阅读说明：本技术 硅片单侧膜淀积的方法 (Method for depositing single-side film of silicon wafer ) 是由 方小磊 刘佳晶 于乐 陈涛 王宣欢 陈艳明 于 2020-12-30 设计创作，主要内容包括：本发明公开了一种硅片单侧膜淀积的方法,提出硅片单侧膜淀积的方法,该方法为通过利用原子层沉积(ALD)设备在低温下实现硅片单侧薄膜淀积,即选择合适的背膜,并将此背膜通过一定的技术手段粘附在硅片的背面以防止硅片背面淀积薄膜,在淀积工艺完成后将背膜剥离即可。一般情况下,背膜可以在200℃-300℃保持12小时而不熔化、收缩或变形。通过背膜的运用,实现了低温下(200℃-300℃)硅片单侧膜沉积的目的,为后续工艺提供了方便条件。此种方法可应用于氧化铝,氧化铪等薄膜的制备,并且具有简便、易操作、成本低等优点。同时,制备的薄膜厚度线性可调(15A-1000A),均匀性好(均匀性小于0.5％)。(The invention discloses a method for depositing a silicon wafer single-side film, which is used for depositing the silicon wafer single-side film at low temperature by utilizing Atomic Layer Deposition (ALD) equipment, namely selecting a proper back film, adhering the back film to the back of the silicon wafer by a certain technical means to prevent the back of the silicon wafer from depositing the film, and stripping the back film after the deposition process is finished. In general, the backing film can be held at 200 ℃ to 300 ℃ for 12 hours without melting, shrinking or deforming. By applying the back film, the purpose of film deposition on the single side of the silicon wafer at low temperature (200-300 ℃) is realized, and convenient conditions are provided for subsequent processes. The method can be applied to the preparation of films of aluminum oxide, hafnium oxide and the like, and has the advantages of simplicity, convenience, easy operation, low cost and the like. Meanwhile, the thickness of the prepared film is linearly adjustable (15A-1000A), and the uniformity is good (the uniformity is less than 0.5%).)

1. A method for single-sided film deposition of a silicon wafer is characterized by comprising the following steps:

s1, setting the indoor temperature to be 22 +/-1 ℃ and the indoor humidity to be 45 +/-10% in a ten-grade clean room;

s2, manually pasting a back film on one side surface of the wafer pasting ring in a clean room, wherein the surface of the back film after being pasted has no wrinkles;

s3, placing a silicon wafer on an operation table with the protection side surface of the silicon wafer facing upwards, and aligning the surface of the back film with the wafer sticking ring with the upper surface of the silicon wafer in a face-to-face mode;

s4, adhering the back film to the surface of the silicon wafer, wherein no air bubble exists between the adhered back film and the silicon wafer;

s5, cutting off the back film and the silicon wafer which are bonded together along the inner ring of the wafer sticking ring;

s6, sending the silicon wafers in the step S5 into an ALD wafer boat for film deposition and setting working parameters of the ALD wafer boat;

s7, fitting a film thickness formula according to the setting in the step 6;

and S8, finishing the silicon wafer processing, and taking out the back film from the ALD wafer boat and stripping the back film.

2. The method of claim 1, wherein the parameters in the ALD boat are set as follows:

the ALD wafer boat rotates at a speed between 2rmp and 10 rmp;

the flow rate of the trimethylaluminum is between 200sccm and 400 sccm;

the oxygen flow is set to 8 sLm;

the nitrogen flow rate is between 0.3sLm and 1 sLm;

the cavity pressure of the ALD wafer boat is set to be between 0.05torr and 0.1 torr;

the pressure valve angle is between 85 and 88 degrees;

the reaction temperature for film deposition is between 250 ℃ and 300 ℃.

3. The method of single-sided film deposition on a silicon wafer according to claim 2, wherein the thickness formula of the film deposition during the film deposition is as follows:

T＝0.0801L+14.75 (1)

wherein T is the film thickness and L is the cycle number.

4. The method of single-sided film deposition on silicon wafers of claim 1, further comprising a utility knife, a clean glove for cutting the object.

5. The method of single-sided film deposition on silicon wafer as claimed in claim 1, wherein the thickness of the back film in step S2 is 20 μm to 200 μm, the width of the back film is 210mm to 250mm, and the temperature that the back film can withstand is 250 ℃ to 300 ℃.

Technical Field

The invention belongs to the technical field of semiconductor chip processing, and particularly relates to a method for depositing a silicon wafer single-side film.

Background

With the increase of the complexity of the semiconductor process, the number of films deposited on the silicon wafer is more and more, and the film structures play various roles, such as surface passivation, device isolation, device protection, doping barrier, metal interlayer dielectric and the like. The thin film deposition refers to a process for depositing a film on a silicon wafer substrate, and is mainly divided into two methods, namely Physical Vapor Deposition (PVD) and Chemical Vapor Deposition (CVD). Physical vapor deposition uses physical methods (such as evaporation, sputtering and the like) to evaporate the coating material and deposit the coating material on the surface of a substrate; chemical vapor deposition deposits a solid film on the wafer surface by chemical reaction of a gas mixture, and the wafer surface and its adjacent areas are heated to provide additional energy to the reaction system.

Atomic Layer Deposition (ALD) is a process by which substances can be deposited on a substrate surface layer by layer in the form of a monoatomic film. It is similar to ordinary chemical vapor deposition, but in an atomic layer deposition process, the chemical reaction of a new atomic film is directly related to the previous one, so that only one layer of atoms can be deposited per reaction. Although the deposition speed is slower, the thickness and the structural high consistency can better meet the nanometer-scale process requirement.

For Atomic Layer Deposition (ALD) equipment, because the front and back surfaces of the silicon wafer are contacted with the process gas, the film prepared by the method can be deposited on the two sides of the silicon wafer. In most cases, the film deposited on the back of the silicon wafer is irrelevant, but some special products require that the film is deposited only on the front side of the silicon wafer, and the film is not allowed to be deposited on the back side, such as double-polished wafers or bonded silicon wafers, and other structures need to be manufactured on the back side. In this case, it is necessary to modify the equipment or develop a special process to meet the product processing requirements.

Disclosure of Invention

In view of the above, the present invention provides a method for single-side film deposition of a silicon wafer, which comprises:

a method for single-side film deposition of a silicon wafer comprises the following steps:

s1, setting the indoor temperature to be 22 +/-1 ℃ and the indoor humidity to be 45 +/-10% in a ten-grade clean room;

s2, manually pasting a back film on one side surface of the wafer pasting ring in a clean room, wherein the surface of the back film after being pasted has no wrinkles;

s3, placing a silicon wafer on an operation table with the protection side surface of the silicon wafer facing upwards, and aligning the surface of the back film with the wafer sticking ring with the upper surface of the silicon wafer in a face-to-face mode;

s4, adhering the back film to the surface of the silicon wafer, wherein no air bubble exists between the adhered back film and the silicon wafer;

s5, cutting off the back film and the silicon wafer which are bonded together along the inner ring of the wafer sticking ring;

s6, sending the silicon wafers in the step S5 into an ALD wafer boat for film deposition and setting working parameters of the ALD wafer boat;

s7, fitting a film thickness formula according to the setting in the step 6;

and S8, finishing the silicon wafer processing, and taking out the back film from the ALD wafer boat and stripping the back film.

Preferably, the parameters in the ALD wafer boat are set as follows: the ALD wafer boat rotates at a speed between 2rmp and 10 rmp; the flow rate of the trimethylaluminum is between 200sccm and 400 sccm; the oxygen flow is set to 8 sLm; the nitrogen flow rate is between 0.3sLm and 1 sLm; the cavity pressure of the ALD wafer boat is set to be between 0.05torr and 0.1 torr; the pressure valve angle is between 85 and 88 degrees; the reaction temperature for film deposition is between 250 ℃ and 300 ℃.

Preferably, the formula of the thickness of the film deposition in the film deposition process is as follows:

T＝0.0801L+14.75 (1)

wherein T is the film thickness and L is the cycle number.

Preferably, the utility knife and the clean gloves are used for cutting objects. The thickness of the back film in the step S2 is between 20 μm and 200 μm, the width of the back film is between 210mm and 250mm, and the temperature which the back film can bear is between 250 ℃ and 300 ℃.

Has the advantages that: the invention provides a method for depositing a single-side film of a silicon wafer, which is a method for depositing the single-side film of the silicon wafer at low temperature by utilizing Atomic Layer Deposition (ALD) equipment, namely, a proper back film is selected, the back film is adhered to the back of the silicon wafer by a certain technical means to prevent the film from being deposited on the back of the silicon wafer, and the back film is stripped after the deposition process is finished. In general, the backing film can be held at 200 ℃ to 300 ℃ for 12 hours without melting, shrinking or deforming. By applying the back film, the purpose of film deposition on the single side of the silicon wafer at low temperature (200-300 ℃) is realized, and convenient conditions are provided for subsequent processes. The method can be applied to the preparation of films of aluminum oxide, hafnium oxide and the like, and has the advantages of simplicity, convenience, easy operation, low cost and the like. Meanwhile, the thickness of the prepared film is linearly adjustable (15A-1000A), and the uniformity is good (the uniformity is less than 0.5%)

Drawings

FIG. 1 is a circular patch ring according to one embodiment of the present invention;

FIG. 2 is a high temperature resistant backing film according to one embodiment of the invention;

FIG. 3 illustrates a back film attached to a wafer ring according to one embodiment of the present invention;

FIG. 4 is a schematic diagram of a finger pad on one side of a wafer attachment ring in accordance with one embodiment of the present invention;

FIG. 5 is a diagram illustrating the effect of the film according to one embodiment of the present invention;

FIG. 6 is a diagram illustrating the operation of cutting a silicon wafer from a wafer ring according to one embodiment of the present invention;

FIG. 7 is a graph illustrating the effect of the consistent size of the back film and the silicon wafer according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of the peeling of the back film according to an embodiment of the present invention.

Detailed Description

In order to make the technical solutions of the present invention better understood, 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.

It is noted that the terms first, second, third, etc. are used herein to describe various components or features, but these components or features are not limited by these terms. These terms are only used to distinguish one element or part from another element or part. Terms such as "first," "second," and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. For convenience of description, spatially relative terms such as "inner", "outer", "upper", "lower", "left", "right", "upper", "left", "right", and the like are used herein to describe the orientation relation of the components or parts in the present embodiment, but these spatially relative terms do not limit the orientation of the technical features in practical use.

A method for single-side film deposition of a silicon wafer comprises the following steps:

s1, setting the indoor temperature to be 22 +/-1 ℃ and the indoor humidity to be 45 +/-10% in a ten-grade clean room;

s2, manually pasting a back film on one side surface of the wafer pasting ring in a clean room, wherein the surface of the back film after being pasted has no wrinkles;

s3, placing a silicon wafer on an operation table with the protection side surface of the silicon wafer facing upwards, and aligning the surface of the back film with the wafer sticking ring with the upper surface of the silicon wafer in a face-to-face mode;

s4, adhering the back film to the surface of the silicon wafer, wherein no air bubble exists between the adhered back film and the silicon wafer;

s5, cutting off the back film and the silicon wafer which are bonded together along the inner ring of the wafer sticking ring;

s6, sending the silicon wafers in the step S5 into an ALD wafer boat for film deposition and setting working parameters of the ALD wafer boat;

s7, fitting a film thickness formula according to the setting in the step 6;

and S8, finishing the silicon wafer processing, and taking out the back film from the ALD wafer boat and stripping the back film.

The method mainly comprises the following specific operations: first, the necessary materials and tools are prepared, including the wafer film ring shown in fig. 1, the high temperature resistant back film shown in fig. 2, a cutter knife or scissors, a cutter blade, dust-free cloth, clean gloves, etc. The thickness of the back film is generally 20-200um, the width is 210-250mm, and the back film can bear 250-300 ℃. Wherein, all tools need to be wiped clean by using isopropanol and then used, and the following manual operations need to be completed in a ten-grade clean room, the indoor temperature is 22 +/-1 ℃, and the humidity is 45% +/-10%. Next, as shown in fig. 3, after cutting off the back film with a proper length by using an art knife and peeling off the substrate layer of the back film, the back film is firmly adhered to the wafer attaching ring, and the back film is required to be larger than the wafer attaching ring and to be flat without wrinkles. Then, as shown in FIG. 4, the silicon wafer is placed on a dust-free cloth on the stage with the side to be protected facing upward, where the side to be protected is the side that does not allow deposition of the thin film. And then, placing the prepared back film right above the silicon chip, wherein the sticky side of the back film faces the silicon chip. At this time, fingers or a clean object with a thickness of 1-2cm are required to be padded on one side of the wafer pasting ring to prevent the back film from contacting the silicon wafer in advance.

As shown in fig. 4 and 5, the art knife is wrapped by one to two layers of dust-free cloth, and the back film is slowly pressed down from one side by using the back surface (non-edging side) of the art knife, so that the back film is adhered to the silicon wafer, bubbles are not allowed to be generated in the operation process, otherwise, the risk of fragments is generated in the subsequent processing process; if air bubbles are generated, the back film can be slowly peeled off and the film can be attached again. And (3) cutting off the back film and the silicon wafer from the wafer sticking ring by using an art designer knife as shown in fig. 6, slowly cutting off the redundant back film along the edge of the silicon wafer as shown in fig. 7 to make the residual back film consistent with the size of the silicon wafer, and then modifying the edge of the cut part for multiple times. Finally, the silicon wafer is transferred to an ALD wafer boat (boat), and parameters such as temperature, pressure, gas flow, valve opening and the like are controlled to perform the process.

In a preferred embodiment, the parameters in the ALD substrate boat are set as follows: the ALD wafer boat rotates at a speed between 2rmp and 10 rmp; the flow rate of the trimethylaluminum is between 200sccm and 400 sccm; the oxygen flow is set to 8 sLm; the nitrogen flow rate is between 0.3sLm and 1 sLm; the cavity pressure of the ALD wafer boat is set to be between 0.05torr and 0.1 torr; the pressure valve angle is between 85 and 88 degrees; the reaction temperature for film deposition is between 250 ℃ and 300 ℃.

The thickness formula of the film deposition in the film deposition process is as follows:

T＝0.0801L+14.75 (1)

wherein T is the film thickness and L is the cycle number.

In a preferred embodiment, the method further comprises an art knife and a clean glove for cutting the object. The thickness of the back film in the step S2 is between 20 μm and 200 μm, the width of the back film is between 210mm and 250mm, and the temperature which the back film can bear is between 250 ℃ and 300 ℃.

The above embodiments are not limited to the technical solutions of the embodiments themselves, and the embodiments may be combined with each other into a new embodiment. The above embodiments are only for illustrating the technical solutions of the present invention and are not limited thereto, and any modification or equivalent replacement without departing from the spirit and scope of the present invention should be covered within the technical solutions of the present invention.