TW201819884A - Sample with sharpening tip, preparing method thereof and analysis method thereof - Google Patents

Abstract

In some embodiments of the invention, a sample with a sharpening tip, a preparing method thereof and an analysis method thereof are provided. The sample with the sharpening tip includes a substrate, a device layer and a heat dissipation layer. The device layer is disposed on the substrate and includes a region of interest. The heat dissipation layer covers exposed surfaces of the substrate and the device layer, and a thermal conductivity of the heat dissipation layer is larger than a thermal conductivity of the substrate.

Description

Needle test piece, preparation method thereof and analysis method thereof

The present invention relates to a test piece, a preparation method thereof and an analysis method thereof, and particularly relates to a needle test piece, a preparation method thereof and an analysis method thereof.

In general, in order to analyze the material composition of a semiconductor device, an atom probe technology is used to analyze a test piece prepared from a semiconductor device. The atom probe technique uses a test piece for materials including metals and semiconductors to heat and provide an electric field so that ions are incident on the mass spectrometer from the surface of the test piece, thereby identifying the ion species by measuring the time and charge required for ion incidence. Current methods for increasing the resolution of mass spectrometry have the disadvantage of being time consuming and costly. Therefore, increasing the resolution of mass spectrometry remains a problem to be solved in the art.

A needle-shaped test piece according to an embodiment of the present invention includes a substrate, an element layer, and a heat dissipation layer. The component layer is disposed on the substrate, including the region of interest. The heat dissipation layer covers the exposed surface of the substrate and the component layer, and the thermal conductivity of the heat dissipation layer is greater than the thermal conductivity of the substrate.

A method for preparing a needle-shaped test piece according to an embodiment of the present invention includes the following steps. A portion of the semiconductor device is cut to form a needle-like test piece including a portion of the substrate and a portion of the element layer containing the region of interest. A heat dissipation layer is formed on the exposed surface of the needle-shaped test piece, and the thermal conductivity of the heat dissipation layer is greater than the thermal conductivity of the substrate.

A method for analyzing a needle-shaped test piece according to an embodiment of the present invention includes the following steps. Providing a needle-shaped test piece comprising a substrate, an element layer and a heat dissipation layer, wherein the element layer is disposed on the substrate and includes a region of interest, the heat dissipation layer covers the exposed surface of the substrate and the element layer, and the thermal conductivity of the heat dissipation layer is greater than the substrate Thermal conductivity. An atom probe technique is performed on the needle-like test piece to analyze the atomic composition in the region of interest.

The following disclosure provides many different embodiments or examples for implementing different features of the subject matter provided. Specific examples of the components and configurations described below are for the purpose of conveying the disclosure in a simplified manner. Of course, these are merely examples and not intended to be limiting. For example, in the following description, forming the second feature over the first feature or on the first feature may include an embodiment in which the second feature is formed in direct contact with the first feature, and may also include a second feature and Embodiments may be formed with a feature such that the second feature may not be in direct contact with the first feature. For the sake of simplicity and clarity, the various features are arbitrarily illustrated as different sizes. Moreover, the present disclosure may reuse device symbols and/or letters in various examples. The repeated use of device symbols is for simplicity and clarity and does not represent a relationship between the various embodiments and/or configurations themselves.

In addition, in order to facilitate the description of the relationship between one component or feature illustrated in the drawings and another component or feature, for example, "under", "under", "lower", "lower", Spatial relative terms for "at, ", above", "upper" and similar terms. In addition to the orientation depicted in the figures, the spatially relative terms are intended to encompass different orientations of the device in use or operation. The device can be otherwise oriented (rotated 90 degrees or at other orientations), while the spatially relative terms used herein are interpreted accordingly.

1 is a flow chart of a method of preparing a needle-like test piece in accordance with some embodiments of the present invention. 2A through 2C are schematic flow charts of a method of preparing a needle-shaped test piece according to some embodiments of the present invention.

Referring to FIG. 1 and FIG. 2A simultaneously, first, step S10 is performed to cut a portion of a semiconductor device (not shown) to form a needle-shaped test piece 102. The needle-shaped test piece 102 includes a portion of the substrate 104 and a portion containing the region of interest 110. Element layer 106. In some embodiments, the semiconductor device is, for example, a wafer that includes a transistor, a resistor, a diode, a photodiode or a fuse element, and the like. The semiconductor device includes a substrate 104 and an element layer 106 disposed in or on the substrate 104. Element layer 106 includes region of interest 110. For example, the semiconductor device includes a fin field effect transistor, and the device layer 106 may be a member of a fin transistor such as a fin, a channel, a gate, a source and a drain, and a dielectric layer, but the present invention does not limit. In some embodiments, substrate 104 includes, for example, a bulk germanium, a doped or undoped germanium substrate, a germanium on insulator (SOI) substrate, or a sapphire upper (SOS) substrate. Of course, in some embodiments, the substrate 104 may also include a suitable element semiconductor such as germanium or diamond, a suitable compound semiconductor such as tantalum carbide, gallium nitride, gallium arsenide or indium phosphide or such as antimony telluride, antimony telluride, arsenic. Suitable alloy semiconductors such as aluminum gallium or phosphorus gallium arsenide. In general, component layer 106 includes a conductor layer and a dielectric layer. The material of the conductor layer includes a metal, doped germanium or polysilicon or the like. The material of the dielectric layer includes an oxide or a nitride such as hafnium oxide, tantalum nitride, titanium nitride, tantalum nitride, titanium aluminum carbide, or the like.

In some embodiments, the method of cutting a semiconductor device includes using a Focused Ion Beam (FIB), an electrochemical method, or any method that produces a needle-like cross section. The focused ion beam method is performed, for example, by locally sputtering a focused ion beam on a surface layer of a portion of a semiconductor device. For example, in an ion beam cutting process, a semiconductor device is selectively etched by injecting a focused ion beam mainly composed of gallium ions into a surface layer of a semiconductor device. Wherein, the indoor vacuum pressure at which the focused ion beam is generated is maintained at about 7 microTorr to about 10 microTorr. As a result, the focused ion beam can strike the surface of the semiconductor device at a very small angle such as 0 to 5 degrees to obtain the needle-like test piece 102.

In the macroscopic view, the shape of the needle-like test piece 102 after the step S10 is, for example, approximates a cone (as shown in Fig. 2A). In some embodiments, the apex angle θ of the acicular test piece 102 is about 12 degrees to 24 degrees. However, at the microscopic level, the needle test piece 102 is substantially a cone having a curved top portion 102a. In some embodiments, the curved top portion 102a is, for example, a hemispherical top. In some embodiments, the curved top portion 102a of the acicular test strip 102 has a diameter d of from about 7 nanometers to about 13 nanometers. In some embodiments, the region of interest 110 has a diameter d of between about 40 nanometers and 60 nanometers. In some embodiments, the vertical distance h between the top 102a of the acicular test piece 102 and the region of interest 110 is between about 50 nanometers and 150 nanometers. In some embodiments, the vertical height of the acicular test strip 102 is, for example, from about 5 microns to 15 microns. In some embodiments, since the substrate 104 occupies the largest proportion of the needle-like test strips 102, the overall characteristics of the needle-like test strips 102 are still most relevant to the material of the substrate 104.

Referring to FIG. 1 and FIG. 2B simultaneously, step S20 is performed to form a heat dissipation layer 120 on the exposed surface of the needle-shaped test piece 102. The thermal conductivity of the heat dissipation layer 120 is greater than the thermal conductivity of the substrate 104. The heat dissipation layer 120 is applied, for example, to the entire exposed surface of the needle-shaped test piece 102, that is, to the side surface of the substrate 104 and the top surface of the side surface of the element layer 106. In some embodiments, the substrate 104 is, for example, a germanium substrate having a thermal conductivity of, for example, 4 watts-meter ^-1 open ^-1 . In some embodiments, the thermal conductivity of the heat dissipation layer 120 is about 10 watts-meter ^-1 . open ^-1 to 2300 watts-meter ^-1 . open ^-1 . For example, the material of the heat dissipation layer 120 is, for example, a metal, including copper, gold, aluminum, or silver. In some embodiments, the material of the heat dissipation layer 120 should avoid mass interference with the analyzed needle-like test piece 102, and the difference between the volatile electric field and the surface material of the needle-like test piece 102 should not be excessive. In some embodiments, the ratio of the thickness of the heat dissipation layer 120 to the thickness of the region of interest 110 is about 1:1 to 1:3. In some embodiments, the thickness of the heat dissipation layer 120 at the side of the acicular test piece 102 is, for example, 20 nm to 40 nm. In some embodiments, the thickness of the heat dissipation layer 120 at the top of the acicular test piece 102 is, for example, 30 nm to 60 nm. The heat dissipation layer 120 has, for example, good adhesion to a main material such as a crucible of the needle-like test piece 102. In some embodiments, the heat dissipation layer 120 is composed of, for example, a single conductor material, but the invention is not limited thereto. In some embodiments, the heat dissipation layer 120 is, for example, conformally formed on the exposed surface of the needle test piece 102. In some embodiments, the method of forming the heat dissipation layer 120 is, for example, a deposition process or a coating process, etc., wherein the deposition process includes a physical vapor deposition process, a chemical vapor deposition process, or a chemical deposition process, and the coating process includes spin coating. Process, etc.

In some embodiments, the heat dissipation layer 120 is formed by a deposition process, for example, the needle test piece 102 is placed in the ion beam sputtering machine 200 to deposit the heat dissipation layer 120. In detail, the ion beam sputtering machine 200 includes, for example, a first ion gun 202, a second ion gun 204, a target 206, and a stage 208. The first ion gun 202 is also disposed opposite to the second ion gun 204. The first ion gun 202 may also be referred to as an upper ion gun, and the second ion gun 204 may also be referred to as a lower ion gun. The target 206 is a material for forming the heat dissipation layer 120, such as a metal target such as copper, gold, aluminum or silver, which is disposed between the first ion gun 202 and the second ion gun 204. The stage 208 is used to carry the needle-like test piece 102 and to fix the needle-shaped test piece 102 thereon, and the stage 208 itself can be rotated and tilted. In the embodiment shown in FIG. 2B, the pedestal 208 is illustrated as an example, but the invention is not limited thereto. In some embodiments (not shown), the stage 208 includes, for example, a base and at least one sub-stage disposed on the base, wherein the coupon accommodates the needle-like test piece 102. That is, the number of needle-like test pieces 102 that can be carried by the stage 208 is determined by the number of sub-stages. In some embodiments (not shown), the submount can include a groove such that a portion of the acicular test piece 102 is positioned in the groove to secure it.

In some embodiments, first, the needle test piece 102 is fixed to the stage 208. Next, the atoms 206a or clusters of the target 206 are forwardly deposited on the needle-like test piece 102 in such a manner that the needle-shaped test piece 102 faces the target 206. Among them, the needle-shaped test piece 102 is rotated by the rotation of the stage 208. In some embodiments, the angle of rotation of the stage 208 is, for example, between 20 rpm and 40 rpm. Then, at the positions of the plurality of inclination angles of the stage 208, the needle-shaped test pieces 102 are respectively deposited at an oblique angle so that the atoms 206a or the clusters of the target 206 are inclined to the needle-like test piece 102. Among them, the needle-shaped test piece 102 can be moved by moving the position of the stage 208. In some embodiments, the tilt angle a of the stage 208 is, for example, -40 degrees to +40 degrees or -80 degrees to +80 degrees, based on the horizontal axis HA. In detail, when a bias is applied to the first ion gun 202 and the second ion gun 204, the first ion gun 202 and the second ion gun 204 cause the ions to accelerate against the target 206, so that the atom 206a or the group being hit A cluster is deposited on the needle test piece 102. In some embodiments, the current intensity of the ion beam 205 striking the target 206 is, for example, 30 mA to 90 mA. In some embodiments, since the acicular test piece 102 is rotated and tilted with the stage 208, the heat dissipation layer 120 may be uniformly formed on the acicular test piece 102 to completely cover the exposure of the acicular test piece 102. surface. Although the apparatus for performing deposition is an ion beam sputtering machine as an example, the present invention is not limited thereto. In other embodiments, other machines that can perform deposition processes or coating processes, etc., can also be used.

Referring to FIG. 2C, a needle-shaped test piece 100 is obtained. In some embodiments, the acicular test strip 100 includes a localized semiconductor device, such as a fin-shaped transistor including a nanoscale. The acicular test piece 100 includes a substrate 104, an element layer 106, and a heat dissipation layer 120. The component layer 106 is disposed on the substrate 104 and includes a region of interest 110. The heat dissipation layer 120 covers the exposed surface of the substrate 104 and the element layer 106, and the thermal conductivity of the heat dissipation layer 120 is greater than the thermal conductivity of the substrate 104.

In some embodiments, when there are defects such as depressions or voids on the surface of the needle-like test piece 102, the filling can also be performed by the ion beam sputtering machine 200 described above, so that the needle-shaped test piece 100 has substantially smoothness. surface. Wherein, the aforementioned recess or void may be caused by a delayer process for removing the semiconductor material or the conductor material, and therefore it is usually necessary to perform a gap filling process or the like for the portion. In addition, in the above embodiments, the film layer is formed on the surface of the needle-shaped test piece 102 by the ion beam sputtering machine 200 as the heat dissipation layer 120 or the cavity filling material, but in other embodiments (not shown) If the target is not placed in the ion beam sputtering machine 200, the ion beam sputtering machine 200 can be used to clean the surface of the test piece 102, that is, by the first ion gun 202 and the first The ions of the diion gun 204 strike the surface of the test piece 102 for cleaning purposes.

3 is a flow chart of a method of analyzing a needle-like test strip in accordance with some embodiments of the present invention. 4 is a schematic diagram of an atom probe technology device in accordance with some embodiments of the present invention. Referring to FIG. 3, first, step S310 is performed to provide a needle-like test piece 100 having the aforementioned structure. In detail, the acicular test strip 100 is from a portion of a semiconductor device that includes a region of interest 110. The acicular test strip 100 is used as a test piece for subsequent testing or characterization of the region of interest 110 of the semiconductor device.

Referring to FIG. 3, next, in step S320, the needle-shaped test strip 100 is subjected to atom probe technology to analyze the atomic composition in the region of interest 110. In some embodiments, atomic probe technology can provide an atomic level stereo image and chemical composition of the region of interest 110. As shown in FIG. 4, the atom probe technology device 400 includes, for example, a laser source 410, a position sensitive detector 420, and a processing unit 430. First, the top of the needle-like test piece 100 is irradiated with a laser pulse 422 generated by the laser source 410. Since the top of the acicular test strip 100 is illuminated by the laser pulse 410, the atoms 412 in the acicular test strip 100 are removed layer by layer (such as peeling). Then, according to the electric field generated between the position sensing detector 420 and the needle test piece 100, the removed atoms 412 are projected onto the position sensing detector 420. Thus, the time between the moment when the laser is pulsed and the time when the removed atom 412 reaches the inductive detector 420 can be used to determine the time of flight of the atom 412 (ie, ion), Confirm the mass-to-charge ratio (ie m/q). The x, y coordinates of the atoms 412 detected on the inductive detector 420 can then be used to reconstruct the atomic home position corresponding to the top of the needle test strip 100. The processing unit 430 can collect the position data by the inductive detector 420 and reconstruct the stereo image of the top of the needle test piece 100 by the atomic type.

In some embodiments, the outer layer of the acicular test piece is provided with a heat dissipation layer, and the thermal conductivity of the heat dissipation layer is greater than the thermal conductivity of the body portion of the acicular test piece. Since the heat dissipation layer has good thermal conductivity, heat accumulation can be prevented from accumulating on the surface of the needle-shaped test piece during the atom probe technique to prevent background noise, thereby greatly improving the resolution of the mass spectrometer. Moreover, in some embodiments, the heat dissipation layer is composed of only a single material, thereby preventing the material of the heat dissipation layer from interfering with the mass spectrometry resolution or increasing the additional burden of mass spectrometry. Further, in some embodiments, the preparation method of the acicular test piece is applied to all of the stacked layers of the semiconductor layer and the conductor layer, and thus can be widely used for preparing test pieces of various semiconductor devices. In addition, in some embodiments, the preparation method of the needle-shaped test piece has a simple procedure and can be achieved by using an existing machine, so that the preparation method of the needle-shaped test piece has the advantages of high productivity and low cost.

In some embodiments, a needle-like test strip includes a substrate, an element layer, and a heat dissipation layer. The component layer is disposed on the substrate, including the region of interest. The heat dissipation layer covers the exposed surface of the substrate and the component layer, and the thermal conductivity of the heat dissipation layer is greater than the thermal conductivity of the substrate.

In some embodiments, a method of preparing a needle-like test strip includes the following steps. A portion of the semiconductor device is cut to form a needle-like test piece including a portion of the substrate and a portion of the element layer containing the region of interest. A heat dissipation layer is formed on the exposed surface of the needle-shaped test piece, and the thermal conductivity of the heat dissipation layer is greater than the thermal conductivity of the substrate.

In some embodiments, an analytical method for a needle-like test strip includes the following steps. Providing a needle-shaped test piece comprising a substrate, an element layer and a heat dissipation layer, wherein the element layer is disposed on the substrate and includes a region of interest, the heat dissipation layer covers the exposed surface of the substrate and the element layer, and the thermal conductivity of the heat dissipation layer is greater than the substrate Thermal conductivity. An atom probe technique is performed on the needle-like test piece to analyze the atomic composition in the region of interest.

The features of the various embodiments are summarized above, and those of ordinary skill in the art will be able to better understand the aspects of the disclosure. It should be understood by those of ordinary skill in the art that the present disclosure may be used as a basis for designing or modifying other processes and structures to achieve the same objectives and/or advantages of the embodiments described herein. It should be understood by those skilled in the art that this equivalent configuration is not to be construed as a departure from the spirit and scope of the disclosure, and Make various changes, substitutions, and changes.

100, 102‧‧‧ needle test piece

102a‧‧‧ top

104‧‧‧Base

106‧‧‧Component layer

110‧‧‧ Area of interest

120‧‧‧heat layer

200‧‧‧Ion Beam Sputtering Machine

202‧‧‧First Ion Gun

204‧‧‧Second ion gun

205‧‧‧Ion Beam

206‧‧‧ Target

206a, 412‧‧‧Atomic

208‧‧‧ stage

400‧‧‧Atomic probe technology equipment

410‧‧‧Laser source

420‧‧‧ Position Sensing Detector

422‧‧‧Laser pulse

430‧‧‧Processing unit

S10, S20, S310, S320‧‧‧ steps

HA‧‧‧ horizontal axis

D‧‧‧diameter

H‧‧‧distance

‧‧‧‧ angle

Θ‧‧‧ top angle

1 is a flow chart of a method of preparing a needle-like test piece in accordance with some embodiments of the present invention. 2A through 2C are schematic flow charts of a method of preparing a needle-shaped test piece according to some embodiments of the present invention. 3 is a flow chart of a method of analyzing a needle-like test strip in accordance with some embodiments of the present invention. 4 is a schematic diagram of an atom probe technology device in accordance with some embodiments of the present invention.

Claims (10)

A needle-shaped test piece comprising: a substrate; a component layer disposed on the substrate, including a region of interest; and a heat dissipation layer covering the exposed surface of the substrate and the component layer, thermal conductivity of the heat dissipation layer Greater than the thermal conductivity of the substrate. The needle-shaped test piece according to claim 1, wherein the heat dissipation layer has a thermal conductivity of about 10 watt·m ^-1 · open ^-1 to 2300 watt · m ^-1 · open ^-1 . The needle-shaped test piece of claim 1, wherein the heat dissipation layer comprises copper, gold, aluminum or silver. The needle-shaped test piece according to claim 1, wherein the curved top portion of the needle-shaped test piece has a diameter of about 7 nm to 13 nm. The needle-shaped test piece according to claim 1, wherein the apex angle of the needle-shaped test piece is about 12 to 24 degrees. The needle-shaped test piece according to claim 1, wherein a vertical distance between a top of the needle-shaped test piece and the region of interest is about 50 nm to 150 nm. A method for preparing a needle-shaped test piece, comprising: cutting a portion of a semiconductor device to form a needle-shaped test piece, the needle-shaped test piece comprising a partial substrate and a partial element layer containing a region of interest; and the needle-shaped test piece A heat dissipation layer is formed on the exposed surface, and the thermal conductivity of the heat dissipation layer is greater than the thermal conductivity of the substrate. The method for producing a needle-shaped test piece according to claim 7, wherein the method of cutting a part of the semiconductor device comprises using a focused ion beam method or an electrochemical method. The method for preparing a needle-shaped test piece according to claim 7, wherein the method of forming the heat dissipation layer comprises a deposition process or a coating process. A method for analyzing a needle-like test piece, comprising: providing a needle-shaped test piece comprising a substrate, an element layer, and a heat dissipation layer, wherein the element layer is disposed on the substrate and includes a region of interest, the heat dissipation layer covering the substrate An exposed surface of the substrate and the element layer, and a thermal conductivity of the heat dissipation layer is greater than a thermal conductivity of the substrate; and an atom probe technique is performed on the needle test piece to analyze the region of interest The atomic composition in .