Handling device

Abstract

A handling device (10) comprises: a vibration plate (20) that holds a product in a contactless manner; a base (12) that supports the vibration plate (20); and a vibration element (40) that applies vibration to the vibration plate (20), thereby generating an ultrasonic holding force in the vibration plate (20). The vibration plate (20) has a peripheral portion (24) that is fixed to the base (12), and a central portion (22) that is connected so as to be capable of vibrating with respect to the peripheral portion (24) and amplifies the vibration applied by the vibration element (40).

Description

Handling Device

[0001] This specification discloses a handling device that uses ultrasound to hold products without contact.

[0002] Handling devices that use ultrasonic waves to hold products without contact have been known for some time. For example, Patent Document 1 discloses a holding device that includes an ultrasonic vibrator, a horn that amplifies and transmits the ultrasonic vibrations generated by the ultrasonic vibrator, and a vibration plate attached to the end of the horn. This holding device holds an object without contact by using the ultrasonic squeeze effect generated on the surface of the vibration plate.

[0003] Patent No. 5402542

[0004] However, such ultrasonic handling devices typically require a long axial horn, which inevitably increases the overall size of the handling fixture in the prior art.

[0005] Therefore, this specification discloses a handling device that can be made even more compact.

[0006] The handling device disclosed in this specification comprises a vibrating plate that holds a product without contact, a base that supports the vibrating plate, and a vibration element that applies vibrations to the vibrating plate to generate an ultrasonic holding force in the vibrating plate, and is characterized in that the vibrating plate has a peripheral portion fixed to the base and a central portion that is connected so as to be able to vibrate relative to the peripheral portion and amplifies the vibrations applied from the vibration element.

[0007] In this case, a groove or a gap penetrating the diaphragm in the thickness direction may be formed between the central portion and the peripheral portion. Also, a gap penetrating the diaphragm in the thickness direction may be formed between the central portion and the peripheral portion, and the central portion and the peripheral portion may be connected by a bridge crossing the gap. Also, the bridge may be disposed symmetrically with respect to the center of the central portion.

[0008] The outer shape of the central portion may be substantially the same as the outer shape of the product.

[0009] The end face of the central portion may protrude further toward the held product than the end face of the peripheral portion.

[0010] A space may be present between the base and the central portion.

[0011] The vibration elements may be fixed to the vibration plate. In this case, the vibration elements may be fixed to the back surface of the peripheral portion. The vibration elements may be arranged symmetrically with respect to the center of the central portion. The vibration elements may be fixed to the vibration plate with an adhesive, and the thickness of the adhesive may be sufficient to fill in any surface roughness of the vibration plate.

[0012] The mass of the diaphragm may be smaller than the mass of the base. The specific gravity of the diaphragm may be smaller than the specific gravity of the base. The diaphragm may be made of a material having a higher vibration Q value than the base. In this case, the diaphragm may be made of aluminum, titanium, or an alloy thereof, and the base may be made of stainless steel, copper, or a copper alloy.

[0013] The central portion may have a suction hole formed therein for sucking the product. In this case, a flexible tube may be provided for fluidly connecting the suction hole to a suction source. The central portion may have a terminal surface formed with a plurality of airflow-forming grooves connected to the suction hole.

[0014] According to the technology disclosed in this specification, the central portion can be vibrated relative to the peripheral portions, so that the central portion can be vibrated appropriately without providing a horn, which results in a smaller handling device.

[0015] Fig. 1 is a bottom view of a handling device; Fig. 2 is a schematic cross-sectional view of a handling device; Fig. 3 is a view explaining the principle of product adsorption; Fig. 4 is a bottom view of an example of another vibrating plate; Fig. 5 is a bottom view of an example of another vibrating plate; Fig. 6 is a cross-sectional view of an example of another vibrating plate; Fig. 7 is a bottom view of an example of another vibrating plate.

[0016] The configuration of the handling device 10 will be described below with reference to the drawings. Fig. 1 is a bottom view of the handling device 10. Fig. 2 is a schematic cross-sectional view of the handling device 10 taken along line A-A. Note that in Fig. 1, only the diaphragm 20 is hatched.

[0017] The handling device 10 is a device that uses ultrasonic waves to hold products in a non-contact manner. In the following, the handling device 10 that holds semiconductor chips will be described as an example of a product. However, the type of product that can be held is not particularly limited. Therefore, the handling device 10 is not limited to semiconductor chips, and may hold other products, such as precision machine parts and precision medical instruments, as products.

[0018] As shown in Figure 2, the handling device 10 is broadly divided into a base 12 and a diaphragm 20. The base 12 is a generally block-shaped member that is fastened to the diaphragm 20. The base 12 is rectangular in plan view, and fastening protrusions 14 that protrude toward the diaphragm 20 are formed at the four corners of the base 12. These fastening protrusions 14 are screwed into fastening portions 34 of the diaphragm 20, which will be described later. In other words, only the fastening protrusions 14 of the base 12 are in contact with the diaphragm 20. Therefore, most of the base 12 is separated from the diaphragm 20, and a space exists between the base 12 and the diaphragm 20.

[0019] The base 12 is connected to a moving mechanism (not shown). For example, when the handling device 10 is applied to a pickup device that picks up the semiconductor chips 100 from a wafer, the handling device 10 is incorporated into a collet that picks up the semiconductor chips 100, and the base 12 is mechanically connected to a collet drive unit that moves the collet in the up, down, left, and right directions.

[0020] The diaphragm 20 is a plate-like member fastened to the base 12. As shown in FIGS. 1 and 2, the diaphragm 20 is roughly divided into a central portion 22 and a peripheral portion 24. The central portion 22 is the portion that actually holds the product. A gap 30 is formed around the periphery of the central portion 22, penetrating through in the thickness direction. As shown in FIG. 3, the semiconductor chip 100, which is the product, is held with a space between it and the bottom surface of the central portion 22. The principle of this holding will be described later. Hereinafter, the surface of the diaphragm 20 that faces the product will be referred to as the "holding surface 37," and the opposite surface will be referred to as the "rear surface 38."

[0021] The outer shape of the central portion 22 is approximately the same as the outer shape of the product to be held. In this example, since the semiconductor chip 100 to be held is rectangular, the central portion 22 is also rectangular. As shown in FIG. 2 , the end surface of the central portion 22 (i.e., the holding surface 37) protrudes slightly downward (i.e., toward the product to be held) from the end surface of the peripheral portion 24. This is to prevent the peripheral portion 24 from coming into contact with the product when picking it up.

[0022] A suction hole 32 is formed at the center of the central portion 22, penetrating in the thickness direction. A suction tube 46 made of a flexible material is airtightly connected to this suction hole 32. The suction tube 46 fluidly connects a suction source 48, such as a vacuum pump, to the suction hole 32. Negative pressure is supplied to the suction hole 32 by the suction source 48 and the suction tube 46. This negative pressure acts on the product in a direction toward the central portion 22, as will be described later.

[0023] The central portion 22 is capable of vibrating relative to the peripheral portion 24. Specifically, as described above, a gap 30 penetrating the central portion 22 and the peripheral portion 24 in the thickness direction is formed between them. The central portion 22 is only partially connected to the peripheral portion 24 via the connecting portions 26. In this example, the connecting portions 26 are four bridges 28 spanning the gap 30. The four bridges 28 are arranged symmetrically around the central portion 22. Specifically, two bridges 28 are provided on each long side of the central portion 22, for a total of four bridges 28. Therefore, the four corners of the central portion 22 are free ends that are not connected to the peripheral portion 24. When vibration is applied to the diaphragm 20, the bridges 28 bend slightly, causing the central portion 22 to vibrate relative to the peripheral portion 24. Note that, as shown in FIG. 2 , in this example, the bridges 28 are made thinner than the peripheral portion 24 so that they can bend easily.

[0024] The peripheral portion 24 is a generally circular portion that completely surrounds the periphery of the central portion 22. As shown in FIG. 1 , the peripheral portion 24 has four fastening portions 34 that protrude radially outward. Each fastening portion 34 has a fastening hole 36 through which a fastening bolt is inserted. As described above, the diaphragm 20 is screwed and fastened to the base 12 at these fastening portions 34.

[0025] 1 and 2, a vibration element 40 is directly fixed to the rear surface 38 of the vibration plate 20. The vibration element 40 is, for example, a unimorph type vibration element formed by bonding a thin piezoelectric element to a metal plate. In this example, the vibration element 40 is fixed to the peripheral portion 24, i.e., the outside of the central portion 22. The vibration elements 40 are also arranged symmetrically with respect to the central portion 22.

[0026] The vibration element 40 is fixed to the vibration plate 20 by, for example, an adhesive. At this time, the thickness of the adhesive is made as thin as possible. For example, the adhesive is made thick enough to fill the surface roughness of the vibration plate 20. The vibration element 40 is electrically connected to an AC power supply 42. The vibration element 40 generates ultrasonic vibrations in response to the AC voltage supplied from the AC power supply 42.

[0027] The mass and material of the diaphragm 20 are selected so that it vibrates efficiently. Specifically, in this example, the size and material of the diaphragm 20 are selected so that the mass of the diaphragm 20 is smaller than the mass of the base 12. Furthermore, the materials of the diaphragm 20 and the base 12 are selected so that the specific gravity of the diaphragm 20 is smaller than the specific gravity of the base 12 and so that the vibration Q value of the diaphragm 20 is larger than the vibration Q value of the base 12. The vibration Q value is a numerical value that represents the damping characteristics of vibration; the larger the vibration Q value, the more difficult the damping and the longer the vibration lasts. The vibration Q value is calculated by dividing the resonance frequency at the resonance peak by ω ０ The frequencies at which the vibration energy becomes half the value of the resonance peak on both the left and right sides of the resonance peak are defined as ω １ , ω ２ In this case, Q = ω ０ / (ω ２ -ω １ A combination that satisfies these conditions may be, for example, a combination in which the material of the diaphragm 20 is aluminum, titanium, or an alloy thereof, and the material of the base 12 is stainless steel, copper, or a copper alloy.

[0028] The controller 50 is physically a computer having a processor 52 and a memory 54. The controller 50 controls the operation of the suction source 48 and the AC power supply 42 so that the product can be properly held in the central section 22. This will be described with reference to FIG.

[0029] When an alternating voltage is applied to the vibration element 40, the vibration plate 20 undergoes ultrasonic vibration. In particular, the central portion 22, which is only partially connected to the base 12, undergoes large ultrasonic vibrations. When the semiconductor chip 100, which is a product, is brought close to the central portion 22 while this ultrasonic vibration is occurring, an ultrasonic squeeze effect occurs between the holding surface 37 of the central portion 22 and the semiconductor chip 100. The ultrasonic squeeze effect occurs when one of two flat plates facing each other across a small gap is vibrated, causing a pressure higher than the external pressure to be generated within the gap due to the influence of viscosity within the gap. When this ultrasonic squeeze effect occurs, an air film Sf is formed between the semiconductor chip 100 and the central portion 22, preventing contact between the two, and a holding force is generated that holds the semiconductor chip 100 on the holding surface 37.

[0030] Here, the holding force generated by the ultrasonic squeeze effect (hereinafter referred to as "ultrasonic holding force") occurs in both a direction perpendicular to the holding surface 37 and a direction parallel to the holding surface 37 (i.e., the planar direction). That is, when the ultrasonic squeeze effect occurs, a force acts on the semiconductor chip 100 in a direction that moves it away from the holding surface 37 or causes it to float up from the holding surface 37. Furthermore, when the ultrasonic squeeze effect occurs, the semiconductor chip 100 tends to remain within the vibration plane. Therefore, even if the semiconductor chip 100 is temporarily displaced in the planar direction due to an external force, the semiconductor chip 100 tends to move in the planar direction so that the entire semiconductor chip 100 is positioned within the vibration plane, and tends to return to a state facing the center portion 22.

[0031] The thickness of the air film (hereinafter referred to as "ultrasonic squeeze film Sf") generated by the ultrasonic squeeze effect, i.e., the floating amount Df of the semiconductor chip 100 from the holding surface 37, increases as the ultrasonic energy increases (i.e., the amplitude of the ultrasonic vibration increases).Furthermore, the ultrasonic holding force also increases as the ultrasonic energy increases.

[0032] In this example, to assist this ultrasonic holding force, a suction force due to negative pressure is also generated in the central portion 22. The controller 50 controls the driving of the suction source 48 and the AC power supply 42 so that the suction force, the ultrasonic holding force, and the gravity acting on the semiconductor chip 100 are balanced when the semiconductor chip 100 is floating above the central portion 22.

[0033] Here, when the ultrasonic squeeze effect occurs, the semiconductor chip 100 tries to position itself within the vibration plane. Therefore, if the outer shape of the central portion 22 is made substantially the same as that of the semiconductor chip 100, the ultrasonic squeeze effect will cause the semiconductor chip 100 to automatically move in the planar direction so that the entire semiconductor chip 100 is positioned within the vibration plane (i.e., within the area inside the outer shape of the central portion 22). In other words, by making the outer shape of the central portion 22 substantially the same as that of the semiconductor chip 100, self-alignment in the planar direction of the semiconductor chip 100 is possible.

[0034] Conventionally, in order to effectively vibrate the central portion 22, a horn that amplifies the vibration has been placed between the vibration element 40 and the central portion 22. However, providing such a horn increases the size of the handling device 10. On the other hand, in this example, as described above, the central portion 22 is only partially connected to the peripheral portion 24. This configuration makes it easier for the central portion 22 to vibrate. Furthermore, in this example, the materials and masses of the central portion 22 and the base 12 are selected so that the central portion 22 vibrates more easily.

[0035] This allows the central portion 22 to vibrate sufficiently even if the vibration element 40 is directly fixed to the vibration plate 20. As a result, according to this example, a horn is not required, and the handling device 10 can be significantly reduced in size.

[0036] If the suction tube 46 connected to the central portion 22 is rigid, the movement of the central portion 22 may be restricted by the suction tube 46. In this case, the central portion 22 cannot vibrate sufficiently, and an appropriate ultrasonic squeezing effect cannot be obtained. In this example, as described above, the suction tube 46 is a flexible tube that can be easily deformed. Therefore, the suction tube 46 does not inhibit the vibration of the central portion 22. As a result, the central portion 22 can be vibrated appropriately.

[0037] The configuration described above is merely an example, and other configurations may be modified as long as the configuration described in claim 1 is included. For example, the outer shape of the central portion 22 may be modified as appropriate. For example, when holding a square semiconductor chip 100, the outer shape of the central portion 22 may be square, as shown in FIG. 4. Furthermore, the outer shape of the central portion 22 may be a geometric shape such as a circle or a triangle, or a non-geometric shape such as a cloud.

[0038] The number and positions of the bridges 28 may also be changed as appropriate. For example, as shown in Fig. 4, one or more bridges may be provided on each of the four sides that form the outline of the rectangular central portion 22. The number of bridges 28 may also be two or more than four.

[0039] The peripheral portion 24 may also be divided into two or more portions. For example, as shown in Fig. 5, the peripheral portion 24 may be divided into two portions and disposed on both the left and right sides of the central portion 22. The shape of the peripheral portion 24 may also be changed as appropriate. For example, the peripheral portion 24 may be substantially rectangular, as shown in Fig. 5.

[0040] In the above description, a gap 30 is formed around the central portion 22, penetrating the central portion 22 in the thickness direction, and the central portion 22 and the peripheral portion 24 are connected by a bridge 28. However, other configurations are possible as long as the central portion 22 can vibrate relative to the peripheral portion 24, in other words, as long as the connecting portion 26 can easily bend. For example, as shown in FIG. 6 , a partitioning groove 60 may be formed around the central portion 22 instead of the gap 30. By forming the partitioning groove 60, a thin-walled portion 62 is formed around the central portion 22. This thin-walled portion 62 functions as the connecting portion 26 connecting the central portion 22 and the peripheral portion 24. Note that this thin-walled portion 62 has less rigidity than the peripheral portion and is easily bent. As a result, the provision of the thin-walled portion 62 allows the central portion 22 to vibrate relative to the peripheral portion 24.

[0041] 7, a plurality of airflow forming grooves 64 connected to the suction holes 32 may be formed on the bottom surface of the central portion 22. When such airflow forming grooves 64 are formed, the positioning accuracy of the semiconductor chip 100 in the surface direction is improved compared to when such airflow forming grooves 64 are not formed. The principle behind this effect is presumably that the formation of the airflow forming grooves 64 increases and stabilizes the airflow in the surface direction that flows between the semiconductor chip 100 and the bottom surface of the central portion 22.

[0042] In another embodiment, the suction holes 32 may be omitted, as well as the airflow forming grooves 64. In other words, the product may be held only by ultrasonic holding force, without relying on suction holding force. Also, although the vibration plate 20 and the base 12 have been described as separate components in the above explanation, they may be integrated. Furthermore, the vibration element 40 may be fixed to another location. For example, the vibration element 40 may be fixed to the side of the vibration plate 20.

[0043] 10 Handling device, 12 Base, 14 Fastening protrusion, 20 Vibration plate, 22 Central portion, 24 Peripheral portion, 26 Connecting portion, 28 Bridge, 30 Gap, 32 Suction hole, 34 Fastening portion, 36 Fastening hole, 37 Holding surface, 38 Back surface, 40 Vibration element, 42 AC power supply, 46 Suction tube, 48 Suction source, 50 Controller, 52 Processor, 54 Memory, 60 Partition groove, 62 Thin portion, 64 Airflow forming groove, 100 Semiconductor chip, Sf Ultrasonic squeeze membrane.

Claims

1. A handling device comprising: a vibration plate for holding a product without contacting it; a base for supporting the vibration plate; and a vibration element for generating an ultrasonic holding force in the vibration plate by applying vibration to the vibration plate, wherein the vibration plate has a peripheral portion fixed to the base, and a central portion connected so as to be able to vibrate relative to the peripheral portion and amplifying the vibration applied from the vibration element.

2. A handling device as claimed in claim 1, characterized in that a groove or a gap penetrating the vibration plate in the thickness direction is formed between the central portion and the peripheral portion.

3. A handling device as described in claim 2, characterized in that a gap is formed between the central portion and the peripheral portion, penetrating the vibration plate in the thickness direction, and the central portion and the peripheral portion are connected by a bridge that crosses the gap.

4. A handling device according to claim 3, characterized in that the bridges are arranged symmetrically with respect to the center of the central portion.

5. A handling device according to claim 1, characterized in that the outer shape of said central portion is substantially the same as the outer shape of said product.

6. A handling device as claimed in claim 1, characterized in that the end face of the central portion protrudes in a direction closer to the product being held than the end face of the peripheral portion.

7. A handling device according to claim 1, characterized in that a space is present between said base and said central portion.

8. A handling device according to claim 1, characterized in that the vibration element is fixed to the vibration plate.

9. A handling device according to claim 8, characterized in that the vibration element is fixed to the rear surface of the peripheral portion.

10. A handling device according to claim 9, characterized in that the vibration elements are arranged symmetrically with respect to the center of the central portion.

11. A handling device according to any one of claims 8 to 10, characterized in that the vibration element is fixed to the vibration plate by an adhesive, and the thickness of the adhesive is sufficient to fill in any surface roughness of the vibration plate.

12. A handling device according to claim 1, characterized in that the mass of the vibration plate is smaller than the mass of the base.

13. A handling device according to claim 1, characterized in that the specific gravity of the vibration plate is smaller than the specific gravity of the base.

14. A handling device according to claim 13, characterized in that the diaphragm is made of a material having a vibration Q value greater than that of the base.

15. A handling device according to claim 13 or 14, characterized in that the vibration plate is made of aluminum, titanium, or an alloy thereof, and the base is made of stainless steel, copper, or a copper alloy.

16. A handling device according to claim 1, characterized in that a suction hole for sucking the product is formed in the central portion.

17. A handling device according to claim 16, characterized in that it comprises a flexible tube fluidly connecting said suction hole with a suction source.

18. A handling device according to claim 16 or 17, characterized in that a plurality of airflow forming grooves connected to the suction holes are formed on the end surface of the central portion.

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