TWI901193B - Polishing pad and method of forming the same and polishing method - Google Patents

Abstract

A polishing pad is provided. The polishing pad includes a polishing layer and at least one detection window. The at least one detection window is located in the polishing layer, wherein the at least one detection window comprises a center portion and a cover portion surrounding the center portion, the cover portion is connected with the center portion, and a ratio of the area of the center portion to the area of the cover portion ranges from about 0.03 to about 5.00.

Description

Polishing pad, manufacturing method thereof, and polishing method

The present invention relates to a polishing pad, a manufacturing method thereof, and a polishing method, and in particular to a polishing pad having a detection window, a manufacturing method of the polishing pad, and a polishing method using the polishing pad.

In the industrial component manufacturing process, lapping is a technology commonly used to flatten the surface of the object being polished. During the lapping process, the object is polished by moving it relative to the polishing pad, and a polishing liquid is optionally provided between the object surface and the polishing pad.

Polishing equipment with an optical detection system typically has a detection window located in a certain area of the polishing layer of the polishing pad. This window allows the user to monitor the polishing progress of the object through the optical detection system while the polishing pad is being polished. This serves as end-point detection and ensures polishing quality.

In some embodiments, a polishing pad with a detection window has a structure in which the detection window material is directly bonded to the polishing layer material. As shown in Figure 1, during the polishing process, a polishing head H, carrying an object S, moves relative to the polishing surface of the polishing pad P in a rotational motion B or a combination of rotational motion B and left-right oscillation C. The shear and normal forces generated during this process can easily damage the interface between the polishing layer and the detection window, causing polishing fluid to leak through the interface between the polishing layer and the detection window during polishing, thereby affecting polishing quality and the performance of the detection window.

Furthermore, the bonding strength between the detection window and the polishing layer is limited by the material used. As the polishing pad wears more and more times, the bonding area between the detection window and the polishing layer decreases, making it difficult for the interface between the detection window and the polishing layer to withstand the stress of the polishing process. Consequently, current polishing pads suffer from insufficient interfacial bonding strength between the detection window and the polishing layer, leading to polishing fluid leakage and thus affecting the lifespan of the polishing pad. Therefore, improving the bonding strength between the detection window and the polishing layer to extend the lifespan of the polishing pad is a topic of active research by technical personnel in this field.

The present invention provides a polishing pad having improved bonding strength between a detection window and a polishing layer.

The polishing pad of the present invention includes a polishing layer and at least one detection window. The at least one detection window is located in the polishing layer, wherein the at least one detection window includes a central portion and a covering portion surrounding the central portion. The covering portion is bonded to the polishing layer, and the ratio of the area of the central portion to the area of the covering portion is between about 0.03 and about 5.00.

The polishing pad manufacturing method of the present invention includes the following steps: First, forming a detection window, which includes: pre-positioning a central portion within a first mold; then, filling the first mold with a coating material and performing a first curing process to form a coating portion that covers the central portion; then, pre-positioning the detection window within a second mold; then, pouring an abrasive layer material into the second mold and performing a second curing process to form an abrasive layer bonded to the coating portion.

The polishing method of the present invention comprises the following steps: providing a polishing pad, wherein the polishing pad is any of the polishing pads described above; applying pressure to an object to press it against the polishing pad; and providing relative motion between the object and the polishing pad to perform the polishing process.

Based on the above, the polishing pad of the present invention comprises a detection window comprising a central portion and a surrounding portion. The surrounding portion is bonded to the polishing layer, and the ratio of the area of the central portion to the area of the surrounding portion is between approximately 0.03 and approximately 5.00. This improves the bonding strength between the detection window and the polishing layer. Furthermore, the detection window covering of the polishing pad of the present invention can be made of a material that exhibits a high bond strength with both the polishing layer and the detection window central portion, thereby overcoming stress issues during the polishing process. This also allows for greater flexibility in the selection and combination of materials for the polishing layer and the detection window central portion, thereby achieving the desired polishing quality for the object.

To make the above features and advantages of the present invention more clearly understood, the following specifically provides an implementation method and provides a detailed description with reference to the accompanying drawings.

In this document, a range expressed as "from a value to another value" is a summary expression method that avoids listing all the values within the range one by one in the specification. Therefore, the description of a specific numerical range covers any numerical value within the range and the smaller numerical range defined by any numerical value within the range, just as if the arbitrary numerical value and the smaller numerical range were explicitly written in the specification.

As used herein, "about" includes the stated value and the mean within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art, taking into account the measurement in question and the particular amount of error associated with the measurement (i.e., the limitations of the measurement system). For example, "about" can mean within one or more standard deviations of the stated value, or, for example, within ±30%, ±20%, ±15%, ±10%, ±5%. Furthermore, as used herein, "about" or "substantially" can be used to select an acceptable range of deviation or standard deviation depending on the measured property or other property, and may not apply to all properties without using a single standard deviation.

It should be understood that when an element such as a layer, film, region, or trench is referred to as being "on," "connected to," or "contacting" another element, it can be directly on or connected/contacting the other element, or intervening elements may also be present. In contrast, when an element is referred to as being "directly on," "directly connected to," or "directly contacting" another element, there are no intervening elements present.

In the drawings, the sizes and thicknesses of layers, regions, and parts are exaggerated for clarity and are not drawn to scale.

Figure 2A is a schematic top view of a polishing pad according to an embodiment of the present invention. Figure 2B is a schematic cross-sectional view taken along line A-A' of Figure 2A.

2A and 2B , the polishing pad 100 includes a polishing layer 102 and a detection window 104. In another embodiment, the polishing pad further includes a base layer disposed below the polishing layer 102, as shown in FIG3 (described in detail below with reference to FIG3 ).

In this embodiment, the polishing layer 102 is formed from a polymer substrate, such as polyester, polyether, polyurethane, polycarbonate, polyacrylate, polybutadiene, or other polymer substrates synthesized from suitable thermosetting resins or thermoplastic resins, but the present invention is not limited thereto. In addition to the polymer substrate, the polishing layer 102 may also include conductive materials, abrasive particles, microspheres, or soluble additives within the polymer substrate.

In this embodiment, the polishing layer 102 has a polishing surface PS and a back surface BS opposite the polishing surface PS. Herein, the polishing surface PS of the polishing layer 102 is also referred to as the top surface, and the back surface BS of the polishing layer 102 is also referred to as the bottom surface. When the polishing pad 100 is used to polish an object, the object comes into contact with the polishing surface PS of the polishing layer 102. It is worth mentioning that, although not shown in FIG. 2A and FIG. 2B , anyone skilled in the art will appreciate that the polishing surface PS includes a groove pattern, and the groove pattern may have a variety of different pattern distributions, such as concentric rings, non-concentric rings, elliptical rings, wavy rings, irregular rings, multiple straight lines, parallel straight lines, radial straight lines, radial arcs, spirals, polygonal grids, or combinations thereof, but the present invention is not limited thereto.

Detection window 104 is located within polishing layer 102. As shown in Figures 2A and 2B , detection window 104 includes a central portion 104a and a surrounding portion 104b surrounding central portion 104a. In other words, detection window 104 consists of two parts. From another perspective, as shown in Figures 2A and 2B , central portion 104a and surrounding portion 104b are in direct contact.

Furthermore, as shown in Figures 2A and 2B , the covering portion 104b is bonded to the polishing layer 102. In other words, the detection window 104 is secured to the polishing layer 102 via the covering portion 104b. In other words, the covering portion 104b is bonded between the central portion 104a and the polishing layer 102. From another perspective, as shown in Figure 2B , the bonding interface between the central portion 104a and the covering portion 104b, as well as the bonding interface between the covering portion 104b and the polishing layer 102, are all smooth surfaces. In other words, in this embodiment, the side surface S1 of the central portion 104a, the inner surface S2 and outer surface S3 of the covering portion 104b, and the inner surface S4 of the polishing layer 102 are all smooth surfaces. However, the present invention is not limited to this. In other embodiments, each of the side surface S1 of the central portion 104a, the inner surface S2 and outer surface S3 of the covering portion 104b, and the inner surface S4 of the polishing layer 102 may be a roughened surface, such as a spiral surface (as shown in FIG4A ), a corrugated surface (as shown in FIG4B ), or a granular surface (as shown in FIG4C ). In other words, in the aforementioned embodiment, the bonding interface between the central portion 104a and the covering portion 104b, as well as the bonding interface between the covering portion 104b and the polishing layer 102, may be a roughened surface. It is worth mentioning that by designing each of the side surface S1 of the central portion 104a, the inner surface S2 and outer surface S3 of the covering portion 104b, and the inner surface S4 of the polishing layer 102 as rough surfaces, the contact area between the central portion 104a, the covering portion 104b and the polishing layer 102 can be increased, thereby increasing the density among the three. In another embodiment, the side surface S1 of the central portion 104a and the inner surface S2 of the covering portion 104b may be designed as rough surfaces, and the outer surface S3 of the covering portion 104b and the inner surface S4 of the polishing layer 102 may be designed as smooth surfaces, thereby increasing the contact area between the central portion 104a and the covering portion 104b and further increasing the bonding strength between the central portion 104a and the covering portion 104b of the detection window 104.

In this embodiment, the ratio of the area of the central portion 104a to the area of the covering portion 104b is between about 0.03 and about 5.00. Specifically, if the ratio of the area of the central portion 104a to the area of the covering portion 104b is less than about 0.03, it means that the area of the covering portion 104b is much larger than the area of the central portion 104a. In this case, due to the excessive area of the covering portion 104b, the polishing area on the polishing surface PS will be reduced, which may easily cause the object (object to be polished) to be polished simultaneously on the polishing area on the polishing surface PS and the covering portion 104b during the polishing process. 4b, or even worse, the object is mainly ground on the top surface TSb of the cover portion 104 during the grinding process rather than on the grinding area on the grinding surface PS that is primarily used to grind the object. This will affect the grinding performance, such as the flatness of the object being worse than expected, the object generating surface dishing, or the object being more susceptible to defects. If the ratio of the area of the central portion 104a to the area of the covering portion 104b is greater than approximately 5.00, it means that the area of the covering portion 104b is less than 1/5 of the area of the central portion 104a. In this case, because the area of the covering portion 104b is too small, that is, the width d of the covering portion 104b is very small, the interfacial bonding force between the central portion 104a and the covering portion 104b, and between the covering portion 104b and the polishing layer 102, due to the excessively small width d, will be unable to withstand the lateral shear force and the positive pressure (in the direction of gravity) applied to the polishing pad by the polishing head carrying the object during the polishing process, thereby causing the interface to separate or break. It is worth mentioning that by designing the area ratio of the central portion 104a to the covering portion 104b to be within a range of about 0.03 to about 5.00, the interfacial bonding strength between the detection window 104 and the polishing layer 102 is enhanced.

In this embodiment, as shown in FIG2B , the central portion 104 a has a top surface TSa and a bottom surface USa facing each other, wherein the top surface TSa of the central portion 104 a is adjacent to the polishing surface PS of the polishing layer 102, and the bottom surface USa of the central portion 104 a is also adjacent to the back surface BS of the polishing layer 102. In other words, the top surface TSa and the bottom surface USa of the central portion 104 a are coplanar with the top surface (i.e., the polishing surface PS) and the bottom surface (i.e., the back surface BS) of the polishing layer 102, respectively. On the other hand, as shown in FIG2B , the covering portion 104 b has a top surface TSb and a bottom surface USb facing each other, wherein the top surface TSb of the covering portion 104 b is adjacent to the polishing surface PS of the polishing layer 102, and the bottom surface USb of the covering portion 104 b is also adjacent to the back surface BS of the polishing layer 102. In other words, the top surface TSb and the bottom surface USb of the covering portion 104 b are coplanar with the top surface (i.e., the polishing surface PS) and the bottom surface (i.e., the back surface BS) of the polishing layer 102, respectively. From another perspective, in the embodiment shown in FIG2B , the top surface TSa of the central portion 104a, the top surface TSb of the cladding portion 104b, and the top surface of the polishing layer 102 (i.e., the polishing surface PS) are all coplanar; and the bottom surface USa of the central portion 104a, the bottom surface USb of the cladding portion 104b, and the bottom surface of the polishing layer 102 (i.e., the back surface BS) are all coplanar.

In this embodiment, the central portion 104a can be made of any material known to those skilled in the art for use as a detection window for a polishing pad. For example, the material of the central portion 104a of the detection window 104 can be a transparent polymer, such as a thermosetting plastic or a thermoplastic plastic. From another perspective, in this embodiment, the material of the central portion 104a is translucent under visible light. Specifically, the transmittance of the central portion 104a is at least 40% for light with a wavelength between 380 nm and 780 nm. Thus, when the polishing pad 100 is used to polish an object, the user can use the optical detection system to detect the polishing condition of the object through the central portion 104a of the detection window 104, so as to detect the end point of the polishing process and ensure the polishing quality.

In this embodiment, the coating portion 104b may include polyester, polyether, polyurethane, polycarbonate, polyacrylate, polybutadiene, or other polymeric substrates synthesized from suitable thermosetting resins or thermoplastic resins. In this embodiment, the material of the coating portion 104b is different from the material of the core portion 104a. Specifically, in one embodiment, the material of the core portion 104a is translucent under visible light, while the material of the coating portion 104b is not translucent under visible light. In another embodiment, the coating portion 104b and the core portion 104a have different hardnesses, and the ratio of the hardness of the core portion 104a to the hardness of the coating portion 104b is no greater than approximately 1.8. Specifically, if the ratio of the hardness of the central portion 104a to the hardness of the covering portion 104b is greater than approximately 1.8, the difference in hardness between the central portion 104a and the covering portion 104b is too large, causing the covering portion 104b to be easily squeezed by the central portion 104a during the polishing process, thereby damaging the interface between the central portion 104a and the covering portion 104b, thereby affecting the service life of the polishing pad. It is worth noting that by designing the ratio of the hardness of the central portion 104a to the hardness of the covering portion 104b to be within a range of no greater than approximately 1.8, not only is the interfacial bonding strength between the detection window 104 and the polishing layer 102 enhanced, but the wear rate of the central portion 104a and the covering portion 104b during the polishing process is also prevented from being significantly different, thereby affecting the polishing quality of the object, the detection quality of the detection window 104, or the life of the polishing pad.

From another perspective, in one embodiment, the material of the coating portion 104b is the same as the material of the polishing layer 102, that is, the coating portion 104b and the polishing layer 102 include the same polymer substrate. The aforementioned polymer substrate may include polyester, polyether, polyurethane, polycarbonate, polyacrylate, polybutadiene, or other polymer substrates synthesized from suitable thermosetting resins or thermoplastic resins. It should be noted that although the coating portion 104b and the polishing layer 102 are made of the same polymer substrate, the coating portion 104b and the polishing layer 102 can selectively have the same or different physical properties (such as hardness, density, or compressibility) by adjusting process conditions (such as, but not limited to, injection volume, gas pressure, reaction temperature, and mold design). Specifically, in one embodiment, polyurethane is selected as the polymer base material of the coating portion 104b and the polishing layer 102, and the coating portion 104b and the polishing layer 102 are manufactured using an injection molding method. By making the coating portion 104b and the polishing layer 102 have different process conditions (such as, but not limited to, injection volume, gas pressure, reaction temperature, and mold design), the resulting coating portion 104b and the polishing layer 102 can have different hardness, density, or compressibility. In other words, by adjusting the process conditions of the coating 104b and the polishing layer 102 (such as, but not limited to, the injection volume, gas pressure, reaction temperature, and mold design), the coating 104b and the polishing layer 102 can achieve predetermined physical properties (such as hardness, density, or compressibility). It is worth noting that by using the same material for the coating 104b and the polishing layer 102, the material properties of the coating 104b and the polishing layer 102 have better material compatibility, thereby effectively improving the interfacial bonding strength between the coating 104b and the polishing layer 102.

In another embodiment, the material of the coating 104b is different from that of the polishing layer 102. It should be noted that although the coating 104b and the polishing layer 102 are made of different polymer substrates, in addition to ensuring better material compatibility between the coating 104b and the polishing layer 102 by selecting different polymer substrates, the coating 104b and the polishing layer 102 can also be selectively adjusted to have similar physical properties (such as hardness, density, or compressibility) between the coating 104b and the polishing layer 102 by adjusting process conditions (such as, but not limited to, injection volume, gas pressure, reaction temperature, and mold design). This allows for better material compatibility between the coating 104b and the polishing layer 102, thereby effectively enhancing the interfacial bonding strength between the coating 104b and the polishing layer 102. It is worth mentioning that by adjusting process conditions (such as, but not limited to, injection volume, gas pressure, reaction temperature, mold design, etc.), the coating 104b and the polishing layer 102 made of different materials can have similar physical properties (such as hardness, density, or compressibility), which provides greater freedom in the selection of materials for the coating 104b and the polishing layer 102.

In this embodiment, the outer contours of the central portion 104a and the covering portion 104b can be designed into various shapes according to actual needs, such as a circle, an ellipse, a spindle, or a raindrop shape. In other words, the outer contours of the central portion 104a and the covering portion 104b can be irregular or regular geometric shapes. As shown in FIG2A , the outer contours of the central portion 104a and the covering portion 104b are both spindle-shaped. In other words, in this embodiment, the outer contours of the central portion 104a and the covering portion 104b are the same in shape and are both irregular. However, the present invention is not limited to this. In another embodiment, the outer contours of the central portion 104a and the covering portion 104b are the same in shape and are both regular geometric shapes. For example, as shown in FIG5A , the outer contours of the central portion 104a and the outer contours of the covering portion 104b are both circular. In another embodiment, the outer contours of the central portion 104a and the outer contours of the covering portion 104b are different. For example, as shown in FIG5B , the outer contour of the central portion 104a is circular, while the outer contour of the covering portion 104b is spindle-shaped; as shown in FIG5C , the outer contour of the central portion 104a is raindrop-shaped, while the outer contour of the covering portion 104b is circular; and as shown in FIG5D , the outer contour of the central portion 104a is raindrop-shaped, while the outer contour of the covering portion 104b is spindle-shaped, but the present invention is not limited thereto.

Furthermore, while Figures 2A and 2B illustrate a single detection window 104, the present invention is not limited thereto. In other embodiments, the number of detection windows 104 may be two, three, or more, depending on practical needs. In other words, as long as at least one detection window 104 is provided in the polishing layer 102, it falls within the scope of the present invention.

In another embodiment, the polishing pad may further include a base layer, which is disposed below the polishing layer. Specifically, as shown in FIG3 , the polishing pad 100′ includes a polishing layer 102 and a base layer 106, wherein the base layer 106 is located below the polishing layer 102. Specifically, the base layer 106 primarily functions to cushion the polishing layer 102 and is secured to a polishing platform (not shown). As shown in FIG3 , the base layer 106 is also located below the covering portion 104b of the detection window 104. Specifically, as shown in FIG3 , the inner surface S5 of the base layer 106 is substantially aligned with the inner surface S2 of the covering portion 104b. In other words, the covering portion 104b completely overlaps with the base layer 106. However, the present invention is not limited thereto. In another embodiment, when the interface between the coating 104b and the polishing layer 102 overlaps with the base layer 106, the inner surface S5 of the base layer 106 is not aligned with the inner surface S2 of the coating 104b (for example, there may be a distance between the inner surface S2 and the inner surface S5). Furthermore, in this embodiment, the base layer 106 may be bonded to the coating 104b and the polishing layer 102 via an adhesive layer (not shown). Furthermore, in this embodiment, the primary material of the base layer 106 may be, for example, polyurethane, polyethylene, polypropylene, a copolymer of polyethylene and ethylene vinyl acetate, or a copolymer of polypropylene and ethylene vinyl acetate, or any other currently known material that can be used for a base layer of a polishing pad.

It is worth mentioning that in this embodiment, by designing the ratio of the area of the central portion 104a to the area of the covering portion 104b to be between approximately 0.03 and approximately 5.00, and by making the bonding interface between the covering portion 104b and the central portion 104a overlap with the base layer 106, the interfacial bonding force between the detection window 104 and the polishing layer 102 can be effectively enhanced. When the polishing pad 100' is used to polish an object, the bonding interface between the covering portion 104b and the polishing layer 102 will not delaminate due to the applied downward pressure, thereby preventing polishing leakage to the delaminated area of the polishing pad and affecting the service life of the polishing pad. As a result, the interfacial bonding force between the detection window 104 and the polishing layer 102 in the polishing pad 100' is enhanced.

To verify the improved interfacial bonding strength between the detection window 104 and the polishing layer 102 proposed in the present invention, an interfacial bonding strength test was conducted. The test method and sample settings used in the experimental test are as follows, and the test results are listed in Tables 1-1 and 1-2.

Bonding strength test method: ASTM D412 standard test method is used to measure the bonding strength between the detection window and the polishing layer.

Samples 1 to 4: All of these samples are single-layer polishing pads with detection windows (i.e., polishing pads without a base layer). Sample 1 is equipped with a conventional detection window, while Samples 2 to 4 are equipped with the detection window of the present invention, comprising a central portion and an enveloping portion. The difference between the detection windows of Samples 2 to 4 lies in the ratio of the central portion area to the enveloping portion area.

Samples 5 to 8: All of these samples are double-layer polishing pads with detection windows (i.e., polishing pads comprising a polishing layer and a base layer). Sample 5 is equipped with a conventional detection window, while Samples 6 to 8 are equipped with the detection window of the present invention, comprising a central portion and an enveloping portion. The difference between the detection windows of Samples 6 to 8 lies in the ratio of the area of the central portion to the area of the enveloping portion.

Table 1-1 Sample 1 Sample 2 Sample 3 Sample 4 Ratio of center area to cladding area without 0.04 1.05 4.54 Bonding force (kgf/mm ² ) 93.6 130.6 128.2 101.5

Table 1-2 Sample 5 Sample 6 Sample 7 Sample 8 Ratio of center area to cladding area without 0.04 1.05 4.54 Bonding force (kgf/mm ² ) 79.9 136.7 118.0 84.9

As shown in Table 1-1, the bonding strength between the conventional detection window and the polishing layer in Sample 1 is 93.6 kgf/ ^mm² , while the bonding strength between the detection window of the present invention and the polishing layer in Samples 2 through 4 is 130.6 kgf/ ^mm² , 128.2 kgf/ ^mm², and 101.5 kgf/ ^mm² , respectively. The different bonding strengths in Samples 2 through 4 are due to the different center-to-cover area ratios. This indicates that the bonding strength between the detection window and the polishing layer in Samples 2 through 4 is superior to that in Sample 1. Similar experimental results can also be seen in Table 1-2. Specifically, the bonding force between the conventional detection window and the polishing layer in Sample 5 was 79.9 kgf/ ^mm² , while the bonding forces between the detection window of the present invention and the polishing layer in Samples 6 through 8 were 136.7 kgf/ ^mm² , 118.0 kgf/ ^mm² , and 84.9 kgf/ ^mm² , respectively. The different bonding forces in Samples 6 through 8 are due to the different area ratios of the center portion to the cladding portion. This indicates that the bonding force between the detection window and the polishing layer in the polishing pads of Samples 6 through 8 is better than that in the polishing pad of Sample 5. The results in Tables 1-1 and 1-2 above demonstrate that, regardless of whether the polishing pad is a single-layer polishing pad or a double-layer polishing pad consisting of a polishing layer and a base layer, replacing a conventional detection window with the detection window of the present invention can enhance the interfacial bonding strength between the detection window and the polishing layer. In other words, a detection window structure comprising a central portion and a covering portion, with a central portion area to covering portion area ratio designed within a range of approximately 0.03 to approximately 5.00, can indeed enhance the interfacial bonding strength between the detection window and the polishing layer in a polishing pad.

Table 2 below lists the bonding strength between the center portion and the cover portion of the detection window measured according to the ASTM D412 standard test method using polishing pad samples with different ratios of the center portion hardness to the cover portion hardness.

Samples 9 to 13 in Table 2 are all single-layer polishing pads having the detection window of the present invention, and Samples 9 to 13 have different ratios of the hardness of the center portion to the hardness of the coating portion.

Table 2 Sample 9 Sample 10 Sample 11 Sample 12 Sample 13 The ratio of the hardness of the center to the hardness of the covering 0.85 0.88 1.00 1.81 2.01 Bonding force (kgf/mm ² ) 217.7 207.3 93.6 87.6 87.8

As shown in Table 2, the ratio of the hardness of the detection window's center to the covering's hardness for Sample 9 is 0.85, resulting in a measured bonding force of 217.7 kgf/ ^mm² between the detection window's center and the covering. As the ratio of the hardness of the detection window's center to the covering's hardness increases to 0.88, 1.00, 1.81, and 2.01 for Samples 10, 13, and 14, the measured bonding forces between the detection window's center and the covering decrease to 207.3 kgf/ ^mm² , 93.6 kgf/ ^mm² , 87.6 kgf/ ^mm² , and 87.8 kgf/ ^mm² , respectively. As can be seen, as the ratio of the hardness of the detection window's center to the hardness of the covering increases, the bonding strength between the detection window's center and the covering decreases. From another perspective, when a trend graph is plotted with the ratio of the hardness of the detection window's center to the hardness of the covering on the horizontal axis and the bonding strength between the detection window's center and the covering on the vertical axis, it can be seen that when the ratio of the hardness of the center to the covering exceeds 1.8, the bonding strength converges and approaches a constant value. This result shows that by designing the ratio of the hardness of the center to the covering to be within a range of approximately 1.8 or less, the bonding strength between the center and the covering can be effectively improved. Furthermore, when the ratio of the hardness of the central portion to the hardness of the covering portion is designed to be within a range of no greater than about 1.8, and the ratio of the area of the central portion to the area of the covering portion is designed to be within a range of about 0.03 to about 5.00, the interfacial bonding strength between the detection window and the polishing layer can be improved (as shown in Tables 1-1 and 1-2 above).

6A to 6F are referenced below to illustrate the manufacturing method of the polishing pad 100. It should be noted that while the polishing pad 100 in the aforementioned embodiments is described using the manufacturing method described below as an example, the manufacturing method of the polishing pad 100 of the present invention is not limited thereto. The materials, thicknesses, and functions of the same or similar components of the polishing pad 100 have been described in detail above and will not be repeated here. Figures 6A to 6F are schematic cross-sectional views of the manufacturing process of a polishing pad according to one embodiment of the present invention.

First, the central portion 104a of the detection window 104 is formed. The central portion 104a has a predetermined outer contour. The outer contour can be an irregular shape or a regular geometric shape. For example, the outer contour can be as shown in Figures 5A to 5D. There are two methods for forming the central portion 104a having the predetermined outer contour. The first method is to pre-form the predetermined outer contour (e.g., a spindle shape) on a mold. After a curing process, the central portion 104a having the predetermined outer contour (e.g., a spindle shape) is obtained. The second method is to pre-form the predetermined outer contour (e.g., a spindle shape) on a mold. After a curing process, a light-transmitting material layer having a regular outer contour (e.g., a rectangle) is obtained. The light-transmitting material layer is then processed (e.g., machined) to form the central portion 104a having the predetermined outer contour (e.g., a spindle shape). In this embodiment, the first manufacturing method is used for explanation. As shown in FIG6A , a center portion 104a having a predetermined outer contour shape is directly formed by using a mold 10. The detailed steps are as follows: Provide a mold 10. The mold 10 has a mold cavity 12, which is used to accommodate molding material. In this embodiment, the shape and size of the mold cavity 12 are related to the shape and size of the outer contour of the center portion 104a to be formed subsequently. That is, as shown in FIG2A , the shape of the mold cavity 12 is spindle-shaped. In addition, in order to enable technical personnel in this field to clearly understand the present invention, in the following figures, only a part of the mold 10 is shown, that is, the upper cover structure of the mold 10 is omitted. Then, the light-transmitting material is filled into the mold cavity 12 of the mold 10, and a curing process is performed to form the center portion 104a in the mold 10. In the present embodiment, the method of filling the light-transmitting material into the mold cavity 12 of the mold 10 includes a pouring method. In the present embodiment, the curing process for curing the light-transmitting material includes an irradiation process, a heating process, a pressurization process, or a static process. In detail, the curing process includes, for example, irradiating or heating the light-transmitting material to cause a polymerization reaction to achieve curing; or, for example, causing the reactants in the light-transmitting material to undergo a natural polymerization reaction to achieve curing; or, for example, pressurizing the light-transmitting material to cause a polymerization reaction to achieve curing. Finally, the mold 10 is removed to obtain a center portion 104a having a predetermined outer contour shape. In this embodiment, the light-transmitting material used to form the center portion 104a is translucent under visible light.

Next, after forming the center portion 104a having a predetermined outer contour shape, a covering portion 104b having a predetermined outer contour shape is formed to obtain the detection window 104. The outer contour shape of the covering portion 104b can be as shown in Figures 5A to 5D. Please refer to Figures 6B and 6C at the same time to explain the method of directly forming the covering portion 104b having a predetermined outer contour shape by using a mold 20. The detailed steps are as follows: As shown in Figure 6B, a mold 20 is provided. The mold 20 has a mold cavity 22, which is used to accommodate molding material. In this embodiment, the shape and size of the mold cavity 22 are related to the shape and size of the outer contour of the covering portion 104b to be formed subsequently. That is, as shown in Figure 2A, the shape of the mold cavity 22 is spindle-shaped. Specifically, as shown in FIG2A , the outer contours of the central portion 104a and the outer contours of the covering portion 104b are identical, and thus the outer contours of the mold 20 can be identical to the outer contours of the mold 10. However, as previously described, the outer contours of the central portion 104a and the outer contours of the covering portion 104b can differ from each other. In this case, the outer contours of the mold 20 can also differ from the outer contours of the mold 10. Furthermore, to facilitate a clear understanding of the present invention by those skilled in the art, only a portion of the mold 20 is depicted in the following figures, i.e., the upper cover structure of the mold 20 is omitted. Subsequently, please continue to refer to FIG6B to arrange the central portion 104a at a specific position within the mold cavity 22 of the mold 20. Specifically, as shown in Figure 6B , the center portion 104a is spaced a distance from the inner edge of the mold 20. In this embodiment, as shown in Figure 6B , the thickness of the center portion 104a corresponds to the depth of the mold cavity 22. Furthermore, the center portion 104a can be secured to a specific position within the mold 20 by pressing the mold 20 against the upper cover structure or by adhesive.

Then, referring to both FIG. 6B and FIG. 6C , the coating material is filled into the mold cavity 22 of the mold 20 so as to surround the central portion 104a in the mold 20. In this embodiment, the method for filling the coating material into the mold cavity 22 of the mold 20 includes a pouring method. Next, a curing process is performed to cure the coating material to form a coating portion 104b that covers the central portion 104a in the mold 20. In this embodiment, the side surface S1 of the central portion 104a is connected to the inner surface S2 of the coating portion 104b. In this embodiment, the curing process for curing the coating material includes a light irradiation process, a heating process, a pressurization process, or a static process. In detail, the curing process includes, for example, irradiating the coating material with light or applying heat to cause a polymerization reaction to achieve curing; or, for example, causing the reactants in the coating material to undergo a natural polymerization reaction to achieve curing; or, for example, applying pressure to the coating material to cause the light-transmitting material to undergo a polymerization reaction to achieve curing. Finally, the mold 20 is removed to obtain the central portion 104a and the coating portion 104b having a predetermined outer contour shape. However, the present invention is not limited to this. In another embodiment, the method of forming the coating portion 104b having a predetermined outer contour shape can be divided into two steps: the first step is to use a mold to obtain a coating material layer having a conventional shape (e.g., a rectangle). The shape and size of the mold cavity 22 of the mold 20 used in this step are unrelated to the predetermined shape and size of the outer contour of the coating portion 104b to be formed subsequently. In this embodiment, after the coating material is cured to form a coating layer, a second step is performed in which the coating layer is processed (e.g., by mechanical processing) to remove a portion of the coating layer to form a coating portion 104b having a predetermined shape (e.g., a spindle shape). In this embodiment, the coating material used to form the coating portion 104b is different from the light-transmitting material used to form the central portion 104a. In this embodiment, as previously described, the predetermined shape is either an irregular shape or a regular geometric shape.

Next, after forming the detection window 104, a polishing layer 102 is formed to be bonded to the covering portion 104b of the detection window 104. Please refer to Figures 6D and 6E at the same time, and the polishing layer 102 is formed by using a mold 30. The detailed steps are as follows: As shown in Figure 6D, a mold 30 is provided. The mold 30 has a mold cavity 32, which is used to accommodate molding material. In this embodiment, the shape and size of the mold cavity 32 are related to the shape and size of the polishing layer 102 to be formed subsequently. That is, as shown in Figure 2A, the shape of the mold cavity 32 is circular. In addition, in order to enable technical personnel in this field to clearly understand the present invention, only a portion of the mold 30 is shown in the following figures, that is, the upper cover structure of the mold 30 is omitted. Next, referring to Figure 6D , a detection window 104 is placed at a specific location within the mold cavity 32 of the mold 30. This specific location corresponds to the position of the optical detection system. In this embodiment, as shown in Figure 6D , the thickness of the detection window 104 is equal to the depth of the mold cavity 32. Furthermore, the detection window 104 can be secured to the specific location of the mold 30 by pressing the mold 30 against the upper cover structure or by adhesive.

Then, referring to both FIG. 6D and FIG. 6E , the polishing layer material is filled into the mold cavity 32 of the mold 30 to surround the detection window 104 in the mold 30. In this embodiment, the method for filling the polishing layer material into the mold cavity 32 of the mold 30 includes a pouring method. Next, a curing process is performed to solidify the polishing layer material to form the polishing layer 102 in the mold 30. In this embodiment, the outer surface S3 of the covering portion 104b is connected to the inner surface S4 of the polishing layer 102. In this embodiment, the curing process for curing the polishing layer material includes a light irradiation process, a heating process, a pressurization process, or a static process. Specifically, the curing process may include, for example, irradiating the polishing layer material with light or applying heat to induce polymerization, thereby achieving curing; or, for example, causing reactants within the polishing layer material to undergo a natural polymerization reaction, thereby achieving curing; or, for example, applying pressure to the polishing layer material to induce polymerization of the light-transmitting material, thereby achieving curing. In one embodiment, the coating material used to form the coating portion 104b is the same as the polishing layer material used to form the polishing layer 102. In another embodiment, the coating material used to form the coating portion 104b is different from the polishing layer material used to form the polishing layer 102.

Finally, referring to both FIG. 6E and FIG. 6F , the mold 30 is removed to obtain a polishing pad 100 having a detection window 104, wherein the detection window 104 includes a central portion 104a and a covering portion 104b surrounding the central portion 104a, wherein the covering portion 104b is bonded to the polishing layer 102, and the ratio of the area of the central portion 104a of the detection window 104 to the area of the covering portion 104b is between approximately 0.03 and approximately 5.00, thereby improving the bonding strength between the detection window 104 and the polishing layer 102.

FIG7 is a schematic cross-sectional view of a manufacturing process for a polishing pad according to another embodiment of the present invention. Referring to FIG7 and FIG6F , the polishing pad 100′ shown in FIG7 is similar to the polishing pad 100 shown in FIG6F . Therefore, identical or similar components are denoted by identical or similar reference numerals, and the related descriptions are omitted. Specifically, the method for manufacturing the polishing pad 100′ differs from the method for manufacturing the polishing pad 100 in that, in the manufacturing process for the polishing pad 100′, after forming the polishing layer 102 and the detection window 104, a base layer 106 is formed beneath the covering portion 104b of the polishing layer 102 and the detection window 104. In one embodiment, for example, a continuous base layer material is first formed below the polishing layer 102 and the detection window 104, and then a portion of the base layer material corresponding to the central portion 104a of the detection window 104 is removed to form the base layer 106. Furthermore, in one embodiment, before forming the base layer 106 below the polishing layer 102 and the covering portion 104b of the detection window 104, an adhesive layer (not shown) may be optionally formed below the polishing layer 102 and the covering portion 104b of the detection window 104 to bond the base layer 106 to the polishing layer 102 and the covering portion 104b of the detection window 104. The adhesive layer is, for example, an adhesive layer, including but not limited to: carrier-free adhesive, double-sided adhesive, UV-curable adhesive, hot melt adhesive, moisture-curable adhesive, or pressure-sensitive adhesive (PSA). The materials of the adhesive layer are, for example, acrylic, epoxy, or polyurethane adhesives. However, the present invention is not limited thereto. In other embodiments, the base layer 106 can be formed directly beneath the polishing layer 102 and the covering portion 104b of the detection window 104 by coating, spraying, stacking, or printing, without the need for an adhesive layer. This also reduces the need to remove some of the base layer material.

FIG8 is a flow chart of a polishing method according to an embodiment of the present invention. This polishing method is suitable for polishing an object. Specifically, this polishing method can be applied to the polishing process for manufacturing industrial components, such as components used in the electronics industry, which may include semiconductors, integrated circuits, micro-electromechanical components, energy conversion, communications, optics, storage disks, and displays. The objects used to manufacture these components may include semiconductor wafers, IIIV wafers, storage device carriers, ceramic substrates, polymer substrates, and glass substrates, but the scope of the present invention is not limited thereto.

Referring to Figure 8 , first, step S10 is performed to provide a polishing pad. Specifically, in this embodiment, the polishing pad includes the polishing layer 100 or 100' described in any of the aforementioned embodiments. The polishing pad 100 and the polishing pad 100' have been described in detail above and will not be further elaborated here.

Next, step S12 is performed to apply pressure to the object, thereby pressing the object onto the polishing pad and causing it to contact the polishing pad. Specifically, as described above, the object contacts the polishing surface PS of the polishing layer 102. Alternatively, applying pressure to the object can be accomplished using, for example, a carrier capable of holding the object.

Next, step S14 is performed to provide relative motion between the object and the polishing pad, thereby polishing the object with the polishing pad to achieve planarization. Specifically, the relative motion between the object and the polishing pad can be achieved by, for example, rotating the polishing platform to drive the polishing pad fixed to the polishing platform to rotate.

In summary, in the polishing pad of the present invention, the detection window includes a central portion and a covering portion surrounding the central portion, the covering portion is bonded to the polishing layer, and the ratio of the area of the central portion to the area of the covering portion is between about 0.03 and about 5.00, thereby achieving improved bonding strength between the detection window and the polishing layer.

Furthermore, in the polishing pad of the present invention, the material selection for the cover portion of the detection window is chosen by selecting a material that has a high degree of adhesion to both the polishing layer and the center portion of the detection window to overcome stress issues during the polishing process. This also allows for greater freedom in the selection and matching of the polishing layer material and the detection window center material, thereby achieving the polishing quality required by the object.

Although the present invention has been disclosed above in the form of embodiments, it is not intended to limit the present invention. Anyone with ordinary skill in the art may make slight modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of the attached patent application.

10, 20, 30: Mold 12, 22, 32: Mold cavity 100, 100', P: Polishing pad 102: Polishing layer 104: Detection window 104a: Center 104b: Cover 106: Base layer B: Rotational BS: Back C: Left-right swing d: Width H: Polishing head S: Object S1: Side surface S2, S4, S5: Inner surface S3: Outer surface PS: Polishing surface S10, S12, S14: Steps TSa, TSb: Top surface USa, USb: Bottom surface

Figure 1 is a schematic cross-sectional view of a conventional polishing system. Figure 2A is a schematic top view of a polishing pad according to one embodiment of the present invention. Figure 2B is a schematic cross-sectional view taken along line A-A' of Figure 2A. Figure 3 is a schematic cross-sectional view of a polishing pad according to another embodiment of the present invention. Figures 4A to 4C are schematic cross-sectional views of the central portion, the cover portion, or the side surface of the polishing layer according to some embodiments of the present invention. Figures 5A to 5D are schematic top views of a detection window according to another embodiment of the present invention. Figures 6A to 6F are schematic cross-sectional views of a manufacturing process for a polishing pad according to one embodiment of the present invention. Figure 7 is a schematic cross-sectional view of a manufacturing process for a polishing pad according to another embodiment of the present invention. Figure 8 is a flow chart of a grinding method according to one embodiment of the present invention.

100: Grinding pad

102: Polishing layer

104: Detection Window

104a: Center

104b: Covering

BS: Back

d: width

S1: Side surface

S2, S4: Inner surface

S3: External surface

PS: Grinding surface

TSa, TSb: Top surface

USa, USb: bottom surface

Claims (18)

A method for manufacturing a polishing pad includes: forming a detection window, including: pre-positioning a central portion in a first mold; filling the first mold with a coating material and performing a first curing process to form a coating portion that covers the central portion, thereby forming the detection window; and forming a polishing layer, including: pre-positioning the detection window in a second mold; and pouring a polishing layer material into the second mold and performing a second curing process to form a polishing layer bonded to the coating portion. The method for manufacturing a polishing pad as described in claim 1, wherein the top surface of the central portion, the top surface of the covering portion, and the top surface of the polishing layer are all coplanar. The method for manufacturing a polishing pad as described in claim 1, wherein the bottom surface of the central portion, the bottom surface of the covering portion, and the bottom surface of the polishing layer are all coplanar. The method for manufacturing a polishing pad as described in claim 1, wherein the central portion is in direct contact with the covering portion. The method for manufacturing a polishing pad as described in claim 1, wherein a ratio of an area of the central portion to an area of the covering portion is between about 0.03 and about 5.00. The method for manufacturing a polishing pad as described in claim 1, wherein the ratio of the hardness of the central portion to the hardness of the covering portion is no greater than about 1.8. The method for manufacturing a polishing pad as described in claim 1, wherein the coating material is the same as the polishing layer material. The method for manufacturing a polishing pad as described in claim 1, wherein the coating material is different from the polishing layer material. The method for manufacturing a polishing pad as described in claim 1, wherein the center portion has a predetermined outer contour shape, and the outer contour shape is an irregular shape or a regular geometric shape. The method for manufacturing a polishing pad as described in claim 9, wherein the method for forming the center portion includes: pouring a light-transmitting material into a third mold and performing a third curing process. The method for manufacturing a polishing pad as described in claim 10, wherein the method for forming the center portion further includes: removing part of the center portion to form a shape having the predetermined outer contour. The method for manufacturing a polishing pad as described in claim 10, wherein the coating material is different from the light-transmitting material. The method for manufacturing a polishing pad as described in claim 10, wherein the light-transmitting material is light-transmitting under visible light. The method for manufacturing a polishing pad as described in claim 10, wherein the first curing process, the second curing process and the third curing process respectively include a light irradiation process, a heating process, a pressurization process or a static process. A method for manufacturing a polishing pad as described in claim 10, wherein the outer contour of the first mold is the same as the outer contour of the third mold. A method for manufacturing a polishing pad as described in claim 10, wherein the outer contour of the first mold is different from the outer contour of the third mold. The method for manufacturing a polishing pad as described in claim 10, wherein forming the detection window further includes: removing part of the covering portion to form a predetermined shape. The method for manufacturing a polishing pad as described in claim 17, wherein the predetermined shape is an irregular shape or a regular geometric shape.