, the stepping direction is determined based on the desired etched device structure, and the stepping direction (e.g., coordinates), laser sub-beam energy, etching time, etc., can be written into the control module to achieve mass production of the product.

[0053] In one embodiment, the minimum critical dimension of the device structure formed by laser etching in step 4) is greater than or equal to 200 nanometers.

[0054] In one embodiment, the device structure includes either an optical waveguide structure or a MEMS device structure.

[0055] In one embodiment, the laser etching depth is between 50 nanometers and 150 nanometers. Furthermore, the etched device structure has vertical and smooth sidewalls.

[0056] like Figure 1As shown, step 5) S15 is performed to clean the target substrate to remove impurities formed by laser etching. The cleaning process includes one or a combination of wet cleaning and dry cleaning processes.

[0057] As described above, the method for fabricating device structures based on laser etching technology of the present invention has the following beneficial effects:

[0058] This invention provides a method for fabricating device structures based on laser etching technology. By controlling multiple laser beams, it enables precise etching of optical waveguides of different positions and shapes without a mask, significantly reducing costs and increasing etching rates. By changing the type and energy of the laser, precise etching of optical waveguides at different depths can be achieved, making it widely applicable in fields such as optical waveguide etching, photolithography, and back-end metal etching in silicon photonics. This invention can be further extended to the development of photolithography for integrated optical paths and back-end metal etching processes for MEMS products. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and has high industrial applicability.

[0059] 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 for fabricating a device structure based on laser etching technology, characterized in that, The preparation method includes: 1) After focusing each of the multiple laser master beams, each laser master beam is divided into multiple laser sub-beams, and the multiple laser sub-beams are arranged at equal intervals; 2) A control module is provided, which is used to independently control each laser sub-beam; 3) Obtain the actual position of the laser sub-beam using a laser marking alignment method, and transmit the actual position to the control module so as to establish a coordinate layer in the control module that corresponds one-to-one with the actual position of each laser sub-beam; 4) Based on the coordinate layer, the control module controls each sub-laser to perform laser etching on the target substrate to form the desired device structure on the target substrate; In step 1), the laser master beam is divided into multiple equally spaced laser sub-beams by a laser beam splitter. Each laser sub-beam has a switch in its channel, and the switch is connected to and controlled by the control module. The parameters that can be independently controlled for each laser sub-beam in step 2) include laser switch, laser energy level, and laser irradiation time; The laser marking alignment method in step 3) includes: providing a feedback structure, after each laser sub-beam is turned on and a mark is formed on the feedback structure, feeding back the position of each mark to the control module, so as to establish a coordinate layer in the control module that corresponds one-to-one with the actual position of each laser sub-beam; the control module converts the programming operation of the laser sub-beam points on the coordinate layer into operation signals to control the actual operation of the laser sub-beams; In step 4), the control module adjusts the laser energy and laser irradiation time in a vacuum environment to control the etching size and depth of the laser etching, thereby forming the required device structure on the target substrate. After the alignment mechanism precisely aligns each laser sub-beam with the target substrate, the control module controls the stepping array to control the laser etching of the entire device structure on the target substrate.

2. The method for fabricating a device structure based on laser etching process according to claim 1, characterized in that: The laser mentioned in step 1) includes one or more of femtosecond lasers, pulsed lasers, laser plasmas, and excimer lasers.

3. The method for fabricating a device structure based on laser etching process according to claim 1, characterized in that: Step 1) The diameter of the laser sub-beam after equal division is 10~50 nanometers.

4. The method for fabricating a device structure based on laser etching process according to claim 1, characterized in that: Step 1) The spacing between the laser sub-beams arranged at equal intervals is 60~100 nanometers.

5. The method for fabricating a device structure based on laser etching process according to claim 1, characterized in that: In step 1), the overall arrangement size of the multiple laser sub-beams has a diameter greater than or equal to the size of the target substrate area to be etched.

6. The method for fabricating a device structure based on laser etching process according to claim 1, characterized in that: The independent control of each laser sub-beam in step 2) is achieved through a system-on-a-chip or a computer program.

7. The method for fabricating a device structure based on laser etching process according to claim 1, characterized in that: The target substrate mentioned in step 4) includes a stack of one or more of silicon dioxide, silicon nitride, monocrystalline silicon, polycrystalline silicon, and polymers.

8. The method for fabricating a device structure based on laser etching process according to claim 1, characterized in that: Step 4) The minimum critical dimension of the device structure formed by the laser etching is greater than or equal to 200 nanometers.

9. The method for fabricating a device structure based on laser etching process according to claim 1, characterized in that: It also includes step 5), which cleans the target substrate to remove impurities formed by laser etching. The cleaning process includes one or a combination of wet cleaning and dry cleaning processes.

10. The method for fabricating a device structure based on laser etching process according to claim 1, characterized in that: The device structure includes either an optical waveguide structure or a MEMS device structure.

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