JPH08339982A - Semiconductor manufacturing equipment, and manufacture of semiconductor device - Google Patents

Abstract

PURPOSE: To suppress a 'dishing phenomenon' whereby the metallic wiring of a semiconductor wafer is made thin abnormally, by sensing the termination of the polishing of its polished film through the change of a reflection light intensity. CONSTITUTION: A semiconductor wafer 20 is held by an absorption cloth 30 and a template 29, and a driving shaft 32 rotated moving up and down via a spherical seat 313 is attached to a steel board 311. In this steel board 311, a recessed portion 314 is formed, and therein, an infrared ray sensor 50 with a pair of light emission and reception portions is buried. The infrared ray emitted from the emission portion reaches the rear surface of the semiconductor wafer 20 via respective through holes 315, 316 of a ceramic board 312 and the absorption cloth 30, and is reflected by the wiring metallic film of a polished surface 201 of the semiconductor wafer 20. Further, the intensity of the reflection light projected on the light reception portion is sensed by an instrumentation circuit connected with the light reception portion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus having a function of detecting a polishing end point when polishing a metal film formed on a semiconductor wafer, and a polishing end point detecting method of a film to be polished (film to be polished). Regarding

[0002]

2. Description of the Related Art A semiconductor device such as an IC or an LSI is designed to design an integrated circuit formed on a semiconductor substrate, a mask forming process for drawing an electron beam used to form the integrated circuit, a single crystal. A wafer manufacturing process for forming a wafer of a predetermined thickness from an ingot, a wafer processing process for forming semiconductor elements such as integrated circuits on the wafer, and an assembly process and inspection for separating the wafer into individual semiconductor substrates and packaging them to form a semiconductor device. It is formed through processes and the like. A manufacturing apparatus required for each process is prepared for each process. In addition to these, equipment such as a pretreatment device and an exhaust gas treatment device, and a manufacturing device necessary for the environment are also used as the semiconductor manufacturing device. Conventionally, trenches such as trenches and contact holes in the semiconductor wafer processing process (trench)
Metal, polysilicon, silicon oxide film (SiO ₂ )
Etchback RIE (Reactive Ion Etchin) is used as a method for flattening the surface after embedding an arbitrary material such as
g) The law is known. In this etchback RIE method, the number of processes such as coating of etchback resist increases,
There are many problems because the RIE damage is likely to occur on the wafer surface, good planarization is difficult, and since a vacuum system is used, the structure is complicated and a dangerous etching gas is used.

Therefore, instead of etchback RIE,
Recently, CMP (Chemical Mechanical Polishing) method has been actively studied. Next, FIG. 9 shows a schematic cross-sectional view of a polishing apparatus for CMP used for flattening the wafer surface, and the configuration thereof will be described below. Polishing board support 2 via bearing 22 on table 21
3 are arranged. The polishing table 2 is placed on the polishing receiver 23.
4 is attached. A polishing cloth 25 for polishing the wafer is attached on the polishing board 24. A drive shaft 26 is connected to the central portions of the polishing receiver 23 and the polishing disc 24 in order to rotate them. The drive shaft 26 is rotated by a motor 27 via a rotating belt 28. On the other hand, the wafer 20 is sucked by a suction plate 31 provided with a template 29 and a suction cloth 30 by vacuum or water filling so as to come to a position facing the polishing cloth 25. The suction plate 31 is provided with a drive shaft 32.
It is connected to the. The drive shaft 32 is rotated by a motor 33 via gears 34 and 35. The drive shaft 32 is fixed to the drive base 36 with respect to vertical movement.

With such a structure, the drive table 36 moves up and down as the cylinder 37 moves up and down, whereby the wafer 20 fixed to the suction disk 31 is polished.
It is pressed against 5 or separated from the polishing cloth 25. A polishing agent is flowed between the wafer 20 and the polishing cloth 25 according to the purpose, whereby the wafer 20 is polished. Although not shown in the drawing, the wafer is moved in the XY direction (horizontal direction) by another driving system during polishing.
It is possible to move to. The polishing method itself is not a new technology, but is a technology used in the manufacturing process in the wafer manufacturing process in the above-described semiconductor device manufacturing process. Hereinafter, polishing of a semiconductor wafer by the polishing method is referred to as CMP or polishing.

Next, with reference to FIG. 10, a method of forming a conventional buried metal wiring on a semiconductor substrate using the above-described polishing apparatus will be described. The figure is a cross-sectional view of a manufacturing process of a semiconductor device including a polishing process. An interlayer insulating film 3 made of SiO ₂ and having a thickness of about 1.0 μm is formed on a semiconductor substrate 1 on which an insulating film ₂ such as SiO ₂ is formed by a normal plasma CVD method. After that, a photoresist 5 having a predetermined pattern is formed on the insulating film 3 by a normal photolithography method.
Using as a mask, the insulating film 3 is RIE-etched to form a wiring groove 4 having a predetermined pattern and a depth of 0.8 μm (FIG. 10A). Next, the photoresist 5 used for the RIE mask is formed by the ordinary O ₂ plasma ashing method.
After removing the Ti, a Ti film with a thickness of 0.1 μm was formed by the sputtering method.
A barrier metal 6 such as N / Ti is deposited on the insulating film 3. Subsequently, a wiring metal film 7 made of an aluminum alloy film such as A1-Si-C having a thickness of 1.0 μm is adhered and formed by a normal high temperature sputtering method, and a high temperature state of about 450 ° C. is set during the sputtering. Thus, the wiring metal film 7 of aluminum alloy is embedded in the wiring groove 4 (FIG. 10B).

Next, a test / test having no wiring groove pattern
Variations such as wiring groove depth, aluminum alloy film thickness, and polishing speed were taken into consideration in the just polishing time calculated based on the polishing speed previously obtained from the sample and the film thickness of the wiring metal film 7 of the aluminum alloy. A polishing time with a margin of 30% is set, and polishing of the metal film 7 for wiring of the aluminum alloy existing other than the wiring groove 4 is performed during the polishing time by the usual aluminum CMP method using the above-described polishing apparatus. Then, the aluminum-embedded wiring 8 having a predetermined pattern is completed (FIG. 10C).

[0007]

In order to realize a high-speed and highly integrated semiconductor element in which at least the minimum pattern size complies with the sub-micron rule, a metal material such as A1 or Cu is buried in a wiring groove having a predetermined fine pattern. "Embedded wiring technology" is essential. It is needless to say that the CMP method for removing the extra metal material for wiring existing other than this wiring groove is one of the important technologies for realizing this "buried wiring technology". In particular, in order to achieve a stable size / shape of the embedded wiring, the end point detection / judgment technology that detects the polishing end point when the excess portion of the wiring metal material existing other than this wiring groove is finished is important. Becomes Generally, as a polishing end point detection method,
It is well known that the rotation torque of a motor for rotating a polishing machine or a head is changed. However, combination of slurry (polishing agent) / polishing cloth, metal wiring material species (A1, Cu, W, etc.) to be polished and underlying insulating film species (plasma SiO ₂ , plasma Si ₃ N ₄ , thermal oxide SiO _2, etc.)
The magnitude of the rotational torque displacement of the motor varies depending on the combination of the above, and it also depends on the wiring groove area, but the metal wiring material remains in the wiring groove even after the polishing of the excess portion of the wiring metal material is completed. Therefore, there is a problem in that the amount of displacement of this rotational torque is very small, the detection sensitivity is low, and it is unstable (FIG. 11).

FIG. 11 is a characteristic diagram showing the dependency of the motor rotation torque on the polishing time. The vertical axis represents the motor rotation torque and the horizontal axis represents the polishing time. As shown in the figure, since there is little change in the motor rotation torque, the time when the metal material such as aluminum or barrier metal other than the wiring groove is lost cannot be clearly determined. In reality, there is no stable and effective polishing end point detection method.Therefore, as shown in the conventional example, when performing the polishing for forming the buried wiring, the polishing speed and the polishing speed previously determined by the test sample without the wiring groove pattern were used. Just polishing time is calculated based on the film thickness of the wiring metal material (A1, Cu, W, etc.), and a margin is taken into consideration in consideration of variations such as the wiring groove depth, the wiring metal material film thickness, and the polishing speed. The "time management method" that sets the added polishing time is adopted.

However, due to fluctuations in polishing speed due to variations in polishing cloth conditions, variations in wiring groove depth / metal wiring material thickness, etc., a difference occurs between the actual and calculated just polishing times, resulting in an abnormally long over time. May result in polishing. In such a case,
Due to both the chemical polishing action of the slurry and the mechanical polishing action of the polishing cloth, a so-called "dishing" phenomenon occurs in which the metal wiring thickness in the wiring groove becomes abnormally thin as shown in FIG. The figure is a partial cross-sectional view of a semiconductor substrate for explaining the dishing phenomenon. In the wiring groove 4 of the interlayer insulating film 3 formed on the semiconductor substrate 1 with the insulating film 2 interposed therebetween, the barrier metal 6 and the aluminum alloy embedded wiring 8 formed thereon are formed. The dishing amount is a / b when the depth from the surface of the interlayer insulating film 3 to the surface of the embedded wiring 8 is a and the depth from the surface of the interlayer insulating film 3 to the bottom of the wiring groove 4 is b. Represented. This dishing amount (a / b) may reach 20 to 35% of the desired embedded wiring thickness, depending on the degree of variation factors.
When the amount of dishing increases in this way, problems such as an increase in wiring resistance and a malfunction / reduction in yield due to variations, a decrease in wiring reliability (a reduction in EM life, etc.) become a problem. Therefore, at present, it is expected that an accurate method of detecting the polishing end point will appear. The present invention has been made under such circumstances, and polishing is performed when a portion other than the wiring groove of the embedded metal wiring formed to fill the wiring groove having a predetermined pattern is removed by the CMP method. An object of the present invention is to provide a semiconductor manufacturing apparatus and a semiconductor device manufacturing method capable of accurately detecting the end point.

[0010]

According to the present invention, a metal film is buried in a wiring groove having a predetermined depth and pattern formed in an insulating film on a semiconductor substrate by a normal high temperature sputtering method, and then the metal film is formed. When forming an embedded wiring by removing unnecessary portions formed other than the wiring groove by polishing, the semiconductor substrate holding mechanism of the polishing apparatus transmits at least the semiconductor substrate and the insulating film and is reflected by the metal film surface. Infrared rays are emitted from the back surface of the semiconductor substrate, and the polishing end point of the metal film is detected by the displacement of the reflected light intensity. In the semiconductor manufacturing apparatus of the present invention, a polishing plate having a polishing cloth attached to the surface thereof, a first drive means having a first drive shaft for rotating the polishing plate, and a polishing film made of a metal film are provided on the main surface. A suction plate having a suction cloth for fixing the formed semiconductor wafer, a second drive means having a second drive shaft for rotating the suction plate, a light emitting section for irradiating the semiconductor wafer with infrared rays, and the semiconductor. An infrared sensor having a light receiving section for receiving the reflected light of the infrared light reflected by the wafer, and a reflected light measuring means for measuring the intensity of the reflected light are provided, and the polishing of the film to be polished is performed by the change of the reflected light intensity. It is characterized by detecting the end point of.

The infrared sensor is attached to the suction plate, and the infrared light emitted from the light emitting portion enters from the back surface of the semiconductor wafer, passes through the semiconductor wafer, and is polished on the main surface. It may be reflected by. The infrared sensor attached to the suction plate faces a field area where a metal film is not formed, such as an electrode pad, a capacitor, and a power line formed on the semiconductor wafer when the semiconductor wafer is attached to the suction cloth. You may be allowed to.
A plurality of the infrared sensors may be attached to the suction plate. When the semiconductor substrate is a silicon semiconductor, the infrared wavelength is 2.5 μm.
You may make it m or more.

The method of manufacturing a semiconductor device according to the present invention is
The step of polishing the semiconductor wafer surface on which the film to be polished is formed by rotating the semiconductor wafer formed through the stopper film for stopping the polishing, and the step of polishing the semiconductor wafer surface during the polishing of the semiconductor wafer surface. The step of irradiating infrared rays from the back surface of the wafer, the step of detecting the reflected light intensity of the infrared rays reflected by the film to be polished of the semiconductor wafer, and the change of the reflected light intensity due to the exposure of the stopper film to the film to be polished Is detected. The polishing target film formed on the semiconductor wafer is made of Al, Cu, Au, T
A metal material selected from i and their alloys is used.

[0013]

[Function] By detecting the polishing end point from the displacement of the reflected light intensity, proper polishing is always ensured regardless of unstable factors such as variations in polishing cloth condition, and abnormal dishing phenomenon is suppressed. Realizes highly stable embedded wiring.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment will be described with reference to FIGS. 1 is a cross-sectional view of a semiconductor device manufacturing process including a polishing step, FIG. 2 is a cross-sectional view of a suction plate holding a semiconductor substrate of a semiconductor manufacturing device having the polishing device shown in FIG. 9 as a basic structure, and FIG. A partially enlarged view of the suction cup of FIG.
4 is a plan view of the suction cup shown in FIG. 2, FIG. 5 is a characteristic diagram showing the polishing time dependence of infrared reflection intensity, and FIG.
[FIG. 3] is a partial cross-sectional view of a semiconductor substrate illustrating a dishing phenomenon. For example, on the semiconductor substrate 1, an insulating film 2 made of SiO ₂ is formed, for example, an interlayer insulating film 3 made of SiO ₂ having a thickness of about 1.0μm by a plasma CVD method. After that, a photoresist 5 having a predetermined pattern is formed on the insulating film 3 by a normal photolithography method, and the insulating film 3 is etched by, for example, RIE using the photoresist 5 as a mask to form a deep layer having a predetermined pattern. A wiring groove 4 having a thickness of 0.8 μm is formed (FIG. 1A). Next, the photoresist 5 used for the RIE mask is removed by a normal O ₂ plasma ashing method, and then a TiN / T film having a thickness of 0.1 μm is formed by a sputtering method.
A barrier metal 6 such as i is deposited on the insulating film 3.

Then, a wiring metal film 7 of aluminum alloy such as A1-Si-Cu having a thickness of 1.0 μm is formed by a normal high temperature sputtering method, and a high temperature state of about 450 ° C. is set during the sputtering. Thus, the wiring metal film 7 of aluminum alloy is embedded in the wiring groove 4 (FIG. 1B). Next, the semiconductor substrate 1 in which the aluminum alloy film of Al—Si—Cu is embedded as a wiring metal film in the wiring groove 4 having a predetermined depth and pattern is provided to the semiconductor substrate holding mechanism 40 of the polishing apparatus and the wiring metal film 7 ( It is installed so that the adherend surface (see FIG. 1B) is pressed against the polishing cloth surface. The semiconductor substrate holding mechanism 40 includes a steel plate 311 such as SUS and a ceramic plate 31 such as alumina.
It is composed of a suction plate 31 composed of two, a template (support ring) 29 provided on the surface of the ceramic plate 312, and a suction cloth 30. The semiconductor wafer 20 is held by the suction cloth 30 and the template 29, and the steel disk 311 is provided with a drive shaft 32 that moves in the vertical direction and rotates via a ball seat 313. A recess 314 is formed in the steel plate 311, and the infrared sensor 50 is embedded in the recess.

The infrared sensor 50 has a pair of a light emitting portion and a light receiving portion. The infrared light emitted from the light emitting portion passes through the through hole 315 of the ceramic board 312 and the through hole 316 of the suction cloth 30 made of urethane or the like. Reach the back surface of the semiconductor wafer 20, pass through the semiconductor wafer 20 and the insulating film 3 on the semiconductor wafer 20, and are reflected by the wiring metal film 7 on the polished surface 201 of the semiconductor wafer 20.
The reflected light passes through the insulating film 3, the semiconductor wafer 20, and the through holes 315 and 316 and is received by the light receiving portion of the infrared sensor 50. The intensity of the reflected light incident on the light receiving portion is detected by a measuring circuit (not shown) connected to this light receiving portion (FIGS. 2 and 3). The infrared ray needs to have a wavelength of 2.5 μm or more so that it can be transmitted through at least the silicon semiconductor substrate and the insulating film and reflected by the metal film surface for wiring. The infrared sensor 50 and the measuring circuit constitute a polishing end point detecting mechanism. The semiconductor substrate holding mechanism 40 pushes the held semiconductor wafer 20 against the polishing platen 24 so that the wiring metal film 7 is in contact with the polishing cloth 25, so that the wiring metal film 7 deposited in the areas other than the wiring groove 4 is removed. Polished until it is gone.

As shown in FIG. 4, in this embodiment, the infrared sensors 50 are attached to nine places on the steel plate. The installation position and installation of the infrared sensor 50 so that the polishing end point mechanism does not detect the polishing end point even if the wiring metal film 7 is left outside the wiring groove 4 or the over polishing causes the polishing end point to be detected. You have to decide the number properly. In order for the polishing end point mechanism to properly determine the polishing end point, one infrared sensor or more infrared sensors may be installed. Further, the infrared sensor 50 is randomly arranged so as not to face the wiring groove 4, and is arranged so as to face a field region where a metal film is not formed such as an electrode pad, a capacitor, and a power supply line formed on the semiconductor wafer. Are needed to accurately detect the polishing endpoint.
FIG. 4 is a plan view of the semiconductor substrate holding mechanism 40, in which nine infrared sensors 50 are randomly arranged. A semiconductor wafer (not shown) is provided on the surface of the ceramic plate 312.
Is formed with a groove 38 for holding a vacuum chuck. The polishing end point mechanism monitors the infrared reflection intensity, and when the infrared reflection intensity changes (point P).
Is determined as the polishing end point.

In FIG. 5, the vertical axis represents infrared reflection intensity and the horizontal axis represents polishing time. Polishing end point (P
At the point), the wiring metal film outside the wiring groove disappears, and infrared rays pass through the semiconductor wafer. The polishing in this embodiment was performed using a colloidal silica-based slurry (concentration 5).
%, PH 9.0) and a non-woven polishing cloth, semiconductor holding mechanism / polishing plate rotation speed = 100/120 rpm-pressurization =
300 / cm ² −Slurry flow rate = 100 ml / min. When the infrared reflection intensity monitored by the polishing end point detection mechanism becomes 7 points out of 9 points as shown in the figure, the polishing end point of this polishing is set, and 25% of overpolishing is based on this. By doing so, the aluminum-embedded wiring 8 having a predetermined pattern is completed (FIG. 1C). The interlayer insulating film 3 having the wiring groove 4 formed therein serves as a stopper film for polishing.

In the embodiment of the present invention, as shown in FIG. 6, the dicing phenomenon is remarkably reduced by proper overpolishing, and the dicing amount is about 50n in steps.
m, which is about 6.3% of the thickness of the embedded metal wiring, and is 10% or less of the thickness of the embedded metal wiring in consideration of the variation in the semiconductor substrate / in the lot / between lots. This can be significantly reduced by about 1/3 to 1/2 of the conventional one. As a result, since it is possible to suppress an increase in wiring resistance and an increase in variation, it is possible to easily improve wiring reliability such as yield and EM life. The figure is a partial cross-sectional view of a semiconductor substrate for explaining the dishing phenomenon. In the wiring groove 4 of the interlayer insulating film 3 formed on the semiconductor substrate 1 with the insulating film 2 interposed therebetween, the barrier metal 6 and the aluminum alloy embedded wiring 8 formed thereon are formed. The dishing amount is a depth from the surface of the interlayer insulating film 3 to the surface of the embedded wiring 8 is a.
And the depth from the surface of the interlayer insulating film 3 to the bottom of the wiring groove 4 is represented by b / a. Although this dishing amount (a / b) depends on the degree of the variation factor, it can be suppressed to 10% or less of the desired embedded wiring thickness in this embodiment.

Next, a second embodiment will be described with reference to FIGS. 7 and 8. In this embodiment, C is embedded in the embedded metal wiring.
u is used. Recently, this CMP technique has begun to be used in a manufacturing process of a highly integrated device, and the present invention can be applied to this process. CVD-SiO on the semiconductor substrate 1
_{The 2} insulating film 2 and the plasma SiO ₂ insulating film 3 are successively formed (FIG. 7A). Next, the plasma SiO ₂ insulating film 3 is patterned to form a groove portion 4 at a predetermined position (FIG. 7B). A wiring metal film (Cu film) 7 is laminated in the groove 4 and on the entire surface of the plasma SiO ₂ insulating film 3 (FIG. 7).
(C)). Next, the Cu film 7 is polished using the plasma SiO ₂ insulating film 3 as a stopper film. Plasma Si
When the O ₂ insulating film 3 is exposed, the polishing of the Cu film 7 is completed so that the Cu film is embedded only in the groove portion 4 and the embedded wiring 8 of the Cu film is formed (FIG. 8).
(A)). By this polishing, the surface of the semiconductor substrate 1 is flattened, and the subsequent formation of the second-layer plasma SiO ₂ insulating film 9 is facilitated (FIG. 8B). The planarization by this CMP method also facilitates the formation of the second and third electrode wirings (not shown). In the CMP method used for manufacturing such a highly integrated device, the effective polishing endpoint detection method of the present invention is used.

In the present embodiment, plasma-SiO ₂ and Al-Si-Cu or Cu were used as the base insulating film and the wiring metal material, but if the predetermined insulation performance and the performance as the metal wiring are satisfied, the plasma Si ₃ N ₄ , Au, W
Other materials such as alloys may also be used, and the depth of the wiring groove formed in the underlying insulating film and the film thickness of the deposited wiring metal material may not be the values shown in the embodiments. When the Si ₃ N ₄ insulating film is used as the stopper film and aluminum or its alloy is used as the wiring metal film, the polishing ratio (Al / Si ₃
N ₄ ) is as large as 200 to 700, but it is not preferable because the parasitic capacitance becomes large. When SiO ₂ is used as the stopper film, the polishing ratio (Al / SiO ₂ ) is 30 to 4
Although not so large as 0, it is useful as a stopper film because the parasitic capacitance is not large. Further, in the semiconductor substrate holding mechanism, a polishing end point detecting mechanism having a pair of an infrared ray emitting portion and a light receiving portion is arranged at 9 points so as not to be influenced by a specific wiring groove pattern. If not, at least one or more points may be installed.

Further, the polishing end point is a point of time when 7 points out of the 9 points of the polishing end point detecting mechanism arranged so that the semiconductor substrate holding mechanism is not affected by a specific wiring groove pattern, indicating the end of displacement. Even when a plurality of end point detection mechanisms are installed in the semiconductor substrate holding mechanism, the polishing end point may be a time point when at least one point shows a displacement change as long as there is no process defect.
Further, the displacement end point as shown in FIG. 5 where the infrared reflection intensity monitored by the polishing end point detection mechanism is determined to be the polishing end point, but if there is no process defect, the displacement start point also indicates the displacement progress point. It goes without saying that arbitrary points are also acceptable. The infrared ray used in the polishing end point detecting mechanism of the present invention may have a wavelength of 2.5 μm or more so that it can penetrate at least the silicon semiconductor substrate and the insulating film such as SiO ₂ , Si ₃ N ₄ .

[0023]

According to the present invention, a metal wiring material is deposited on a wiring groove having a predetermined depth and a pattern formed in an insulating film layer on a semiconductor substrate and embedded in the wiring groove. When removing an unnecessary portion other than the wiring groove by polishing to form a buried wiring, infrared rays transmitted from at least the semiconductor substrate and the insulating film and reflected by the metal wiring film surface from the semiconductor substrate holding mechanism of the polishing apparatus are removed. By emitting light through the semiconductor substrate and detecting the polishing end point of the metal wiring film by the displacement of its reflection intensity, it is possible to always ensure proper overpolishing regardless of instability factors such as variations in polishing cloth conditions. It realizes embedded wiring with high stability of size and shape by suppressing various dicing phenomena. As a result, since it is possible to suppress an increase in wiring resistance and an increase in variation, it is possible to easily improve wiring reliability such as yield and EM life.

[Brief description of drawings]

FIG. 1 is a sectional view of a manufacturing process of a semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a suction plate holding a semiconductor substrate of the polishing apparatus of the present invention.

3 is a partially enlarged view of the suction plate and the polishing plate of FIG.

FIG. 4 is a plan view of the suction plate shown in FIG.

FIG. 5 is a characteristic diagram showing the polishing time dependence of the infrared reflection intensity of the present invention.

FIG. 6 is a partial cross-sectional view of a semiconductor substrate illustrating a dishing phenomenon of the present invention.

FIG. 7 is a cross-sectional view of the manufacturing process of the semiconductor device of the second embodiment.

FIG. 8 is a cross-sectional view of the manufacturing process of the semiconductor device of the second embodiment.

FIG. 9 is a polishing apparatus according to the present invention and a conventional polishing apparatus.

FIG. 10 is a sectional view of a conventional semiconductor device manufacturing process.

FIG. 11 is a characteristic diagram showing the polishing time dependence of the conventional infrared reflection intensity.

FIG. 12 is a partial cross-sectional view of a semiconductor substrate illustrating a conventional dishing phenomenon.

[Explanation of symbols]

1 ... Semiconductor substrate, 2, 3, 9 ... Insulating film,
4 ... Wiring groove, 5 ... Photoresist, 6.
..Barrier metal, 7 ... Wiring metal film, ...
・ Embedded wiring, 20 ・ ・ ・ Semiconductor wafer, 21
... Stand, 22 ... Bearing, 23 ... Polishing disk receiver, 24 ... Polishing disk, 25 ... Polishing cloth, 26 ... Drive shaft, 27, 33 ... Motor, 28 ... ..Rotary belts, 29 ... Templates, 30 ... Suction cloths, 31 ... Suction boards,
32 ... drive shaft, 34, 35 ... gear,
36 ... Drive base, 37 ... Cylinder, 38 ...
・ Vacuum chuck groove, 40 ... Semiconductor substrate holding mechanism, 50 ... Infrared sensor, 201 ... Polished surface, 311 ... Steel plate, 312 ...
・ Ceramic board, 313 ... Ball seat, 314 ...
Recesses, 315, 316 ... Through holes, 501 ... Light emitting portion, 502 ... Light receiving portion

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[Procedure amendment]

[Submission date] September 7, 1995

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

[Figure 4]

Claims (7)

[Claims] 1. A polishing disk having a polishing cloth attached to the surface thereof, a first drive means having a first drive shaft for rotating the polishing disk, and a polishing film made of a metal film formed on the main surface. A suction plate having a suction cloth for fixing the semiconductor wafer, a second drive means having a second drive shaft for rotating the suction plate, a light emitting unit for irradiating the semiconductor wafer with infrared light, and a reflection by the semiconductor wafer. Infrared sensor having a light receiving section for receiving the reflected light of the infrared ray, and a reflected light measuring means for measuring the intensity of the reflected light, the end point of the polishing of the polishing target film by the change in the reflected light intensity. A semiconductor manufacturing apparatus characterized by detecting. 2. The infrared sensor is attached to the suction plate, and the infrared light emitted from the light emitting portion is incident on the back surface of the semiconductor wafer, passes through the semiconductor wafer, and is formed on the main surface thereof. The semiconductor manufacturing apparatus according to claim 1, which is reflected by a film to be polished. 3. The infrared sensor attached to the suction plate is an electrode pad formed on the semiconductor wafer when the semiconductor wafer is attached to the suction cloth.
3. The capacitor according to claim 2, which is opposed to a field region where a metal film is not formed, such as a capacitor and a power line.
The semiconductor manufacturing apparatus according to. 4. The semiconductor manufacturing apparatus according to claim 2, wherein a plurality of the infrared sensors are attached to the suction plate. 5. The semiconductor manufacturing apparatus according to claim 1, wherein, when the semiconductor substrate is a silicon semiconductor, the wavelength of the infrared rays is 2.5 μm or more. 6. A step of rotating a semiconductor wafer having a film to be polished through a stopper film for stopping polishing to polish the surface of the semiconductor wafer having the film to be polished, and a step of polishing the surface of the semiconductor wafer. A step of irradiating infrared rays from the back surface of the semiconductor wafer during polishing, a step of detecting the reflected light intensity of the infrared rays reflected by the film to be polished of the semiconductor wafer, and a change in the reflected light intensity due to the exposure of the stopper film. The method for manufacturing a semiconductor device is characterized by detecting the polishing end point of the film to be polished from. 7. The semiconductor device according to claim 6, wherein the film to be polished formed on the semiconductor wafer is made of a metal material selected from Al, Cu, Au, Ti and alloys thereof. Manufacturing method.