阅读说明：本技术 表面浮雕光栅结构的制作方法 (Method for manufacturing surface relief grating structure ) 是由 王晶 于 2019-08-16 设计创作，主要内容包括：本发明提供了一种表面浮雕光栅结构的制作方法。该方法包括基片涂胶、母板压印、压印胶镀膜、压印胶去除以及刻蚀基片的过程,通过在母板直接压印第一光栅结构而得到第二光栅结构,避免了光栅结构制造过程中曝光与显影的过程,从而简化了光栅结构的生产工艺；一个母板先后生产多个子板,多个母板可同时生产多个子板,可以实现光栅结构的批量生产过程。增设压印胶镀膜过程,选择刻蚀速率与基片不同的第一金属膜,在进行基片刻蚀过程时,可以控制离子束的功率而达到精准控制基片刻蚀深度的效果；同时离子束的发射线与基片表面的夹角非直角,使得刻蚀槽面形成倾斜槽面,以得到基片表面形成梯形夹缝的目标光栅结构。(The invention provides a method for manufacturing a surface relief grating structure. The method comprises the processes of substrate gluing, motherboard imprinting, imprinting glue coating, imprinting glue removing and substrate etching, and the second grating structure is obtained by directly imprinting the first grating structure on the motherboard, so that the processes of exposure and development in the manufacturing process of the grating structure are avoided, and the production process of the grating structure is simplified; a plurality of daughter boards can be sequentially produced by one mother board, and a plurality of daughter boards can be simultaneously produced by a plurality of mother boards, so that the batch production process of the grating structure can be realized. Additionally arranging an imprinting adhesive film coating process, selecting a first metal film with an etching rate different from that of the substrate, and controlling the power of an ion beam to achieve the effect of accurately controlling the etching depth of the substrate during the substrate etching process; meanwhile, the included angle between the emission line of the ion beam and the surface of the substrate is not a right angle, so that the etched groove surface forms an inclined groove surface, and a target grating structure with a trapezoidal crack formed on the surface of the substrate is obtained.)

1. A method for manufacturing a surface relief grating structure is characterized by comprising the following steps:

gluing a substrate: providing a substrate for manufacturing the grating structure, and coating an imprinting adhesive layer on the surface of the substrate to obtain a substrate;

stamping the mother board: providing a grating mother board, wherein the grating mother board is provided with a plurality of rectangular strip-shaped grating structures, pressing the grating mother board into an imprinting adhesive layer of the substrate in a nano imprinting mode to separate the grating mother board from the imprinting adhesive layer to form a first grating structure, and etching part of the imprinting adhesive layer to obtain a second grating structure with rectangular gaps;

coating a stamping glue: plating a metal film on the surface of the second grating structure, so that the metal film comprises a first metal film layer plated and attached to the surface of the residual imprinting adhesive layer and a second metal film layer plated and attached in the rectangular crack and positioned on the substrate, and a third grating structure is obtained;

removing the stamping glue: removing the first metal film layer and the residual imprinting adhesive layer to obtain a fourth grating structure with a second metal film layer;

etching the substrate: and etching the second metal film layer on the fourth grating structure and the substrate by adopting an ion beam to obtain a target grating structure with a trapezoidal crack formed on the surface of the substrate, wherein the included angle between the emission line of the ion beam and the surface of the substrate is not a right angle.

2. A method for fabricating a surface relief grating structure according to claim 1, wherein the step of coating the substrate with a glue further comprises the steps of:

and heating the substrate subjected to gluing on a heating plate to remove redundant solvent, measuring the thickness by using a film thickness meter, and if the thickness does not meet the specified requirement, continuously repeating the gluing process of the mother board until the measured thickness reaches the target thickness.

3. A method for fabricating a surface relief grating structure as claimed in claim 1, wherein an anti-sticking process is further required before the rectangular grating master is pressed into the imprinting glue layer in the master imprinting step.

4. A method for making a surface relief grating structure according to claim 1, further comprising the following steps in the master imprinting step:

removing residual glue: and removing residual glue in the first grating structure through inductive coupling equipment to enable the bottom of the rectangular crack of the first grating structure to be directly exposed out of the substrate, so as to obtain the second grating structure.

5. The method of claim 1, wherein the metal film has a different etching rate than the substrate during the step of coating the imprint resist.

6. The method for manufacturing a surface relief grating structure according to claim 1, wherein the step of removing the imprint glue specifically comprises the following steps:

and removing the residual imprinting adhesive layer and the first metal film layer plated and attached to the surface of the residual imprinting adhesive layer by using acetone or water ultrasound with the residual imprinting adhesive layer as a sacrificial layer.

7. The method for fabricating a surface relief grating structure according to claim 1, wherein after the step of etching the substrate, the following steps are performed:

cleaning a substrate: and cleaning the second metal film layer which is not etched away by using an acid solution to form the grating structure with the asymmetric trapezoid seams.

8. The method of claim 1, wherein the width of the bottom of the trapezoidal slit is 80-120 nm.

9. The method of claim 1, wherein the rectangular grating mother substrate is made of silicon or plastic, and the substrate is made of glass.

[ technical field ] A method for producing a semiconductor device

The invention relates to the field of grating manufacturing, in particular to a manufacturing method of a surface relief grating structure.

[ background of the invention ]

Gratings are important components of various spectral analysis instruments, and are increasingly used in emerging fields such as metering, imaging, information processing, succession optics and optical communication. In recent years, with the rapid development of semiconductor processes, a new optical application product is developed, which is an AR (augmented reality) product. AR is an enhancement to reality and is a fusion of virtual and real images. The head-mounted AR equipment in the market at present mostly adopts an optical projection principle, namely, the real scene and the virtual scene are fused through a lens arranged in front of eyes. The Hololens product from Microsoft is the product in the market at present, and the experience effect is the best. The method adopts a three-layer waveguide surface relief grating scheme, and is realized by the design of three regions (an incident region, an expansion region and an emergent region). The incident area is coupled into the grating, the light collimated by the collimating mirror is coupled into the waveguide to realize total reflection, and the higher the refractive index of the grating and the waveguide is, the better the refractive index of the waveguide is; the expansion area is used for deflecting the grating, changes the transmission direction of light rays and realizes the expansion of the pupil in the x direction, the efficiency is not required to be high, but the efficiency is designed to be higher along with the propagation; the exit region achieves expansion of the pupil in the y-direction and couples light out of the waveguide, also incrementally with propagation.

Because the position of the maximum diffraction value is transferred to other dispersive diffraction orders from the zero-order spectrum without dispersion, the blazed grating has high efficiency and is greatly applied to an incident area; tilted gratings are also often applied in the entrance and exit areas. The grating of the expansion region requires a groove-shaped grating section which can be designed into an asymmetric trapezoid due to the requirement. Because of the wide application of the inclined grating and the blazed grating, the common patents relate to the processing of the inclined grating and the blazed grating, but the groove-shaped grating with the asymmetric trapezoid cross section has less research because of a small number of application fields.

The groove-shaped grating has a wide range of applications, and is classified into a positive-diffraction grating, a blazed grating, a echelle grating, and the like according to the shape of a cross section. For the trapezoidal surface relief grating with the asymmetric cross section, the traditional method is to firstly perform laser direct writing, then develop and finally etch to obtain the grating. Laser direct writing is the variable dose exposure of a resist material coated on a substrate surface with a laser beam of variable intensity, followed by development to form the desired relief profile in the resist surface. Because the device is formed at one time and has no discretization approximation, the manufacturing precision and the diffraction efficiency of the device are greatly improved compared with the device manufactured by the traditional semiconductor process alignment.

The biggest problem with laser direct writing is the inability to precisely control the profile depth. The depth of the processed contour is related to various factors such as exposure intensity, scanning speed, resist material, developing formula, ambient temperature, developing temperature and the like, the influence of any factor can cause contour depth error, the depth error can be controlled only by depending on the experience of operators and constant working conditions, the working efficiency is low, and the controllability is low.

[ summary of the invention ]

The invention aims to provide a method for manufacturing a surface relief grating structure with high efficiency and high controllability.

The technical scheme of the invention is as follows:

a method for manufacturing a surface relief grating structure comprises the following steps:

gluing a substrate: providing a substrate for manufacturing the grating structure, and coating an imprinting adhesive layer on the surface of the substrate to obtain a substrate;

stamping the mother board: providing a grating mother board, wherein the grating mother board is provided with a plurality of rectangular strip-shaped grating structures, pressing the grating mother board into an imprinting adhesive layer of the substrate in a nano imprinting mode to separate the grating mother board from the imprinting adhesive layer to form a first grating structure, and etching part of the imprinting adhesive layer to obtain a second grating structure with rectangular gaps;

coating a stamping glue: plating a metal film on the surface of the second grating structure, so that the metal film comprises a first metal film layer plated and attached to the surface of the residual imprinting adhesive layer and a second metal film layer plated and attached in the rectangular crack and positioned on the substrate, and a third grating structure is obtained;

removing the stamping glue: removing the first metal film layer and the residual imprinting adhesive layer to obtain a fourth grating structure with a second metal film layer;

etching the substrate: and etching the second metal film layer on the fourth grating structure and the substrate by adopting an ion beam to obtain a target grating structure with a trapezoidal crack formed on the surface of the substrate, wherein the included angle between the emission line of the ion beam and the surface of the substrate is not a right angle.

Preferably, the substrate gluing step further comprises the following processes:

and heating the substrate subjected to gluing on a heating plate to remove redundant solvent, measuring the thickness by using a film thickness meter, and if the thickness does not meet the specified requirement, continuously repeating the gluing process of the mother board until the measured thickness reaches the target thickness.

Preferably, in the step of imprinting the master plate, an anti-adhesion treatment process is also required before the rectangular grating master plate is pressed into the imprinting glue layer.

Preferably, the following process is further included in the master imprinting step:

removing residual glue: and removing residual glue in the first grating structure through inductive coupling equipment to enable the bottom of the rectangular crack of the first grating structure to be directly exposed out of the substrate, so as to obtain the second grating structure.

Preferably, in the step of coating the imprint resist, the etching rate of the metal film is different from that of the substrate.

Preferably, the imprint resist removing step specifically includes the following processes:

and removing the residual imprinting adhesive layer and the first metal film layer plated and attached to the surface of the residual imprinting adhesive layer by using acetone or water ultrasound with the residual imprinting adhesive layer as a sacrificial layer.

Preferably, after the step of etching the substrate, the following process is also required:

cleaning a substrate: and cleaning the second metal film layer which is not etched away by using an acid solution to form the grating structure with the asymmetric trapezoid seams.

Preferably, the width of the bottom of the trapezoidal crack is 80-120 nm.

Preferably, the rectangular grating mother board is made of a silicon wafer or a plastic sheet.

The invention has the beneficial effects that:

in the manufacturing process of the grating structure, the first grating structure is obtained by directly impressing the substrate on the mother board, so that the processes of exposure and development in the manufacturing process of the grating structure are avoided, and the production process of the grating structure is simplified; a plurality of daughter boards can be sequentially produced by one mother board, and a plurality of daughter boards can be simultaneously produced by a plurality of mother boards, so that the batch production process of the grating structure can be realized. Additionally arranging an imprinting adhesive film coating process, selecting a first metal film with an etching rate different from that of the substrate, and controlling the power of an ion beam to achieve the effect of accurately controlling the etching depth of the substrate during the substrate etching process; meanwhile, the included angle between the emission line of the ion beam and the surface of the substrate is not a right angle, so that the etched groove surface forms an inclined groove surface, and a target grating structure with a trapezoidal crack formed on the surface of the substrate is obtained. The ion beam etching efficiency of the invention is high, which is suitable for large-area processing and mass production, and has wide application and more equipment resources. Compared with a laser direct writing method, the method has the advantages that the predetermined ion beam etching parameters are set, one-step forming is realized, the efficiency is high, the controllability is high, the target grating structure can better meet the size requirement, and the operation is simpler.

[ description of the drawings ]

FIG. 1 is a schematic flow chart of a method for fabricating a surface relief grating structure according to the present invention;

FIG. 2 is a schematic diagram of the present invention for fabricating a target grating structure;

FIG. 3 is an enlarged, fragmentary, schematic view of the substrate of FIG. 2, indicated by circle A, in accordance with the present invention;

FIG. 4 is an enlarged, fragmentary view of a first grating structure of the present invention as indicated by circle B in FIG. 2;

FIG. 5 is an enlarged, fragmentary view of a second grating structure of the present invention, indicated by circle C in FIG. 2;

FIG. 6 is an enlarged, fragmentary view of a third grating structure of the present invention, indicated by circle D in FIG. 2;

FIG. 7 is an enlarged, partial schematic view of a fourth grating structure of the present invention, as indicated by circle E in FIG. 2;

FIG. 8 is an enlarged, fragmentary view of a fifth grating structure of the present invention, indicated by circle F in FIG. 2;

FIG. 9 is a partially enlarged schematic view of the target grating structure of FIG. 2, indicated by the circle G;

FIG. 10 is a front view of a target grating structure of the present invention;

FIG. 11 is a schematic view of the ion beam etching principle of the present invention.

[ detailed description ] embodiments

The invention is further described with reference to the following figures and embodiments.

Referring to fig. 1-2, the present invention discloses a method for manufacturing a surface relief grating structure, comprising the following steps:

before coating the imprinting adhesive layer, a substrate is required to be placed in cleaning equipment, absolute ethyl alcohol and acetone are put into the cleaning equipment for soaking, residual organic matters are removed, and then a large amount of deionized water is used for washing and drying; the substrate is typically made of glass.

S1, gluing the substrate: referring to fig. 3, a substrate 101 for manufacturing the grating structure is provided, and an imprint glue layer 102 is coated on the surface of the substrate 101 to obtain a substrate 11; coating a layer of imprinting glue on the substrate 101, wherein the thickness of single spin coating is not changed when the glue concentration and the spin coating speed are not changed, so that the specific thickness is required to be achieved through multiple spin coating; in the case of a constant photoresist concentration, the thicker the film thickness required, the faster the spin coating rate is required.

Heating the substrate 101 subjected to gluing on a heating plate to remove redundant solvent, measuring the thickness by using a film thickness gauge, and if the thickness does not meet the specified requirement, continuously repeating the gluing process of the substrate 101 until the measured thickness meets the specified requirement; the hot drying process is mainly used for realizing the thickness uniformity in the gluing process.

S2, mother board stamping: referring to fig. 4-5, by means of precise alignment, transferring a pattern of a mother board is completed at a designated position of a substrate 101, providing a grating mother board, where the grating mother board has a plurality of rectangular strip-shaped grating structures, pressing the grating mother board into an imprinting adhesive layer 102 of a substrate 11 in a nano imprinting manner, so that the grating mother board is separated from the imprinting adhesive layer 102 to obtain a first grating structure 12, and removing residual adhesive in the first grating structure 12 by using inductive coupling equipment to directly expose the bottom of a rectangular gap of the first grating structure 12 to the substrate 101, so as to obtain a second grating structure 13 with a rectangular gap;

the imprinting adhesive layer 102 is made of ultraviolet adhesive, which is anaerobic, nitrogen is introduced to expel oxygen before imprinting, and nitrogen is continuously introduced to maintain the nitrogen atmosphere during exposure.

Post-imprinting release processes are critical to imprinting patterns. In order to facilitate the demolding of the grating mother board, anti-adhesion treatment is generally required to be performed on the grating mother board.

The anti-sticking treatment process comprises two modes: one is ozone treatment for 30min to hydroxylate the surface of the grating mother board; the other method is soaking in perfluorodecyl trichlorosilane for 24 hours.

S3, impression glue coating: referring to fig. 6, a metal film 103 with a different etching rate from that of the substrate 101 is evaporated on the surface of the second grating structure 13, so that the metal film 103 includes a first metal film 1031 plated on the surface of the remaining imprint glue layer 102 and a second metal film 1032 plated in the rectangular gap and located on the substrate 101, thereby obtaining a third grating structure 14;

specifically, a magnetron sputtering or an evaporation plating machine is used to prepare for etching a first metal film layer 1031 on a substrate base material, which is a metal chromium layer. The etch rates of different materials are different, and the ratio of the etch rates of the substrate 101 to the mask is referred to as the selectivity ratio, with larger selectivity ratios favoring substrate etching. Because the etching selection ratio of the base material to the photoresist is too small, the transfer of the pattern on the substrate 101 can not be realized, and therefore, the metal chromium layer is required to be evaporated.

S4, removing the stamping glue: referring to fig. 7, the first metal film 1031 and the remaining imprinting adhesive layer 102 are removed to obtain a fourth grating structure 15 having a second metal film 1032; taking the residual imprinting glue layer 102 as a sacrificial layer, ultrasonically removing the residual imprinting glue layer 102 and the first metal film layer 1031 plated on the surface of the residual imprinting glue layer 102 by using acetone or water, specifically, after ultrasonic treatment, separating the imprinting glue layer 102 and the first metal film layer 1031 from the substrate 101, and further cleaning to remove the first metal film layer 1031. The second metal film layer 1032 thus becomes a mask for the substrate 101.

S5, etching the substrate 101: referring to fig. 8-10, the second metal film 1032 on the fourth grating structure 15 and the substrate 101 are etched by ion beams to obtain a fifth grating structure 16, and the second metal film 1032 that has not been etched is cleaned by an acidic solution to obtain a target grating structure with a trapezoidal gap formed on the surface of the substrate 101, wherein an included angle between an emission line of the ion beams and the surface of the substrate 101 is not a right angle.

And controlling corresponding power according to the etching rate of the substrate 101 and the etching rate of the second metal film layer 1032, etching the fourth grating structure 15 by using an inductively coupled reactive ion etching device, and simultaneously etching the second metal film layer 1032 and the part of the substrate 101 which is not covered by the second metal film layer 1032 to obtain a fifth grating structure 16 until the substrate 101 reaches the target etching depth to obtain the target grating structure.

The gas type and power of the inductively coupled reactive ion etching equipment can be accurately controlled, and the optimal control power can be calculated as long as the selection ratio between the substrate 101 and the second metal film layer 1032 can be confirmed, so that the target etching depth can be reached, and finally the etching depth can be controlled and the grating structure can be completely transferred.

In an embodiment of the present invention, in the step of etching the substrate 101, the process of implementing the non-orthogonal angle between the emission line of the ion beam and the developed surface of the substrate 101 includes: the substrate 101 is fixed, and the ion beam is controlled to rotate by a preset angle, so that the emission line of the ion beam is obliquely irradiated to the surface of the substrate 101.

In another embodiment of the present invention, in the step of etching the substrate 101, the process of implementing the non-orthogonal angle between the emission line of the ion beam and the surface of the substrate 101 includes: the ion beam is fixed, and the substrate 101 is controlled to rotate by a predetermined angle, so that the emission line of the ion beam is obliquely irradiated onto the surface of the substrate 101.

In the embodiment, the width of the bottom of the trapezoidal crack can meet the precision requirement of 80-120nm by controlling the inclination angle of the emission line of the ion beam and the etching line width of the metal film layer, the controllability is high, and the quality of the target grating structure after etching is better.

Referring to fig. 11, the emission line of the ion beam is obliquely irradiated onto the surface of the substrate 101, the second metal film 1032 on the surface of the substrate 101 is a rectangular film, and the ion beam etching rate at the corresponding position of the substrate 101 not shielded by the second metal film 1032 is the same and deepest, so as to form the bottom of the etching gap; emitting lines irradiated on the side wall of the second metal film layer 1032, and the thickness of the second metal film layer 1032 etched by ion beams is gradually changed, so that a crack side wall with a first inclination angle is formed on the surface of the substrate 101 etched by the second metal film layer 1032 by etching; the emission lines partially irradiated on the surface of the second metal film 1032 and penetrating through the sidewall of the second metal film 1032 are formed by etching the surface of the substrate 101 etched in the second metal film 1032 to form a second inclined-angle slit sidewall because the thickness of the second metal film 1032 etched by the ion beam is gradually changed and is different from the etching efficiency of the emission lines directly irradiated on the sidewall of the second metal film 1032. The crack side wall with the first inclination angle, the crack side wall with the second inclination angle and the bottom of the crack form a complete asymmetric trapezoidal crack.

In the manufacturing process of the grating structure, the first grating structure 12 is obtained by directly stamping the substrate 11 on the mother board, so that the processes of exposure and development in the manufacturing process of the grating structure are avoided, and the production process of the grating structure is simplified; a plurality of daughter boards can be sequentially produced by one mother board, and a plurality of daughter boards can be simultaneously produced by a plurality of mother boards, so that the batch production process of the grating structure can be realized. Additionally arranging an imprinting adhesive coating process, selecting a first metal film with an etching rate different from that of the substrate 101, and controlling the power of an ion beam to achieve the effect of accurately controlling the etching depth of the substrate 101 in the substrate 101 etching process; meanwhile, the included angle between the emission line of the ion beam and the surface of the substrate 101 is not a right angle, so that the etched groove surface forms an inclined groove surface, and a target grating structure with a trapezoidal crack formed on the surface of the substrate 101 is obtained. The ion beam etching efficiency of the invention is high, which is suitable for large-area processing and mass production, and has wide application and more equipment resources. Compared with a laser direct writing method, the method has the advantages that the predetermined ion beam etching parameters are set, one-step forming is realized, the efficiency is high, the controllability is high, the target grating structure can better meet the size requirement, and the operation is simpler.

The above are only embodiments of the present invention, and it should be noted that, for those skilled in the art, modifications can be made without departing from the inventive concept of the present invention, but these are all within the scope of the present invention.