阅读说明：本技术 一种基于电泳技术的自动化刻蚀机构及其使用方法 (Automatic etching mechanism based on electrophoresis technology and use method thereof ) 是由 许红梅 闫艳琴 王迪 于 2021-09-09 设计创作，主要内容包括：本发明公开了一种基于电泳技术的自动化刻蚀机构,包括操作面,刻蚀液操纵组件,操作面上阵列设置有若干安装槽；每个硅片根据光刻胶图案黏附有刻蚀腔体,每个刻蚀腔体的上方均对应有刻蚀操纵组件；每层刻蚀腔体均由增强纤维构筑而成,增强纤维通过若干支撑纤维固定；每个刻蚀腔体从顶层向下以三个增强纤维为涂布周期布置有亲疏水性不同的增强纤维,涂布周期包括两个超亲水介质层、一个涂布有超疏水介质层；刻蚀操纵组件包括若干等角度布置的喷头和导电纤维；每个喷头能够自动切换到刻蚀操纵组件的中心实现下料；导电纤维沿同心圆轨迹运动。该设备基于电泳操纵液滴的技术,通过电场的强弱变化,液滴表面的电荷发生迁移,改变液体表面的张力,达到平整液面的目的。(The invention discloses an automatic etching mechanism based on an electrophoresis technology, which comprises an operation surface and an etching liquid control assembly, wherein a plurality of mounting grooves are formed in the operation surface in an array manner; each silicon chip is adhered with an etching cavity according to the photoresist pattern, and an etching control assembly is correspondingly arranged above each etching cavity; each layer of etching cavity is constructed by reinforced fibers, and the reinforced fibers are fixed by a plurality of supporting fibers; each etching cavity is provided with reinforced fibers with different hydrophilicity and hydrophobicity from the top layer to the bottom layer by taking three reinforced fibers as a coating period, and the coating period comprises two super-hydrophilic dielectric layers and one super-hydrophobic dielectric layer; the etching control component comprises a plurality of nozzles and conductive fibers which are arranged at equal angles; each spray head can be automatically switched to the center of the etching control assembly to realize blanking; the conductive fibers follow concentric circular tracks. The device is based on the technology of manipulating liquid drops through electrophoresis, charges on the surfaces of the liquid drops are transferred through the change of the strength of an electric field, the tension of the surfaces of the liquid drops is changed, and the purpose of leveling the liquid level is achieved.)

1. An automatic etching mechanism based on an electrophoresis technology comprises an operation surface, wherein a plurality of etching liquid control assemblies are arranged above the operation surface; each silicon chip is adhered with an etching cavity according to the photoresist pattern, and the etching control assembly is correspondingly arranged above each etching cavity;

the etching cavities are at least three layers, and the cross sections of the etching cavities in adjacent layers are consistent in size; each layer of the etching cavity is constructed by reinforced fibers, and each layer of the reinforced fibers is fixed by a plurality of supporting fibers; the reinforced fibers with different hydrophilicity and hydrophobicity are arranged in each etching cavity from the top layer downwards in three reinforced fibers as a coating period, and the coating period comprises two super-hydrophilic medium layers and one super-hydrophobic medium layer;

the etching control assembly comprises a plurality of nozzles which are arranged at equal angles and at least three conductive fibers; each spray head can be automatically switched to the center of the etching control assembly to realize blanking, and each spray head corresponds to different solutions or solutions with different concentrations; the conductive fibers move along concentric circular tracks.

2. An automated etching mechanism based on electrophoresis technology according to claim 1, characterized in that: and the etching control assembly applies direct current or low-frequency alternating current voltage to the corresponding electrode connected with each conductive fiber respectively.

3. An automated etching mechanism based on electrophoresis technology according to claim 1, characterized in that: the frequency of the voltage of the conductive fibers at the outer edge is greater than the conductive fibers inside the concentric circles.

4. An automated etching mechanism based on electrophoresis technology according to claim 1, characterized in that: the etching liquid at least comprises hydrofluoric acid, nitric acid or a mixed solution of hydrofluoric acid and nitric acid, and the etching time is between 200s and 400 s.

5. An automated etching mechanism based on electrophoresis technology according to claim 1, characterized in that: the surface of the reinforcing fiber of the top layer is coated with a super-hydrophobic medium layer, and liquid drops can form affinity with the surface of the reinforcing fiber, so that the contact surface of liquid and the reinforcing fiber is higher than the middle liquid level, and an inner concave liquid level with low middle part and high periphery is formed.

6. An automated etching mechanism based on electrophoresis technology according to claim 1, characterized in that: the height of each layer of the etching cavity is determined according to the preset amount of each solution.

7. An automated etching mechanism based on electrophoresis technology according to claim 1, characterized in that: and the surface of the etching control assembly is also provided with an optical detection unit so as to detect the flatness of the liquid level in the etching cavity.

8. An automated etching mechanism based on electrophoresis technology according to claim 1, characterized in that: the cross section of the conductive fiber is in a shape like a Chinese character ' mi ', a triangle or a C '.

9. Use method of an automated etching mechanism based on electrophoresis technology according to any of claims 1-8, characterized in that it comprises the following steps:

s1, the etching control component corresponding to each silicon chip moves downwards at the same time, after alignment, one of the nozzles automatically switches to the center and drips a certain amount of etching liquid to the etching cavity according to a preset amount, and the liquid surface forms an inward recess with a low middle part and a high periphery due to surface tension;

s2, detecting the flatness of the liquid level by the optical detection unit, controlling the movement of the conductive fibers on the concentric tracks, and applying voltage to corresponding electrodes connected with the conductive fibers;

s3, under the action of an electric field, the charges on the surfaces of the liquid drops are transferred, the surface tension of the liquid changes, and peripheral liquid drops diffuse towards the center to realize the leveling of the liquid level;

and S4, after the spray heads are restored, other spray heads are automatically switched to the center to drop a certain amount of etching liquid to the etching cavity according to the preset amount, and the operations of S2 and S3 are repeated.

10. The use method of the automatic etching mechanism based on the electrophoresis technology as claimed in claim 9, wherein: and at least controlling the movement of the conductive fibers at the outer edge according to the concave degree of the surface of the dropwise added solution in the etching cavity, wherein the frequency of the voltage of the conductive fibers at the outer edge is high, and the charge generation and migration rate of the surface of the liquid drop is high.

Technical Field

The invention relates to the technical field of silicon wafer processing or the technical field of electronics, in particular to an automatic etching mechanism based on an electrophoresis technology and a using method thereof.

Background

Electrophoresis is an important means in biochemical analysis, and refers to the effect of charged particles in a liquid (or gel) moving under the action of a uniform electric field. Due to the difference of migration speed of different components in the suspension body in the liquid (or colloid) under the action of electric field, the electrophoresis effect can be effectively used for separating substances including DNA, protein, cells and the like, and can also be used for analyzing the molecular structure of the substances.

As device feature sizes shrink, the accuracy requirements for device fabrication become higher and higher. During semiconductor manufacturing, unwanted material is removed from the wafer surface by etching. The etching requirements depend on the type of feature to be formed, such as aluminum alloy interconnects, polysilicon gates, shallow trench isolation regions. Due to the complex structure of the device, the wafer has a large number of materials requiring different etching parameters, which makes the degree of accuracy of etching difficult to control. As the feature size is reduced, the dimension control requirement in the use method is more strict, but the reduction of the feature size makes the etching precision more difficult to control and detect, and simultaneously, the new process also brings more difficulty and higher requirement to the etching process. The existing etching equipment cannot accurately control the etching liquid dripped on each silicon wafer, and further cannot control the etching depth and the surface etching of the silicon wafer is not flat.

In view of the above, there is a need to improve etching equipment in the prior art to solve the problems that the etching depth of the silicon wafer is difficult to control accurately and the etching on the surface of the silicon wafer is not flat.

Disclosure of Invention

The invention overcomes the defects of the prior art, provides an automatic etching mechanism based on an electrophoresis technology and a using method thereof, and aims to solve the problems that the accuracy of the etching depth of a silicon wafer is difficult to control, and the etching on the surface of the silicon wafer is not smooth.

In order to achieve the purpose, the invention adopts the technical scheme that: an automatic etching mechanism based on an electrophoresis technology comprises an operation surface, wherein a plurality of etching liquid control assemblies are arranged above the operation surface; each silicon chip is adhered with an etching cavity according to the photoresist pattern, and the etching control assembly is correspondingly arranged above each etching cavity;

the etching cavities are at least three layers, and the cross sections of the etching cavities in adjacent layers are consistent in size; each layer of the etching cavity is constructed by reinforced fibers, and each layer of the reinforced fibers is fixed by a plurality of supporting fibers; the reinforced fibers with different hydrophilicity and hydrophobicity are arranged in each etching cavity from the top layer downwards in three reinforced fibers as a coating period, and the coating period comprises two super-hydrophilic medium layers and one super-hydrophobic medium layer;

the etching control assembly comprises a plurality of nozzles which are arranged at equal angles and at least three conductive fibers; each spray head can be automatically switched to the center of the etching control assembly to realize blanking, and each spray head corresponds to different solutions or solutions with different concentrations; the conductive fibers move along concentric circular tracks.

In a preferred embodiment of the present invention, the etching control assembly applies a dc voltage or a low frequency ac voltage to the corresponding electrode connected to each of the conductive fibers.

In a preferred embodiment of the present invention, the frequency of the voltage of the conductive fiber at the outer edge is greater than that of the conductive fiber at the inner side of the concentric circles.

In a preferred embodiment of the invention, the etching liquid at least comprises hydrofluoric acid, nitric acid or a mixed solution of hydrofluoric acid and nitric acid, and the etching time is between 200s and 400 s.

In a preferred embodiment of the invention, the surface of the reinforcing fiber of the top layer is coated with a super-hydrophobic medium layer, and liquid drops can form affinity with the surface of the reinforcing fiber, so that the contact surface of liquid and the reinforcing fiber is always higher than the middle liquid level, and an inner concave liquid level with low middle and high periphery is formed.

In a preferred embodiment of the present invention, the height of each layer of the etching chamber is determined according to a predetermined amount of each solution.

In a preferred embodiment of the present invention, an optical detection unit is further mounted on the surface of the etching control assembly to detect the flatness of the liquid level in the etching chamber.

In a preferred embodiment of the present invention, the cross section of the conductive fiber is in a shape like a Chinese character ' mi ', a triangle or a C '.

The invention provides a use method of an automatic etching mechanism based on an electrophoresis technology, which is characterized by comprising the following steps:

s1, the etching control component corresponding to each silicon chip moves downwards at the same time, after alignment, one of the nozzles automatically switches to the center and drips a certain amount of etching liquid to the etching cavity according to a preset amount, and the liquid surface forms an inward recess with a low middle part and a high periphery due to surface tension;

s2, detecting the flatness of the liquid level by the optical detection unit, controlling the movement of the conductive fibers on the concentric tracks, and applying voltage to corresponding electrodes connected with the conductive fibers;

s3, under the action of an electric field, the charges on the surfaces of the liquid drops are transferred, the surface tension of the liquid changes, and peripheral liquid drops diffuse towards the center to realize the leveling of the liquid level;

and S4, after the spray heads are restored, other spray heads are automatically switched to the center to drop a certain amount of etching liquid to the etching cavity according to the preset amount, and the operations of S2 and S3 are repeated.

In a preferred embodiment of the present invention, the movement of the conductive fibers at the outer edge is at least controlled according to the degree of concavity of the surface of the dropwise added solution in the etching cavity, the frequency of the voltage of the conductive fibers at the outer edge is high, and the charge transfer rate on the surface of the liquid drop is high.

In a preferred embodiment of the invention, the etching speed and the proportion of the solution in the etching cavity are controlled by calculating the mass of the liquid in all etching cavities and the dripping proportion of all the liquid, and the surface flatness of the silicon wafer is controlled by adjusting the proportion of the added acetic acid.

In a preferred embodiment of the present invention, the etching chamber of the present invention can be added with corrosive liquid, such as formic acid, acetic acid, etc. The reinforced fiber of the etching cavity adopts polyphenylene sulfide fiber, so that the chemical resistance and the heat stability of the etching cavity are good.

The invention solves the defects in the background technology, and has the following beneficial effects:

(1) the invention provides an array etching device, which is based on the technology of manipulating liquid drops through electrophoresis, and the electric charges on the surfaces of the liquid drops are transferred through the change of the strength of an electric field, so that the tension of the surfaces of the liquid is changed, and the aim of leveling the liquid level is fulfilled. The device has a high etching selection ratio, and the proportion of each solution can be accurately controlled.

(2) According to the invention, the super-hydrophilic medium layer is coated on the surface of the reinforced fiber at the top layer, and the liquid drops can form adsorption force with the surface of the reinforced fiber, so that the contact surface of liquid and the reinforced fiber is always higher than the middle liquid level, and an inner concave liquid level with low middle and high periphery is formed.

(3) According to the invention, direct current or low-frequency alternating current voltage is applied to corresponding electrodes connected with the conductive fibers, the frequency of the voltage of the conductive fibers at the outer edge is greater than that of the inner side of the concentric circle, the inner concave liquid surface can receive the action of an electric field, the surface charges of peripheral liquid drops move strongly, and the liquid drops move towards the center, so that the aim of compensating the empty groove of the inner concave liquid surface is fulfilled.

(4) According to the invention, three reinforcing fibers with different hydrophilicity and hydrophobicity are arranged in each etching liquid filling device from the top layer to the bottom layer by taking the three reinforcing fibers as a coating period, the coating period comprises two super-hydrophilic medium layers and one super-hydrophobic medium layer, the affinity of the surface of each reinforcing fiber to the liquid surface is improved by the aid of the amphiphilic-hydrophobic structure, an inwards concave liquid surface structure is easily formed, the structure is favorable for building a more three-dimensional liquid structure, and the actual amount of the added etching liquid is closer to the pre-measurement amount.

(5) The invention controls the etching speed and the proportion of the solution in the etching cavity by calculating the mass of the liquid in all etching cavities and the dripping proportion of all the liquid, and the surface evenness of the silicon wafer is adjusted by adjusting the proportion of the added acetic acid.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts;

FIG. 1 is a perspective block diagram of a preferred embodiment of the present invention;

FIG. 2 is a perspective view of an etch chamber according to a preferred embodiment of the present invention;

FIG. 3 is a perspective view of an etching solution manipulation assembly of a preferred embodiment of the present invention;

in the figure: 1. an operation surface; 11. a silicon wafer; 2. an etching liquid handling assembly; 21. a spray head; 22. a conductive fiber; 23. an optical detection unit; 3. etching the cavity; 31. a reinforcing fiber; 32. supporting the fibers.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.

In the description of the present application, it is to be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in the orientation or positional relationship indicated in the drawings for convenience in describing the present application and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated in a particular manner, and are not to be considered limiting of the scope of the present application. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the invention, the meaning of "a plurality" is two or more unless otherwise specified.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art through specific situations.

As shown in fig. 1, a three-dimensional structure diagram of an automated etching mechanism based on electrophoresis technology is shown. The device is based on the technology of manipulating liquid drops through electrophoresis, charges on the surfaces of the liquid drops are transferred through the change of the strength of an electric field, the tension of the surfaces of the liquid drops is changed, and the purpose of leveling the liquid level is achieved. The device has a high etching selection ratio, and the proportion of each solution can be accurately controlled.

The etching equipment comprises an operation surface 1 and a plurality of etching liquid control assemblies 2 arranged above the operation surface 1, and is characterized in that a plurality of mounting grooves for mounting silicon wafers 11 are arranged on the operation surface 1 in an array manner; each silicon chip 11 is adhered with an etching cavity 3 according to the photoresist pattern, and an etching control assembly is correspondingly arranged above each etching cavity 3.

As shown in fig. 2, the etching cavities 3 are at least three layers, and the cross-sections of the etching cavities 3 in adjacent layers are consistent in size. Each layer of etching cavity 3 is constructed by reinforced fibers 31, and each layer of reinforced fibers 31 is fixed by a plurality of supporting fibers 32; from the top layer to the bottom of each etching cavity 3, three reinforcing fibers 31 are arranged in a coating period of reinforcing fibers 31 with different hydrophilicity and hydrophobicity, and the coating period comprises two super-hydrophilic dielectric layers and one super-hydrophobic dielectric layer. The amphiphilic structure improves the affinity of the surface of the reinforced fiber 31 to the liquid level, and is easier to form an inner concave liquid level structure, and the structure is favorable for constructing a more three-dimensional liquid structure, and the actual amount of the added etching liquid is closer to the pre-measurement. According to the invention, the super-hydrophilic medium layer is coated on the surface of the reinforced fiber 31 at the top layer, and the liquid drops can form adsorption force with the surface of the reinforced fiber 31, so that the contact surface of the liquid and the reinforced fiber 31 is always higher than the middle liquid level, and an inner concave liquid level with low middle and high periphery is formed.

It should be noted that, the liquid in the enclosed space with alternate hydrophilicity and hydrophobicity is constructed into a stable structure with side surfaces varying in size and interval in the vertical direction. If only one super-hydrophilic medium layer is coated on the reinforcing fiber 31, the liquid in the enclosed space can be completely attached to the surface of the fiber, so that a cylindrical structure with staggered and uneven side surfaces is formed, and the accurate measurement of the thickness of the liquid in the later period is inconvenient.

The basic two-dimensional structure for forming each etching chamber 3 of the present invention is not limited to a rectangle, a circle, a star, or an ellipse, and any closed surrounding pattern is suitable for the basic two-dimensional structure of the present invention, and the basic two-dimensional structure of the present invention is preferably a square, where the square is a × a, and a is 500 μm to 2.0 mm.

The supporting fiber 32 is made of high-strength fiber materials, preferably aramid fiber 1414, the fiber is high in strength and stable in chemical performance, and is suitable for serving as a support of the etching cavity 3, and when liquid is dripped into the surrounding space of the etching cavity 3, the etching cavity 3 is guaranteed not to deform.

The etching chamber 3 of the present invention may be dropped with corrosive liquids, such as formic acid, acetic acid, and the like. The reinforced fiber 31 of the etching cavity 3 adopts polyphenylene sulfide fiber, so that the etching cavity 3 is ensured to have good chemical resistance stability and excellent thermal stability. Even if the strength of the fiber is not changed for one week under the boiling point, formic acid and acetic acid with the temperature of 93 ℃ have no influence, and the fiber can be strongly degraded only under the condition of a strong oxidant, namely the etching cavity 3 can detect the liquid thickness of any solution except the strong oxidant with certain temperature and certain concentration.

As shown in fig. 3, the etching manipulation assembly includes a plurality of nozzles 21 arranged at equal angles, and at least three conductive fibers 22. Each spray head 21 can be automatically switched to the center of the etching control assembly to realize blanking, and each spray head 21 corresponds to different solutions or solutions with different concentrations.

The conductive fibers 22 move along concentric tracks, and the cross section of the conductive fibers 22 is in a shape like a Chinese character ' mi ', a triangle or a C '. The etching manipulation assembly applies a dc or low frequency ac voltage to the respective electrodes connected to each conductive fiber 22. The outer edge of the conductive fibers 22 has a voltage with a frequency greater than the inner concentric circle of conductive fibers 22.

It should be noted that, in the present invention, a dc or low frequency ac voltage is applied to the corresponding electrodes connected to the conductive fibers 22, the frequency of the voltage of the conductive fibers 22 at the outer edge is greater than that at the inner side of the concentric circles, the inner concave liquid surface can receive the action of the electric field, the surface charges of the peripheral liquid droplets move strongly, and the liquid droplets move toward the center, thereby achieving the purpose of compensating the empty slot of the inner concave liquid surface.

The invention adds liquid drops into the enclosed space of the etching cavity 3, and the etching liquid control component 2 is not limited to the use of devices such as a burette, a quantitative liquid adding device, a digital automatic burette and the like, and aims to accurately control the quantity and the volume of the liquid drops added into the etching cavity 3 in a certain way.

The etching liquid at least comprises hydrofluoric acid, nitric acid or a mixed solution of the hydrofluoric acid and the nitric acid, and the etching time is between 200s and 400 s. The invention controls the etching speed and the proportion of the solution in the etching cavity 3 by calculating the mass of the liquid in all the etching cavities 3 and the dripping proportion of all the liquid, and the surface evenness of the silicon chip 11 is adjusted by adjusting the proportion of the added acetic acid.

The surface of the reinforcing fiber 31 of the top layer is coated with a super-hydrophobic medium layer, and liquid drops can form affinity with the surface of the reinforcing fiber 31, so that the contact surface of liquid and the reinforcing fiber 31 is always higher than the middle liquid level, and an inner concave liquid level with low middle and high periphery is formed.

The height of each layer of the etching chamber 3 is determined according to a predetermined amount of each solution.

The surface of the etching manipulation assembly also carries an optical detection unit 23 to detect the flatness of the liquid level in the etching chamber 3.

According to the wet use method, after the photoetching process, the image corresponding to the GDS-II file is accurately copied to the surface of the silicon wafer 11 through the photoresist or other photoresists by the photoetching process, so that the etching area of the wet process is determined, and materials of the area, which is not covered by the photoresist, on the top layer of the silicon wafer 11 are removed through an acidic solution.

The invention provides a use method of an automatic etching mechanism based on an electrophoresis technology, which is characterized by comprising the following steps:

s1, the etching control component corresponding to each silicon chip 11 moves downwards at the same time, after alignment, one of the nozzles 21 automatically switches to the center to drop a certain amount of etching liquid to the etching cavity 3 according to a preset amount, and the liquid surface forms an inward recess with low middle and high periphery due to surface tension;

s2, detecting the flatness of the liquid level by the optical detection unit 23, controlling the conductive fiber 22 on the concentric track to move, and applying voltage to the corresponding electrode connected with the conductive fiber 22;

s3, under the action of an electric field, the charges on the surfaces of the liquid drops are transferred, the surface tension of the liquid changes, and peripheral liquid drops diffuse towards the center to realize the leveling of the liquid level;

s4, after the spray head 21 is recovered, other spray heads 21 are automatically switched to the center to drop a certain amount of etching liquid to the etching cavity 3 according to a preset amount, and the operations of S2 and S3 are repeated.

According to the concave degree of the surface of the dropwise added solution in the etching cavity 3, at least the movement of the conductive fibers 22 at the outer edge is controlled, the frequency of the voltage of the conductive fibers 22 at the outer edge is high, and the charge generation and migration rate of the surface of the liquid drop is high.

The etching speed and the proportion of the solution in the etching cavity 3 are controlled by calculating the mass of the liquid in all the etching cavities 3 and the dripping proportion of all the liquid, and the surface flatness of the silicon wafer 11 is adjusted by adjusting the proportion of the added acetic acid.

In light of the foregoing description of the preferred embodiment of the present invention, it is to be understood that various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.