阅读说明：本技术 一种非晶硅薄膜的沉积方法及沉积设备 (Deposition method and deposition equipment for amorphous silicon film ) 是由 尹勇 王晓龙 陆鸣晔 于 2019-04-22 设计创作，主要内容包括：本发明公开了一种非晶硅薄膜的沉积方法及沉积设备,其中沉积方法包括：在半导体晶圆片沉积前利用流体喷洗半导体晶圆片,所述流体的喷射压力大于预设压力值；检验喷洗处理后的半导体晶圆片的表面的颗粒,直到所述半导体晶圆片的表面的颗粒数量小于预设数量时,停止所述利用流体喷洗半导体晶圆片的操作；清洗CVD机台沉积腔体,并在所述沉积腔体中沉积预设厚度的非晶硅薄膜,进行覆盖保护；将半导体晶圆片通过CVD机台的传送机构,传入所述沉积腔体进行非晶硅薄膜沉积。本发明能解决薄膜脱膜的问题。(The invention discloses a deposition method and deposition equipment for an amorphous silicon film, wherein the deposition method comprises the following steps: before the semiconductor wafer is deposited, spraying and washing the semiconductor wafer by using fluid, wherein the spraying pressure of the fluid is greater than a preset pressure value; checking particles on the surface of the semiconductor wafer after spray-washing treatment, and stopping the operation of spray-washing the semiconductor wafer by using the fluid until the number of the particles on the surface of the semiconductor wafer is less than a preset number; cleaning a CVD machine deposition cavity, and depositing an amorphous silicon film with a preset thickness in the deposition cavity for covering protection; and conveying the semiconductor wafer into the deposition cavity for amorphous silicon film deposition through a conveying mechanism of the CVD machine. The invention can solve the problem of film stripping.)

1. A method for depositing an amorphous silicon thin film, comprising:

before the semiconductor wafer is deposited, spraying and washing the semiconductor wafer by using fluid, wherein the spraying pressure of the fluid is greater than a preset pressure value;

checking particles on the surface of the semiconductor wafer after spray-washing treatment, and stopping the operation of spray-washing the semiconductor wafer by using the fluid until the number of the particles on the surface of the semiconductor wafer is less than a preset number;

cleaning a deposition cavity of a Chemical Vapor Deposition (CVD) machine, depositing an amorphous silicon film with a preset thickness in the deposition cavity, and performing covering protection;

and conveying the semiconductor wafer into the deposition cavity for amorphous silicon film deposition through a conveying mechanism of the CVD machine.

2. The method of claim 1, wherein the step of transferring the semiconductor wafer into the deposition chamber for deposition of the amorphous silicon thin film via the transport mechanism of the CVD tool further comprises:

and cleaning a CVD machine deposition cavity, and depositing an amorphous silicon film with a preset thickness in the deposition cavity for covering protection.

3. The method of claim 1 or 2, wherein the step of rinsing the semiconductor wafer with a fluid prior to deposition of the semiconductor wafer comprises:

before the semiconductor wafer is deposited, cleaning solution is sprayed on the surface of the semiconductor wafer by using a spray head positioned above the surface of the semiconductor wafer, so as to clean the surface of the semiconductor wafer.

4. The method of claim 3, wherein a distance between a nozzle of the shower head and the semiconductor wafer is 10 to 20mm, and a rotation speed of the semiconductor wafer during the spray rinsing is 2000 to 4000rmp, so as to clean the wafer surface of the semiconductor wafer.

5. The method of claim 4, wherein the predetermined pressure is 15MPa and the injection pressure of the fluid is less than 25 MPa.

6. The method of claim 5, wherein the size of the particles is less than 0.2um, and the predetermined number is 50 particles.

7. The method of claim 6, wherein the step of cleaning the CVD tool deposition chamber comprises:

using gas C₂F₆And O₂The proportion range is 1: 2-2: 1, and the CVD machine deposition cavity is cleaned for 10-30 s under the high power of 1000-2500W and the pressure of 5-10 mTorr.

8. The method of claim 7, wherein the step of depositing the amorphous silicon thin film with a predetermined thickness in the deposition chamber comprises:

and depositing an amorphous silicon film with the thickness of 500-2000A in the deposition cavity to cover the surface of the cavity.

9. An apparatus for depositing an amorphous silicon thin film, comprising:

the spray-washing device is used for spray-washing the semiconductor wafer by using fluid before the semiconductor wafer is deposited, wherein the spray pressure of the fluid is greater than a preset pressure value;

the inspection device is used for inspecting particles on the surface of the semiconductor wafer after the spray-washing treatment, and when the number of the particles on the surface of the semiconductor wafer is smaller than a preset number, the spray-washing device is prompted to stop the operation of spray-washing the semiconductor wafer by using the fluid;

the deposition device is used for cleaning a deposition cavity of the CVD machine, depositing an amorphous silicon film with a preset thickness in the deposition cavity and performing covering protection;

and the conveying device is used for conveying the semiconductor wafer into the deposition cavity through the CVD machine to carry out amorphous silicon film deposition.

10. The deposition apparatus as claimed in claim 9, further comprising a spray rinsing device for spraying a rinsing liquid onto the wafer surface of the semiconductor wafer by using a spray head positioned above the wafer surface of the semiconductor wafer to clean the wafer surface of the semiconductor wafer before the semiconductor wafer is deposited.

Technical Field

The invention relates to the field of chemical vapor deposition in semiconductor integrated circuit manufacturing, in particular to a deposition method and deposition equipment for an amorphous silicon film.

Background

A wafer-level Chemical Vapor Deposition (CVD) amorphous silicon (α -Si) growth process is a technique that uses Plasma (Plasma-Plasma electron cloud) to dissociate gases and deposit a thin film on a substrate (typically a wafer). The reaction gas is ionized to form plasma under the excitation of an external electric field, a series of complex physical and chemical reactions occur in the plasma and on the surface of the substrate, and SiH4 is decomposed by glow discharge to prepare the amorphous silicon film. The deposited amorphous silicon film has the advantages of high resistance temperature coefficient, low thermal conductivity, good mechanical property and being prepared by a method completely compatible with a silicon integration process.

Micro-electromechanical systems (MEMS) are micro devices that integrate micro sensors, micro actuators and control circuits, interfaces, and communications. MEMS is a revolutionary new technology, is widely applied to high and new technology industries, and is a key technology related to national science and technology development, economic prosperity and national defense safety. MEMS focuses on ultra-precision machining, and relates to the fields of microelectronics, materials, mechanics, chemistry and mechanics. Its disciplinary surface includes physical, chemical and mechanical branches of force, electricity, light, magnetism, sound and surface at micro-scale. Common products include MEMS accelerometers, MEMS microphones, micro-motors, micro-pumps, MEMS optical sensors, MEMS pressure sensors, MEMS gyroscopes, MEMS humidity sensors, MEMS gas sensors, and the like, as well as integrated products thereof.

In the MEMS process, amorphous silicon thin films are used in a variety of devices to provide unique properties to electronic devices. The amorphous silicon thin film can be deposited on a silicon wafer substrate, and is often subjected to a Peeling phenomenon of the amorphous silicon thin film, and is found through experiments to be strongly related to wafer particles. The position of the particles is easy to cause the film to bulge and fall off, and the common process of direct deposition after the wafer surface is sprayed and washed cannot meet the strict requirement of amorphous silicon deposition on the particles, so a new amorphous silicon film deposition process needs to be developed to solve the problem of amorphous silicon film demoulding.

Disclosure of Invention

In view of the above, the present invention is directed to a method for depositing an amorphous silicon thin film to solve the problem of film peeling.

Specifically, the invention provides a deposition method of an amorphous silicon film, which comprises the following steps: before the semiconductor wafer is deposited, spraying and washing the semiconductor wafer by using fluid, wherein the spraying pressure of the fluid is greater than a preset pressure value;

checking particles on the surface of the semiconductor wafer after spray-washing treatment, and stopping the operation of spray-washing the semiconductor wafer by using the fluid until the number of the particles on the surface of the semiconductor wafer is less than a preset number;

cleaning a CVD machine deposition cavity, and depositing an amorphous silicon film with a preset thickness in the deposition cavity for covering protection;

and conveying the semiconductor wafer into the deposition cavity for amorphous silicon film deposition through a conveying mechanism of the CVD machine.

Further, after the step of transferring the semiconductor wafer into the deposition chamber for amorphous silicon thin film deposition through the conveying mechanism of the CVD machine, the method further comprises:

and cleaning a CVD machine deposition cavity, and depositing an amorphous silicon film with a preset thickness in the deposition cavity for covering protection.

Further, the step of rinsing the semiconductor wafer with a fluid prior to deposition of the semiconductor wafer comprises:

before the semiconductor wafer is deposited, cleaning solution is sprayed on the surface of the semiconductor wafer by using a spray head positioned above the surface of the semiconductor wafer, so as to clean the surface of the semiconductor wafer.

Furthermore, the distance between a nozzle of the spray head and the semiconductor wafer is 10-20 mm, and the rotating speed of the semiconductor wafer during spray washing is 2000-4000 rmp, so that the surface of the semiconductor wafer is cleaned.

Further, the preset pressure value is 15Mpa, and the injection pressure of the fluid is also less than 25 Mpa.

Further, the size of the particles is less than 0.2um, and the preset number is 50.

Further, the step of cleaning the deposition chamber of the CVD tool comprises:

using gas C₂F₆And O₂The ratio is in the range of 1: 2-2: 1, high power of 1000-2500W and 5 ℃And cleaning the deposition cavity of the CVD machine for 10-30 s under the pressure of 10 mTorr.

Further, the step of depositing an amorphous silicon thin film with a preset thickness in the deposition cavity and performing coverage protection includes:

and depositing an amorphous silicon film with the thickness of 500-2000A in the deposition cavity to cover the surface of the cavity.

According to another aspect, the present invention provides an apparatus for depositing an amorphous silicon thin film, comprising:

the spray-washing device is used for spray-washing the semiconductor wafer by using fluid before the semiconductor wafer is deposited, wherein the spray pressure of the fluid is greater than a preset pressure value;

the inspection device is used for inspecting particles on the surface of the semiconductor wafer after the spray-washing treatment, and when the number of the particles on the surface of the semiconductor wafer is smaller than a preset number, the spray-washing device is prompted to stop the operation of spray-washing the semiconductor wafer by using the fluid;

the deposition device is used for cleaning a deposition cavity of the CVD machine, depositing an amorphous silicon film with a preset thickness in the deposition cavity and performing covering protection;

and the conveying device is used for conveying the semiconductor wafer into the deposition cavity through the CVD machine to carry out amorphous silicon film deposition.

Before the semiconductor wafer is deposited, the spray washing device sprays the cleaning solution to the surface of the semiconductor wafer by using the spray head positioned above the surface of the semiconductor wafer, so as to clean the surface of the semiconductor wafer.

Furthermore, the distance between a nozzle of the spray head and the semiconductor wafer is 10-20 mm, and the rotating speed of the semiconductor wafer during spray washing is 2000-4000 rmp, so that the surface of the semiconductor wafer is cleaned.

Further, the preset pressure value is 15Mpa, and the injection pressure of the fluid is also less than 25 Mpa.

Further, the size of the particles is less than 0.2um, and the preset number is 50.

Further, cleaning the deposition chamber of the CVD tool comprises: using gas C₂F₆And O₂The proportion range is 1: 2-2: 1, and the CVD machine deposition cavity is cleaned for 10-30 s under the high power of 1000-2500W and the pressure of 5-10 mTorr.

Further, depositing an amorphous silicon film with a preset thickness in the deposition cavity, and performing coverage protection comprises: and depositing an amorphous silicon film with the thickness of 500-2000A in the deposition cavity to cover the surface of the cavity.

The deposition method of the amorphous silicon film adopts the steps that firstly, a semiconductor wafer is sprayed and washed by fluid before being deposited, and the spraying pressure of the fluid is greater than a preset pressure value; secondly, checking the particles on the surface of the semiconductor wafer after spray-washing treatment, and stopping the operation of spray-washing the semiconductor wafer by using the fluid until the number of the particles on the surface of the semiconductor wafer is less than a preset number; cleaning the CVD machine deposition cavity again, depositing an amorphous silicon film with a preset thickness in the deposition cavity, and performing covering protection; and (3) conveying the semiconductor wafer into the deposition cavity through a conveying mechanism of the CVD machine for amorphous silicon film deposition, wherein the surface of the deposited amorphous silicon film is uniform and flat, and the phenomenon of film stripping is avoided.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention. In the drawings, like reference numerals are used to indicate like elements. The drawings in the following description are directed to some, but not all embodiments of the invention. For a person skilled in the art, other figures can be derived from these figures without inventive effort.

FIG. 1 is a flow chart of a method for depositing an amorphous silicon thin film according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a high pressure spray rinsing in a deposition method of an amorphous silicon thin film according to an embodiment of the present invention; and

fig. 3 is a schematic structural diagram of an amorphous silicon thin film deposition apparatus according to an embodiment of the present invention.

Detailed Description

The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.

Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.

Fig. 1 is a flowchart of a deposition method of an amorphous silicon thin film according to an embodiment of the present invention. As shown in fig. 1, a method for depositing an amorphous silicon thin film includes:

step 101: before the semiconductor wafer is deposited, spraying and washing the semiconductor wafer by using fluid, wherein the spraying pressure of the fluid is greater than a preset pressure value; the improved wafer subjected to high-pressure spray washing can remove small-particle-size particle residues on the surface of the wafer at the level of 0.2 um;

step 102: checking particles on the surface of the semiconductor wafer after spray-washing treatment, and stopping the operation of spray-washing the semiconductor wafer by using the fluid until the number of the particles on the surface of the semiconductor wafer is less than a preset number;

step 103: cleaning a CVD machine deposition cavity, and depositing an amorphous silicon film with a preset thickness in the deposition cavity for covering protection; the problem that particles fall on a wafer on the wall of a cavity body when the cavity body is deposited can be solved by cleaning and pre-covering the cavity body of a machine table before deposition;

step 104: and conveying the semiconductor wafer into the deposition cavity for amorphous silicon film deposition through a conveying mechanism of the CVD machine.

Preferably, after step 104, the method further comprises:

and cleaning a CVD machine deposition cavity, and depositing an amorphous silicon film with a preset thickness in the deposition cavity for covering protection. After deposition, the machine cavity needs to be subjected to cavity cleaning and pre-deposition covering protection again to prepare for the deposition of the next wafer

Preferably, step 101 may comprise:

before the semiconductor wafer is deposited, cleaning solution is sprayed on the surface of the semiconductor wafer by using a spray head positioned above the surface of the semiconductor wafer, so as to clean the surface of the semiconductor wafer.

Further preferably, the distance between the nozzle of the spray head and the semiconductor wafer is 10-20 mm, and the rotation speed of the semiconductor wafer during spray washing is 2000-4000 rmp, so that the surface of the semiconductor wafer is cleaned. The preset pressure value is 15Mpa, and the jet pressure of the fluid is smaller than 25 Mpa. The size of the particles is less than 0.2um, and the preset number is 50.

Preferably, step 103 may comprise:

first, using a gas C₂F₆And O₂Cleaning a CVD machine deposition cavity for 10-30 s at a high power of 1000-2500W and a pressure of 5-10 mTorr in a ratio range of 1: 2-2: 1;

and secondly, depositing an amorphous silicon film with the thickness of 500-2000A in the deposition cavity to cover the surface of the cavity.

In the embodiment, the particle level is controlled by cleaning the wafer and cleaning and protecting the machine cavity before the wafer is deposited, so that amorphous silicon particles are improved, and the problem of film stripping is solved.

First, an improved high pressure spray rinse is used for wafer cleaning prior to deposition. The high-pressure cleaning refers to cleaning the surface of a semiconductor wafer by spraying a cleaning solution onto the surface of the wafer through a spray head positioned above the surface of the wafer. The wafer is cleaned by deionized water, in the embodiment, the rotating speed of the normal wafer rotating spray cleaning is increased from 1000rmp (revolutions per minute) to 2000-4000 rmp, the pressure of the nozzle is increased from 10MPa to 15-25 MPa, and the distance between the nozzle and the wafer needs to be controlled within the range of 10-20 mm. Can effectively improve the cleaning effect of the particles (particles), and the number of the particles (particles) with the Particle diameter of 0.2um after cleaning is controlled to be less than 50.

Secondly, the treatment of plasma cleaning and film layer covering protection is carried out on the CVD machine deposition cavity before deposition. First using clean gas C₂F₆And O₂Cleaning the cavity for 10-30 s at the high power of 1000-2500W and the pressure of 5-10 mTorr in a proportion range of 1: 2-2: 1, and removing residues covered before the cavity is used; after cleaning, an amorphous silicon film with the thickness of 500-2000A needs to be deposited again to cover the surface of the cavity, so that the defective parts in the cavity can be covered and protected by the uniform film layer, and particles generated on the wall of the cavity are prevented from falling onto the wafer during cavity deposition.

Fig. 2 is a schematic diagram of high-pressure spray rinsing in a deposition method of an amorphous silicon thin film according to an embodiment of the present invention. As shown in fig. 2, the present embodiment provides a method for depositing an amorphous silicon thin film, which includes first placing a wafer on which an amorphous silicon thin film is to be deposited into a cleaning machine, and cleaning the wafer by using an improved high-pressure spray cleaning process; secondly, putting the cleaned wafer into a detection machine, confirming whether the number of 0.2um particles after cleaning is less than 50 particles, and otherwise, cleaning again; before the wafer is deposited again, the CVD machine station uses the plasma to clean the cavity for 10-30 s, then an amorphous silicon film with the thickness of 500-2000A is deposited in the cavity again for covering protection, finally the wafer is conveyed into the cavity through the machine station conveying mechanism to be deposited with the amorphous silicon film, the surface of the deposited amorphous silicon film is even and flat, and OM (optical microscope) inspection is carried out, and no film stripping phenomenon is found; and then surface particle detection is carried out, the number of 0.2um particles can be less than 50, and the process requirement is met.

Fig. 3 is a schematic structural diagram of an apparatus 300 for depositing an amorphous silicon thin film according to an embodiment of the present invention. The deposition apparatus 300 includes: a spray rinsing device 301, a checking device 302, a depositing device 303 and a conveying device 304. The spray rinsing device 301 sprays the semiconductor wafer with a fluid before the semiconductor wafer is deposited, wherein the spray pressure of the fluid is greater than a preset pressure value. The inspection device 302 inspects the particles on the surface of the semiconductor wafer after the spray rinsing process, and prompts the spray rinsing device to stop the operation of spray rinsing the semiconductor wafer with the fluid until the number of the particles on the surface of the semiconductor wafer is less than a preset number. And the deposition device 303 is used for cleaning the deposition cavity of the CVD machine, depositing an amorphous silicon film with a preset thickness in the deposition cavity and performing covering protection. And the conveying device 304 is used for conveying the semiconductor wafer into the deposition cavity through the CVD machine for amorphous silicon film deposition.

Before the semiconductor wafer is deposited, the spray rinsing apparatus 301 sprays a cleaning solution onto the wafer surface of the semiconductor wafer by using a spray head located above the wafer surface of the semiconductor wafer, and cleans the wafer surface of the semiconductor wafer. The distance between a nozzle of the spray head and the semiconductor wafer is 10-20 mm, and the rotation speed of the semiconductor wafer during spray washing is 2000-4000 rmp, so that the surface of the semiconductor wafer is cleaned. The preset pressure value is 15Mpa, and the injection pressure of the fluid is also less than 25 Mpa. The size of the particles is less than 0.2um, and the preset number is 50.

Wherein, wash CVD board deposit cavity and include: using gas C₂F₆And O₂The proportion range is 1: 2-2: 1, and the CVD machine deposition cavity is cleaned for 10-30 s under the high power of 1000-2500W and the pressure of 5-10 mTorr. The amorphous silicon film with the preset thickness is deposited in the deposition cavity, and the covering protection comprises the following steps: and depositing an amorphous silicon film with the thickness of 500-2000A in the deposition cavity to cover the surface of the cavity.

The invention has been described with reference to a few embodiments. However, other embodiments of the invention than the one disclosed above are equally possible within the scope of the invention, as would be apparent to a person skilled in the art from the appended patent claims.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [ device, component, etc ]" are to be interpreted openly as referring to at least one instance of said device, component, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.