JP3291946B2 - Chemical mechanical polishing apparatus and chemical mechanical polishing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to chemical mechanical polishing (Chemical mechanical polishing) suitable for use in flattening a substrate surface such as a semiconductor wafer by a combination of chemical polishing and mechanical polishing.
MechanicalPolishing (CMP) equipment and chemical machinery
It relates to a polishing method .

[0002]

2. Description of the Related Art With the increase in the density of semiconductor devices, the wiring technology of circuit boards has been increasingly miniaturized and multilayered. However, the progress of such high integration also causes a reduction in the reliability of the device itself. The reason is that the step of the interlayer insulating film becomes large and steep due to the progress of miniaturization and multilayering of the wiring, and the processing accuracy and reliability of the wiring formed thereon are significantly reduced. For this reason, under the current situation where the step coverage of the aluminum wiring cannot be significantly improved, it is urgently necessary to improve the flatness of the interlayer insulating film. Various techniques such as a coating method, a reflow method, an etching method, a PVD method, and a CVD method have been disclosed as techniques for forming and planarizing an interlayer insulating film.
When applied to multi-layered wiring layers, improvement in connection failure between wirings has become an important theme due to lack of flatness when wiring spacing is wide, voids in interlayer films at wiring spacings, and the like. . Therefore, as a means for solving such inconvenience, recently, a chemical mechanical polishing method applying mirror polishing of a silicon wafer has been proposed, and this method is regarded as promising as a technique capable of globally flattening the wafer surface.

FIG. 2 is a schematic side view showing the structure of a conventional chemical mechanical polishing apparatus. Conventional chemical mechanical polishing equipment,
A rotatable polishing table 31, and the polishing table 31
A polishing cloth 32 stretched on the surface of the substrate, and a substrate holder 33 rotatably provided facing the polishing table 31.
And a supply nozzle 35 for supplying an abrasive (slurry) 34 to the polishing cloth 32. A substrate 36 such as a wafer serving as a workpiece is held on the lower end surface of the substrate holding unit 33, and the polishing table 31 and the substrate holding unit 33 are rotated by a polishing pressure adjuster (not shown) in a state where they are rotated. It is pressed against the polishing cloth 32 on the table. As a result, the lower surface (processed surface) of the substrate 36 is polished flat by both the chemical polishing action by the alkali in the polishing agent 34 and the mechanical polishing action by the silica.

[0004]

However, in the above-described conventional apparatus, since the abrasive 34 is supplied from the supply nozzle 35 provided next to the substrate holder 33, the abrasive 34 is excessively supplied to the peripheral portion of the substrate 36. Therefore, there is a problem that the abrasive 34 cannot be sufficiently spread to the central portion of the substrate 36. Therefore, an apparatus that solves such a problem has been proposed by the present applicant. This is an apparatus disclosed in Japanese Patent Application Laid-Open No. Hei 5-13389, which employs a configuration as shown in FIG. That is, a plurality of abrasive supply holes 43 are formed in a polishing cloth 42 stretched on the surface of the polishing table 41, and the abrasives are supplied from the polishing table 1 side through the abrasive supply holes 43 as shown by arrows in the drawing. Is to supply.

However, in the chemical mechanical polishing apparatus shown in FIG. 3, the polishing agent supplied to the central portion A of the substrate is
Since it is diffused toward the peripheral portion B of the substrate, it is difficult to uniformly control the polishing rate at the substrate central portion A and the polishing speed at the substrate peripheral portion B.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has a polishing table having a polishing cloth stretched on a surface thereof, and a rotatably supported state facing the polishing table. And a substrate holding mechanism for holding the substrate in the substrate holding portion and pressing the processing surface of the substrate against the surface of the polishing table via the polishing cloth, and a substrate holding mechanism. An abrasive supply system having a plurality of abrasive supply holes, supplying an abrasive from the polishing table side through the abrasive supply holes, and an abrasive discharge hole formed in the polishing cloth corresponding to the abrasive supply holes And an abrasive discharging system for discharging the abrasive to the polishing table side through the abrasive discharging hole. The present invention also provides a
Can be rotated while facing the polishing table on which the cloth is stretched
The substrate is held by the substrate holding section supported by the
Press the working surface to the surface of the polishing table via the polishing cloth,
Polishing tape is passed through a plurality of polishing agent supply holes formed in the polishing cloth.
Supply abrasive from the cable side and rotate the substrate holder
In the chemical mechanical polishing method, the polishing
The polishing table side through the abrasive discharge hole drilled in the polishing cloth
So that the abrasive is discharged.

[0007]

In the chemical mechanical polishing apparatus according to the present invention, the abrasive supplied from the polishing table side to the surface of the polishing cloth through the abrasive supply hole is used to polish the abrasive provided in correspondence with the abrasive supply hole. Since the substrate is discharged to the polishing table through the discharge holes, diffusion of the abrasive from the central portion to the peripheral portion of the substrate is suppressed. In addition, the chemical mechanical polishing method of the present invention
Through a plurality of abrasive supply holes formed in the polishing cloth.
While supplying the abrasive from the polishing table side.
Through the abrasive discharge holes drilled in the polishing cloth corresponding to the supply holes
By discharging the abrasive to the polishing table side, the substrate
Diffusion of abrasive from the center to the periphery
become.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a view showing the configuration of a first embodiment of a chemical mechanical polishing apparatus according to the present invention, in which (a) is a schematic plan view and (b) is a schematic side view. In FIG. 1, reference numeral 1 denotes a polishing table, and the surface (upper surface) of the polishing table 1 is formed with a very high degree of flatness because it serves as a reference surface during polishing. On the surface of the polishing table 1, a polishing cloth 2 made of, for example, artificial leather is stretched. On the other hand, above the polishing table 1, a substrate holding unit 4 rotatably supported by a rotating shaft 3 is provided. This substrate holding unit 4
Is for holding the substrate 5 at the lower end surface thereof by, for example, an attraction force by evacuation, and is arranged so as to face the polishing table 1 as shown in FIG.

Here, in the apparatus configuration of the present embodiment, a plurality of abrasive supply holes 6 are formed in the polishing pad 2 stretched on the polishing table 1. These abrasive supply holes 6
This is for supplying an abrasive to the surface (upper surface) of the polishing cloth 2, and is arranged concentrically with respect to the rotation center of the substrate holder 3, for example, as shown in the figure. Each of the abrasive supply holes 6 is provided with an abrasive supply passage 7 formed on the polishing table 1 side.
Are in communication with each other. The abrasive sent from an abrasive supply unit (not shown) is supplied to the surface of the polishing pad 2 from the abrasive supply hole 6 through the abrasive supply passage 7 as shown by an arrow in the figure. .

Further, as described above, the abrasive supply system including the abrasive supply hole 6, the abrasive supply passage 7, and the abrasive supply section (not shown) is composed of a plurality of systems (three systems in the illustrated example). In addition, each system has an abrasive supply hole 6 arranged concentrically with respect to the rotation center of the substrate holding portion 4.
Each is provided in an independent form. In other words, the first abrasive supply path and the abrasive supply section (not shown) are connected to the abrasive supply holes 6 arranged on the innermost concentric circle, and the abrasive supply holes 6 arranged on the outermost concentric circle. A second abrasive supply path and an abrasive supply unit (not shown) are connected to the hole 6, and a third abrasive supply path 7 and an abrasive supply are connected to the abrasive supply hole 6 arranged on the center concentric circle. Unit (not shown) is connected.

In addition, the polishing pad 2 is provided with the abrasive supply holes 6.
For example, a plurality of abrasive discharge holes 8 are formed in an alternate arrangement with the abrasive supply holes 6. These abrasive discharge holes 8 are for discharging the abrasive supplied to the surface of the polishing pad 2, and are concentric with the rotation center of the substrate holding unit 3 like the above-mentioned abrasive supply holes 6. Are located. Each of the abrasive discharge holes 8 communicates with an abrasive discharge passage 9 formed on the side of the polishing table 1. Then, the abrasive supplied to the surface of the polishing pad 2 is discharged through the abrasive discharge hole 8 by the discharge operation of the abrasive discharge section (not shown) (a suction operation by vacuuming or an exhaust operation by an exhaust fan). It is taken into the passage 9 and discharged through the abrasive discharge passage 9 to a waste tank or the like.

Further, as described above, the abrasive discharge system including the abrasive discharge hole 8, the abrasive discharge passage 9, and the abrasive discharge portion (not shown) is composed of a plurality of systems (three systems in the illustrated example). In addition, each system has an abrasive discharge hole 8 arranged concentrically with respect to the rotation center of the substrate holding unit 4.
Each is provided in an independent form. That is, like the above-mentioned abrasive supply hole 6, the first abrasive discharge passage 9 and the abrasive discharge portion (not shown) are connected to the abrasive discharge hole 8 arranged on the innermost concentric circle. A second abrasive discharge passage 9 and an abrasive discharge portion (not shown) are connected to the abrasive discharge hole 6 arranged on the outermost concentric circle, and the abrasive discharge hole 8 arranged on the middle concentric circle. Are connected to a third abrasive discharge path and an abrasive supply unit (not shown).

In addition, in this embodiment, an opening / closing valve 10 is provided in the abrasive supply passage 7 of each abrasive supply system as a means for controlling the amount of the abrasive supplied from the abrasive supply hole 6. The amount of the abrasive supplied to the abrasive supply holes 6 arranged on the concentric circles can be individually controlled by appropriately adjusting the opening of the on-off valve 10. As for the abrasive discharge system, an opening / closing valve 11 is connected to the abrasive discharge passage 9 of each abrasive discharge system as a means for controlling the amount of the abrasive discharged from the abrasive discharge hole 8. The discharge amount of the abrasive from the abrasive discharge holes 8 arranged on each concentric circle can be individually controlled by appropriately adjusting the opening degree of the opening / closing valve 11.

Next, the operation of the chemical mechanical polishing apparatus according to this embodiment will be described. First, when the substrate 5 is held on the lower end surface of the substrate holding unit 4 in a state facing the polishing table 1, the abrasive (not shown) sent through the abrasive supply passage 8 is supplied from the abrasive supply hole 6 to the polishing pad. 2, that is, the interface between the substrate 5 and the polishing cloth 2 during polishing. Next, the substrate 5 held by the substrate holding unit 4 rotates with the rotation of the rotating shaft 3, and the polishing cloth 2 on the polishing table 1 is applied with a pressing force of a polishing pressure adjuster (not shown).
Is pressed against.

At this time, if it is desired to polish the central part of the substrate 5 more than the peripheral part, it is arranged on the innermost concentric circle by appropriately adjusting the opening degree of the opening / closing valve 10 in each abrasive supply system. The supply amount of the polishing agent from the polishing agent supply port 6 is set to be larger than the supply amount of the polishing agent from the polishing agent supply port 6 arranged on the outermost concentric circle.
When it is desired to polish the peripheral portion of the polishing pad more, the supply amount of the polishing agent from the polishing agent supply port 6 arranged on the outermost concentric circle by adjusting the opening degree of the opening / closing valve 10 is adjusted on the innermost concentric circle. Is set to be larger than the supply amount of the abrasive from the abrasive supply port 6 arranged in the above.

At this time, in the case of the polishing apparatus of this embodiment,
The abrasive supplied to the central portion of the substrate 5 was disposed in the abrasive discharge hole 8 disposed on the innermost concentric circle, and the abrasive supplied to the peripheral portion of the substrate 5 was disposed on the outermost concentric circle. Abrasive supplied to the innermost and outermost intermediate portions is taken into the abrasive discharge holes 8, respectively, and taken into the abrasive discharge holes 8 arranged on the concentric middle circle, from which individual abrasive discharge passages 9 are provided. Is discharged to a waste tank via the As described above, in this embodiment, not only the supply of the abrasive to the surface of the polishing pad 2 but also the discharge of the abrasive from the surface of the polishing pad 2 can be performed. Is effectively suppressed, and the polishing rate in the surface to be processed of the substrate 5 can be uniformly controlled over the entire substrate.
Further, in the present embodiment, the amount of the abrasive discharged from each of the abrasive discharge holes 8 can be independently controlled by appropriately adjusting the opening degree of the on-off valve 11 provided in each of the abrasive discharge systems. Therefore, the polishing rate in the processing surface of the substrate 5 can be finely controlled for each area.

In the structure of the above embodiment, the abrasive supply holes 6 and the abrasive discharge holes 8 are arranged alternately and concentrically with respect to the polishing pad 2. For example, various deformations such as arranging radially from the center of rotation of the substrate holding unit 4, arranging in a matrix over the entire area of the polishing cloth, and arranging regularly while changing the distance between holes for each area. An example is conceivable, and it is not particularly limited to one mode.

[0018]

As described above, according to the chemical mechanical polishing apparatus of the present invention, in addition to the polishing agent supply system for supplying the polishing agent from the polishing table side to the polishing cloth surface, the polishing machine surface Equipped with an abrasive discharge system that discharges the supplied abrasive to the polishing table side, diffusion of the abrasive from the central part of the substrate to the peripheral part is suppressed, and the polishing rate within the processing surface of the substrate is uniform. Can be controlled. Again
According to Ming's chemical mechanical polishing method, multiple
Abrasive from the polishing table side through the number of abrasive supply holes
While supplying it to the polishing pad corresponding to the abrasive supply hole.
The abrasive is discharged to the polishing table through the
Abrasive from the center to the periphery of the substrate
Is suppressed, and the polishing rate within the processing surface of the substrate is reduced.
Can be controlled uniformly. As a result, the uniformity of the polishing rate within the same substrate is greatly improved, and the polishing rate can be arbitrarily controlled for each area within the surface to be processed. And greatly contributes to improvement in reliability and yield as a semiconductor device.

[Brief description of the drawings]

FIG. 1 is a view showing a configuration of an embodiment of a chemical mechanical polishing apparatus according to the present invention.

FIG. 2 is a diagram showing a configuration of a conventional device.

FIG. 3 is a diagram showing a configuration of another conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polishing table 2 Polishing cloth 3 Rotation axis (one component of a substrate holding mechanism) 4 Substrate holding part 5 Substrate 6 Abrasive supply hole 7 Abrasive supply path 8 Abrasive discharge hole 9 Abrasive discharge path 10 Open / close valve (supply amount) 11) Open / close valve (for discharge control)

Claims (4)

(57) [Claims] 1. A polishing table having a polishing cloth stretched on a surface thereof, and a substrate holding portion rotatably supported in a state facing the polishing table, wherein the substrate holding portion holds the substrate. A substrate holding mechanism that presses the surface to be processed of the substrate to the surface of the polishing table via the polishing cloth; and a plurality of abrasive supply holes drilled in the polishing cloth. An abrasive supply system for supplying an abrasive from the polishing table side, an abrasive discharge hole formed in the polishing cloth corresponding to the abrasive supply hole, and the polishing table through the abrasive discharge hole A chemical mechanical polishing apparatus comprising: an abrasive discharge system for discharging an abrasive on a side. 2. The abrasive discharging system according to claim 1, wherein said abrasive discharging system includes means for controlling an amount of discharged abrasive.
A chemical mechanical polishing apparatus as described. 3. The abrasive discharging system according to claim 2, wherein said abrasive discharging system comprises a plurality of systems, and means for controlling the amount of the abrasive discharged is provided for each system. Chemical mechanical polishing equipment. (4) Polishing table with polishing cloth stretched on the surface
In the substrate holding part rotatably supported in a state facing the
Holding the board, The surface to be processed of the substrate is placed on the polishing table through the polishing cloth.
Press against the surface of the Through a plurality of abrasive supply holes drilled in the polishing cloth;
Supply abrasive from the polishing table side, In the chemical mechanical polishing method for rotating the substrate holding part,
hand, An abrasive drilled in the polishing cloth corresponding to the abrasive supply hole.
The abrasive is discharged to the polishing table through the abrasive discharge hole
A chemical mechanical polishing method.