JP2002334858A - Apparatus for polishing semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for polishing a semiconductor wafer in which an end-point detector for polishing, capable of simply and surely detecting the presence or absence of a metal film on a surface under polishing of a semiconductor wafer, is provided in a dual-damascene polishing removal process. SOLUTION: A plurality of electrodes 22 are arranged on a polishing head 6, which polishes a semiconductor wafer having a metal film containing copper or aluminum on a surface to be polished, where the distance between neighboring electrodes is longer than the chip width on the wafer. Through-holes 21 are arranged in the polishing pad 5, at positions that correspond to the electrodes 22. Presence or absence of the metal film on the scribe lines of he wafer is detected by an electrical signal processing means 24, by which a voltage is applied between electrodes to measure the resistance value between electrodes, and the end point of the polishing is determined knowing the status of the metal film on all over the wafer surface from the detected result. Since the presence or the absence of the metal film can be detected during the polishing, it is possible to remove the metal film by polishing and to keep adequate metal material in the wiring grooves of the wafer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus for a substrate such as a semiconductor wafer, and more particularly to a polishing apparatus provided with a polishing end point detecting device.

[0002]

2. Description of the Related Art Semiconductor devices such as Si, GaAs, InP and the like or semiconductor substrates such as quartz or glass substrates having a plurality of island-shaped semiconductor regions formed on the surface thereof are becoming increasingly finer and multi-layered. It is required to flatten the outer surface with high precision. Furthermore, the emergence of SOI wafers and 3
From the necessity of three-dimensional integration, flattening of the outer surface of the substrate is desired.

As a technique for planarizing such a substrate, a chemical mechanical polishing (CMP) apparatus has been conventionally known, and is widely used in the semiconductor industry. Chemical mechanical polishing (CMP) is a dual damascene process (Dual damas
cene process), it is also applied when polishing and removing a metal layer on a semiconductor wafer surface.

Next, polishing in a dual damascene process will be described with reference to FIG. In the dual damascene process, as shown in FIG. 8A, after an insulating film 102 is formed on a semiconductor wafer 101, a wiring groove 104 and a contact hole 10 are formed in the insulating film 102.
Then, as shown in FIG. 8B, a metal film 105 containing copper or aluminum is formed on the insulating film 102 so as to bury a metal material in the wiring groove 104 and the contact hole 103. . The semiconductor wafer 101 on which the metal film 105 is formed is chemically and mechanically polished, and as shown in FIG. 8C, all the metal film 105 on the insulating film 102 protruding from the wiring groove 104 is removed. In the polishing in such a dual damascene process, the metal film on the insulating film 102 is surely removed and the wiring groove 10 is removed.
It is important that a sufficient amount of the metal material is left in 4.

Therefore, in the polishing of the dual damascene process, the presence or absence of the metal film 105 on the insulating film 102 of the semiconductor wafer 101 is constantly measured, and the polishing is terminated when the metal film 105 on the insulating film 102 is gone. It becomes important.

Therefore, conventionally, the end point of polishing is detected by measuring the thickness of a layer on the surface of a semiconductor wafer by using a laser or other optical device.

Further, by using a polishing pad having an electrode embedded therein and measuring a current flowing between the electrode and a metal contact for detecting an end point provided on the surface to be polished of the wafer, the polishing is performed during polishing. A technique for detecting the thickness of a layer on a wafer surface is also disclosed in U.S. Pat. No. 4,793,895.

This technique will be described with reference to FIG. 9. Referring to FIG.
The positive electrode 20 is provided on the polished surface.
2 and a polishing pad 201 in which a negative electrode 203 is embedded.
A voltage is applied between the negative electrode 203 and the DC power source 206. When the positive electrode 202 and the negative electrode 203 come into contact with the metal pattern 205 of the wafer 204 during polishing, the wafer 2
A current flows through the inside of the wafer 2, for example, by measuring the current value with an oscilloscope 207 or the like.
The layer thickness of the polished surface No. 04 is detected.

[0009]

However, the above-mentioned conventional polishing end point detecting technique has the following problems. In other words, in the technology that measures the thickness of the layer on the semiconductor wafer surface using a laser or other optical device to detect the end point of polishing, the polishing end point is detected only based on partial information of the wafer due to mechanical limitations. Therefore, there is a problem that sufficient information cannot be obtained in order to control the entire surface to be polished with high reliability, and when trying to obtain information on the entire surface of the wafer, the mechanism becomes complicated and cost increases. There was a problem.

In the case of the technique disclosed in the above-mentioned US Pat. No. 4,793,895, it is necessary to make the wafer and the electrode come into contact with each other, and there is a problem that a contact failure is caused by polishing debris, and a metal pattern for detecting an end point is formed. There is a problem in that it must be provided on a wafer in advance, and a special process for that is required.

Therefore, the present invention has been made in view of the problems and unsolved problems of the above prior art,
Provided is a semiconductor substrate polishing apparatus provided with a polishing end point detection apparatus that can easily and reliably detect the presence or absence of a metal film on a surface to be polished of a semiconductor substrate such as a wafer during a dual damascene polishing removal process. It is intended to do so.

[0012]

To achieve the above object, a semiconductor substrate polishing apparatus according to the present invention has a substrate chuck for holding a semiconductor substrate and at least one small hole for supplying a polishing liquid. A polishing head, a polishing pad held by the polishing head and having a through hole at a portion corresponding to the small hole for supplying the polishing liquid, and a polishing surface of the polishing pad held by the substrate chuck when polishing a semiconductor substrate. Means for contacting the surface to be polished of the semiconductor substrate to be or opposed at a distance of 100 μm or less, a polishing apparatus for polishing a semiconductor substrate having a metal film containing copper or aluminum on the surface to be polished, A plurality of electrodes are disposed on the surface of the polishing head that holds the polishing pad so that the distance between the electrodes is longer than the chip width on the semiconductor substrate. A means for measuring the resistance value between the electrodes when polishing the semiconductor substrate while providing a through-hole at each of the portions corresponding to the electrodes, and that the measured resistance value between the electrodes exceeds a preset value. Determining means for ending the polishing of the semiconductor substrate when at least one of the interelectrode resistance values exceeds a preset value.

According to the present invention, there is provided an apparatus for polishing a semiconductor substrate, comprising: a substrate chuck for holding a semiconductor substrate; a polishing head having at least one small hole for supplying a polishing liquid; and a polishing head held by the polishing head for supplying the polishing liquid. A polishing pad having a through-hole at a position corresponding to the small hole, and when polishing the semiconductor substrate, bringing the polishing surface of the polishing pad into contact with the surface to be polished of the semiconductor substrate held by the substrate chuck, or 100 μm
A polishing apparatus for polishing a semiconductor substrate having a metal film containing copper or aluminum on a surface to be polished. Are arranged such that the distance between the electrodes is longer than the chip width on the semiconductor substrate, and a through-hole is provided in each of the portions of the polishing pad corresponding to the electrodes. Means for measuring the resistance value between the electrodes, means for measuring the polishing time, and means for determining that the measured interelectrode resistance value has exceeded a preset value, and at least one interelectrode resistance value is determined in advance. The polishing of the semiconductor substrate is terminated when a time equal to or less than 1/5 of the time required up to the set value is exceeded.

Further, in the semiconductor substrate polishing apparatus of the present invention, the measured inter-electrode resistance is the resistance between any pair of electrodes.

[0015]

According to the semiconductor substrate polishing apparatus of the present invention, a plurality of electrodes are arranged on the surface of the polishing head holding the polishing pad so that the distance between the electrodes is longer than the chip width on the semiconductor substrate. When a semiconductor substrate is polished with a polishing liquid interposed, a voltage is applied between the electrodes to detect the presence or absence of a metal film on the scribe line of the semiconductor substrate, and to detect the presence or absence of a metal film on the scribe line of the semiconductor substrate. Is representative of the state of the metal film on the semiconductor substrate, the presence or absence of the metal film on the polished surface of the semiconductor substrate is determined by determining that at least one inter-electrode resistance exceeds a desired set resistance. Detection is made, and that time is defined as the polishing end time. This makes it possible to detect the presence or absence of the metal film on the surface to be polished during the polishing of the semiconductor substrate, to polish and remove the metal film, and to leave a sufficient metal material in the wiring groove.

Further, a point in time at which a predetermined time has elapsed from the point in time when at least one interelectrode resistance value has exceeded a desired set resistance value is detected and the polishing end point is determined, whereby the surface to be polished of the semiconductor substrate is detected. Can be reliably removed by polishing, and a sufficient metal material can be left in the wiring groove.

Further, since the polishing liquid is interposed between the electrode and the surface to be polished of the semiconductor substrate, even if foreign matter such as polishing debris is present between the electrode and the semiconductor substrate, conduction is not hindered, and the resistance value between the electrodes is stabilized. As a result, since the electrodes do not contact the semiconductor substrate, the presence or absence of a metal film can be detected without damaging the polished surface of the semiconductor substrate.

[0018]

Embodiments of the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a schematic diagram showing a first embodiment of a semiconductor substrate polishing apparatus according to the present invention. FIG. 2 is a schematic view showing a semiconductor substrate polishing apparatus according to a first embodiment of the present invention. FIG. 3 is a diagram showing a configuration of a polishing head according to one embodiment,
(A) is a schematic sectional view, (b) is its bottom view.

In FIG. 1, a wafer chuck 2 for holding a semiconductor wafer 1 as a semiconductor substrate having a metal film containing copper or aluminum on a surface to be polished is accommodated in a container 10 and is rotated by a rotating drive of the wafer chuck 2. A swing drive unit 4 for swinging the drive unit 3 and the wafer chuck 2 is provided. The container 10 is for receiving all the polishing liquid supplied from the polishing head 6 side during the polishing of the semiconductor wafer 1 and collecting the polishing liquid via the discharge pipe 10a. The inner surface of the container 10 is formed of a conductor, and the electric shock is prevented. It is electrically grounded to prevent it. These parts are called polishing station A. Note that the surface of the semiconductor wafer is divided into a plurality of chip areas.

A conditioning station B for conditioning the polishing surface of the polishing pad 5 is provided beside the polishing station A. The conditioning station B includes a polishing pad 5.
A conditioning tool 11 for conditioning the polishing surface and a driving means 12 for driving the conditioning tool 11 are provided. The surface of the conditioning tool 11 is formed by embedding diamond in a nylon brush or resin.

The polishing head 6 for holding the polishing pad 5 so as to face the semiconductor wafer 1 held on the wafer chuck 2 includes a rotation driving means 7 for driving the polishing head 6 to rotate, and an up-and-down operation for moving the polishing head 6 up and down. A moving means 9 for moving the dynamic driving means 8 and the polishing head 6 between the polishing station A and the conditioning station B is provided.

In the polishing head 6, the polishing pad 5
As shown in FIGS. 2A and 2B, a plurality of electrodes 22 are arranged in a grid pattern, and the distance between the electrodes is longer than the chip size on the semiconductor wafer 1. You. An example of the positional relationship between the electrodes 22 (a to i) and the chips 1a on the semiconductor wafer 1 is shown in FIG.
Will be described later). Further, at least one small hole 25 for supplying the polishing liquid is provided in the center portion of the polishing head 6 (four holes on the same circumference in FIG. 2), and these small holes 25 are not shown. A polishing liquid supply pipe 26 communicating with the polishing liquid supply means is connected, and the polishing liquid is supplied from the polishing liquid supply means to the polishing liquid supply pipe 2 when polishing the semiconductor wafer 1.
Through the small holes 25, the semiconductor wafer 1 is supplied between the polishing surface of the polishing pad 5 and the surface to be polished of the semiconductor wafer 1. Polishing head 6
Are connected to the electric signal processing means 24 via electric wires 30, respectively.
It is preferable that each of the electric wires 30 connecting the electric signal processing means 24 and the electric signal processing means 24 is formed of a shield wire. The polishing pad 5 held by the polishing head 6 is provided with through holes 21 at portions corresponding to the small holes 25 for supplying the polishing liquid and the electrodes 22 of the polishing head 6.

The electric signal processing means 24 includes a semiconductor wafer 1
At the time of polishing, a voltage is applied between arbitrary electrodes and a current value flowing between the electrodes is measured. From the voltage and the current value, the polishing liquid around the electrode and the metal film on the surface to be polished of the semiconductor wafer 1 are measured. The combined resistance value can be detected. When polishing the semiconductor wafer 1, the polishing liquid supplied between the surface to be polished of the semiconductor wafer 1 and the polishing surface of the polishing pad 5 is applied to the plurality of electrodes 22 provided on the polishing head 6 and the semiconductor wafer 1. To electrically couple the metal film on the surface to be polished. When detecting the interelectrode resistance value, as described above, only the resistance value between any pair of electrodes can be measured, or the resistance value between any pair of electrodes can be sequentially measured, and as a result, All the interelectrode resistance values can be measured, and furthermore, a large number of interelectrode resistance values can be measured simultaneously.

Further, the electric signal processing means 24 may be built in the polishing head 6, and the measurement result may be transmitted to a receiving / control means provided outside the polishing head by radio or optical signal. This makes it possible to simplify the wiring from the polishing head.

It is preferable that the polishing head 6 and the polishing pad 5 cover an area in contact with the polishing liquid with an insulator, and it is desirable that the polishing head 6 and the polishing pad 5 are made of a low dielectric substance. Thereby, a measurement error can be reduced.

Although a groove for flowing a polishing liquid can be provided on the polishing surface of the polishing pad 5, it is desirable that the groove for the polishing liquid be provided so as not to intersect with the through hole 21 corresponding to the electrode 22. Thereby, when measuring the resistance value between the electrodes, there is an effect that the resistance value of the substantial polishing liquid can be increased and the resistance value of the metal film on the semiconductor wafer can be accurately measured.

When the polishing surface of the polishing pad 5 is not deteriorated by polishing, the polishing pad 5 can be formed integrally with the polishing head 6.

The plurality of electrodes 22 provided on the polishing head 6
It is desirable that the electrodes are arranged uniformly over the entire surface of the polishing pad. Instead of the grid-like arrangement shown in FIG.
2 can be evenly arranged on a plurality of concentric circles. By uniformly arranging the plurality of electrodes 22 over the entire surface of the polishing pad 5, it becomes possible to measure the metal film on the surface to be polished of the semiconductor wafer 1 widely and uniformly. Further, it is preferable that the electrode 22 is disposed at a position several μm to several hundred μm behind the polishing surface of the polishing pad 5, and the electrode 22 is disposed such that the surface of the electrode 22 is located at an intermediate portion of the thickness of the polishing pad 5. I do. This allows
The electrode 22 does not come into contact with the surface to be polished of the semiconductor wafer 1, and further has the effect of making it difficult for air to stay on the surface of the electrode 22. In addition, by setting the surface area of the electrodes to several mm ² , the influence on the measurement of the interelectrode resistance can be reduced.

Next, polishing of the semiconductor wafer and detection of the polishing end point in the polishing apparatus of the present embodiment configured as described above will be described.

First, the semiconductor wafer 1 is set on the wafer chuck 2 prior to polishing. On the other hand, the polishing head 6
Is moved to the conditioning station B by the moving means 9, the polishing head 6 is lowered by the vertical movement driving means 8, and the polishing pad 5 held by the polishing head 6 is brought into contact with the conditioning tool 11. Then, the conditioning tool 11 is rotated by the rotation driving means 12 and the polishing head 6 is simultaneously rotated by the rotation driving means 7 to condition the polishing surface of the polishing pad 5. This conditioning may be performed for each polishing.

When polishing the semiconductor wafer, the polishing head 6 is moved to the polishing station A by the moving means 9, and the polishing head 6 is lowered by the vertical movement driving means 8, so that the polishing pad 5 is moved to the polishing surface of the semiconductor wafer 1. Or, the polishing pad 5 and the surface to be polished of the semiconductor wafer 1 are opposed to each other so that the distance between them is 100 μm or less, and the polishing pad 5 is rotationally driven by the rotation driving means 7 of the polishing head 6. You. Further, the wafer chuck 2 holding the semiconductor wafer 1 is rotationally driven by the rotation driving means 3 and further oscillated by the oscillating driving means 4. At the same time, the polishing liquid is supplied from a polishing liquid supply means (not shown) to the polishing surface of the polishing pad 5 and the semiconductor wafer 1 through the small holes 25 of the polishing head 6 and the through holes 21 of the polishing pad 5 through the polishing liquid supply pipe 26. And the surface to be polished. Thus, the polished surface of the semiconductor wafer 1 is polished.

When the semiconductor wafer is polished with the polishing liquid interposed therebetween, the electric signal processing means 24 applies a voltage between arbitrary electrodes, measures a current value flowing between the electrodes, and measures the voltage. From the current value, the combined resistance value of the polishing liquid around each electrode 22 and the metal film on the polished surface of the semiconductor wafer 1 is detected as the inter-electrode resistance value. At this time, the resistance value between the electrodes at multiple points can be measured at the same time, and the resistance value between any pair of electrodes can be sequentially measured, and as a result, all the resistance values between the electrodes can be measured.

Here, the relationship between the inter-electrode resistance and the metal film on the semiconductor wafer according to the present embodiment will be described. The metal film thickness and the inter-electrode resistance have a correlation as shown in FIG. 3, and the inter-electrode resistance increases as the metal film becomes thinner. Further, the metal film area ratio occupied by the metal film in the area between the electrodes and the interelectrode resistance have a correlation as shown in FIG. 4 according to the direction of the line and space (L & S). That is, when the direction of the line and space (L & S) is the electrode direction (b), the interelectrode resistance does not correlate with the metal film area ratio, but the direction of the line and space (L & S) is In the case of orthogonality (a), the interelectrode resistance decreases as the metal film area ratio increases. From these results, it is difficult to detect the thickness of the metal film by the inter-electrode resistance value, but if there is a region without the metal film between the electrodes, the thickness of the metal film can be easily detected by the inter-electrode resistance. A portion of the semiconductor wafer where the metal film is completely removed by polishing is a scribe line. By taking the inter-electrode distance longer than the distance between the scribe lines (that is, the chip width) and measuring the inter-electrode resistance value, the presence or absence of a metal film on the scribe line of the semiconductor wafer can be detected. Therefore, it is considered that the presence or absence of the metal film on the scribe line is representative of the state of the metal film on the semiconductor wafer, and the end of polishing can be determined by detecting the presence or absence of the metal film on the scribe line.

This will be further described with reference to FIG. 5 regarding the positional relationship between the electrodes arranged in a grid and the chips of the semiconductor wafer in which the distance between the electrodes is longer than the width of the chips on the semiconductor wafer. In FIG. 5, 1a is a chip formed on the semiconductor wafer 1, and 1b is a scribe line between the chips 1a. Reference numerals 22 (a to i) denote electrodes arranged in a grid on the polishing head. The resistance measured at the electrode a is determined by the resistance between the eight electrodes b to i around the electrode a. For example, the electrodes a, b, d, f, and h have the same potential, the electrodes c, e, g, and i have the same potential, and there is a potential difference between the electrodes a and c. Considering the case where the metal film 1c remains between the electrodes a in this case,
Is lower than the resistance values of the other electrodes, and it can be determined that the metal film 1c remains.
Further, by sequentially measuring the resistance value between the pair of electrodes, the presence or absence of the metal film 1c on the scribe line 1b between the pair of electrodes can be detected ignoring the influence of the other metal films. Therefore, the resolution of the measurement can be increased as compared with the case where the presence or absence of the metal film is detected by a large number of electrodes.

As described above, as the polishing of the metal film on the surface to be polished of the semiconductor wafer progresses, the distance between the electrodes is formed to be longer than the width of the chip of the semiconductor wafer, and the resistance between the electrodes arranged in a grid is formed. Changes as shown in FIG. Therefore, when the resistance value between at least one electrode exceeds a desired set resistance value, there is no metal film on the scribe line on the semiconductor wafer, and the presence or absence of the metal film on the scribe line is determined by the presence of the metal film on the semiconductor wafer. As a representative of the state, it can be determined that the metal film on the surface to be polished of the semiconductor wafer has disappeared, and polishing is terminated at that point.

After the polishing, the semiconductor wafer 1 is removed from the wafer chuck 2 by means not shown, and the polishing process is completed.

As described above, the presence or absence of the metal film on the scribe line is detected by the resistance value between the electrodes formed so that the distance between the electrodes is longer than the width of the chip, and at least one resistance value between the electrodes is set to a desired set resistance value. Is determined, the presence or absence of the metal film on the scribe line of the semiconductor wafer is represented as the state of the metal film on the semiconductor wafer, and the presence or absence of the metal film on the polished surface of the semiconductor wafer is detected. By finishing the polishing at this point, the metal film can be removed by polishing and a sufficient metal material can be left in the wiring groove.

Further, since the polishing liquid is interposed between the electrode and the surface to be polished of the semiconductor wafer, even if foreign matter such as polishing debris is present between the electrode and the semiconductor wafer, conduction is not hindered.
The interelectrode resistance can be measured stably. Also,
Since the electrodes are located in the through-holes of the polishing pad, the resistance between the electrodes can be detected without contacting the semiconductor wafer and without damaging the polished surface of the semiconductor wafer. Furthermore, since the presence or absence of the metal film on the surface to be polished of the semiconductor wafer can be detected during polishing, the metal film of the semiconductor wafer, particularly, the metal material in the wiring groove is not excessively removed.

(Second Embodiment) Next, a second embodiment of the polishing apparatus of the present invention will be described with reference to FIG. This embodiment is different from the above-described first embodiment in the method of determining the polishing end point. Other configurations are the same as those of the above-described embodiment. The description will be made with reference to FIGS. 1 and 2 using the same reference numerals.

In the first embodiment described above, the presence or absence of a metal film on a scribe line of a semiconductor wafer is used as a representative value of the presence or absence of a metal film on a semiconductor wafer, and at least one inter-electrode resistance value is a desired set resistance value. Is determined to be the polishing end point. However, depending on the conditions, this may not be the case. For example, even if it is detected that the metal film on the scribe line of the semiconductor wafer is polished and removed, there may be a case where an extra metal film still remains in the chip of the semiconductor wafer. Therefore, in this embodiment, the metal film on the surface to be polished of the semiconductor wafer can be surely removed.

In this embodiment, in addition to the polishing apparatus described in the first embodiment, a means for measuring a polishing time is further provided, and at least one inter-electrode resistance value is set to a desired value from the start of polishing. The time T required to exceed the set resistance value is measured, and the polishing is continued from that time until the time elapses αT obtained by multiplying the elapsed time T by a predetermined coefficient α. Then, it is determined that the metal film on the surface to be polished of the semiconductor wafer 1 is gone, and the polishing is terminated. Here, the coefficient α is the specific resistance of the polishing liquid, the distance between the polished surface of the polishing pad 5 and the polished surface of the semiconductor wafer 1,
This is a value set in advance in consideration of the specific resistance of the metal film on the surface to be polished of the semiconductor wafer 1, and is set in the range of 0 <α <1/5.

At the time of polishing according to this embodiment, similarly to the above-described embodiment, a voltage is applied between arbitrary electrodes by the electric signal processing means 24, and a current value flowing between the electrodes is measured. From the current value, the combined resistance value of the polishing liquid around each electrode and the metal film on the polished surface of the semiconductor wafer is detected as the inter-electrode resistance value. This resistance value changes as shown in FIG. 7 as polishing proceeds. In the above-described embodiment, when at least one inter-electrode resistance value exceeds a desired set resistance value, it is determined that polishing is completed, but in the present embodiment, at least one inter-electrode resistance value is a desired setting value. At the time when αT time has elapsed from the time when the resistance value is exceeded, it is determined that the metal film on the surface to be polished of the semiconductor wafer has disappeared, and the polishing is terminated. That is, the polishing is further performed for a time equal to or less than １ ／ of the time T required for the polishing from the time when at least one inter-electrode resistance exceeds a desired set resistance.

As described above, in this embodiment, the metal film on the scribe line of the semiconductor wafer can be polished and removed, and the excess metal film in the chip of the semiconductor wafer can be surely polished and removed.

[0045]

As described above, according to the present invention,
A plurality of electrodes are arranged on the surface of the polishing head that holds the polishing pad so that the distance between the electrodes is longer than the chip width on the semiconductor substrate, and when polishing the semiconductor substrate with a polishing liquid interposed, By applying a voltage between the electrodes, the presence or absence of a metal film on the scribe line of the semiconductor substrate is detected, and the presence or absence of the metal film on the scribe line of the semiconductor substrate is representative of the state of the metal film on the semiconductor substrate. By judging that at least one inter-electrode resistance value exceeds a desired set resistance value, the presence or absence of a metal film on the surface to be polished of the semiconductor substrate is detected, and that time is regarded as the polishing end time. This makes it possible to detect the presence or absence of the metal film on the surface to be polished during the polishing of the semiconductor substrate, to polish and remove the metal film, and to leave a sufficient metal material in the wiring groove.

Further, a point in time at which at least one inter-electrode resistance value exceeds a desired set resistance value and a predetermined time has elapsed from the time point is detected and the polishing end point is detected. Can be reliably removed by polishing, and a sufficient metal material can be left in the wiring groove.

Further, since the polishing liquid is interposed between the electrode and the surface to be polished of the semiconductor substrate, even if foreign matter such as polishing debris exists between the electrode and the semiconductor substrate, conduction is not hindered, and the resistance value between the electrodes is stabilized. As a result, since the electrodes do not contact the semiconductor substrate, the presence or absence of a metal film can be detected without damaging the polished surface of the semiconductor substrate.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a semiconductor substrate polishing apparatus according to the present invention.

FIGS. 2A and 2B show the configuration of a polishing head in a semiconductor substrate polishing apparatus according to a first embodiment of the present invention, wherein FIG. 2A is a schematic cross-sectional view and FIG.

FIG. 3 is a table showing a correlation between a metal film thickness and a resistance value between electrodes.

FIG. 4 is a table showing a correlation between a metal film area ratio and a resistance value between electrodes.

FIG. 5 is an explanatory diagram showing a positional relationship between electrodes and chips on a semiconductor wafer.

FIG. 6 is a table for explaining a method of detecting a polishing end point in the first embodiment of the semiconductor substrate polishing apparatus of the present invention.

FIG. 7 is a chart for explaining a method of detecting a polishing end point in a second embodiment of the semiconductor substrate polishing apparatus of the present invention.

FIG. 8 is a process diagram illustrating a dual damascene process.

FIG. 9 is a schematic diagram illustrating a polishing end point detecting means in a conventional polishing apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 semiconductor wafer (semiconductor substrate) 1a chip 1b scribe line 1c metal film 2 wafer chuck 3 rotation drive unit 4 swing drive unit 5 polishing pad 6 polishing head 7 rotation drive unit 8 vertical drive unit 9 transfer unit 10 container 11 conditioning tool DESCRIPTION OF SYMBOLS 12 Driving means 21 Through-hole 22 Electrode 24 Electric signal processing means 25 Small hole (for supplying polishing liquid) 26 Polishing liquid supply pipe 30 Electric wire

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) B24B 37/00 B24B 37/00 K 37/04 37/04 K 49/10 49/10 F term (reference) 3C034 AA19 BB92 CA02 CB01 DD01 3C058 AA07 AA09 AA19 BA01 BA09 BB02 BC01 BC02 CA01 CB05 DA12 DA17

Claims (3)

[Claims] A substrate chuck for holding a semiconductor substrate;
A polishing head having at least one or more polishing liquid supply holes, a polishing pad held by the polishing head and having a through hole in a portion corresponding to the polishing liquid supply holes, and a method of polishing a semiconductor substrate. Means for contacting the polishing surface of the polishing pad with the surface to be polished of the semiconductor substrate held by the substrate chuck or facing the polishing pad at a distance of 100 μm or less, wherein the surface to be polished contains copper or aluminum. In a polishing apparatus for polishing a semiconductor substrate having a metal film, a plurality of electrodes are disposed on a surface side of the polishing head that holds a polishing pad such that a distance between the electrodes is longer than a chip width on the semiconductor substrate. A means for measuring a resistance value between each electrode when polishing a semiconductor substrate while providing a through hole at a portion corresponding to the electrode in the polishing pad, Means for determining that the interelectrode resistance exceeds a preset value, and terminating polishing of the semiconductor substrate when at least one interelectrode resistance exceeds the preset value. Polishing equipment. 2. A substrate chuck for holding a semiconductor substrate,
A polishing head having at least one or more polishing liquid supply holes, a polishing pad held by the polishing head and having a through hole in a portion corresponding to the polishing liquid supply holes, and a method of polishing a semiconductor substrate. Means for contacting the polishing surface of the polishing pad with the surface to be polished of the semiconductor substrate held by the substrate chuck or facing the polishing pad at a distance of 100 μm or less, wherein the surface to be polished contains copper or aluminum. In a polishing apparatus for polishing a semiconductor substrate having a metal film, a plurality of electrodes are disposed on a surface side of the polishing head that holds a polishing pad such that a distance between the electrodes is longer than a chip width on the semiconductor substrate. Means for providing a through hole at a portion corresponding to the electrode in the polishing pad, and measuring a resistance value between the electrodes when polishing the semiconductor substrate; and a polishing time. Means for measuring, and means for determining that the measured inter-electrode resistance value exceeds a preset value, wherein at least one of the inter-electrode resistance values exceeds a preset value, and is required to be used from then on. A polishing apparatus for polishing a semiconductor substrate, wherein the polishing of the semiconductor substrate is terminated when a time equal to or less than 1/5 of the time has elapsed. 3. The semiconductor substrate polishing apparatus according to claim 1, wherein the measured inter-electrode resistance is a resistance between an arbitrary pair of electrodes.