KR102426015B1 - Apparatus and method for inspecting polycrystal silicon layer - Google Patents

Abstract

The present invention relates to an inspection apparatus and an inspection method for a polysilicon film, an irradiation unit irradiating X-rays to a crystallized polysilicon film, a detection unit detecting X-rays diffracted from the polysilicon film, and the X-rays from the detection unit - A control unit for receiving the diffraction angle and diffraction intensity data of the line, calculating the degree of crystallinity of the polysilicon film, and determining whether the polysilicon film is defective.

Description

Polysilicon film inspection apparatus and inspection method

The present invention relates to a polysilicon film inspection apparatus and inspection method.

Most flat panel display devices such as organic light emitting diode displays and liquid crystal displays include thin film transistors. In particular, low-temperature polycrystalline silicon thin film transistors (LTPS TFTs) are widely used because they have excellent carrier mobility and thus can be applied to high-speed operation circuits and can also be configured in CMOS circuits.

The low-temperature polycrystalline silicon thin film transistor includes a polycrystalline silicon film formed by crystallizing an amorphous silicon film. Methods of crystallizing the amorphous silicon film include a solid phase crystallization method, an excimer laser crystallization method, and a crystallization method using a metal catalyst.

Among the various crystallization methods, the crystallization method using a laser is widely used because it can produce a polycrystalline silicon film with excellent properties with a relatively low thermal effect on the substrate because it can be processed at a low temperature, and has a relatively high electron mobility of 100 cm2/Vs or more. have.

Meanwhile, research is being conducted on a method of inspecting the crystallinity or crystal grain of the polysilicon film by confirming whether the polysilicon film is properly crystallized.

An object of the present invention is to provide a polysilicon film inspection apparatus and inspection method capable of precisely and stably inspecting a crystallized polysilicon film.

An apparatus for inspecting a polysilicon film according to an embodiment of the present invention includes an irradiation unit irradiating X-rays to the crystallized polysilicon film, a detection unit detecting X-rays diffracted from the polysilicon film, and the X-ray from the detection unit. and a controller configured to receive the line diffraction angle and diffraction intensity data, calculate the degree of crystallinity of the polysilicon film, and determine whether the polysilicon film is defective.

The control unit may include a calculation unit for calculating a Miller Index from the diffraction angle and diffraction intensity of the detected X-rays, and a determination unit for judging the failure of the polysilicon film according to the ratio of the area index calculated from the calculation unit. have.

(a는 규소막의 격자상수)에 따라 면지수[hkl]을 계산할 수 있다. The calculation unit, λ = 2d Calculate the distance d between gratings according to sinθ (λ is the wavelength of the irradiated X-ray and θ is twice the diffraction angle),

The plane index [hkl] can be calculated according to (a is the lattice constant of the silicon film).

The determination unit may determine that the polysilicon film has a good quality when the ratio of the area index [100] is 50% or more.

The polysilicon layer may be crystallized according to an excimer laser annealing (ELA) crystallization method, a solid phase crystallization method, a super grain silicon (SGS) crystallization method, or a heat treatment process.

A method of inspecting a polysilicon film according to an embodiment of the present invention includes the steps of irradiating X-rays to the crystallized polysilicon film, detecting X-rays diffracted from the polysilicon film, and the detected in the detection step. and determining whether the polysilicon film is defective by calculating the degree of crystallinity of the polysilicon film using the diffraction angle and diffraction intensity data of the X-rays.

Determining whether the polysilicon film is defective may include calculating a Miller Index from the detected X-ray diffraction angle and diffraction intensity, and according to the ratio of the area index calculated in the calculating step, polycrystalline silicon It may include the step of determining whether the film is defective.

The step of calculating the surface index,

(a는 규소막의 격자상수)에 따라 면지수[hkl]을 계산하는 단계를 포함할 수 있다. calculating the distance d between gratings according to λ = 2dsinθ (λ is the wavelength of the irradiated X-ray and θ is twice the diffraction angle), and

The method may include calculating the plane index [hkl] according to (a is the lattice constant of the silicon film).

In the step of determining the defect of the polysilicon layer, if the ratio of the area index [100] of the polysilicon layer is 50% or more, it may be determined as a good product.

The polysilicon layer may be crystallized according to an excimer laser annealing (ELA) crystallization method, a solid phase crystallization method, a super grain silicon (SGS) crystallization method, or a heat treatment process.

The polysilicon film can be precisely and stably inspected through the polysilicon film inspection apparatus and method according to an embodiment of the present invention.

1 is a block diagram showing a polysilicon film inspection apparatus according to an embodiment of the present invention.
2 is a diagram illustrating an amorphous silicon film having a low degree of crystallinity.
3 is a diagram illustrating an amorphous silicon film having a high degree of crystallinity.
4 is a flowchart illustrating a polysilicon film inspection method according to an embodiment of the present invention.

With reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. However, the present invention may be embodied in several different forms and is not limited to the embodiments described herein.

In addition, throughout the specification, the same reference numerals are assigned to the same or similar components.

In addition, since the size and thickness of each component shown in the drawings are arbitrarily indicated for convenience of description, the present invention is not necessarily limited to the illustrated bar.

In order to clearly express various layers and regions in the drawings, the thicknesses are enlarged. Throughout the specification, like reference numerals are assigned to similar parts. When a part of a layer, film, region, plate, etc. is said to be “on” another part, it includes not only cases where it is “directly on” another part, but also cases where there is another part in between. Conversely, when we say that a part is "just above" another part, we mean that there is no other part in the middle.

Hereinafter, an apparatus for inspecting a polysilicon film and a method thereof according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3 .

1 is a block diagram showing an apparatus for inspecting a polysilicon film according to an embodiment of the present invention, FIG. 2 is a view showing an amorphous silicon film having a low degree of crystallinity, and FIG. 3 is a view showing an amorphous silicon film having a high degree of crystallinity.

As shown in FIG. 1 , the polysilicon film inspection apparatus 100 includes an irradiation unit 110 , a detection unit 120 , and a control unit 130 .

The polysilicon film 210 to be inspected by the polysilicon film inspection method according to an embodiment of the present invention is formed on the substrate 200 . The substrate 200 may be made of a glass or plastic material, for example, a glass substrate on which an insulating film (not shown) is formed. As the insulating layer, a silicon oxide (SiO ₂ ) layer, a silicon nitride (SiN) layer, or a stacked layer thereof may be formed. Such an insulating layer may prevent diffusion of impurities from the substrate 200 to the polysilicon layer 210 .

The polysilicon layer 210 according to the present embodiment is crystallized according to an ELA (Excimer Laser Annealing) crystallization method. However, the present invention is not limited thereto and may be crystallized by various crystallization methods such as a solid phase crystallization method, a super grain silicon (SGS) crystallization method, or a heat treatment process.

The irradiation unit 110 irradiates X-rays to the surface of the polysilicon film 210 . The polysilicon film inspection apparatus 100 according to the present embodiment is configured to set the irradiation angle ω by fixing the position of the irradiation unit 110 to which X-rays are irradiated and rotating the substrate 200 uniaxially. The irradiation angle ω refers to an angle between the irradiated X-rays and the substrate 200 . At this time, the detection unit 120 is located at an angle of 2θ (ω=θ) with respect to the X-ray to be irradiated. The positioning of the irradiation unit 110 and the detection unit 120 is referred to as a 2θ-ω method. In this embodiment, the irradiator 110 irradiates X-rays to the polysilicon film 210 according to the 2θ-ω method.

At this time, the detector 120 detects the diffraction angle θ and the diffraction intensity of the X-ray signal diffracted from the polysilicon layer 210 . The diffraction angle θ refers to an angle θ that is diffracted from the incident X-ray while satisfying Bragg's law for the substrate 200 . The diffraction intensity is detected by counting the number of times the diffracted X-ray signal is detected by the detector 120 per second. The X-ray signal detected by the detector 120 is transmitted to the controller 130 .

The control unit 130 analyzes the diffraction angle and diffraction intensity of the X-rays transmitted from the detection unit 120 to evaluate the degree of preferential orientation of the polysilicon film 210 , that is, the degree of crystallinity, to determine whether the polysilicon film 210 is defective. do. The control unit 130 according to the present embodiment may include a calculation unit 131 and a determination unit 132 .

The calculator 131 calculates a distance between crystals according to the detected X-ray diffraction angle and diffraction intensity, and calculates a Miller Index of the crystal plane of the polysilicon layer 210 using the lattice constant.

The calculator 131 according to the present embodiment calculates the distance between the grids by using the Bragg angle of the peak having the strongest intensity. That is, the distance d between gratings is calculated according to Bragg's law, λ = 2dsinθ (λ = wavelength of the irradiated X-ray, θ = twice the diffraction angle, d = distance between gratings).

에 따라 격자간의 거리 d와 Si의 격자상수 a를 이용하여 면지수 [hkl]을 계산한다. After that, the calculating unit 131 calculates the interplanar distance of the cubic system.

Calculate the plane index [hkl] using the distance d between the lattices and the lattice constant a of Si.

The determination unit 132 determines whether the polysilicon layer 210 is defective according to the aspect ratio [hkl] of the polysilicon layer 210 calculated by the calculation unit 131 .

At this time, the determination unit 132 according to the present embodiment determines that the polysilicon film 210 has a good quality when the ratio of the surface index [100] is 50% or more.

If the laser energy density or laser irradiation time is excessively reduced in the process of forming the polysilicon film 210 by irradiating the amorphous silicon film with an excimer laser to crystallize it, as shown in FIG. is increased If the degree of crystallinity of the polysilicon film 210 is too low, the required characteristics cannot be satisfied.

On the other hand, if the energy density of the laser is increased or the laser irradiation time is increased, as shown in FIG. 4 , the degree of crystallinity is increased to satisfy the required properties. However, if the energy density of the laser or the laser irradiation time is excessively increased, the surface roughness due to the crystallization protrusion rapidly increases, and the loss in the process increases.

The control unit 130 according to the present embodiment analyzes the diffraction angle and the diffraction intensity of the X-ray signal detected by the detection unit 120 to calculate the Miller Index in the direction perpendicular to the diffraction plane to calculate the polysilicon film. By evaluating the crystallinity of 210, it is possible to control the energy density or irradiation time of the laser to reduce the loss of the process and to proceed with an appropriate degree of crystallinity.

Hereinafter, a method for inspecting a polysilicon film according to an embodiment of the present invention will be described in detail with reference to FIG. 4 along with FIGS. 1 to 3 described above.

4 is a flowchart illustrating a polysilicon film inspection method according to an embodiment of the present invention.

Referring to FIG. 4 , in the polysilicon film inspection method according to an embodiment of the present invention, an X-ray signal is first irradiated to the surface of the polysilicon film 210 ( S100 ). In this case, the polysilicon film 210 to be inspected is formed on the substrate 200 . The substrate 200 may be made of a glass or plastic material, for example, a glass substrate on which an insulating film is formed. The polysilicon layer 210 according to the present embodiment is crystallized according to an ELA (Excimer Laser Annealing) crystallization method. However, the present invention is not limited thereto and may be crystallized by various crystallization methods such as solid phase crystallization, super grain silicon (SGS) crystallization, or a heat treatment process.

In the step of irradiating X-rays to the surface of the polysilicon film 210 ( S100 ), the position of the irradiation unit 110 to which the X-rays are irradiated is fixed and the substrate 200 is uniaxially rotated, so that the irradiation angle ω ) is configured to set The irradiation angle ω refers to an angle between the irradiated X-rays and the substrate 200 . At this time, the detector 120 for detecting the X-ray signal diffracted from the polysilicon layer 210 is located at an angle of 2θ (ω=θ) with respect to the X-ray to be irradiated. The positioning of the irradiation unit 110 and the detection unit 120 is referred to as a 2θ-ω method. In this embodiment, the irradiator 110 irradiates X-rays to the polysilicon film 210 according to the 2θ-ω method.

Thereafter, an X-ray signal diffracted from the polysilicon layer 210 is detected ( S200 ). The X-ray signal detection step S200 detects the diffraction angle and diffraction intensity of the X-ray signal diffracted from the polysilicon film 210 . The diffraction angle θ refers to an angle θ that is diffracted from the incident X-ray while satisfying Bragg's law for the substrate 200 . The diffraction intensity can be detected by counting the number of times a diffracted X-ray signal is detected per second.

Next, the degree of preferential orientation of the polysilicon film 210, that is, the degree of crystallinity, is determined by analyzing the diffraction angle and diffraction intensity of the X-rays detected in the X-ray signal detection step (S200) (S300).

In the crystallinity determination step (S300) according to this embodiment, the distance between crystals is calculated according to the diffraction angle and diffraction intensity of the detected X-rays, and the plane index in the direction perpendicular to the diffraction plane using the lattice constant (Miller Index) ) to determine the degree of crystallinity.

In the crystallinity determination step S300 according to the present embodiment, the distance between the lattices is calculated using the Bragg angle of the peak having the strongest intensity detected in the detection step S200 . That is, the distance d between gratings is calculated according to Bragg's law, λ = 2dsinθ (λ = wavelength of the irradiated X-ray, θ = twice the diffraction angle, d = distance between gratings).

에 따라 격자간의 거리 d와 Si의 격자상수 a를 이용하여 면지수 [hkl]을 계산한다. Afterwards, the formula for calculating the interplanar distance of the cubic system

Calculate the plane index [hkl] using the distance d between the lattices and the lattice constant a of Si.

Next, it is determined whether the polysilicon film 210 is defective according to the ratio of the plane index calculated in the crystallinity determination step (S300) (S400). The determination step (S400) according to this embodiment determines that the polysilicon film 210 has a good quality product when the area index [100] ratio is 50% or more, and is determined as a defective product when the area index [100] ratio is less than 50%. do.

If the laser energy density or laser irradiation time is excessively reduced in the process of forming the polysilicon film 210 by irradiating the amorphous silicon film with an excimer laser to crystallize it, as shown in FIG. is increased If the degree of crystallinity of the polysilicon film 210 is too low, the required characteristics cannot be satisfied.

On the other hand, if the energy density of the laser is increased or the laser irradiation time is increased, as shown in FIG. 4 , the degree of crystallinity is increased to satisfy the required properties. However, if the energy density of the laser or the laser irradiation time is excessively increased, the surface roughness due to the crystallization protrusion rapidly increases, and the loss in the process increases.

The inspection method of the polysilicon film according to this embodiment analyzes the diffraction angle and diffraction intensity of the X-ray signal detected from the polysilicon film 210 and calculates the Miller Index in the direction perpendicular to the diffraction plane. By evaluating the crystallinity of the polysilicon layer 210 , it is possible to control the energy density or irradiation time of the laser to reduce process loss and achieve an appropriate degree of crystallinity.

Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also provided. is within the scope of the

100: polysilicon film inspection device
110: investigation unit
120: detection unit
130: control unit
131: arithmetic unit
132: judgment unit
200: substrate
210: polycrystalline silicon film

Claims (10)

An irradiation unit that irradiates X-rays to the crystallized polycrystalline silicon film,
a detector for detecting X-rays diffracted from the polysilicon film, and
a control unit for receiving the diffraction angle and diffraction intensity data of the X-rays from the detection unit, calculating the crystallinity of the polysilicon film, and determining whether the polysilicon film is defective;
The control unit is
a calculator for calculating a Miller Index from the detected X-ray diffraction angle and diffraction intensity; and
Comprising a determination unit for judging the failure of the polysilicon film according to the ratio of the plane index calculated from the calculation unit
Inspection apparatus for polycrystalline silicon film. delete In claim 1,
The calculator calculates the distance d between the gratings according to λ = 2dsinθ (λ is the wavelength of the irradiated X-ray and θ is twice the diffraction angle),

A polysilicon film inspection device that calculates the plane index [hkl] according to (a is the lattice constant of the silicon film). In claim 1,
The determination unit is a polysilicon film inspection device that determines that the polysilicon film has a good quality when the ratio of the area index [100] is 50% or more. In claim 1,
The polysilicon film is an inspection apparatus for a polysilicon film which is crystallized according to an excimer laser annealing (ELA) crystallization method, a solid phase crystallization method, a super grain silicon (SGS) crystallization method, or a heat treatment process. Irradiating X-rays to the crystallized polycrystalline silicon film,
detecting X-rays diffracted from the polysilicon film, and
and determining whether the polysilicon film is defective by determining the degree of crystallinity of the polysilicon film using the diffraction angle and diffraction intensity data of the X-ray detected in the X-ray detection step,
The step of determining whether the polysilicon film is defective,
calculating a Miller Index from the diffraction angle and diffraction intensity of the detected X-rays, and
and determining whether the polysilicon film is defective according to the ratio of the plane index calculated in the calculating step. delete In claim 6,
The step of calculating the surface index,
calculating the distance d between gratings according to λ = 2dsinθ (λ is the wavelength of the irradiated X-ray and θ is twice the diffraction angle), and

A method of inspecting a polysilicon film, comprising the step of calculating a plane index [hkl] according to (a is a lattice constant of the silicon film). In claim 6,
Determining the defect of the polysilicon film comprises:
An inspection method of a polysilicon film in which the ratio of the area index [100] of the polysilicon film is 50% or more, which is determined to be a good product. In claim 6,
The polysilicon film is an ELA (Excimer Laser Annealing) crystallization method, a solid phase crystallization method (solid phase crystallization), SGS (Super Grain Silicon) crystallization method, or an inspection method of the polysilicon film crystallized according to a heat treatment process.

Images