Non-contact adsorption porous ceramic suction cup and manufacturing method thereof

Abstract

The invention discloses a non-contact adsorption porous ceramic suction cup and a manufacturing method thereof, a special gas circuit structure is arranged in a base, blowing airflow and adsorption airflow between the suction cup and an adsorbed workpiece are balanced, and non-contact adsorption clamping is realized by utilizing the comprehensive effect of gas suspension and vacuum adsorption prepressing; according to the invention, gas flows out on the whole porous ceramic surface, that is, a layer of gas film exists between the porous ceramic plate and an adsorbed workpiece, so that the adsorbed workpiece is uniformly subjected to the action of suspension force, and the problem of cracking of the workpiece caused by non-uniform stress in the non-contact adsorption process is further reduced; the vacuum adsorption holes distributed in the base are used for adsorption, the adsorption force is strong and stable, and the adsorption force equivalent to that of a common contact type porous ceramic suction cup can be obtained; due to the fact that the borne load is even, stable gaps can be formed between the porous ceramic plates, a precise plane is further formed, and high precision retentivity is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of vacuum adsorption, and in particular relates to a non-contact adsorption porous ceramic suction cup and a manufacturing method thereof. Background Art

[0002] In recent years, with the urgent need for damage-free and pollution-free wafers in the semiconductor industry, non-contact and low-stress adsorption and clamping methods have gained widespread attention. At present, the non-contact suction cups used in the industry all adopt the Bernoulli principle, that is, the suction cup ejects a high-speed airflow at a certain angle and direction. When the high-speed airflow contacts the workpiece, the airflow diffuses horizontally outward along the diameter of the suction cup from the center of the end face where the air jet is located, and takes away local air to form a low-pressure area between the suction cup and the workpiece. Under the action of air pressure, an adsorption force is generated to adsorb the workpiece on the suction cup.

[0003] However, due to the limitation of the Bernoulli suction cup principle, the size of the suction cup is limited. When the suction cup is large, the gas flow rate in the outer area of ​​the suction cup will decrease, and sufficient negative pressure will not be generated, which will cause the area to be unable to adsorb the workpiece or the adsorbed workpiece to sag, and the flatness of the adsorbed workpiece cannot be guaranteed. Therefore, the Bernoulli suction cup cannot adsorb larger workpieces. In addition, the Bernoulli suction cup has poor uniformity of adsorption force and relatively loud noise during operation. It can only be used in the handling process, and cannot be used in strict processes such as wafer measurement. Summary of the invention

[0004] The purpose of the present invention is to provide a non-contact adsorption porous ceramic suction cup and a method for manufacturing the same in view of the deficiencies of the above-mentioned prior art, which utilizes gas suspension and vacuum adsorption pre-pressing to achieve contactless, low-stress and high-precision adsorption clamping.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: A non-contact adsorption porous ceramic suction cup comprises a base, an adhesive layer and a porous ceramic plate, wherein the base and the porous ceramic plate are connected as a whole through the adhesive layer; The porous ceramic plate is provided with crisscrossed micropores inside, and the micropores are interconnected and penetrate the entire porous ceramic plate; The base is provided with a sink for embedding the porous ceramic plate and multiple vacuum channels and adsorption holes for adsorbing the workpiece. The vacuum channel is located inside the base and has multiple deep holes and is connected to a negative pressure gas source through a first air connection hole. The adsorption holes are arranged in a circular or linear array at intervals and are connected to the internal vacuum channel; The sink is designed to be circular or polygonal, and a gas flow channel for dispersing compressed air is opened at the bottom thereof and connected to a positive pressure gas source through a second gas connection hole. The gas flow channel includes a plurality of concentric annular grooves and a plurality of straight grooves radiating outward from the geometric center or crisscrossing straight grooves.

[0006] The top of the adsorption hole is in the same plane as the microporous ceramic.

[0007] A plurality of bosses for machining adsorption holes are reserved in the sink.

[0008] The base is made of stainless steel, aluminum alloy, alumina ceramics, silicon carbide ceramics, marble or PEEK.

[0009] The bonding layer is made of an organic polymer adhesive and has a thickness of 0.1-0.2 mm.

[0010] The porous ceramic plate has a micropore diameter of 2-20 μm and a porosity of 40-50 vol%.

[0011] The width of the gas flow channel is 2-6 mm, the spacing is 10-50 mm, and the depth is 0.5-1.5 mm.

[0012] A method for manufacturing a non-contact adsorption porous ceramic suction cup comprises the following steps: (1) Processing of porous ceramic suction cup base: By means of mechanical processing, a sink for embedding porous ceramic plates and multiple vacuum channels for adsorbing workpieces are processed on the base, and multiple bosses are reserved inside the sink for processing adsorption holes; A gas flow channel for dispersing compressed air is machined at the bottom of the sink; The vacuum flow channel is located inside the base. After processing, its opening is sealed and tested for tightness; (2) Processing porous ceramic plates: Grind the end surface of the sintered porous ceramic plate to make it smooth, with a thickness of 4-6mm and a flatness of ≦0.08mm; (3) Bonding the porous ceramic plate to the substrate: The upper surface of the base obtained in step (1) is roughened and cleaned, and then an adhesive is applied to embed the porous ceramic plate obtained in step (2). The bonding surface of the porous ceramic plate is brought into contact with the upper surface of the base by applying pressure, and the porous ceramic suction cup is obtained after the adhesive is naturally cured.

[0013] In step (1), the adsorption holes have a diameter of 3-6 mm and a spacing of 10-40 mm.

[0014] The beneficial effects of the present invention are: (1) The present invention discloses a non-contact adsorption porous ceramic suction cup and a method for making the same. A special air path structure is set in the base to balance the blowing airflow and adsorption airflow between the suction cup and the adsorbed workpiece, and the combined effect of gas suspension and vacuum adsorption pre-pressure is utilized to achieve non-contact adsorption clamping. Gas flows out on the entire porous ceramic surface, that is, there is a layer of air film between the porous ceramic plate and the adsorbed workpiece, so that the adsorbed workpiece is evenly affected by the suspension force, thereby reducing the problem of cracking of the workpiece due to uneven force during the non-contact adsorption process. Adsorption is performed through the vacuum adsorption holes arranged on the base, and the adsorption force is strong and stable, which can obtain an adsorption force equivalent to that of an ordinary contact porous ceramic suction cup. Due to the uniform load, a stable gap can be formed between the porous ceramic plates, thereby forming a precise plane with high precision retention.

[0015] (2) The porous ceramic suction cup of the present invention utilizes the combined effect of gas suspension and vacuum adsorption pre-pressure to achieve contactless adsorption clamping. The workpiece in non-contact adsorption is evenly supported by the air film. Since the load is evenly distributed, a stable gap can be formed between the porous ceramic plates, thereby forming a precise plane. Therefore, it has a high precision retention. In addition, the gap can be adjusted by adjusting the air supply pressure of the blowing airflow and the adsorption airflow, which has a high adjustment accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 It is a schematic diagram of the adsorption principle of the porous ceramic suction cup of the present invention; Figure 3 It is a top view of the base; Figure 4 is a cross-sectional view of the base; Figure 5 is a top view of the structure of Example 1; Figure 6 is a structural cross-sectional view of Example 1; Figure 7 is the optical detection result of the porous vacuum chuck adsorbing the wafer in Example 1; Figure 8 is a top view of the structure of Example 2; Fig. 9 It is a structural cross-sectional view of Example 2. DETAILED DESCRIPTION

[0017] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0018] The present invention provides a non-contact adsorption porous ceramic suction cup and a manufacturing method thereof, such as Figures 1 to 9 shown.

[0019] A non-contact adsorption porous ceramic suction cup comprises a base 1, an adhesive layer 2 and a porous ceramic plate 3, wherein the base 1 and the porous ceramic plate 3 are connected as a whole via the adhesive layer 2; the porous ceramic plate 3 is provided with criss-crossed micro pores inside, and the micro pores are interconnected and run through the entire porous ceramic plate 3.

[0020] The base 1 is provided with a sink for embedding the porous ceramic plate 3 and a plurality of vacuum channels 8 and adsorption holes 4 for adsorbing the workpiece. The vacuum channel 8 is located inside the base and has a plurality of deep holes and is connected to a negative pressure gas source through a first air connection hole, while the adsorption holes 4 are arranged in a circular or linear array at intervals and are connected to the internal vacuum channel 8; the top of the adsorption hole 4 is in the same plane as the microporous ceramic; an external vacuum source is sucked through the vacuum channel 8 inside the base and the adsorption holes 4 on the surface, thereby forming an adsorption force on the surface of the workpiece.

[0021] The sinking platform is set to be circular or polygonal, and its bottom is also provided with a gas flow channel 7 for dispersing compressed air and connected to a positive pressure gas source through a second air connection hole, and the gas flow channel 7 includes a plurality of concentric annular grooves and a plurality of straight grooves or criss-cross straight grooves radiating outward from the geometric center; the compressed air is evenly dispersed to the porous ceramic plate 3 embedded in the sinking platform through the gas flow channel 7, and then flows out evenly through the porous ceramic plate 3, thereby forming a uniform and stable backblowing airflow on the surface of the porous ceramic plate, so that the workpiece 5 floats on the porous ceramic surface with a very small gap 6.

[0022] During processing, multiple bosses are reserved in the sink for processing adsorption holes.

[0023] In this embodiment, the base 1 is made of stainless steel, aluminum alloy, alumina ceramics, silicon carbide ceramics, marble or PEEK; the bonding layer is made of an organic polymer adhesive to connect the porous ceramic plate and the base into a whole, and has a thickness of 0.1-0.2 mm.

[0024] The porous ceramic plate 3 is formed by putting inorganic powders such as alumina or silicon carbide into a molding mold, pressing and sintering, and forming countless criss-crossing micropores inside it through a sintering reaction. The micropores are interconnected and penetrate the entire porous ceramic plate; the pore size and porosity of the micropores on the surface of the porous ceramic plate are uniform, and the pore size of the micropores is 2-20μm and the porosity is 40-50 vol%.

[0025] The width of the gas flow channel 7 is 2-6 mm, the spacing is 10-50 mm, and the depth is 0.5-1.5 mm.

[0026] A method for manufacturing a non-contact adsorption porous ceramic suction cup comprises the following steps: (1) Processing of porous ceramic suction cup base: By means of mechanical processing, a sink for embedding porous ceramic plates and multiple vacuum channels for adsorbing workpieces are processed on the base, and multiple bosses are reserved inside the sink for processing adsorption holes; The sink inlaid with porous ceramic plates is circular or polygonal in shape, with an outline size slightly larger than the corresponding workpiece size by 3-5mm and a depth of 4-6mm.

[0027] The adsorption holes are located on the bosses reserved in the sink inlaid with porous ceramic plates and are connected with the vacuum flow channel. The diameter of the adsorption holes is 3-6 mm, which is consistent with the diameter of the vacuum flow channel. The adsorption holes are arranged in a circular or linear array with a spacing of 10-40 mm. When arranged in a circular array, 6-12 holes are arranged on each circle.

[0028] A gas flow channel for dispersing compressed air is machined at the bottom of the sink; The gas flow channel is located below the sink for inlaying the porous ceramic plate on the base, and is composed of multiple concentric annular grooves and multiple straight grooves radiating outward from the geometric center or criss-crossing straight grooves, with a width of 2-6mm, a spacing of 10-50mm, and a depth of 0.5-1.5mm.

[0029] The vacuum flow channel is located inside the base. After processing, its opening is sealed and tested for tightness; Preferably, the vacuum flow channel is composed of 6-12 deep holes inside the base, with a diameter of 3-6 mm; after processing, the hole openings are sealed by welding or installing plugs; after sealing, a sealing test is performed, that is, the wafer is adsorbed at the adsorption hole, the vacuum pressure range is -80KPa to -85KPa, and the flow meter in the vacuum air path is read after 10 minutes, and the flow meter reading is 0-0.1L / min.

[0030] (2) Processing porous ceramic plates: The end surface of the sintered porous ceramic plate is ground flat, the thickness is controlled at 4-6mm, and the flatness is ≤0.08mm; then, the porous ceramic plate of corresponding shape and size is matched according to the shape and size of the base sink.

[0031] (3) Bonding the porous ceramic plate to the substrate: The upper surface of the base obtained in step (1) is roughened and cleaned, and then an adhesive is applied to embed the porous ceramic plate obtained in step (2). The bonding surface of the porous ceramic plate is brought into contact with the upper surface of the base by applying pressure, and the porous ceramic suction cup is obtained after the adhesive is naturally cured.

[0032] The non-contact adsorption porous ceramic suction cup and its manufacturing method, by arranging a special air path structure in the base, balancing the blowing airflow and adsorption airflow between the suction cup and the adsorbed workpiece, and utilizing the comprehensive effect of gas suspension and vacuum adsorption pre-pressure, thereby realizing non-contact adsorption clamping; gas flows out on the entire porous ceramic surface, that is, there is a layer of air film between the porous ceramic plate and the adsorbed workpiece, so that the adsorbed workpiece is evenly affected by the suspension force, thereby reducing the problem of cracking of the workpiece due to uneven force during the non-contact adsorption process; adsorption is carried out through the vacuum adsorption holes arranged on the base, the adsorption force is strong and stable, and the adsorption force equivalent to that of an ordinary contact porous ceramic suction cup can be obtained; due to the uniform load, a stable gap can be formed between the porous ceramic plates, thereby forming a precise plane with high precision retention.

[0033] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0034] Example 1 A Φ303×5mm sink is milled on a Φ320×20 aluminum alloy base, and 44 Φ6 bosses are reserved in the sink, and the upper surface of the boss is in the same plane as the upper surface of the base. The bosses are concentric circles and evenly distributed, with a total of 5 layers arranged from the geometric center of the base outward, and their diameters are Φ40mm, Φ80mm, Φ130mm, Φ180mm, Φ230mm, and Φ280mm respectively. From the center outward, the number of bosses arranged in each layer is 4, 8, 8, 8, 8, and 8, respectively.

[0035] 8 evenly distributed Φ4 holes are processed on the side of the base, which are processed deeply to the center, and M5 threads are processed at the hole mouths. After processing, they are sealed with M5 plugs to obtain vacuum flow channels; 44 Φ4 vacuum holes, i.e. adsorption holes, are processed on 44 bosses. The vacuum holes are concentric with the Φ6 bosses and are connected with the deep holes, i.e. vacuum flow channels; 1 M5 threaded hole, i.e. the first air connection hole, is processed on the back of the base, which is connected with the deep hole and serves as the air connection hole for the vacuum adsorption source.

[0036] Seven concentric annular grooves are milled on the bottom of the sink table, with a width of 4mm and a depth of 1mm. The center diameters of the annular grooves are Φ24mm, Φ60mm, Φ105mm, Φ155mm, Φ205mm, Φ255mm and Φ296mm from the inside to the outside; 8 evenly distributed straight grooves are machined from the center to the outside, with a width of 4mm and a depth of 1mm, which penetrate all the concentric annular grooves; an M5 through hole is machined in the straight groove, i.e., the second air hole, which serves as the air hole for the positive pressure blowing air source; after completing the above processing, the base substrate of the porous ceramic suction cup can be obtained.

[0037] The two end surfaces of the porous ceramic plate with an average pore size of 10 μm and a porosity of 41% are ground flat, the thickness is controlled at 5 mm, and the flatness of the two end surfaces is ≤ 0.08 mm.

[0038] The surface of the base is roughened and cleaned, and then an adhesive is applied to the surface and the porous ceramic plate of the present invention is inserted; the base is then placed on a marble slab, and a 350×350×15 mm marble slab is placed on it for pressing. After the adhesive is naturally cured for 24 hours, the porous ceramic suction cup of the present invention can be obtained.

[0039] The porous ceramic suction cup can stably adsorb 12-inch silicon wafers under the blowing pressure of 50kPa and the adsorption vacuum pressure of -80kPa. The gap between the wafer and the porous ceramic plate is about 60um. During optical inspection, the 12-inch can remain stationary without vibration. Under the uniform support of the uniform air film, the problems such as sagging deformation caused by gravity are solved, the flatness of the workpiece itself is guaranteed, the distortion of the inspection results is avoided, and the inspection process requirements can be met.

[0040] Example 2 A 325×225×4mm sink is machined on a flat marble base, and 55 Φ8 bosses are reserved in the sink, and the upper surface of the boss is in the same plane as the upper surface of the base. The bosses are evenly distributed linearly, with a total of 5 rows and 11 columns; the row spacing is 40mm, and the column spacing is 30mm.

[0041] 12 Φ6 holes are processed on the side of the base, 11 of which penetrate in the Y direction and 1 penetrates in the X direction. M8 threads are processed at the hole mouths. After processing, they are sealed with M8 plugs to obtain vacuum flow channels; 55 Φ6 vacuum holes are processed on 55 bosses, which are adsorption holes. The adsorption holes are concentric with the Φ8 bosses and are connected with the deep holes, i.e., the vacuum flow channels; 1 Rc1 / 8 threaded hole is processed on the back of the base, i.e., the first air connection hole, which is connected with the deep hole and serves as the air connection hole for the vacuum adsorption source.

[0042] 72 crisscross straight grooves are milled on the bottom of the sink, with a width of 4mm and a depth of 1.5mm; there are 72 crisscross straight grooves in total, of which 12 are evenly arranged in the X direction with a spacing of 30mm, and 6 are evenly arranged in the Y direction with a spacing of 40mm. A Rc1 / 8 hole is machined in the straight groove, i.e., the second air connection hole, and its bottom hole is connected as the air connection hole for the positive pressure blowing air source; after completing the above processing, the base body of the porous ceramic suction cup can be obtained.

[0043] The two end surfaces of the porous ceramic plate with an average pore size of 2-5 μm and a porosity of 50% are ground flat, the thickness is controlled at 4 mm, and the flatness of the two end surfaces is ≤ 0.08 mm.

[0044] The surface of the base is roughened and cleaned, and then an adhesive is applied to the surface and the porous ceramic plate of the present invention is inserted; the base is then placed on a marble slab, and a 350×350×15 mm marble slab is placed on it for pressing. After the adhesive is naturally cured for 24 hours, the porous ceramic suction cup of the present invention can be obtained.

[0045] Under the action of blowing pressure of 80kPa and adsorption vacuum pressure of -80kPa, the porous ceramic suction cup can stably adsorb glass with a size of 320×220×1mm, and the gap between the glass and the porous ceramic plate is about 50um; the glass can remain stationary on the porous ceramic surface without vibration.

[0046] If the words "first", "second" and the like are used in this patent to limit components, those skilled in the art should know that the use of "first" and "second" is only for the convenience of describing the present invention and simplifying the description, and the above words have no special meaning.

[0047] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the invention claimed for protection. The scope of protection claimed for the present invention is defined by the attached claims and their equivalents.

[0048] In the description of the present invention, it is necessary to understand that the terms "front", "rear", "left", "right", "center", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the protection content of the present invention.

Claims

1. A non-contact adsorption porous ceramic suction cup, characterized in that: It comprises a base, an adhesive layer and a porous ceramic plate, wherein the base and the porous ceramic plate are connected as a whole through the adhesive layer; The porous ceramic plate is provided with crisscrossed micropores inside, and the micropores are interconnected and penetrate the entire porous ceramic plate; The base is provided with a sink for embedding the porous ceramic plate and multiple vacuum channels and adsorption holes for adsorbing the workpiece. The vacuum channel is located inside the base and has multiple deep holes and is connected to a negative pressure gas source through a first air connection hole. The adsorption holes are arranged in a circular or linear array at intervals and are connected to the internal vacuum channel; The sink is designed to be circular or polygonal, and a gas flow channel for dispersing compressed air is opened at the bottom thereof and connected to a positive pressure gas source through a second gas connection hole. The gas flow channel includes a plurality of concentric annular grooves and a plurality of straight grooves radiating outward from the geometric center or crisscrossing straight grooves.

2. The non-contact adsorption porous ceramic suction cup according to claim 1, characterized in that: The top of the adsorption hole is in the same plane as the microporous ceramic.

3. The non-contact adsorption porous ceramic suction cup according to claim 1, characterized in that: A plurality of bosses for machining adsorption holes are reserved in the sink.

4. The non-contact adsorption porous ceramic suction cup according to claim 1, characterized in that: The base is made of stainless steel, aluminum alloy, alumina ceramics, silicon carbide ceramics, marble or PEEK.

5. The non-contact adsorption porous ceramic suction cup according to claim 1, characterized in that: The bonding layer is made of an organic polymer adhesive and has a thickness of 0.1-0.2 mm.

6. The non-contact adsorption porous ceramic suction cup according to claim 1, characterized in that: The porous ceramic plate has a micropore diameter of 2-20 μm and a porosity of 40-50 vol%.

7. The non-contact adsorption porous ceramic suction cup according to claim 1, characterized in that: The width of the gas flow channel is 2-6 mm, the spacing is 10-50 mm, and the depth is 0.5-1.5 mm.

8. A method for manufacturing a non-contact adsorption porous ceramic suction cup according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Processing of porous ceramic suction cup base: By means of mechanical processing, a sink for embedding porous ceramic plates and multiple vacuum channels for adsorbing workpieces are processed on the base, and multiple bosses are reserved inside the sink for processing adsorption holes; A gas flow channel for dispersing compressed air is machined at the bottom of the sink; The vacuum flow channel is located inside the base. After processing, its opening is sealed and tested for tightness; (2) Processing porous ceramic plates: Grind the end surface of the sintered porous ceramic plate to make it smooth, with a thickness of 4-6mm and a flatness of ≦0.08mm; (3) Bonding the porous ceramic plate to the substrate: The upper surface of the base obtained in step (1) is roughened and cleaned, and then an adhesive is applied to embed the porous ceramic plate obtained in step (2). The bonding surface of the porous ceramic plate is brought into contact with the upper surface of the base by applying pressure, and the porous ceramic suction cup is obtained after the adhesive is naturally cured.

9. The method for manufacturing a non-contact adsorption porous ceramic suction cup according to claim 8, characterized in that: In step (1), the adsorption holes have a diameter of 3-6 mm and a spacing of 10-40 mm.

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