JP2023141624A - Abrasive pad and polished product manufacturing method - Google Patents

Abstract

To provide an abrasive pad with excellent surface smoothness, and a polished product manufacturing method with use thereof.SOLUTION: An abrasive pad has a polishing layer, and an end point detection window provided in an opening of the polishing layer. In the abrasive pad, when a free induction attenuation curve of spin-spin relaxation of 1H, which is obtained by measuring by Solid Echo method with use of pulse NMR, is waveform-separated into three curves derived from three components of a crystal phase, an intermediate phase, and an amorphous phase in order of shorter relaxation time, a ratio of an abundance ratio Lw20 of the amorphous phase of the end point detection window to an abundance ratio Lp20 of the amorphous phase of the polishing layer (Lp20/Lw20) at 20°C is 0.5 to 2.0, and a ratio of an abundance ratio Sw80 of the crystal phase of the end point detection window to an abundance ratio Sp80 of the crystal phase of the polishing layer (Sp80/Sw80) at 80°C is 0.5 to 2.0.SELECTED DRAWING: Figure 1

Description

The present invention relates to a polishing pad and a method of manufacturing a polished product using the same.

In semiconductor manufacturing processes, chemical mechanical polishing (CMP) is used in planarization after forming an insulating film and in the process of forming metal wiring. One of the important techniques required for chemical mechanical polishing is polishing end point detection, which detects whether the polishing process is complete. For example, overpolishing or insufficient polishing with respect to the target polishing end point directly leads to product defects. Therefore, in chemical mechanical polishing, it is necessary to strictly control the polishing amount by detecting the polishing end point.

Chemical-mechanical polishing is a complex process, and the polishing rate is affected by the operating conditions of the polishing equipment, the quality of consumables (slurry, polishing pad, dresser, etc.), and variations in conditions over time during the polishing process. Change. Furthermore, in recent years, the accuracy and in-plane uniformity of residual film thickness required in semiconductor manufacturing processes have become increasingly strict. Due to these circumstances, it is becoming more difficult to detect the polishing end point with sufficient accuracy.

The main methods for detecting the polishing end point include the optical end point detection method, torque end point detection method, and eddy current end point detection method. The end point is detected by irradiating light onto the wafer through the member and monitoring the reflected light.

As a polishing pad using such an optical end point detection method, for example, Patent Document 1 describes a polishing pad that can suppress the accumulation of slurry in the grooves of a window member and improve the detection accuracy of the polishing rate. In order to provide a polishing pad having a pad body and a transparent window member integrally formed in a part of the pad body, the surface of the window member is recessed from the surface of the pad body. It is disclosed that

Japanese Patent Application Publication No. 2002-001647

By the way, one method for manufacturing a polishing pad having a window as described above is to fill a resin composition with a window member fixed to a mold and cure it, and then slice the obtained cured product. For example, the method may include a method of applying a dressing treatment afterwards. Since the window member and the cured product of the resin composition are made of different materials, their physical properties are quite different, but for example, there is a risk that the window portion may become dented or cracked when sliced. . Further, when performing a dressing process, there is a possibility that the window portion becomes depressed due to the difference in the amount of wear between the window portion and the polishing layer.

When such depressions are formed, slurry and polishing debris tend to accumulate there, causing scratches and the like, which may deteriorate the surface quality of the object to be polished. Further, if the amount of wear on the window portion is smaller than that on the polishing layer, as polishing progresses, the window portion becomes more likely to remain than the polishing layer, and as a result, the window portion becomes convex. Such a convex window may also cause scratches and the like, which may deteriorate the surface quality of the object to be polished.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a polishing pad with excellent flatness during slicing processing and dressing processing, and a method of manufacturing a polished workpiece using the same.

The present inventors have made extensive studies to solve the above problems. As a result, the present inventors have found that the above-mentioned problems can be solved by having a predetermined relationship between the end point detection window and the polishing layer in analysis by pulsed NMR, and have completed the present invention.

That is, the present invention is as follows.
[1]
comprising a polishing layer and an end point detection window provided in an opening of the polishing layer,
The free induction decay curves of spin-spin relaxation of 1H obtained by measurement using the solid echo method using pulsed NMR are shown in order of shortest relaxation time. When the waveform is separated into two curves,
The ratio (Lp20/Lw20) of the abundance ratio Lw20 of the amorphous phase in the end point detection window to the abundance ratio Lp20 of the amorphous phase in the polishing layer at 20° C. is 0.5 to 2.0,
The ratio (Sp80/Sw80) of the abundance ratio Sw80 of the crystal phase in the end point detection window to the abundance ratio Sp80 of the crystal phase in the polishing layer at 80° C. is 0.5 to 2.0.
polishing pad.
[2]
The ratio (Mp20/Mw20) of the abundance ratio Mw20 of the intermediate phase in the end point detection window to the abundance ratio Mp20 of the intermediate phase in the polishing layer at 20° C. is 0.7 to 1.5.
The polishing pad according to [1].
[3]
The ratio (Mp80/Mw80) of the abundance ratio Mw80 of the intermediate phase in the end point detection window to the abundance ratio Mp80 of the intermediate phase in the polishing layer at 80° C. is 0.5 to 1.5.
The polishing pad according to [1] or [2].
[4]
The difference between the abundance ratio Lw20 and the abundance ratio Lp20 (|Lp20−Lw20|) is 10 or less,
The polishing pad according to any one of [1] to [3].
[5]
The difference between the abundance ratio Sw80 and the abundance ratio Sw80 (|Sp80−Sw80|) is 15 or less,
The polishing pad according to any one of [1] to [4].
[6]
The end point detection window includes polyurethane resin WI,
The polyurethane resin WI contains a structural unit derived from an aliphatic isocyanate.
The polishing pad according to any one of [1] to [5].
[7]
The polishing layer includes a polyurethane resin P,
The polyurethane resin P contains a structural unit derived from an aromatic isocyanate.
The polishing pad according to any one of [1] to [6].
[8]
The polishing layer includes hollow fine particles dispersed in the polishing layer.
The polishing pad according to any one of [1] to [7].
[9]
A polishing step of polishing an object to be polished using the polishing pad according to any one of [1] to [8] in the presence of a polishing slurry to obtain a polished workpiece;
an end point detection step of detecting the end point using an optical end point detection method during the polishing;
A method of manufacturing a polished workpiece.

According to the present invention, it is possible to provide a polishing pad with excellent flatness during slicing processing and dressing processing, and a method for manufacturing a polished workpiece using the same.

FIG. 1 is a schematic perspective view of a polishing pad of this embodiment. FIG. 3 is a schematic cross-sectional view of an end point detection window portion of the polishing pad according to the present embodiment. FIG. 7 is a schematic cross-sectional view of another aspect of the end point detection window portion of the polishing pad according to the present embodiment. 1 is a schematic diagram showing a film thickness control system installed in CMP. FIG. 3 is a diagram showing the surface state of the end point detection window portion of the polishing pad of Example 1 after slicing and before dressing. FIG. 3 is a diagram showing the surface state of the end point detection window portion of the polishing pad of Example 1 after slicing and before dressing. FIG. 7 is a diagram showing the surface state of the end point detection window portion of the polishing pad of Comparative Example 1 after slicing and before dressing. FIG. 3 is a diagram showing the surface state of the end point detection window portion of the polishing pad of Example 1 after dressing. FIG. 7 is a diagram showing the surface state of the end point detection window portion of the polishing pad of Example 2 after dressing. FIG. 7 is a diagram showing the surface state of the end point detection window portion of the polishing pad of Comparative Example 1 after dressing.

Hereinafter, embodiments of the present invention (hereinafter referred to as "this embodiment") will be described in detail with reference to the drawings as necessary, but the present invention is not limited thereto, and the gist thereof Various modifications are possible without departing from the above. In addition, in the drawings, the same elements are given the same reference numerals, and overlapping explanations will be omitted. In addition, the positional relationships such as top, bottom, left, and right are based on the positional relationships shown in the drawings, unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the illustrated ratios.

1. Polishing Pad The polishing pad of this embodiment has a polishing layer and an end point detection window provided in the opening of the polishing layer, and has a 1H spin obtained by measuring by the solid echo method using pulsed NMR. - When the free induction decay curve of spin relaxation is waveform-separated into three curves derived from the three components of crystalline phase, intermediate phase, and amorphous phase in order of shortest relaxation time, the non-linearity of the end point detection window at 20°C is The ratio of the abundance ratio Lw20 of the crystalline phase to the abundance ratio Lp20 of the amorphous phase of the polishing layer (Lp20/Lw20) is 0.5 to 2.0, and the crystalline phase of the end point detection window at 80°C is The ratio of the abundance ratio Sw80 to the abundance ratio Sp80 of the crystal phase of the polishing layer (Sp80/Sw80) is 0.5 to 2.0.

As a result, flatness can be improved from the viewpoint that convex portions are less likely to occur during slicing processing, and flatness can be improved from the viewpoint that the end point detection window is less likely to be overpolished than the polishing layer during dressing processing. I can do it. In this embodiment, these two types of flatness are collectively referred to simply as "flatness."

FIG. 1 shows a schematic perspective view of the polishing pad of this embodiment. As shown in FIG. 1, the polishing pad 10 of this embodiment has a polishing layer 11 that is a polyurethane sheet, and an end point detection window 12, and if necessary, a cushion is provided on the opposite side of the polishing surface 11a. It may have a layer 13.

2 and 3 show sectional views around the end point detection window 12 in FIG. 1. As shown in FIGS. 2 and 3, an adhesive layer 14 may be provided between the polishing layer 11 and the cushion layer 13, and the surface of the cushion layer 13 is bonded to the table 22 in FIG. An adhesive layer 15 may be provided for this purpose. The polishing surface 11a of the polishing pad of this embodiment may be flat as shown in FIG. 2, or may be uneven with grooves 16 formed therein as shown in FIG. The grooves 16 may be formed by a plurality of grooves having various shapes such as concentric circles, lattice shapes, radial shapes, etc., singly or in combination.

1.1. End Point Detection Window The end point detection window is a transparent member provided in the opening of the polyurethane sheet, and serves as a transmission path for light from the film thickness detection sensor in optical end point detection. In this embodiment, the end point detection window is circular, but may have a square, rectangular, polygonal, oval, or other shape as necessary.

In this embodiment, in the process of manufacturing a polishing pad, when slicing is performed, the end point detection window may become recessed or cracked than the polishing layer, and when dressing processing is performed, the end point detection window may become depressed or cracked than the polishing layer. From the viewpoint of suppressing the detection window from being recessed or protruding from the polishing layer and improving flatness, parameters regarding the end point detection window and the pulse NMR of the polishing layer are defined.

1.1.1. Pulse NMR
Pulse NMR is one type of solid-state NMR, and is a method of detecting a response signal to a pulse and determining the ¹ H nuclear magnetic relaxation time (an index representing the mobility of molecules) of a sample. In response to the pulse, a free induction decay signal (FID signal) is obtained.

Pulse NMR is an analysis method for evaluating the mobility of the polymer molecular chain as a whole system, and the mobility can be evaluated by measuring the relaxation time of the resin composition and the signal intensity at that time. Generally, the lower the mobility of the polymer chain, the shorter the relaxation time, so the signal intensity decays faster, and the relative signal intensity decreases in a shorter time when the initial signal intensity is taken as 100%. Furthermore, the higher the mobility of the polymer chain, the longer the relaxation time, so the decay of the signal intensity becomes slower, and the relative signal intensity, when the initial signal intensity is taken as 100%, gradually decreases over a long period of time.

For example, when a resin is measured, the resulting FID is the sum of the FIDs of multiple components with different relaxation times, and by separating this using the least squares method, the relaxation time of each component can be detected. When a three-component approximation of the free induction decay curve at a given temperature obtained by measurement using the solid echo method of pulsed NMR is performed, the signal obtained by the measurement is the least mobile component (crystalline phase), the intermediate It is possible to classify the origin of the motile component (intermediate phase) or the most mobile component (amorphous phase), and also to determine the abundance ratio of these components.

Specifically, by fitting the free induction decay curve measured by the solid echo method of pulsed NMR using the following formula (1), the three components of the crystalline phase, intermediate phase, and amorphous phase can be approximated. can be obtained, and each component fraction can be obtained by approximation to the three components.
M(t)=αexp(−(1/2)(t/T _α ) ² ) sinbt/bt+βexp(−(1/Wa)(t/T _β ) ^Wa )+γexp(−t/T _γ )... (Formula 1)
α: Composition fraction of crystal phase T _α : Relaxation time of crystal phase (unit: msec)
β: Composition fraction of intermediate phase T _β : Relaxation time of intermediate phase (unit: msec)
γ: Composition fraction of amorphous phase T _γ : Relaxation time of amorphous phase (unit: msec)
t: Observation time (unit: msec)
Wa: Shape factor b: Shape factor

According to such pulsed NMR measurement results, the motility of the polishing layer and the end point detection window can be evaluated. In this embodiment, pulsed NMR is used to evaluate whether the movability of the polishing layer and end point detection window is similar at a temperature of 20° C. corresponding to dressing and a temperature of 80° C. corresponding to slicing.

Specifically, at 20° C., the ratio of the abundance ratio Lw20 of the amorphous phase in the end point detection window to the abundance ratio Lp20 of the amorphous phase in the polishing layer (Lp20/Lw20) is 0.5 to 2.0. , preferably from 0.6 to 1.7, more preferably from 0.7 to 1.5, even more preferably from 0.8 to 1.2. When the ratio (Lp20/Lw20) is within the above range, the movability of the materials constituting the polishing layer and the end point detection window becomes similar during dressing. Therefore, the polishing layer and the end point detection window can be treated uniformly during the dressing process, and the flatness after the dressing process is further improved.

Further, the ratio (Sp80/Sw80) between the abundance ratio Sw80 of the crystal phase in the end point detection window and the abundance ratio Sp80 of the crystal phase in the polishing layer at 80° C. is 0.5 to 2.0, preferably 0. It is from 6 to 1.7, more preferably from 0.9 to 1.5, even more preferably from 1.0 to 1.3. When the ratio (Sp80/Sw80) is within the above range, the movability of the materials constituting the polishing layer and the end point detection window becomes similar in slicing. Therefore, the polishing layer and the end point detection window can be uniformly processed in the slicing process, and the flatness after the slicing process is further improved.

The ratio (Mp20/Mw20) between the abundance ratio Mw20 of the intermediate phase in the end point detection window and the abundance ratio Mp20 of the intermediate phase in the polishing layer at 20° C. is preferably 0.7 to 1.5, more preferably 0. .7 to 1.3, more preferably 0.7 to 1.1. When the ratio (Mp20/Mw20) is within the above range, the polishing layer and the end point detection window can be uniformly processed in the dressing process, and the flatness after the dressing process tends to be further improved.

The ratio (Mp80/Mw80) between the abundance ratio Mw80 of the intermediate phase in the end point detection window and the abundance ratio Mp80 of the intermediate phase in the polishing layer at 80° C. is preferably 0.5 to 1.5, more preferably 0. .7 to 1.4, more preferably 0.8 to 1.3. When the ratio (Mp80/Mw80) is within the above range, the polishing layer and the end point detection window can be processed uniformly in the slicing process, and the flatness after the slicing process tends to be further improved.

The difference between the abundance ratio Lw20 and the abundance ratio Lp20 (|Lp20−Lw20|) is preferably 10 or less, more preferably 0 to 8.0, and even more preferably 0 to 5.0. When the difference (|Lp20−Lw20|) is within the above range, the polishing layer and the end point detection window can be processed uniformly in the dressing process, and the flatness after the dressing process tends to be further improved.

The difference between the abundance ratio Sw80 and the abundance ratio Sw80 (|Sp80−Sw80|) is preferably 15 or less, more preferably 0 to 12, and even more preferably 0 to 8.0. When the difference (|Sp80−Sw80|) is within the above range, the polishing layer and the end point detection window can be processed uniformly in the slicing process, and the flatness after the slicing process tends to be further improved.

The abundance ratio Sw20 of the crystal phase in the end point detection window at 20° C. is preferably 30 to 65%, more preferably 35 to 60%, and still more preferably 40 to 55%.

The abundance ratio Mw20 of the mesophase in the end point detection window at 20° C. is preferably 15 to 45%, more preferably 20 to 40%, and even more preferably 25 to 35%.

The abundance ratio Lw20 of the amorphous phase in the end point detection window at 20° C. is preferably 10 to 40%, more preferably 15 to 35%, and even more preferably 20 to 30%.

When the abundance ratio Sw20, abundance ratio Mw20, and abundance ratio Lw20 of the end point detection window at 20° C. are each within the above ranges, the polishing layer and the end point detection window can be uniformly treated in the dressing process, and the dressing The flatness after treatment tends to be further improved. Note that the sum of the abundance ratio Sw20, the abundance ratio Mw20, and the abundance ratio Lw20 is 100%.

The abundance ratio Sw80 of the crystal phase in the end point detection window at 80° C. is preferably 15 to 50%, more preferably 20 to 45%, and even more preferably 25 to 40%.

The abundance ratio Mw80 of the mesophase in the end point detection window at 80° C. is preferably 10 to 35%, more preferably 15 to 30%, and still more preferably 20 to 25%.

The abundance ratio Lw80 of the amorphous phase in the end point detection window at 80° C. is preferably 30 to 60%, more preferably 35 to 55%, and even more preferably 40 to 50%.

Since the abundance ratio Sw80, abundance ratio Mw80, and abundance ratio Lw80 of the end point detection window at 80° C. are each within the above ranges, the polishing layer and the end point detection window can be processed homogeneously in the slicing process, and the slicing The flatness after treatment tends to be further improved. Note that the sum of abundance ratio Sw80, abundance ratio Mw80, and abundance ratio Lw80 is 100%.

The measurement conditions for pulsed NMR measurement are not particularly limited, but the measurement can be performed under the conditions described in Examples.

1.1.3. Constituent Materials The material constituting the end point detection window is not particularly limited as long as it is a transparent member that can function as a window, but examples include polyurethane resin WI, polyvinyl chloride resin, polyvinylidene fluoride resin, polyether sulfone resin, and polystyrene. resin, polyethylene resin, polytetrafluoroethylene resin, etc. Among these, polyurethane resin WI is preferred. By using such a resin, the pulse NMR characteristics and transparency can be more easily adjusted, and the flatness can be further improved.

The polyurethane resin WI can be synthesized from a polyisocyanate and a polyol, and includes structural units derived from the polyisocyanate and structural units derived from the polyol.

1.1.3.1. Structural units derived from polyisocyanates Structural units derived from polyisocyanates are not particularly limited, but include, for example, structural units derived from alicyclic isocyanates, structural units derived from aliphatic isocyanates, and structural units derived from aromatic isocyanates. Units are listed. Among these, the polyurethane resin WI preferably contains a structural unit derived from an alicyclic isocyanate and/or an aliphatic isocyanate, and more preferably contains a structural unit derived from an aliphatic isocyanate. Thereby, each value related to pulse NMR can be easily adjusted within the above range, transparency can be further improved, and flatness during dressing and slicing can be further improved.

Examples of alicyclic isocyanates include, but are not limited to, 4,4'-methylene-bis(cyclohexyl isocyanate) (hydrogenated MDI), cyclohexylene-1,2-diisocyanate, cyclohexylene-1,4-diisocyanate, Examples include isophorone diisocyanate.

Examples of aliphatic isocyanates include, but are not limited to, hexamethylene diisocyanate (HDI), pentamethylene diisocyanate (PDI), tetramethylene diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, and trimethylene diisocyanate. , trimethylhexamethylene diisocyanate and the like.

Aromatic isocyanates include, but are not particularly limited to, phenylene diisocyanate, 2,6-tolylene diisocyanate (2,6-TDI), 2,4-tolylene diisocyanate (2,4-TDI), xylylene diisocyanate, Examples include naphthalene diisocyanate and diphenylmethane-4,4'-diisocyanate (MDI).

1.1.3.2. Structural Units Derived from Polyols Structural units derived from polyols are not particularly limited, but include, for example, low-molecular polyols with a molecular weight of less than 300 and high-molecular polyols with a molecular weight of 300 or more.

Examples of low-molecular polyols include, but are not limited to, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, and 1,4-butylene glycol. Butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexane glycol, 2,5-hexanediol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, tricyclode Low-molecular polyols having two hydroxyl groups such as candimethanol and 1,4-cyclohexanedimethanol; low-molecular polyols having three or more hydroxyl groups such as glycerin, hexanetriol, trimethylolpropane, isocyanuric acid, and erythritol. One type of low-molecular polyol may be used alone, or two or more types may be used in combination.

Among these, low molecular weight polyols having three or more hydroxyl groups are preferred, and glycerin is more preferred. By using such a low-molecular-weight polyol, the pulsed NMR characteristics can be easily adjusted within the above range, the amount of wear can be adjusted, the flatness can be further improved, the transparency can be further improved, and the durability of the window can be improved. Yellowing tends to improve.

The content of the structural unit derived from the low-molecular polyol having three or more hydroxyl groups is preferably 8.0 to 30 parts by mass, more preferably 10 to 30 parts by mass, per 100 parts by mass of the structural unit derived from polyisocyanate. The amount is 25 parts by weight, more preferably 12.5 to 20 parts by weight. By having the content of the structural unit derived from a low-molecular polyol having three or more hydroxyl groups within the above range, pulse NMR characteristics can be easily adjusted within the above range, flatness can be further improved, and transparency can be improved. In addition to further improving the yellowing resistance of windows, the yellowing resistance of windows also tends to be improved.

Further, examples of the polymer polyol include, but are not limited to, polyether polyol, polyester polyol, polycarbonate polyol, polyether polycarbonate polyol, polyurethane polyol, epoxy polyol, vegetable oil polyol, polyolefin polyol, acrylic polyol, and vinyl monomer-modified polyol. Examples include polyols. The polymer polyols may be used alone or in combination of two or more.

The number average molecular weight of the high molecular weight polyol is preferably 300 to 3,000, more preferably 500 to 2,500. By using such a polymer polyol, the pulse NMR characteristics tend to be easily adjusted within the above range.

Among these, polyether polyol is preferred, and poly(oxytetramethylene) glycol is more preferred. By using such a polymer polyol, the pulse NMR characteristics can be easily adjusted within the above range. Furthermore, flatness can be further improved, transparency can be further improved, and the yellowing resistance of windows tends to be further improved.

The content of the structural unit derived from the polyether polyol is preferably 60 to 130 parts by mass, preferably 65 to 120 parts by mass, and more preferably It is 70 to 110 parts by mass. By having the content of the structural unit derived from the polyether polyol within the above range, the pulsed NMR characteristics can be easily adjusted within the above range, the flatness can be further improved, and the transparency is further improved. The yellowing resistance of windows tends to be improved.

Further, as the polyol, it is preferable to use a low-molecular polyol and a high-molecular polyol in combination, and it is more preferable to use a low-molecular polyol having three or more hydroxyl groups and a polyether polyol in combination. This makes it easy to adjust the pulse NMR characteristics within the above range. Furthermore, flatness can be further improved, transparency can be further improved, and the yellowing resistance of windows tends to be further improved.

From the above viewpoint, the content of the polyether polyol is preferably 2.0 to 15.0 parts, more preferably 3.0 to 12.5 parts per part of the low molecular weight polyol having three or more hydroxyl groups. parts, more preferably 4.0 to 9.0 parts.

1.2. Polishing Layer The polishing layer of this embodiment has an opening in which an end point detection window is embedded. Although the position of the opening is not particularly limited, it is preferable to provide it at a position in the radial direction corresponding to the film thickness detection sensor 23 installed on the table 22. Although the number of openings is not particularly limited, they are arranged at similar radial positions so that the windows pass over the film thickness detection sensor 23 multiple times when the polishing pad 10 attached to the table 22 rotates once. It is preferable to have a plurality of them.

The form of the polishing layer is not particularly limited, but includes, for example, a foamed resin molded product, a non-foamed molded product, a resin-impregnated base material in which a fiber base material is impregnated with a resin.

Here, the resin foam molding refers to a foam that does not have a fiber base material and is made of a predetermined resin. The shape of the foam is not particularly limited, and examples thereof include spherical cells, substantially spherical cells, teardrop-shaped cells, and open cells in which each cell is partially connected.

In addition, a non-foamed resin molded product refers to a non-foamed product that does not have a fiber base material and is made of a predetermined resin. A non-foamed material refers to one that does not have bubbles as described above. In the first embodiment, non-foamed molded resin products include those in which a curable composition is adhered and cured on a base material such as a film. More specifically, resin cured products formed by the labia coater method, small-diameter gravure coater method, reverse roll coater method, transfer roll coater method, kiss coater method, die coater method, screen printing method, spray coating method, etc. Included in non-foamed molded products.

Further, the term "resin-impregnated base material" refers to one obtained by impregnating a fiber base material with a resin. Here, the fiber base material is not particularly limited, and examples thereof include woven fabrics, nonwoven fabrics, knitted fabrics, and the like.

1.2.1. Pulse NMR
The abundance ratio Sp20 of the crystal phase in the polishing layer is preferably 40 to 65%, preferably 45 to 60%, and preferably 50 to 55%.

The abundance ratio Mp20 of the intermediate phase in the polishing layer is preferably 10 to 40%, preferably 15 to 35%, and preferably 20 to 30%.

The abundance ratio Lp20 of the amorphous phase in the polishing layer is preferably 10 to 35%, preferably 15 to 30%, and preferably 20 to 25%.

When the abundance ratio Sp20, abundance ratio Mp20, and abundance ratio Lp20 of the end point detection window at 20° C. are each within the above ranges, the polishing layer and the end point detection window can be uniformly treated in the dressing process, and the dressing The flatness after treatment tends to be further improved. Note that the sum of abundance ratio Sp20, abundance ratio Mp20, and abundance ratio Lp20 is 100%.

The abundance ratio Sp80 of the crystal phase of the polishing layer is preferably 25 to 50%, preferably 30 to 45%, and preferably 35 to 40%.

The abundance ratio Mp80 of the intermediate phase in the polishing layer is preferably 10 to 40%, preferably 15 to 35%, and preferably 20 to 30%.

The abundance ratio Lp80 of the amorphous phase in the polishing layer is preferably 25 to 50%, preferably 30 to 45%, and preferably 35 to 40%.

Since the abundance ratio Sp80, abundance ratio Mp80, and abundance ratio Lp80 of the end point detection window at 80° C. are each within the above ranges, the polishing layer and the end point detection window can be processed homogeneously in the slicing process, and the slicing The flatness after treatment tends to be further improved. Note that the sum of abundance ratio Sp80, abundance ratio Mp80, and abundance ratio Lp80 is 100%.

The measurement conditions for pulsed NMR measurement are not particularly limited, but the measurement can be performed under the conditions described in Examples.

1.2.2. Polyurethane Sheet In the following, a polyurethane sheet will be exemplified as an example of the polishing layer. The polyurethane resin P constituting the polyurethane sheet is not particularly limited, and examples thereof include polyester polyurethane resins, polyether polyurethane resins, and polycarbonate polyurethane resins. These may be used alone or in combination of two or more.

Such a polyurethane resin P can be synthesized using a polyisocyanate and a polyol, and a reaction product of a urethane prepolymer and a curing agent is particularly preferable. Here, the urethane prepolymer can be synthesized using polyisocyanate and polyol. The polyisocyanate, polyol, and curing agent that constitute the polyurethane resin P will be described below.

1.2.2.1. Structural units derived from polyisocyanates Structural units derived from polyisocyanates are not particularly limited, but include, for example, structural units derived from alicyclic isocyanates, structural units derived from aliphatic isocyanates, and structural units derived from aromatic isocyanates. Units are listed. Among these, aromatic isocyanates are preferred, and 2,4-tolylene diisocyanate (2,4-TDI) is more preferred.

As the alicyclic isocyanate, aliphatic isocyanate, and aromatic isocyanate, the same ones as those exemplified for the end point detection window can be exemplified.

1.2.2.2. Structural Units Derived from Polyols Structural units derived from polyols are not particularly limited, but include, for example, low-molecular polyols with a molecular weight of less than 300 and high-molecular polyols with a molecular weight of 300 or more. Among these, it is preferable to use at least a low-molecular polyol, and it is preferable to use a low-molecular polyol and a high-molecular polyol in combination.

As the low-molecular polyol and the high-molecular polyol, the same ones as those exemplified in the end point detection window can be exemplified. Among these, as the low-molecular polyol, a low-molecular polyol having two hydroxyl groups is preferred, and diethylene glycol is more preferred. Further, as the polymer polyol, polyether polyol is preferable, and poly(oxytetramethylene) glycol is more preferable.

1.2.2.3. Curing Agent The curing agent is not particularly limited, and examples thereof include polyamines and polyols. The curing agents may be used alone or in combination of two or more.

Examples of polyamines include, but are not limited to, aliphatic polyamines such as ethylene diamine, propylene diamine, and hexamethylene diamine; alicyclic polyamines such as isophorone diamine and dicyclohexylmethane-4,4'-diamine; and 3,3'- Dichloro-4,4'-diaminodiphenylmethane (MOCA), 4-methyl-2,6-bis(methylthio)-1,3-benzenediamine, 2-methyl-4,6-bis(methylthio)-1,3- Examples include aromatic polyamines such as benzenediamine and 2,2-bis(3-amino-4-hydroxyphenyl)propane.

Among these, aromatic polyamines are preferred, and 3'-dichloro-4,4'-diaminodiphenylmethane (MOCA) is more preferred.

As the polyol, the same polyols as those exemplified in the end point detection window can be exemplified. Among these, polymer polyols are preferred, polyether polyols are more preferred, and polypropylene glycol is even more preferred.

1.2.2.4. Hollow Fine Particles The polishing layer preferably includes hollow fine particles dispersed therein. Specifically, the polyurethane sheet is preferably a foamed polyurethane sheet containing a polyurethane resin P and hollow fine particles dispersed in the polyurethane resin P. Such a polyurethane sheet has closed cells derived from hollow fine particles, and the pulsed NMR characteristics tend to be easily adjusted within the above range.

As the hollow fine particles, commercially available ones may be used, or those obtained by synthesis by conventional methods may be used. The material for the outer shell of the hollow fine particles is not particularly limited, but examples include polyvinyl alcohol, polyvinylpyrrolidone, poly(meth)acrylic acid, polyacrylamide, polyethylene glycol, polyhydroxyether acrylate, maleic acid copolymer, and polyethylene oxide. , polyurethane, acrylonitrile-vinylidene chloride copolymer, acrylonitrile-methyl methacrylate copolymer, vinyl chloride-ethylene copolymer, and the like.

The shape of the hollow fine particles is not particularly limited, and may be, for example, spherical or approximately spherical. Further, when the hollow microparticles are inflatable balloons, they may be used in an unexpanded state or in an inflated state.

The average particle size of the hollow fine particles contained in the polyurethane sheet is preferably 5 to 200 μm, more preferably 5 to 80 μm, even more preferably 5 to 50 μm, and particularly preferably 5 to 35 μm. When the average particle diameter is within the above range, the pulse NMR characteristics tend to be easily adjusted within the above range. The average particle size can be measured using a laser diffraction particle size distribution analyzer (for example, Mastersizer-2000 manufactured by Spectris Co., Ltd.).

1.3. Others The polishing pad of this embodiment may have a cushion layer on the side opposite to the polishing surface of the polishing layer, and may be provided between the polishing layer and the cushion layer or on the surface of the cushion layer that is not on the polishing layer side (polishing layer side). The surface to be bonded to the machine) may have an adhesive layer. In this case, the cushion layer and the adhesive layer have an opening at the same location as the end point detection window of the polishing layer.

2. Method for manufacturing a polishing pad The method for manufacturing the polishing pad of this embodiment is not particularly limited, but for example, a mold to which a window member serving as an end point detection window is fixed is filled with a resin composition constituting a polishing layer. The steps include a step of curing to obtain a resin block in which a window member is embedded, and a step of slicing the obtained resin block to obtain a polyurethane sheet having an end point detection window in the opening. Then, the polished surface of the obtained polyurethane sheet may be subjected to a dressing treatment.

Note that the temperature during slicing is preferably 70°C to 100°C. Further, the temperature in the dressing treatment is preferably 20°C to 30°C. This tends to further improve flatness.

3. Method for manufacturing a polished product The method for manufacturing a polished product according to the present embodiment includes a polishing step of polishing an object to be polished using the polishing pad in the presence of a polishing slurry to obtain a polished product, and a polishing step during the polishing. and an end point detection step of performing end point detection using an optical end point detection method.

3.1. Polishing process The polishing process may be primary lapping (rough lapping), secondary lapping (finish lapping), primary polishing (rough polishing), or secondary polishing (finish polishing). ), or it may also serve as polishing. Note that "lapping" here refers to polishing at a relatively high rate using coarse abrasive grains, and "polishing" refers to polishing at a relatively low rate using fine abrasive grains. Say to polish for.

Among these, the polishing pad of this embodiment is preferably used for chemical mechanical polishing (CMP). Hereinafter, a method for manufacturing a polished product according to the present embodiment will be described using chemical mechanical polishing as an example, but the method for manufacturing a polished product according to this embodiment is not limited to the following.

The object to be polished is not particularly limited, but includes, for example, materials such as semiconductor devices and electronic components, particularly Si substrates (silicon wafers), SiC (silicon carbide) substrates, GaAs (gallium arsenide) substrates, glass, hard disks, and LCDs. Examples include thin substrates (objects to be polished) such as substrates for (liquid crystal displays). In particular, semiconductor devices having metal wiring such as W (tungsten) and Cu (copper) can be mentioned.

As the polishing method, a conventionally known method can be used and is not particularly limited. For example, first, the object to be polished, which is held on a holding surface plate arranged to face the polishing pad, is pressed against the polishing surface side, and the polishing pad and/or the holding surface plate is rotated while supplying slurry from the outside. let The polishing pad and the holding surface plate may rotate in the same direction at different rotational speeds, or may rotate in different directions. Furthermore, the object to be polished may be polished while moving (rotating) inside the frame during the polishing process.

The slurry may contain water, chemical components such as oxidizing agents such as hydrogen peroxide, additives, abrasive grains (abrasive particles; for example, SiC, SiO ₂ , Al ₂ O _{3 )} depending on the object to be polished and the polishing conditions. , CeO ₂ ) and the like.

3.2. End Point Detection Step The method for manufacturing a polished workpiece according to the present embodiment includes an end point detection step in which the end point is detected using an optical end point detection method in the polishing step. Specifically, a conventionally known method can be used as the end point detection method using the optical end point detection method.

FIG. 4 shows a schematic diagram of the end point detection method using the optical end point detection method. This schematic diagram shows a chemical mechanical polishing process in which a wafer W held by a top ring 21 is pressed onto a polishing pad 10 stuck on a table 22 while flowing a slurry 24 to scrape and flatten the uneven film on the surface of the wafer W. . The polishing apparatus 20 has a film thickness detection sensor 23 mounted on the table 22 to monitor the film thickness in order to detect the end point of a predetermined film thickness at the same time as planarization and terminate the process with high accuracy. The film thickness detection sensor 23 can detect the polishing end point by, for example, irradiating the polished surface of the wafer W with light and measuring and analyzing the spectral intensity characteristics of the reflected light.

More specifically, the film thickness detection sensor 23 makes light incident on the surface of the wafer W through the end point detection window 12, and detects the light reflected by the film on the wafer W (wafer surface) and the film on the wafer W. Changes in film thickness can be detected by detecting the strength or weakness of the reflection intensity, which is caused by the phase difference between the light reflected at the interface between the wafer and the substrate.

Hereinafter, the present invention will be explained in more detail using Examples and Comparative Examples. The present invention is not limited in any way by the following examples. In addition, "part" shall mean a part by mass.

[Manufacturing example 1: End point detection window 1]
100 parts of 4,4' methylene bis(cyclohexyl isocyanate), 90.6 parts of poly(oxytetramethylene) glycol (PTMG) having a number average molecular weight of 1000, and 16.7 parts of glycerin are reacted to form an end point detection window. A transparent member No. 4 was obtained.

[Manufacturing example 2: End point detection window 2]
100 parts of 4,4' methylene bis(cyclohexyl isocyanate), 103.6 parts of poly(oxytetramethylene) glycol (PTMG) having a number average molecular weight of 1000, and 15.9 parts of glycerin are reacted to form an end point detection window. A transparent member No. 2 was obtained.

[Manufacturing example 3: End point detection window 3]
100 parts of 4,4' methylene bis(cyclohexyl isocyanate), 78.6 parts of poly(oxytetramethylene) glycol (PTMG) having a number average molecular weight of 650, 4.5 parts of glycerin, and 10.5 parts of ethylene glycol. was reacted to obtain a transparent member that would become the end point detection window 3.

[Example 1]
2,4-tolylene diisocyanate (2,4-TDI), poly(oxytetramethylene) glycol (PTMG) with a number average molecular weight of 650, poly(oxytetramethylene) glycol (PTMG) with a number average molecular weight of 1000, and diethylene glycol (DEG). ), 2.9 parts of unexpanded hollow fine particles (average particle size: 8.5 μm) whose shell portion is made of acrylonitrile-vinylidene chloride copolymer are added to 100 parts of a urethane prepolymer with an NCO equivalent of 420. The mixture was mixed to obtain a urethane prepolymer mixture. The obtained urethane prepolymer mixture was charged into a first liquid tank and kept at 60°C. In addition, separately from the first liquid tank, 28.0 parts of 3,3'-dichloro-4,4'-diaminodiphenylmethane (methylenebis-o-chloroaniline) (MOCA) as a curing agent was placed in a second liquid tank. The mixture was heated and melted at 120° C., mixed, and further defoamed under reduced pressure to obtain a curing agent melt.

Next, each of the liquids in the first liquid tank and the second liquid tank was injected from each inlet of a mixer equipped with two inlets, and stirred and mixed to obtain a mixed liquid.

Then, the obtained liquid mixture was poured into a mold in which the end point detection window 1 obtained as described above was installed in advance, and was primarily cured at 80° C. for 30 minutes. The formed block-shaped molded product was extracted from the mold and was secondarily cured in an oven at 120° C. for 4 hours to obtain a urethane resin block. The obtained urethane resin block was allowed to cool to 25°C.

Thereafter, it was heated again in an oven at 120° C. for 5 hours and then subjected to slicing treatment, and the sliced surface was subjected to grinding (buffing) treatment as required to obtain a polyurethane foam sheet. A polishing pad was obtained by attaching a double-sided tape to the back side of the obtained polyurethane sheet, attaching a cushion layer thereto, and then attaching a double-sided tape to the surface of the cushion layer.

In addition, when evaluating the cross section around the end point detection window after the dressing process, the polishing pad obtained as described above was subjected to the dressing process under the following conditions.
(Dress conditions)
Polishing machine used: Speedfam, product name “FAM-12BS”
Surface plate rotation speed (polishing pad rotation speed): 50 rpm
Flow rate: 100ml/min (Pure water at 20°C was dripped from the center of rotation of the polishing pad.)
Dresser: Diamond dresser manufactured by 3M, model number "A188"
Dresser rotation speed: 100rpm
Dress pressure: 0.115kg/cm2
Dresser rotation direction: Rotate in the same direction as the polishing pad Test time: 60 minutes

[Example 2]
A polishing pad was obtained in the same manner as in Example 1 except that the end point detection window 2 of Production Example 3 was used.

[Comparative example 1]
A polishing pad was obtained in the same manner as in Example 1 except that the end point detection window 3 of Production Example 3 was used.

[Pulse NMR]
Equipment: Minispec MQ20 (manufactured by Bruker Biospin Co., Ltd.)
Nuclide: ^1H
Measurement: _T2
Measurement method: Solid echo method Number of integration: 256 times Repetition time: 1.0 sec
Measurement temperature: 20℃, 80℃ (measurement started 60 minutes after the device temperature reached the measurement temperature and the sample was set)
Using the above apparatus and conditions, ten sample pellets each having a diameter of 8 mm and weighing approximately 50 mg were prepared and filled into a sample tube, and a pulse NMR measurement was performed to obtain an attenuation curve.
The obtained attenuation curve was fitted and analyzed using the above equation (1), and the relaxation times of the crystalline phase, intermediate phase, and amorphous phase in the polyurethane resin were obtained. Note that the fitting and analysis used the software attached to the above measuring device.

[Cross-sectional evaluation]
For each pad obtained as described above, the area around the end point detection window after slicing and before dressing (the area surrounded by the broken line S in FIG. 2), and the end point detection after dressing (evaluation 1). A cross section (evaluation 2) of the area around the window (the area surrounded by the broken line S in Fig. 2) was measured using a laser microscope (VK-X1000, manufactured by KEYENCE) with a size of approximately 14 mm x 1 mm on the surface of the diameter portion of the end point detection window. The area was magnified 200 times and observed in connected mode, and the profile of height information was measured based on the obtained laser image.

The results are shown in FIGS. 5A-C and 6A-C. Note that FIGS. 5A to C and 6A to C show the cross-sectional measurement results of two end point detection windows, where cross-sectional measurements were performed in the slice direction and in the direction orthogonal to the slice direction for each end point detection window. It shows.

In evaluation 1, if the end point detection window was within ±50 μm from the polished surface, it was marked as ○, and otherwise it was marked as ×. In addition, in evaluation 2, if the cross-sectional image is flat (the height is the same from the edge to the center), it is marked as ○, and if it is convex (the height is higher from the edge to the center), it is marked as ×. .

The polishing pad of the present invention has industrial applicability as a pad suitably used for polishing semiconductor wafers and the like.

DESCRIPTION OF SYMBOLS 10... Polishing pad, 11... Polishing layer, 11a... Polishing surface, 12... End point detection window, 13... Cushion layer, 14, 15... Adhesive layer, 16... Groove, 20... Polishing device, 21... Top ring, 22... Table , 23...Film thickness detection sensor, 24...Slurry, W...Wafer

Claims (9)

comprising a polishing layer and an end point detection window provided in an opening of the polishing layer,
The free induction decay curves of spin-spin relaxation of 1H obtained by measurement using the solid echo method using pulsed NMR are shown in order of shortest relaxation time. When the waveform is separated into two curves,
The ratio (Lp20/Lw20) of the abundance ratio Lw20 of the amorphous phase in the end point detection window to the abundance ratio Lp20 of the amorphous phase in the polishing layer at 20° C. is 0.5 to 2.0,
The ratio (Sp80/Sw80) of the abundance ratio Sw80 of the crystal phase in the end point detection window to the abundance ratio Sp80 of the crystal phase in the polishing layer at 80° C. is 0.5 to 2.0.
polishing pad. The ratio (Mp20/Mw20) of the abundance ratio Mw20 of the intermediate phase in the end point detection window to the abundance ratio Mp20 of the intermediate phase in the polishing layer at 20° C. is 0.7 to 1.5.
The polishing pad according to claim 1. The ratio (Mp80/Mw80) of the abundance ratio Mw80 of the intermediate phase in the end point detection window to the abundance ratio Mp80 of the intermediate phase in the polishing layer at 80° C. is 0.5 to 1.5.
The polishing pad according to claim 1 or 2. The difference between the abundance ratio Lw20 and the abundance ratio Lp20 (|Lp20−Lw20|) is 10 or less,
The polishing pad according to any one of claims 1 to 3. The difference between the abundance ratio Sw80 and the abundance ratio Sw80 (|Sp80−Sw80|) is 15 or less,
The polishing pad according to any one of claims 1 to 4. The end point detection window includes polyurethane resin WI,
The polyurethane resin WI contains a structural unit derived from an aliphatic isocyanate.
The polishing pad according to any one of claims 1 to 5. The polishing layer includes a polyurethane resin P,
The polyurethane resin P contains a structural unit derived from an aromatic isocyanate.
The polishing pad according to any one of claims 1 to 6. The polishing layer includes hollow fine particles dispersed in the polishing layer.
The polishing pad according to any one of claims 1 to 7. A polishing step of polishing an object to be polished using the polishing pad according to any one of claims 1 to 8 in the presence of a polishing slurry to obtain a polished workpiece;
an end point detection step of detecting the end point using an optical end point detection method during the polishing;
A method of manufacturing a polished workpiece.