JP2000021824A - Layer opening method in local region of semiconductor element and apparatus thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a layer opening method/device in the local region of a semiconductor element, which specify an arbitrary observation desired part, polish it, and open a layer even if a wafer is as it is. SOLUTION: A process where a fine polishing brush 12 is brought close to an observation desire part 11 of a semiconductor wafer 10 from above, a process where the polishing brush 12 is brought into contact with the semiconductor wafer 10 while polishing compound is applied to it, and the polishing brush 12 is moved and only a region to which the polishing brush 12 is brought close is polished mechanically and a process where polishing waste occurring in the polishing process is removed, and a layer is opened during the manufacture process of the semiconductor wafer 10 are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an analysis of a pattern abnormality or the like which occurs in a manufacturing process of a semiconductor integrated circuit and an analysis of confirmation of a fine contact hole opening by polishing only a specific portion. , Open locally,
The present invention relates to a method and an apparatus for opening a layer in a local region of a semiconductor element, which can be performed during a manufacturing process without affecting other regions of a semiconductor wafer.

[0002]

2. Description of the Related Art A semiconductor device is formed by building a multilayer structure of a multilayer film on a wafer by repeating photolithography and etching steps by applying photographic technology. Therefore, when a defect such as a pattern abnormality is detected during the manufacturing process, or when confirming the opening of a fine contact hole, to detect this, cut out the periphery of the desired observation point, and use polishing or solvent. By opening the upper layer by SEM (Secondary Electr)
on Microscope) and the like, it was necessary to evaluate by observation using an electron microscope or the like.

FIG. 7 is a process chart showing a conventional method for observing a semiconductor device by layer opening. Hereinafter, a representative layering method actually used will be described with reference to FIG. First, as shown in FIG. 7 (a), when an abnormality is detected during the manufacturing process, the wafer 1 is sampled by selecting the periphery of an abnormal part (a desired observation point) 2 by cleaving the wafer or the like.
Create

[0006] Next, as shown in FIG. 7 (b), the sample 3 is immersed in a solvent 4, and portions unnecessary for observation are etched. By using an etching solvent having a different selection ratio in combination for each laminated film, it is possible to open a layer to a desired observation position. On the other hand, as shown in FIG. 7 (c), by polishing the surface of the sample piece 3, a portion unnecessary for observation can be cut. That is, the surface of the sample piece 3 is pressed against the polishing pad 5 while applying the polishing material 7 from the nozzle 6 to the polishing pad 5. At this time, if necessary, it is possible to make a slight angle between the pad surface and the surface of the sample piece 3. By rotating the polishing pad 5, it is possible to open the layer up to the desired observation point 2.

[0005]

However, in the above-mentioned conventional method, it is necessary to form a specimen by cleaving the wafer and completely open the upper layer. At the time of this processing, it is inevitable that a completely unrelated area is affected. In order to perform the above-described analysis, it is necessary to extract a wafer, and since other chips in the wafer must be stopped at that time, there is a problem that the yield is reduced. Was.

Furthermore, since the analysis is performed after the wafer is destroyed, it has not been possible to introduce these analysis techniques into the manufacturing process. According to the present invention, the above problems are eliminated, even if the wafer is left as it is, an arbitrary observation desired portion is specified, polished, and a layer opening method in a local region of a semiconductor element capable of opening the layer and the method. An apparatus can be provided.

[0007]

According to the present invention, there is provided a method for opening a layer in a local region of a semiconductor device, comprising the steps of: Bringing the polishing brush into contact with the semiconductor element while applying a polishing agent, moving the polishing brush, and mechanically polishing only a region where the polishing brush is in contact with the semiconductor device. Removing the polishing debris generated in the polishing step, and opening the layer during the manufacturing process of the semiconductor element.

[2] In a layering apparatus in a local region of a semiconductor element, means for positioning a semiconductor element, means for obtaining coordinate information of a desired observation point of the semiconductor element, and setting at a desired observation point of the semiconductor element This is provided with a fine polishing brush and driving means for the polishing brush.

[0009]

Embodiments of the present invention will be described below in detail. FIG. 1 is a schematic diagram showing a method for locally opening a specific portion of a semiconductor wafer according to a first embodiment of the present invention. (1) First, as shown in FIG.
1 is a fine polishing brush (hereinafter simply referred to as a brush) from above the semiconductor wafer (hereinafter simply referred to as a wafer) 10.
Move 12 closer.

Therefore, the brush 12 is applied to the wafer 1 while applying an abrasive such as diamond paste on the wafer 10.
After the brush 12 is brought into contact with zero, the brush 12 is vibrated back and forth. At this time, by using a soft material such as felt as the material of the brush 12, it is possible to minimize scratches entering the sample surface during polishing. In addition, polishing debris generated at the time of polishing can be completely removed by performing cleaning such as scribe cleaning, which is one of the usual semiconductor manufacturing processes.
(Mechanical Polish). In addition, in FIG.1 (b), 13 is an opening part.

The wafer is set so that coordinate position information of the observation desired portion 11 can be obtained.
On the other hand, for example, as shown in FIG. 1C, the brush 12 is held by a hand 31 of an industrial articulated robot (hereinafter, simply referred to as a robot) 20, and the robot 20 When the position information is taught, the robot 20 moves the brush 12 to the position of the desired observation position 11 on the wafer and performs positioning.

Therefore, a brush is driven by a driving device 32 mounted on the hand 31 of the robot 20, in this case, a vibrating device (for example, a minute vibrator) in a linear direction to perform polishing. The control unit of the robot 20 is a CPU
(Central processing unit) 21, I / F (output interface) 22, storage device (memory) 23, I / F (input interface) 24, and the like.

Therefore, mechanical polishing proceeds only in the area of the wafer where the brush is desired to be observed, and the upper layer can be opened only in a local area. As described above, according to the first embodiment, it is possible to open the upper layer only in the local region without affecting other regions in the wafer at all. For this reason, local analysis which cannot be normally introduced during the manufacturing process can be easily executed.

In addition, it is possible to perform an analysis that cannot be generally confirmed in a manufacturing process, such as observation of a portion where a pattern abnormality or the like is detected, confirmation of an opening of a fine contact hole, analysis of a composition inside a particle, and the like. Further, the present invention can be applied to a chip at a product level. That is, the present invention can be applied not only to the above-described wafer but also to a chip at a product level, that is, it is possible to open a local region for a semiconductor element. Next, a second embodiment of the present invention will be described.

FIG. 2 is a schematic view showing a second embodiment of the present invention, showing a method of locally opening a specific portion of a wafer. As shown in FIG. 2, after giving the coordinate information to the wafer 40, the coordinate position information of the observation desired portions 41, 42, 43 of the wafer can be designated. Then, the robot [Fig.
(See (c))], the observation desired portions 41, 4 of the wafer.
When the coordinate position information 2, 43 is taught, the hand (see FIG. 1C) moves the brush (not shown) to the designated coordinate position and is positioned.

Accordingly, the brush is driven by a linear vibration device (for example, a minute vibrator) mounted on the hand of the robot to perform polishing. As described above, according to the second embodiment, in addition to the effects of the first embodiment, it is possible to easily open the upper layer of the local region simply by giving the coordinates of the observation desired portion. Further, by sharing these coordinates with another semiconductor manufacturing apparatus such as a defect inspection apparatus, it is possible to greatly reduce the trouble of searching for an open layer.

Next, a third embodiment of the present invention will be described. FIG. 3 is a perspective view showing a method for locally opening a specific portion of a wafer according to a third embodiment of the present invention. As shown in this figure, the robot [see FIG.
4, 55 and 56 are attached so that arbitrary observation desired portions 51, 52 and 53 of the wafer 50 can be simultaneously polished.

In this case, coordinate position information of a plurality of observation desired portions 51, 52, 53 on the wafer 50 is taught by a robot having a plurality of hands (not shown), and the brushes 54, 55, 56 are positioned at the respective coordinate positions, and the respective brushes 54, 55,
The polishing can be performed by the simultaneous operation of the vibrating device 56 mounted on a plurality of hands.

As described above, according to the third embodiment, in addition to the effects of the first and second embodiments, by simultaneously operating a plurality of polishing brushes, a plurality of desired observation locations can be simultaneously opened. In addition, it is possible to shorten the time required for opening the layer. Next, a fourth embodiment of the present invention will be described. FIG. 4 is a schematic view showing a method for locally opening a specific portion of a wafer according to a fourth embodiment of the present invention.

According to this embodiment, the operation of the brush 60 is controlled, for example, by a method of locally opening a specific portion of the wafer.
As shown in FIG. 4, a path 62 programmed in the robot can be set for the movement operation of the robot hand at the polishing point 61. This programmed path 62 can be changed freely. As described above, according to the fourth embodiment, in addition to the effects of the first and second embodiments, the operation of the polishing brush is freely set, so that the open layer region is set regardless of the size of the polishing brush. It becomes possible.

Next, a fifth embodiment of the present invention will be described. FIG. 5 is a view showing a polished state of a specific portion of a semiconductor device according to a fifth embodiment of the present invention by a local layering method. In this embodiment, a method of locally opening a specific portion of a semiconductor element is as follows. As shown in FIG. 5A, the shape of a brush is a cylindrical body 71, and the cylindrical body 71 is centered on an axis 72 of the cylindrical body. As shown in FIG. 5B, by rotating a small motor mounted on the hand, and by rotating a cylindrical brush,
An arc-shaped opening 73 can be formed in the semiconductor element 70.

As described above, according to the fifth embodiment, in addition to the effects of the first to third embodiments, an arc-shaped open section can be obtained by using a cylindrical polishing brush. FIG. 5 (b)
As shown in the figure, the depth d of the open layer is given by the following equation (1) from the radius D of the brush and the opening diameter 2r of the sample surface. d = r ² / D (1) Since the radius D of the brush is known, the depth of the opening can be accurately obtained by checking the opening diameter 2r. For example, when D = 15 mm, r is required to be 122.5 μm so that d becomes 1 μm. further,
If this opening shape is used, it is possible to evaluate the depth of the contact hole by determining the distance between the hole bottom and the center of the opening, especially for the evaluation of a fine contact hole opening. It can be used for process management.

It is also possible to form a hole-shaped depression by rotating the brush by a small motor with reference to the center position of a normal brush. Next, a sixth embodiment of the present invention will be described. FIG. 6 is a view showing a state of polishing a specific portion of a semiconductor device according to a sixth embodiment of the present invention by a local layer-opening method.

In this embodiment, an abrasive having a large difference in polishing rate depending on the material is used. in this way,
By using a polishing agent having a large difference in polishing rate depending on the material, for example, as shown in FIG. 6A, only the metal film 83 that reflects the light laminated on the silicon oxide film 82 of the semiconductor element 80 is used. Can be locally polished. At this time, the metal film 83 of the abrasive and the silicon oxide film 8
As shown in FIG. 6B, since the selectivity with respect to 2 is large,
Polishing of the metal film 83 alone can be completed while the lower silicon oxide film 82 is hardly polished.

As described above, according to the sixth embodiment, in addition to the effects of the first to third embodiments, only a specific laminated film can be polished. This is expected to increase the dispersion, especially when there is a step of depositing a metal film after the CMP process, because the metal reflects light, making it difficult to confirm the alignment mark and the wafer number. But
It becomes possible to open only the metal film by designating those regions, and it is possible to suppress variations in semiconductor elements.

It should be noted that the present invention is not limited to the above embodiment, and various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0027]

As described above, according to the present invention, the following effects can be obtained. (A) An arbitrary observation desired portion can be specified, polished, and the layer can be opened with the wafer as it is.

(B) The upper layer can be opened only in a local area without affecting other areas in the wafer at all. For this reason, local analysis which cannot be normally introduced during the manufacturing process can be easily executed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a method for locally opening a specific portion of a wafer according to a first embodiment of the present invention.

FIG. 2 is a schematic view illustrating a method for locally opening a specific portion of a wafer according to a second embodiment of the present invention.

FIG. 3 is a perspective view showing a method for locally opening a specific portion of a wafer according to a third embodiment of the present invention.

FIG. 4 is a schematic view showing a method for locally opening a specific portion of a wafer according to a fourth embodiment of the present invention.

FIG. 5 is a view showing a polished state of a specific portion of a semiconductor device according to a fifth embodiment of the present invention by a local layering method.

FIG. 6 is a diagram showing a polished state of a specific portion of a semiconductor device according to a sixth embodiment of the present invention by a local layering method.

FIG. 7 is a process chart showing a conventional method for observing a semiconductor device by layer opening.

[Explanation of symbols]

10, 40, 50 Semiconductor wafer 11, 41, 42, 43, 51, 52, 53 Observation desired position 12, 54, 55, 56, 60 Polishing brush 13 Opening position 20 Industrial articulated robot 21 CPU (Central processing unit) ) 22 I / F (output interface) 23 Storage device (memory) 24 I / F (input interface) 31 Hand 32 Drive device 61 Polishing point 62 Programmed path 70 Semiconductor element 71 Cylindrical body 72 Cylindrical axis 73 Arc shape Opening location of 80 substrate 82 silicon oxide film 83 metal film

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Norio Hirashi 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. F-term (reference) 4M106 AA01 AA07 AB17 DJ07

Claims (2)

[Claims] 1. A step of: (a) bringing a fine polishing brush from above a desired observation point of a semiconductor element; and (b) contacting the polishing brush with the semiconductor element while applying an abrasive, Moving the polishing brush, a step of mechanically polishing only the area where the polishing brush is in contact,
(C) removing polishing debris generated in the polishing step, and performing a step of opening the layer during the step of manufacturing the semiconductor element. (A) positioning means for a semiconductor element;
(B) means for obtaining coordinate information of a desired observation position of the semiconductor element; (c) a fine polishing brush settable at the desired observation position of the semiconductor element; and (b) driving means for the polishing brush. An apparatus for opening a layer in a local region of a semiconductor element.