JP2002228608A - Electrical flaw inspection device for semiconductor device and method thereof for semiconductor device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrical flaw inspection device for semiconductor device and a method using the same. SOLUTION: A semiconductor device, wherein a plurality of conductive lines, insulating films for insulating them and conductive pads formed between the insulating films are provided on a semiconductor substrate, is prepared. Subsequently, electrons or holes are accumulated on the surfaces of the conductive pads and, thereafter, the conductive pads having electrons or holes accumulated thereon are irradiated with primary electron beam. Succeedingly, the voltage contrast between the conductiver pads is detected by secondary electrons discharged from the conductiver pads irradiated with the primary electron beam to judge the electrical flaw present in the semiconductor substrate. By this constitution, electrons or holes are accumulated on the surfaces of the conductive pads by using an ion generator or by regulating the energy of the primary electron beam. The voltage contrast due to secondary electrons can be detected as a bright of dark image at the time of judgment of the electrical flaw.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting electrical defects of a semiconductor device and a method for inspecting defects of a semiconductor device using the same.

[0002]

2. Description of the Related Art During a manufacturing process of a semiconductor device, various defects causing malfunction or failure of the semiconductor device occur. These defects can be roughly classified into two. That is, physical defects that cause physical abnormalities on the surface of the semiconductor substrate, such as particles, and electrical defects that generate electrical defects without physical defects. Physical defects can be easily detected using a general image measuring device, but electrical defects are difficult to detect with a general surface inspection device.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an apparatus for inspecting an electrical defect of a semiconductor device in a nondestructive manner. It is another object of the present invention to provide a method for inspecting an electrical defect of a semiconductor device using the apparatus for inspecting an electrical defect of a semiconductor device.

[0004]

In order to achieve the above object, an apparatus for inspecting electrical defects of a semiconductor device according to the present invention comprises an auxiliary chamber for mounting a semiconductor substrate, and a hole ( An ion generator for doping cations or electrons (anions) and a main chamber connected to the auxiliary chamber and including a stage for mounting a semiconductor substrate. An electron beam source for scanning a semiconductor substrate located in the main chamber with a primary electron beam for inspecting an electrical defect is included. A signal processing unit for detecting and amplifying an electrical signal based on voltage contrast of secondary electrons generated from the semiconductor substrate by the scanned primary electron beam is included. An image display unit is connected to the signal processing unit so that the electric signal processed by the signal processing unit is image-processed so that the electric signal can be seen. A data analysis unit that analyzes electrical signals processed by the signal processing unit to determine electrical defects and performs statistical processing, and can receive and output data of physical defects of the semiconductor substrate from an external computer, and each component is A central computer that can be controlled and a stage adjuster that tracks the location of physical defects on the semiconductor substrate transmitted from the central computer. The stage adjuster includes a stage mover for moving a stage in the main chamber and a laser interferometer adjuster connected thereto. In particular, the image processing unit includes an image processing unit that performs image processing on the electric signal processed by the signal processing unit to determine an electric defect, and feeds back the electric defect to the central computer according to an installed electric defect classification procedure flowchart.

Further, a method for inspecting an electrical defect of a semiconductor device according to the present invention has a plurality of conductive lines on a semiconductor substrate and a conductive pad formed between insulating films insulating the conductive lines. And providing a semiconductor device. Next, after accumulating electrons or holes on the surface of the conductive pad, the conductive pad on which the electrons or holes are stored is irradiated with a primary electron beam. Subsequently, the voltage contrast of the conductive pad is detected based on the secondary electrons emitted from the conductive pad irradiated with the primary electron beam to determine an electrical defect existing in the semiconductor substrate. The step of accumulating electrons or holes on the surface of the conductive pad is performed by using an ion generator or by adjusting the energy of the primary electron beam. When determining an electrical defect, it is determined whether a defect image obtained by voltage contrast due to secondary electrons is a bright image or a dark image.

In addition, a method for inspecting electrical defects of a semiconductor device, which is an example of the present invention, is directed to a method of inspecting a semiconductor substrate for a plurality of conductive lines and a conductive film formed between insulating films for insulating the conductive lines. A semiconductor element having pads is prepared. Next, after accumulating electrons on the surface of the conductive pad,
After irradiating the primary electron beam, a defect image obtained by voltage contrast between conductive pads caused by secondary electrons emitted is primarily detected. After determining whether the primary detected defect image is a dark image, 1
Next, if the detected defect image is dark, holes are accumulated on the surface of the conductive pad. After irradiating a primary electron beam to the conductive pad in which the holes are accumulated, a defect image obtained by voltage contrast between the conductive pads caused by the emitted secondary electrons is secondarily detected. It is determined that the conductive pad whose secondary detected defect image is a dark image has a physical defect, and the conductive pad of a non-dark image has an electric defect due to a junction leakage source. If the primary detected defect image is not a dark image, holes are accumulated on the surface of the conductive pad. After irradiating a primary electron beam to the conductive pad in which holes are accumulated, a defect image obtained by voltage contrast between the conductive pads caused by the emitted secondary electrons is detected tertiary. A conductive pad whose tertiary detected defect image is a dark image has an electrical defect due to an unetched contact portion, and a conductive pad whose image is not a dark image includes the conductive pad and the conductive line. It is determined that there is an electrical defect due to the short circuit during the period.

Further, a method for inspecting electrical defects of a semiconductor device, which is an example of the present invention, comprises a method of forming a conductive line on a semiconductor substrate and a conductive pad formed between insulating films for insulating the conductive line. A semiconductor element having the same is prepared. After accumulating holes on the surface of the conductive pad, a primary image is primary-detected to detect a defect image obtained by voltage contrast generated by secondary electrons emitted after irradiation with primary electrons. It is determined whether the primary detected defect image is a dark image. If the primary detected defect image is a dark image, electrons are accumulated on the surface of the conductive pad. A defect image obtained by voltage contrast caused by secondary electrons emitted after irradiating primary electrons to a conductive pad in which electrons are accumulated is secondarily detected. It is determined that the conductive pad whose secondary detected defect image is a dark image has a physical defect, and that the conductive pad whose image is not a dark image has an electric defect due to an unetched contact portion. . If the primary detected defect image is not a dark image, electrons accumulate on the surface of the conductive pad. After irradiating a primary electron beam to a conductive pad in which electrons are stored, a defect image obtained by a voltage contrast generated by secondary electrons emitted is tertiary detected. A conductive pad whose tertiary detected defect image is a dark image has an electrical defect due to a junction leakage source, and a conductive pad which is not a dark image has a short circuit between the conductive pad and the conductive line. It is determined that there is an electrical defect.

As described above, the apparatus for inspecting an electrical defect of a semiconductor device according to the present invention detects an electrical defect of the semiconductor device by accumulating electrons or holes on the surface of a pad of the semiconductor device before inspecting the electrical defect. And can be categorized by type.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention described below can be modified in various other forms, and the scope of the present invention is not limited to the embodiments described in detail below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. FIG. 1 is a schematic view illustrating an apparatus for inspecting electrical defects of a semiconductor device according to the present invention.

The electric defect inspection apparatus shown in FIG. 1 is used for supporting a semiconductor substrate (semiconductor wafer, not shown) for forming a semiconductor element, and an auxiliary chamber 3 for loading the semiconductor substrate. And a main chamber 15 including a stage (not shown) on which a semiconductor substrate is loaded, and a vacuum connected to the main chamber 15 and the auxiliary chamber 13 for adjusting the vacuum of the main chamber 15 and the auxiliary chamber 13. A vacuum control unit 16 for performing a pattern image on a semiconductor substrate loaded in the main chamber 15 by an optical means such as a microscope.
And a pattern aligning unit 35 that performs recognition in accordance with the original image stored in the memory and performs alignment substantially.

Further, the electrical defect inspection apparatus is connected to the main chamber 15 for inspecting an electrical defect of a semiconductor substrate located in the main chamber 15, and has an electron beam source unit 19 for scanning a primary electron beam. And a signal processing unit 21 for detecting and amplifying an electrical signal based on voltage contrast of secondary electrons generated from the semiconductor substrate by the scanned primary electron beam. In particular, an ion generation unit 17 connected to the auxiliary chamber 13 and previously doping holes (cations) or electrons (anions) on the surface of the semiconductor substrate in the auxiliary chamber 13
Contains. The ion generation unit 17 can easily detect an electrical defect generated in the semiconductor substrate by type.

The electrical defect inspection apparatus is connected to a signal processing section 21, and performs image processing on the electrical signal processed by the signal processing section 21 to display it as visible data; Connected to the signal processing unit 21
And a data analysis unit 25 capable of analyzing the electrical signal processed in the step (1) to determine an electrical defect and performing statistical processing.

Further, the electrical defect inspection apparatus can receive and output the position data of the physical defect of the semiconductor substrate from the external computer 26, and can control each component, and the central computer 27 transmits the data. And a stage adjusting unit 37 including a laser interferometer adjusting unit 29 and a stage moving unit 31 for tracking the position of a physical defect of the semiconductor substrate. Before tracking the position of a physical defect on a semiconductor substrate, it is necessary to determine a reference point of an alignment mark capable of precisely aligning the semiconductor substrate. The reference point of the alignment mark is determined by measuring the alignment mark input to the central computer and the alignment mark of the actual semiconductor substrate and comparing them relatively, and then finely adjusting the alignment mark using the stage adjusting unit 37. .

The physical defect position data transmitted from the central computer 27 is image-processed and fed back to the stage adjusting unit 37, and the electric signal by the secondary electrons processed by the signal processing unit 21 is illuminated or brightened. An image processing unit 33 is provided which performs implicit image processing and feeds it back to the central computer 27 based on the installed electrical defect classification flowchart.

Hereinafter, referring to FIGS. 2 to 5, FIG.
A method for inspecting an electric defect of a semiconductor element by using the electric defect inspection apparatus for a semiconductor element will be described in detail.
First, when a semiconductor element is irradiated with a primary electron beam using the semiconductor element electrical defect inspection apparatus of FIG.
For example, what is the yield of secondary electrons emitted by an oxide film or silicon?

FIG. 2 is a graph showing a secondary electron yield depending on a potential difference between a front surface and a back surface of a semiconductor substrate when the apparatus for inspecting electrical defects of a semiconductor device of FIG. 1 is used. The X axis shows the potential difference between the front and back surfaces of the semiconductor substrate when the primary electron beam is applied, and the Y axis shows the secondary electron yield, which is the ratio of secondary electrons emitted to the primary electron beam. Is shown. In particular, SE
si (second electron yield in silicon) is 2
SEox (second electron yield in ox
ide) indicates the secondary electron yield of the oxide film.

Referring to FIG. 2, when the secondary electron yield cannot exceed 1, the number of emitted electrons is smaller than the number of electrons applied to the surface of the semiconductor wafer.
Electrons are accumulated on the surface of the (semiconductor wafer), for example, the surface of the conductive pad. Conversely, if the secondary electron yield exceeds 1, more electrons are emitted than electrons applied to the semiconductor substrate, so holes accumulate on the surface of the semiconductor substrate, for example, the surface of the conductive pad. Is done. This allows
A region where the secondary electron yield is 1 or less is an electron generating region, and a region where the secondary electron yield is 1 or more is a hole generating region. If electrons or holes are accumulated on the surface of the semiconductor substrate in this way, as described later, the electrical defect can be more easily inspected and classified using the electrical defect inspection apparatus for a semiconductor device of FIG. The method of accumulating electrons and holes on the surface of the semiconductor device can be performed using the ion generator of the electrical defect inspection apparatus of FIG. FIG. 2 typically shows the secondary electron yield in silicon and oxide films, but other substances also have an electron generation region and a hole generation region.

Next, when a primary electron beam is irradiated on the surface of a semiconductor device using the electrical defect inspection apparatus shown in FIG. 1, how a defect image is indicated by the type of an electrical defect will be described with reference to FIGS. This will be described in detail with reference to FIG. Electrical defects are classified into a resistive defect generated from an unetched contact portion and a leaky defect generated by a junction leakage source or a short circuit between the contact portion and a conductive line.

The semiconductor device used in FIGS. 3 to 5 is a semiconductor substrate 100 having an active region limited by an isolation insulating film 102.
A gate insulating film (not shown), a polysilicon film 104 and a silicide film 106, for example, a conductive line 10 constituted by a tungsten silicide film and serving as a gate electrode.
8. A plurality of gate patterns in which the capping insulating films 110 are sequentially stacked are formed. In the semiconductor device used in the present invention, a spacer 112 is formed so as to surround and insulate these gate patterns.
A conductive pad 114 electrically connected to the impurity region 116, for example, a source or drain region, is formed between them. The conductive pad 114 is formed of a polysilicon film, a tungsten film, an aluminum film, or a copper film doped with impurities. In this embodiment, a gate electrode is taken as an example of the conductive line 108, but the present invention can be applied to a bit line and the like.

FIGS. 3 (A) and 3 (B) are shown to explain a defect image which appears when a semiconductor element having an unetched contact portion is inspected by using the electric defect inspection apparatus of FIG. It is a drawing. Referring to FIG. 3 (A), when the electrical defect inspection apparatus of FIG. 1 is used, the energy of the primary electron beam is increased to increase the potential difference between the front surface and the back surface of the semiconductor substrate 100, so that the secondary Electron yield of 1
Make it smaller. In this case, as described above, since electrons emitted are smaller than electrons applied to the semiconductor substrate 100, electrons are accumulated on the surfaces of the conductive pads 114a and 114b. In particular, in the conductive pad 114b having the contact portion 150 which has not been etched, the electron e cannot move to the semiconductor substrate 100 and the conductive pad 11 having the open contact portion does not move.
More electrons e remain on the surface compared to 4a.

Next, a primary electron beam is applied to the surface of the semiconductor substrate 100 including the conductive pads 114a and 114b using the electrical defect inspection apparatus shown in FIG. At this time, the electrons e remaining in the contact portion 150 which has not been etched play a role of increasing the repulsive force more than the adjacent open contact portion. As a result, the conductive pad 114b having the unetched contact portion 150 emits more secondary electrons than the conductive pad 114a having the open contact portion, thereby displaying a bright image (bright image).

Referring to FIG. 3B, first, the energy of the primary electron beam is reduced using the electrical defect inspection apparatus of FIG. 1 to reduce the potential difference between the front surface and the back surface of the semiconductor substrate 100. Thereby, the secondary electron yield is made larger than 1.
In this case, as described above, since more electrons are emitted than electrons applied to the semiconductor substrate 100, the conductive pad 11
Holes h accumulate on the surfaces of 4c and 114d. In particular, in the case of the conductive pad 114d where the unetched contact portion 150 exists, the hole h cannot move to the semiconductor substrate 100,
A larger amount of holes h remain on the surface as compared to the conductive pad 114c having an open contact portion.

Next, a primary electron beam is applied to the surface of the semiconductor substrate 100 including the conductive pads 114c and 114d using the electrical defect inspection apparatus shown in FIG. At this time, the conductive pad 11
Since the holes existing on the surfaces of 4c and 114d act as traps for emitting secondary electrons, the conductive pad 114d having the unetched contact portion 150 is emitted from the conductive pad 114c having the open contact portion. Shows dark (dark) image with few secondary electrons.

FIGS. 4A and 4B are views for explaining a defect image appearing when a semiconductor device having a junction leakage source is inspected using the electric defect inspection apparatus of FIG. is there. Referring to FIG. 4A, first, as described above, the secondary pad yield is made smaller than 1 and the conductive pads 114e, 1
Accumulate electrons on the surface of 14f. At this time, the conductive pad 114f having the leakage source portion 160 leaks electrons and escapes to the source portion 160, so that only a small amount of electrons e are accumulated on the surface.

Next, a primary electron beam is applied to the surface of the semiconductor substrate 100 including the conductive pads 114e and 114f by using the electrical defect inspection apparatus shown in FIG. At this time, the semiconductor substrate 100
Is a P-type and has an N-type junction region, a conductive pad 114f having a leakage source portion 160 as shown in FIG.
Shows a dark image because the amount of secondary electrons emitted is smaller than that of the conductive pad 114e having no leakage source. When the semiconductor substrate 100 is N-type and has a P-type junction region, a reverse bias is applied, so that the amount of surface charge does not change, and the conductive pad having the leakage source portion 160 is provided. 114f and other conductive pads 114e cannot be distinguished from the defect image.

Referring to FIG. 4B, first, as described above, the secondary pad yield is made larger than 1, and the conductive pads 114g, 1
The hole h is accumulated on the surface of 14h. Next, a primary electron beam is applied to the surface of the semiconductor substrate 100 including the conductive pads 114g and 114h using the electrical defect inspection apparatus of FIG.

At this time, when the semiconductor substrate 100 is P-type and has an N-type junction region, a reverse bias is applied as shown in FIG. Is unchanged, and the conductive pad 114h having the leakage source portion 160
And the other conductive pad 114g cannot be distinguished from the defective image. When the semiconductor substrate 100 is N-type and has a P-type junction region, a positive bias is applied, so that the conductive pad 114h having the leakage source portion 160 is provided.
Shows a bright image when a hole comes out of the leak source portion 160.

FIGS. 5A and 5B illustrate a defect image that appears when a semiconductor element in which a conductive pad and a conductive line are short-circuited is inspected using the electric defect inspection apparatus of FIG. FIG. Referring to FIG. 5A, first, electrons are accumulated on the surfaces of the conductive pads 114i and 114j with a secondary electron yield smaller than 1 as described above. Next, a primary electron beam is applied to the surface of the semiconductor substrate 100 including the conductive pads 114i and 114j using the electrical defect inspection apparatus of FIG. At this time, the conductive pad 114j is a conductive line 108 having electrons, for example, a silicide film 106.
When a short circuit is caused, electrons cannot escape to the conductive line 108, so that relatively many electrons remain on the surface. Therefore, when the primary electron beam is applied, the conductive line 108 and the short-circuited conductive pad 114j increase the amount of secondary electrons emitted from the conductive pad 108 and the shorted conductive pad 114j.

Referring to FIG. 5B, first, as described above, the secondary electron yield is made greater than 1 and the conductive pads 114k, 1
The hole h is accumulated on the surface of 14l. Next, a primary electron beam is applied to the surface of the semiconductor substrate 100 including the conductive pads 114k and 114l using the electrical defect inspection apparatus of FIG.
At this time, in the conductive line 108 having electrons, for example, the conductive pad 114l short-circuited with the silicide film 106, the hole h escapes to the conductive line 108, and a relatively small amount of the hole h exists on the surface. Accordingly, the conductive line 108 having a hole when the primary electron beam is applied and the shorted conductive pad 114l show a bright image due to an increase in the amount of secondary electrons emitted from the conductive pad 108 when the primary electron beam is not applied.

As described above with reference to FIGS. 3 to 5, the voltage contrast due to the secondary electrons emitted after the application of the primary electron beam to the surface of the conductive pad is detected, and this is used as a bright or dark image. An electrical defect of a semiconductor element can be inspected. In FIGS. 3 to 5, the bright or dark image is determined by comparing the conductive pads. However, a bright or dark image can be determined based on a reference value. In FIGS. 3 to 5, the energy of the primary electron beam was adjusted as a method for laminating electrons and holes on the surfaces of the conductive pads 114a to 114l. Can also.

Incidentally, a resistive electrical defect, for example, a defect image of a semiconductor device having a conductive pad 114b having a non-etched contact portion, and a leaky electrical defect, for example, a conductive pad 114j and a conductive line 108, The defect image of the semiconductor element shorted between the conductive pads 11
4b and 114j show the same bright image when electrons are accumulated on the surface. Therefore, when an electrical defect occurs during a manufacturing process of a semiconductor device, it is necessary to classify the type of the electrical defect according to the electrical defect. Only if the electrical defects can be classified in this way, the electrical defects generated during the manufacturing process of the semiconductor element can be accurately cured and can be fed back to the previous manufacturing process.

Next, a description will be given, with reference to FIGS. 6 and 7, of how the electrical defects of the semiconductor device can be classified and inspected based on the description of FIGS. The semiconductor element used as a sample in FIGS. 6 and 7 includes a plurality of conductive lines 108 on a semiconductor substrate 100 and an insulating film 11 for insulating the conductive lines 108 as described in FIGS.
0,112 and conductive pads 114a to 114l formed between the insulating films 110,112.

FIG. 6 is a flowchart showing an example of a method for inspecting an electrical defect of a semiconductor device, which can classify electrical defects using the apparatus for inspecting an electrical defect of a semiconductor device of FIG. Specifically, electrons are accumulated on the surface of the conductive pad by adjusting the primary electron beam energy to a high value so that the secondary electron yield is less than 1 (step 201). Next, a primary electron beam is irradiated on the conductive pad in which electrons are stored, and a defect image obtained from a voltage contrast between the conductive pads caused by secondary electrons emitted is primarily detected (step 203). Next, after electrons are accumulated on the surface of the conductive pad, the primary detected defect image becomes dark (dark).
It is determined whether the image is an image (step 205).

Subsequently, if the primary detected defect image is a dark image, the primary electron beam energy is adjusted again to accumulate holes on the surface of the conductive pad (step 207). Next, a defect image obtained from a voltage contrast between the conductive pads caused by secondary electrons emitted after irradiating the conductive pad in which the holes are accumulated with the primary electron beam is detected (step 209). After accumulating holes on the surface of the conductive pad, it is determined whether the secondary detected defect image is dark (step 21).
1). The secondary detected defect image is a dark image,
If the primary electron beam energy is at a minimum, it indicates that the conductive pad, which is a dark image, has a physical defect (steps 213 and 215). If the secondary detected defect image is a dark image and the primary electron beam energy is not the lowest value, steps 207 and 207 are steps of lowering the primary electron beam energy and detecting the defect image.
Return to 09. The secondary defect image detected after accumulating holes on the surface of the conductive pad is not a dark image, indicating that the conductive pad has a defect image due to a junction leakage source (step 217).

Next, if the primary detected defect image is not a dark image, the primary electron beam energy is adjusted again to accumulate holes on the surface of the conductive pad.
(Step 307). Next, after the primary electron beam is irradiated on the conductive pad in which the holes are accumulated, the defect image obtained by the voltage contrast between the conductive pads by the emitted secondary electrons is tertiarily detected (step 309). After accumulating holes on the surface of the conductive pad, it is determined whether the tertiary detected defect image is a dark image (step 311). The tertiary detected defect image is a dark image, indicating that the conductive pad has a defect due to a non-etched contact portion (step 317). If the tertiary detected defect image is not dark, it is determined whether or not the primary electron beam energy is the lowest value (step 31).
3). If the minimum value, the non-dark image indicates that the conductive pad has an electrical defect due to a short circuit between the contact portion and the conductive line (step 315); otherwise, the primary electron beam energy is again reduced. Then, the process returns to the process of detecting a defective image.

In short, when detecting defects with an electrical defect inspection apparatus after accumulating electrons, a conductive pad having a dark image indicates an electrical defect due to junction leakage or a physical defect. When inspecting after accumulating holes, the defect image of the conductive pad having the junction leakage is inverted, but the defect image of the conductive pad having the physical defect is not inverted. Then, when the defect is detected by the electrical defect inspection apparatus after the electrons are accumulated, the conductive pad having the non-dark defect image is short-circuited between the contact portion and the conductive line or the unetched contact portion. When inspecting after an electrical defect due to a circuit but accumulating holes in the surface, the defect image of the conductive pad having a non-etched contact portion is inverted and includes a short circuit between the contact portion and the line. The defect image of the conductive pad does not reverse.

FIG. 7 is a flow chart showing another example of a method for inspecting an electrical defect of a semiconductor device which can classify an electrical defect using the apparatus for inspecting an electrical defect of a semiconductor device of FIG. Holes are accumulated on the surface of the conductive pad of the semiconductor device loaded in the auxiliary chamber 13 of FIG. 1 by using the ion generator 17 (step 401). Next, the semiconductor element having accumulated holes is transferred to the main chamber of the electrical defect inspection apparatus.
Loading to 15 (step 403). Next, after the primary electron beam is irradiated from the main chamber 15 of the electrical defect inspection apparatus to the conductive pad in which the holes are accumulated, a defect image obtained by voltage contrast by secondary electrons emitted is primarily detected ( Step 404). Next, it is determined whether the primary detected defect image is a dark image (step 405).

If the primary detected defect image is a dark image, the semiconductor device is unloaded into the auxiliary chamber 13 of the electrical defect inspection device (step 407). Electrons are accumulated on the surface of the conductive pad of the semiconductor device unloaded into the auxiliary chamber 13 using the ion generator 17 (step 409). Next, after a primary electron beam is irradiated on the conductive pad in which electrons are accumulated, a defect image obtained by a voltage contrast due to the emitted secondary electrons is secondarily detected (step 410). Next, it is determined whether the secondary detected defect image is dark (step 4).
11). The conductive pad whose secondary detected defect image is a dark image indicates that the conductive pad has a physical defect (step 413), and otherwise indicates that it has an electric defect due to the non-etched contact portion. (Step 51
Five).

Next, if the primary detected defect image is not a dark image, the semiconductor device is unloaded into the auxiliary chamber 13 of the electrical defect inspection apparatus (step 50).
7). Next, electrons are accumulated on the surface of the conductive pad of the semiconductor element unloaded into the auxiliary chamber 13 using the ion generator 17 (step 509). Next, after irradiating a primary electron beam to the conductive pad in which the electrons are accumulated, a tertiary defect image obtained by voltage contrast by the emitted secondary electrons is detected (step 510).
Next, it is determined whether the tertiary detected defect image is dark (step 511). If the tertiary detected defect image is a dark image, it indicates that the conductive pad has an electrical defect due to a junction leakage source (step 51).
3), otherwise indicate an electrical fault due to a short circuit between the contact and the conductive line
(Step 515).

In short, when a defect is detected by the electrical defect inspection apparatus after the holes are accumulated, the conductive pad, which is a dark image, has a physical defect or an electrical defect due to a non-etched contact portion. When testing after storing electrons, the defect image of the conductive pad having the non-etched contact portion is inverted, but the defect image of the conductive pad having the physical defect is not inverted. Then, after accumulating holes, a defect is detected by an electrical defect inspection device, and if the conductive pad does not have a dark defect image, a junction leakage source or a short circuit between the contact portion and the conductive line. Indicates that an electrical defect has occurred, but when inspecting after accumulating electrons on the surface, the defect image of the conductive pad having a short circuit between the contact portion and the conductive line does not reverse to a dark image The conductive pad having the junction leakage source is inverted.

[0041]

As described above, the apparatus for inspecting an electrical defect of a semiconductor device according to the present invention accumulates electrons or holes on the surface of a pad of the semiconductor device before inspecting the electrical defect, so that the electrical defect of the semiconductor device is eliminated. Can be detected and classified according to type. In particular, the apparatus for inspecting electrical defects of a semiconductor device according to the present invention uses an ion generator connected to an auxiliary chamber, or accumulates electrons or holes in conductive pads of the semiconductor device by adjusting the energy of a primary electron beam. can do.

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating an apparatus for inspecting electrical defects of a semiconductor device according to the present invention.

FIG. 2 is a graph showing a secondary electron yield depending on a potential difference between a front surface and a back surface of a semiconductor substrate when the apparatus for inspecting electrical defects of a semiconductor device of FIG. 1 is used.

FIG. 3 is a view for explaining a defect image that appears when a semiconductor device having a contact portion that has not been etched is inspected using the electrical defect inspection apparatus of FIG. 1;

FIG. 4 is a view illustrating a defect image that appears when a semiconductor device having a junction leakage source is inspected using the electrical defect inspection apparatus of FIG. 1;

5 is a view illustrating a defect image that appears when a semiconductor device in which a conductive pad and a conductive line are short-circuited is inspected using the electrical defect inspection apparatus of FIG. 1;

FIG. 6 is a flowchart illustrating an example of a method for inspecting an electrical defect of a semiconductor device, which can classify electrical defects using the apparatus for inspecting an electrical defect of a semiconductor device of FIG. 1;

FIG. 7 is a flowchart illustrating another example of a method for inspecting an electrical defect of a semiconductor device, which can classify electrical defects using the apparatus for inspecting an electrical defect of a semiconductor device of FIG. 1;

[Explanation of symbols]

 11 Handler unit 13 Auxiliary chamber 15 Main chamber 16 Vacuum control unit 17 Ion generation unit 19 Electron beam source unit 21 Signal processing unit 23 Image display unit 25 Data analysis unit 26 External computer 27 Central Computer 29 ... Interferometer adjuster 31 ... Stage moving unit 32 ... Optical means 33 ... Image processing unit 35 ... Pattern aligning unit 37 ... Stage adjusting unit

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kim Deok-Yong 900 Toung-dong, Gunpo-si, Gyeonggi-do, Republic of Korea No.106, 503, Toa Apartment F-term (Reference) 2G001 AA03 AA05 BA07 CA03 GA01 GA06 GA12 HA12 HA13 KA03 LA11 MA05 PA11 2G132 AA00 AF13 AG00 AL11 4M106 AA01 AA02 BA02 CA16 DH24 DJ03 DJ15 DJ18 DJ20 DJ24

Claims (11)

[Claims] 1. An auxiliary chamber for loading a semiconductor substrate, an ion generator for doping holes (cations) or electrons (anions) on a surface of the semiconductor substrate in the auxiliary chamber, and an auxiliary chamber connected to the auxiliary chamber. A main chamber including a stage on which the semiconductor substrate is mounted; an electron beam source for scanning a semiconductor substrate positioned in the main chamber with a primary electron beam for inspecting an electrical defect; A signal processing unit for detecting and amplifying an electrical signal based on a voltage contrast of secondary electrons generated from the semiconductor substrate by the electron beam; and analyzing the electrical signal processed by the signal processing unit to determine an electrical defect. A data analyzing unit for performing statistical processing; and receiving and outputting position data of a physical defect of the semiconductor substrate from an external computer, and controlling each component. A central computer, a stage adjusting unit to track the position of the physical defects of the semiconductor substrate transferred from the central computer, the electrical signal processed by the signal processing unit performs image processing,
And an image processing unit that feeds back to the central computer based on the installed electrical defect classification flowchart procedure. 2. The semiconductor device according to claim 1, wherein the stage adjuster comprises a stage mover for moving a stage in the main chamber, and a laser interferometer adjuster connected to the stage mover. Electrical defect inspection equipment. 3. The signal processing unit according to claim 1, wherein the signal processing unit is connected to an image display unit that performs image processing on the electric signal processed by the signal processing unit and displays the processed data as visible data. An electrical defect inspection device for semiconductor devices. 4. A plurality of conductive lines on a semiconductor substrate,
Providing a semiconductor device having an insulating film for insulating the conductive line and a conductive pad formed between the insulating film; accumulating electrons or holes on the surface of the conductive pad; Irradiating a conductive pad with accumulated electrons or holes with a primary electron beam; and detecting a voltage contrast of the conductive pad with secondary electrons emitted from the conductive pad irradiated with the primary electron beam. Determining an electrical defect existing in the semiconductor substrate. 5. The method of claim 4, wherein the step of accumulating electrons or holes on the surface of the conductive pad is performed using an ion generator. 6. The electrical defect of a semiconductor device according to claim 4, wherein the step of accumulating electrons or holes on the surface of the conductive pad is performed by adjusting energy of a primary electron beam. Inspection methods. 7. The semiconductor device according to claim 4, wherein the electrical defect is determined based on whether the defect image obtained by the voltage contrast due to the secondary electrons is a bright image or a dark image. Electrical defect inspection method. 8. A plurality of conductive lines on a semiconductor substrate,
Providing a semiconductor element having a conductive pad formed between insulating films that insulate the conductive lines; storing electrons on the surface of the conductive pad; Irradiating the pad with a primary electron beam and primary detecting a defect image obtained by voltage contrast between the conductive pads generated according to secondary electrons emitted; and detecting the primary detected defect image. Judging whether the image is a dark image, if the primary detected defect image is dark, accumulating holes on the surface of the conductive pad; and a conductive pad accumulating the holes. Detecting a defect image obtained by voltage contrast between the conductive pads generated according to the secondary electrons emitted after irradiating a primary electron beam to the substrate. If the secondary detected defect image is a dark image, the conductive pad has a physical defect. If the secondary detected defect image is not a dark image, the conductive pad has a junction leakage. Determining that there is an electrical defect due to a source; storing the hole on the surface of the conductive pad if the primary detected defect image is not a dark image; and conductive pad storing the hole. Irradiating a primary electron beam to the semiconductor device, and tertiarily detecting a defect image obtained by a voltage contrast between the conductive pads generated according to the secondary electrons emitted; In the case of an image, the conductive pad has an electrical defect due to the non-etched contact, and in the case of a non-dark image, the conductive pad has the conductive defect. Electrical defect inspection method for a semiconductor device characterized by comprising a step of determining to have an electrical defect due to a short circuit between the sexual pad and the conductive lines. 9. The electrical defect of the semiconductor device according to claim 8, wherein the step of accumulating electrons or holes on the surface of the conductive pad is performed by adjusting energy of a primary electron beam. Inspection methods. 10. A step of preparing a semiconductor device having a conductive line on a semiconductor substrate and a conductive pad formed between insulating films for insulating the conductive line; Accumulating holes, irradiating the conductive pads with accumulated holes with primary electrons, and primary detecting a defect image obtained by voltage contrast generated according to secondary electrons emitted; Determining whether the primary detected defect image is a dark image; and storing the electrons on the surface of the conductive pad if the primary detected defect image is a dark image; A step of irradiating a conductive pad storing the electrons with primary electrons and then secondary detecting a defect image obtained by a voltage contrast generated according to the secondary electrons emitted. If the second detected defect image is a dark image, the conductive pad has a physical defect, and if the image is not dark, the conductive pad has an electrical defect due to a non-etched contact portion. Judging, if the primary detected defect image is not a dark image, accumulating electrons on the surface of the conductive pad; and irradiating the conductive pad storing the electrons with a primary electron beam. Thereafter, a third step of detecting a defect image obtained by voltage contrast generated according to the emitted secondary electrons, and if the third detected defect image is a dark image, the conductive pad is electrically connected to a junction leakage source. If the conductive pad has a defect and is not a dark image, the conductive pad has an electrical defect due to a short circuit between the conductive pad and the conductive line. Electrical defect inspection method for a semiconductor device characterized by comprising the steps of disconnection. 11. The method of claim 10, wherein the step of accumulating electrons or holes on the surface of the conductive pad is performed using an ion generator.