KR20020072722A - Method for inspecting semiconductor circuit pattern - Google Patents

Abstract

PURPOSE: A method for easily inspecting a semiconductor circuit pattern formed on a semiconductor substrate or a dielectric film substrate is provided without losses of the substrate and time required for pattern analysis. CONSTITUTION: The method employs a hollow etchant injector(30) capable of performing a partial etching of the circuit pattern(2) such as line/space pattern or contact hole pattern formed on the substrate(1) such as a wafer. The etchant injector(30) has a diameter of the order of nanometer or micrometer. In the method, the etchant injector(30) is placed on a portion of the pattern(2) in a clean room and then applies a wet etchant(31) to the pattern(2). Therefore, the pattern(2) is partially wet-etched to allow pattern analysis without a loss of the substrate(1). Preferably, the etchant injector(30) is formed of material such as Teflon, polyethylene, polypropylene, acetal and polymer.

Description

Semiconductor circuit pattern inspection method {METHOD FOR INSPECTING SEMICONDUCTOR CIRCUIT PATTERN}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting a pattern formed on a semiconductor substrate, and specifically, a wet etching solution using a line or space and a contact hole pattern formed on a wafer using an etching solution inlet tube of nano or micrometer size. The present invention relates to a semiconductor circuit pattern inspection method capable of easily analyzing a pattern shape by injecting and partially etching.

As a method of inspecting a pattern formed on a semiconductor substrate, a pattern analysis method using an out-line SEM (Scanning Electron Microscope) and a pattern analysis method using an in-line FIB (focused ion beam) There is this.

The pattern inspection method using an out-line SEM is a method of cutting a cross section of a wafer, and then photographing a pattern formation cross section by SEM equipment in order to confirm a pattern formed in a semiconductor device manufacturing process using an extremely fine pattern. However, this method has a problem that it takes more than one day to prepare and analyze the specimen by bringing the wafer out of the clean room as well as the cost loss caused by the wafer cutting. FIG. 1 shows the shape of the pattern 5 in which the generated pattern was photographed using an out-line SEM.

In order to solve the above problems, the in-line FIB method was used to analyze the pattern while preventing the loss of the wafer by installing the FIB equipment in a clean room. However, the FIB device uses a principle of ionizing and accelerating a large specific gravity element such as Ga or As, and physically cutting the wafer surface using the same, and analyzing the cross section of the pattern. However, this method causes problems such as contaminating the wafer with metallic and changing device characteristics since the wafer is processed using the metal element Ga or As as described above. As a result, this method also cannot use the wafer in subsequent processes, resulting in wafer loss in the same way as the above method of cutting the wafer.

An object of the present invention is to provide a semiconductor circuit pattern inspection method capable of wet etching only a local portion of a pattern formed on a semiconductor substrate in a clean room.

FIG. 1 is a diagram illustrating a pattern shape in which the generated pattern is photographed using an out-line SEM.

It is a figure explaining the concept of pattern analysis by this invention.

3 is a cross-sectional view of the etching liquid inlet tube used in the present invention.

4 is a schematic diagram of a peripheral system for explaining movement of a wafer to be locally wetted.

5 is a system configuration diagram of a semiconductor circuit local wet etching machine used in the practice of the present invention.

6 is a procedure flowchart showing the procedure of the pattern inspection method of the present invention.

7 is a partial cross-sectional view of a semiconductor substrate with contact holes formed on the semiconductor substrate.

8 is a partial cross-sectional view of a substrate in which a plurality of layers are stacked on a semiconductor substrate or a dielectric substrate.

The above object of the present invention is a method for inspecting a pattern formed on a semiconductor substrate or a dielectric film substrate, comprising: placing a hollow etching solution inlet tube having a diameter of nano to micrometer size on top of a portion of the pattern and etching solution input Exposing the wet etchant to the pattern using a tube to partially wet etch the pattern, wherein the etchant inlet tube used herein comprises Teflon, Polythethelene, Polypropylene and Acetal ( It can be achieved by a semiconductor circuit pattern inspection method, characterized in that it is formed by at least one selected from a polymer of acetal).

SUMMARY OF THE INVENTION The above object of the present invention is a method for inspecting a pattern formed on a semiconductor substrate or a dielectric film substrate using a circuit local wet etcher having a hollow etchant inlet tube having a diameter of nano to micrometers in size. A pattern to be inspected for the etching liquid inlet tube while specifying a loading step and a pattern position to be inspected in the substrate, and moving the etching liquid inlet tube to the designated pattern position and keeping the wet etching liquid unexposed to the outside of the etching liquid inlet tube. A pattern contact step of contacting the substrate, an etching solution injection step of injecting the wet etchant into the pattern to be inspected, an ultrapure water injection step of injecting ultrapure water into a location to be inspected, an ultrapure water removal step of removing the ultrapure water diluted with the wet etchant, and an unloading of the substrate And a substrate removing step of inspecting the etched pattern shape. A semiconductor circuit pattern inspection method can be achieved.

In addition, the above object of the present invention is a method for inspecting a pattern formed on a semiconductor substrate or a dielectric film substrate using a circuit local wet etching machine having a hollow etching solution inlet tube having a diameter of nano to micrometer size. A loading step of loading and specifying a pattern position to be inspected in the substrate, a moving step of moving the etchant input tube to the designated pattern position, and an etchant exposure step of partially exposing the wet etchant to a convex shape using a capillary phenomenon to the outside of the etchant input tube. And an etching solution injection step of bringing the exposed wet etching solution into contact with the pattern, an ultrapure water injection step of injecting ultrapure water into a position to be inspected, an ultrapure water removal step of removing the wet etchant and diluted ultrapure water, and a substrate removal step of unloading a substrate. And inspecting the etched pattern shape It can also attain by the semiconductor circuit pattern inspection method characterized by the above-mentioned.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. 2 is a view for explaining a method of partially wet etching a pattern according to the present invention. (a) shows that a plurality of strip-shaped oxide films 2 are formed on part of the semiconductor substrate 1. The size of the wafer is preferably a wafer having a diameter such as 6 inches to 12 inches. Although (a) shows that a plurality of oxide films are formed in a part of a semiconductor substrate at a wide interval, in actual cases, they are formed in a densely packed nanometer size or micrometer size, and FIG. 2 is enlarged for convenience of description. It is only illustrated. In order to determine whether such an oxide film pattern is normally formed, in this invention, the etching liquid 31 is exposed to contact with the pattern using the etching liquid injecting pipe 30 of a nano or micrometer size. Such wet etching enables easy pattern analysis without damaging the entire substrate by etching only a portion of the pattern to be analyzed on the semiconductor substrate as shown in (b).

3 shows a cross-sectional view of an etching liquid inlet tube used in the present invention. (a) is a longitudinal cross-sectional view in the longitudinal direction of the etchant inlet tube showing the shape of the end portion of the etchant inlet tube gradually narrowing, (b) is a cross section of the body cylindrical portion of the etchant inlet tube, and (c) is the etchant The cross-sectional shape of the end part of the etching liquid injecting tube which was thrown in is shown. As shown in (a) and (c), the end portion of the etching solution inlet tube has a diameter of 10 nm to 1 mm.

The etchant inlet tube according to the present invention should not be etched into the wet etchant and the etchant inlet tube should not be blunt even when frequently contacted with the pattern formed on the substrate. Therefore, diamond, cubic boron nitride (c-BN; Cubic Boron Nitride) and sapphire ( It is preferable to form at least one selected from materials such as Sapphire and Al oxide. Alternatively, the etching solution inlet tube according to the present invention may be formed of at least one material selected from polymers such as Teflon, polyethylene, polypropylene, and acetal.

4 is a schematic diagram of a peripheral system for explaining movement of a wafer to be locally wetted. A plurality of wafers are stored in the wafer cassette 210, the wafers to be analyzed are taken out using the wafer handler 230, and the wafers are mounted in the correct positions using the wafer aligner 220, and then the wafers are placed. Place on process stage 190.

5 illustrates a semiconductor circuit local wet etcher used in the practice of the present invention. The semiconductor circuit local wet etching machine mounts the wafer 1 and has a process stage 190 which is responsible for moving the mounted wafer in the x and y directions, an etchant cartridge 110 for storing the etchant, and the etchant on the semiconductor substrate. An etchant inlet tube 30 for exposing to a local region, an etchant cartridge support means 120 for supporting an etchant cartridge, and an etchant cartridge support means 120 and a semiconductor circuit local wet etchant body 150. Support and movement of the z-axis movement bar 130 and the z-axis movement motor 140 for moving the z-axis movement bar 130 and the process stage 190 for supporting the process stage 190 and moving them in the x-axis and y-axis directions. The unit 170 and the x-axis y-axis moving motor 160 for driving the same. In this case, in some cases, the Z-axis movement bar 160 can be moved to all of the x, y, and z axes, and the process stage is fixed, or the Z-axis movement bar 160 is fixed, and the process stage 190 is x, y. You can also move it to the z axis.

The semiconductor circuit local wet etcher is located in a chamber separated by a vertical dividing wall 180. The robot arm 240 is used to move the wafer into the chamber and then onto the process stage 190. The x-axis y-axis moving motor 160 and the z-axis moving motor 140 are driven to position the etchant injection tube 100 in the portion to be wet etched. How to apply pressure directly to the etchant or pressurize the gas in contact with the surface of the opposing etchant into which the etchant is introduced while the etchant does not come into contact with the pattern formed on the wafer to be etched until the etching is started or the temperature of the etchant Using the raising means (temperature raising means of 200 in FIG. 5 and heat transfer means connected to the etching liquid cartridge or etching liquid inlet tube) to increase the volume of the etching liquid so that the etching liquid is exposed out of the etching liquid inlet tube so that the etching can proceed. .

That is, in order to solve the loss of the wafer for the pattern analysis and the delay of the analysis (Delay), etc., a method of selectively adding a small amount of etchant to a desired region is used. Specifically, the etching pattern is contacted in the direction perpendicular to the pattern by using an etching solution inlet tube of nano or micrometer size, and the pattern is etched in the vertical direction and the etching cross section is examined. Using this local wet etching method, the analysis can be performed very quickly, and the remaining wafer portions except for the analysis region can be used as it is, thereby reducing the cost of preventing wafer loss. This is because these operations can be performed at room temperature and atmospheric pressure in the clean room, and also do not affect the pattern and device characteristics of other regions by partially etching fine patterns using etching liquid.

The method of contacting the wet etching liquid with the pattern formed on the substrate from the etching liquid injecting tube includes a contact method in which the etching liquid injecting tube is directly contacted with the substrate to inject the etching liquid, and the etching liquid injecting tube is in a non-contact manner in which only the etching liquid is in contact with the substrate. Can be used. The first contact method first starts etching while the etchant inlet tube is brought into direct contact with the substrate and the capillarity caused by the surface tension of the wet etchant is used to maintain the concave etchant surface against the outside of the nano or micrometer size tubes. The etching solution is not brought into contact with the pattern formed on the wafer as the etching target material until now. Then, by directly applying pressure to the etchant or by applying pressure to a gas in contact with the surface of the etchant opposite the etching site or by increasing the temperature of the etchant to increase the volume of the etchant so that the etchant is exposed to the outside of the etchant inlet tube. This is the way to make progress. In the second non-contact method, only the etchant is brought into contact with the substrate without directly contacting the etchant injector. The etching solution is exposed to the outside of the etchant injector in the same or similar manner as the first method, but the etchant is exposed to the end face of the end of the etchant injector. The etching solution is brought into contact with the substrate in a state in which the etching solution is held in the shape of a hemisphere and suspended in the shape of hemispheres from the time it starts to form by the surface tension. In the latter case, it is important to keep the etchant in direct contact with the pattern while keeping the etchant inlet tube not in direct contact with the pattern. To maintain this gap accurately, measure the height of the pattern using a laser displacement sensor or There may be a method of focusing and measuring the height at this time. At this time, the interval between the etching liquid inlet tube and the pattern is preferably maintained at 10um to 1mm as a range related to the radius of the end of the etching liquid inlet tube.

6 is a procedure flowchart showing the procedure of the pattern inspection method of the present invention. The semiconductor substrate on which the pattern to be analyzed is formed is loaded into the equipment. (Step s1) Specify the analysis position and move the nanometer size etchant input tube to the analysis position. (Step s2) Of course, in this case, the semiconductor substrate may be moved instead of moving the etching liquid inlet tube. Next, the etching solution is exposed to the portion to be analyzed for wet etching. (Step s3) In the next step, ultrapure water (De-ionized Water) is injected. (Step s4) The reason why the ultrapure water is injected is to adjust the etching degree by diluting the pattern with the ultrapure water since the etching solution is continuously present on the wafer surface. At this time, the injection amount of ultrapure water is preferably used from 1 to 100 times the injection amount of the etching solution. Next, a step (s5 step) of sucking the injected ultrapure water again is necessary. This is to remove chemical residues present on the pattern, and the principle applied here is to use pressure differences. Finally the partially wet etched substrate is unloaded from the equipment. (Step s6) After partial etching of the pattern formed on the substrate using the above method, it is possible to easily inspect the etched pattern shape.

7 is a partial cross-sectional view of a semiconductor substrate having contact holes formed in a size of 0.1 um to 1.0 um on a semiconductor substrate or dielectric film. An oxide film 2 is formed on the semiconductor substrate or the dielectric film 1, and a junction can be formed by filling a metal into a contact hole 3 formed between the oxide films. By partially wet etching a pattern formed in a specific region in order to analyze the contact hole pattern formed in the above manner, only a partial pattern can be easily inspected without affecting the entire pattern.

8 shows a partial cutaway view of a substrate in which a plurality of layers are stacked on a semiconductor substrate or a dielectric substrate. A cross-sectional view of a structure in which a hard mask oxide layer is stacked on an upper layer on which gates, bit lines, and metal patterns are formed, and generally, types of materials to be stacked vary according to the degree of integration.

Table 1 shows the constituent materials of each part of FIG. 8 when forming a 64M DRAM.

Drawing number Gate forming material Bit line forming material Metal forming material 40 polysilicon polysilicon W or Al 50 WSix WSix W or Al 60 SiO2 SiO2 SiO2

Table 2 shows the constituent materials of each part of FIG. 8 when forming 256M DRAM. In the lamination material of the gate of Table 2, a WN layer is further laminated between polysilicon and tungsten.

Drawing number Gate forming material Bit line forming material Metal forming material 40 polysilicon W Al 50 W W Al 60 SiO2 SiO2 SiO2

In each case, the material to be laminated is different, and therefore, a wet etchant suitable for this purpose must be used to clarify the pattern analysis.

When inspecting the hard mask oxide layer (SiO2) pattern formed on the lower line / space layer, only the hard mask oxide layer, which is the pattern to be inspected, should be etched without etching the line / space layer of the lower layer. Thus, hydrofluoric acid (HF) and water are used as the wet etching solution. It is preferable to use the wet etching liquid containing (H2O). Hydrofluoric acid (HF) serves to etch the hard mask oxide film. In this case, the volume ratio of water and hydrofluoric acid is preferably 10: 1 to 100: 1. When using hydrofluoric acid in an amount greater than 10: 1, it is etched down to the line / space layer, which is the lower layer, and less than 100: 1. If hydrofluoric acid is used, a problem arises in that it is not etched.

When inspecting the polysilicon pattern formed on the lower interlayer oxide film, only the polysilicon, which is the pattern to be inspected, should be etched without etching the lower interlayer oxide film. Therefore, the wet etching solution containing nitric acid (HNO3) and hydrofluoric acid (HF) is used as the wet etching solution. It is preferable to use. Nitric acid (HNO 3) oxidizes polysilicon and hydrofluoric acid (HF) serves to etch polysilicon. In this case, the volume ratio of nitric acid and hydrofluoric acid is preferably 50: 1 to 1000: 1, and when using an amount of hydrofluoric acid of more than 50: 1, the lower layer is etched to an interlayer oxide film, and the amount of hydrofluoric acid is less than 1000: 1. In this case, the problem of not etching occurs.

When inspecting the tungsten pattern formed on the lower interlayer oxide film, the lower interlayer oxide film should be etched instead of etching the tungsten, which is the pattern to be inspected. Therefore, the wet etching solution containing nitric acid (HNO 3) and hydrofluoric acid (HF) may be used as the wet etching solution. It is preferable to use. Nitric acid (HNO 3) oxidizes tungsten and hydrofluoric acid (HF) serves to etch polysilicon. In this case, the volume ratio of nitric acid and hydrofluoric acid is preferably 1: 1 to 100: 1, and when using more than 1: 1 hydrofluoric acid, the underlying layer is etched to the interlayer oxide film, and less than 100: 1 hydrofluoric acid. In this case, the problem of not etching occurs.

In the case of inspecting the aluminum pattern formed on the lower interlayer oxide film, the lower interlayer oxide film should be etched instead of etching, so only the aluminum, which is the pattern to be inspected, should be etched. It is desirable. Phosphoric acid (H3PO4) oxidizes aluminum and nitric acid (HNO3) serves to etch. In this case, the volume ratio of phosphoric acid and nitric acid is preferably 1: 1 to 100: 1. When using nitric acid in an amount greater than 1: 1, it is etched to the interlayer oxide film as the lower layer, and less than 100: 1 in nitric acid. In this case, the problem of not etching occurs.

Since the wet etching solution can be selectively sprayed in a specific region by the semiconductor circuit pattern inspection method according to the present invention, it is possible to reduce the loss of the wafer and the time required for analysis that damage the entire wafer by the pattern analysis.

In addition, since the pattern inspection of the present invention can be performed at room temperature and atmospheric pressure in a clean room, the analyzed wafer can be used as it is and thus cost reduction effect can be obtained.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary and should be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. . Therefore, the true scope of protection of the present invention should be defined by the technical spirit of the appended claims.

Claims (3)

A method of inspecting a pattern formed on a semiconductor substrate or a dielectric film substrate, Placing a hollow etchant input tube having a diameter of nano to micrometers size on top of a portion of the pattern; And Exposing the wet etchant to the pattern using the etchant inlet tube to partially wet etch the pattern, wherein the etchant inlet tube is Teflon, polyethylene, polypropylene, and acetal; And at least one selected from a group of polymers of acetal). A method of inspecting a pattern formed on a semiconductor substrate or a dielectric film substrate using a circuit local wet etcher having a hollow etchant input tube having a diameter of nano to micrometer size, the method comprising: Loading the substrate; A moving step of designating a pattern position to be inspected in the substrate and moving the etching liquid input pipe to the designated pattern position; A pattern contacting step of bringing the etchant input tube into contact with the pattern to be inspected while keeping the wet etchant not exposed to the outside of the etchant input tube; An etching solution injection step of injecting the wet etching solution into the pattern to be inspected; Ultrapure water injection step of injecting ultrapure water to the position to be examined; An ultrapure water removing step of removing the ultrapure water diluted with the wet etchant; And And removing the substrate to unload the substrate and inspecting the etched pattern shape. A method of inspecting a pattern formed on a semiconductor substrate or a dielectric film substrate using a circuit local wet etcher having a hollow etchant input tube having a diameter of nano to micrometer size, the method comprising: Loading the substrate; A moving step of designating a pattern position to be inspected in the substrate and moving the etching liquid input pipe to the designated pattern position; An etchant exposure step of partially exposing the wet etchant to a convex shape by using a capillary phenomenon to the outside of the etchant inlet tube; Etching liquid injection step of bringing the exposed wet etching liquid into contact with the pattern; Ultrapure water injection step of injecting ultrapure water to the position to be examined; An ultrapure water removing step of removing the ultrapure water diluted with the wet etchant; And And removing the substrate to unload the substrate and inspecting the etched pattern shape.