ATTACHMENT AND DETACHMENT DEVICE

Abstract

An attachment and detachment device that excels in responsiveness to attachment and detachment of a workpiece even when the workpiece is thin while utilizing an electrostatic chuck method is provided. The attachment and detachment device that enables suction and separation of a workpiece includes a machinable ceramic layer, an adhesion activating layer provided on the machinable ceramic layer, an electrode layer provided on the adhesion activating layer, and a dielectric layer provided on the electrode layer, wherein the electrode layer is covered with the adhesion activating layer and the dielectric layer, and the dielectric layer has a volume resistivity of 10.sup.9 to 10.sup.12 Ω.Math.cm.

Claims

1. An attachment and detachment device enabling suction and separation of a workpiece, the device comprising: a machinable ceramic layer; an adhesion activating layer provided on the machinable ceramic layer; an electrode layer provided on the adhesion activating layer; and a dielectric layer provided on the electrode layer, wherein the electrode layer is covered with the adhesion activating layer and the dielectric layer, and the dielectric layer has a volume resistivity of 10.sup.9 to 10.sup.12 Ω.Math.cm.

2. The attachment and detachment device according to claim 1, wherein the workpiece has a thickness of 0.001 to 1.5 mm.

3. The attachment and detachment device according to claim 1, wherein the workpiece is any of a conductor, a semiconductor, or an insulator.

4. The attachment and detachment device according to claim 1, wherein the workpiece is any of a flake, foil, paper, or a film.

5. The attachment and detachment device according to claim 1, wherein the adhesion activating layer has a volume resistivity of 10.sup.9 to 10.sup.12 Ωcm or 10.sup.14 to 10.sup.16 Ωcm.

6. The attachment and detachment device according to claim 1, wherein the dielectric layer and/or the electrode layer includes a sealing hole.

7. The attachment and detachment device according to claim 1, wherein the adhesion activating layer includes a sealing hole.

8. The attachment and detachment device according to claim 1, wherein the electrode layer constitutes a unipolar electrode or a bipolar electrode to which voltages having different polarities are applied.

9. The attachment and detachment device according to claim 1, wherein the electrode layer includes a plurality of partitioned regions partitioned in an array.

10. The attachment and detachment device according to claim 2, wherein the workpiece is any of a conductor, a semiconductor, or an insulator.

11. The attachment and detachment device according to claim 2, wherein the workpiece is any of a flake, foil, paper, or a film.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 is a schematic explanatory cross-sectional view showing an example of an attachment and detachment device in a workpiece transfer device of the present invention.

[0025] FIG. 2 is a schematic explanatory diagram showing a manufacturing procedure of the attachment and detachment device according to the present invention.

DESCRIPTION OF EMBODIMENTS

[0026] Hereinafter, the present invention will be described with reference to the figures.

[0027] FIG. 1 shows an example of an attachment and detachment device of the present invention. The attachment and detachment device 10 according to the present example includes a machinable ceramic layer 1 made of machinable ceramics, an adhesion activating layer 4 which is formed of a second ceramic sprayed film on the machinable ceramic layer 1, an electrode layer 5 (5a and 5b) formed of a metal sprayed film, and a dielectric layer 6 which is formed of a first ceramic sprayed film to cover the electrode layer 5, and the dielectric layer 6 has a volume resistivity of 10.sup.9 to 10.sup.12 Ω.Math.cm. Further, an external DC power supply 7 (7a and 7b) is connected to the electrode layer 5 via a power supply terminal 3. In the example of FIG. 1, an electrode 5a is a positive electrode, an electrode 5b is a negative electrode, and these constitute bipolar electrodes. Also, although an example of an attachment and detachment device having a set of bipolar electrodes is shown here, it may be configured such that the electrode layer 5 has a plurality of partitioned regions partitioned in an array, and each bipolar electrode (or unipolar electrode) corresponding to each partitioned region is provided, so that electrodes to be operated can be selected in accordance with a shape of a workpiece W.

[0028] The workpiece W sucked and separated by the attachment and detachment device 10 is a conductor, a semiconductor, or an insulator having a thickness of 0.001 to 1.5 mm. For example, a lead frame used when a semiconductor package such as an LSI is manufactured is made of a conductor such as a Cu alloy and has a thickness of about 0.01 to 1.5 mm. In the case of transferring (supplying) such a lead frame to a die bonding device or the like, it is generally performed at room temperature. Thus, if the attachment and detachment device 10 of the present invention is used for transferring such a lead frame, the dielectric layer 6 has a volume resistivity of the above value.

[0029] Further, the adhesion activating layer 4 in this case may have a volume resistivity of 10.sup.9 to 10.sup.12 Ω.Math.cm as in the dielectric layer 6, and the volume resistivity may be set to 10.sup.14 to 10.sup.16 Ω.Math.cm, which is relatively high, but the volume resistivity is preferably 10.sup.9 to 10.sup.12 Ω.Math.cm from the viewpoint of reducing the residual charge when the power supply is turned off. In the case of sucking the lead frame as described above, a voltage of about DC±200 to 500 V may be applied respectively to the electrodes 5a and 5b, and in the case of requiring a higher suction force, or in a case in which the workpiece is thick or has some warpage, it is preferable that the volume resistivity of the adhesion activating layer 4 be 10.sup.9 to 10.sup.12 Ω.Math.cm since a higher applied voltage is required (about DC±750 to 1,500 V).

[0030] As a method of obtaining such an attachment and detachment device 10, for example, it can be manufactured by the procedure as shown in FIG. 2. First, as shown in FIG. 2(a), a plate-shaped machinable ceramic is prepared, and if necessary, machining such as cutting or polishing to a predetermined size is performed thereon to prepare the machinable ceramic layer 1. In that case, the machining may be performed in accordance with a size and a shape of the lead frame to be sucked, and the thickness is not particularly limited, but it is preferably about 3 to 30 mm in consideration of handling and the like. Further, through holes 2 for fitting power supply terminals 3 for feeding the electrodes 5a and 5b may be prepared in advance. In that case, since the machinable ceramic itself is an insulator (generally, the volume resistivity is about 10.sup.14 to 10.sup.15 Ω.Math.cm), it is not particularly necessary to attach a sleeve for the purpose of insulation.

[0031] Next, as shown in FIG. 2(b), the power supply terminals 3 are mounted into the through holes 2 formed in the machinable ceramic layer 1. In that case, while considering a thickness of the adhesion activating layer 4, tip portions of the power supply terminals 3 are made to protrude toward the electrode layer 5 so that they can be connected to the electrode layer 5. Further, in this case, a surface of the machinable ceramic layer 1 may be blasted.

[0032] Next, as shown in FIG. 2(c), the second ceramic sprayed film is sprayed to form the adhesion activating layer 4. In the case of the attachment and detachment device for attaching and detaching a lead frame, the thickness of the adhesion activating layer 4 is about 0.03 to 1.0 mm.

[0033] Next, as shown in FIG. 2(d), the metal sprayed film is sprayed to form the electrode layer 5. In that case, a part of the electrode may be removed so that the electrode layer 5 (electrodes 5a and 5b in the example of FIG. 2) having a predetermined shape is formed by performing masking processing in accordance with a shape of the electrode using a heat-resistant masking tape or a heat-resistant resist, etc., or using a method such as blasting after spraying the electrode layer without masking processing. Also, a thickness of each electrode forming the electrode layer 5 is about 0.03 to 0.15 mm, as in the previous case.

[0034] Next, as shown in FIG. 2(e), the first ceramic sprayed film is sprayed to cover the electrode layer 5 to form the dielectric layer 6. As in the previous case, as the thickness of the dielectric layer 6 here, it is preferable that the thickness of the dielectric layer 6 provided on a surface of the electrode layer 5 be about 0.1 to 1.0 mm.

[0035] Then, after the thermal spraying process is completed, the dielectric layer 6, the electrode layer 5, and the adhesion activating layer 4 are subjected to sealing processing, and a method thereof is not particularly limited and for example, impregnation processing may be performed using a resin solution having a predetermined solid content concentration. Next, the dielectric layer 6 is surface-polished, and if necessary, surface roughness is adjusted by wrapping or polishing, and thus the attachment and detachment device can be obtained.

EXAMPLES

[0036] Hereinafter, an example of the present invention will be described in more detail.

[0037] Four types of attachment and detachment devices were prepared as shown in Table 1 below in the present example. Devices 1 and 2 are attachment and detachment devices according to the example of the present invention. Devices 3 and 4 are comparative examples. Among them, the device 1 includes an electrode layer configured of two square electrodes having a size of 136 mm×8.15 mm×thickness 0.05 mm formed by a tungsten (W) sprayed film and a dielectric layer made of Al.sub.2O.sub.3—TiO.sub.2 sprayed film of 140 mm×170 mm×thickness 0.3 mm on a machinable ceramic layer consisting of 140 mm×170 mm×thickness 9.65 mm Photoveel (a product name manufactured by Ferrotec Ceramics Corporation) via an adhesion activating layer made of an Al.sub.2O.sub.3—TiO.sub.2 sprayed film having a size of 140 mm×170 mm×thickness 0.05 mm. Also, the device 2 is the same as the device 1 except that it includes an adhesion activating layer made of an Al.sub.2O.sub.3 sprayed film having a size of 140 mm×170 mm×thickness 0.05 mm. Further, the device 3 is the same as the device 1 except that the adhesion activating layer is not used. Furthermore, the device 4 uses a metal base material made of aluminum instead of the machinable ceramic layer and uses a polyimide film as the dielectric layer or the like. In addition, in attachment and detachment devices of these devices 1 to 3, the dielectric layer, the electrode layer, and the adhesion activating layer are sealed with a silicone impregnating agent. Also, the volume resistivities of the dielectric layer, the adhesion activating layer, and the machinable ceramic layer are as shown in the table (the volume resistivity is a value after the sealing processing).

TABLE-US-00001 TABLE 1 Attachment and detachment Laminated Volume device structure Material resistivity Device 1 Dielectric layer Al.sub.2O.sub.3—TiO.sub.2 3.86 × 10.sup.11 Ω .Math. cm sprayed film Electrode layer W sprayed film (Conductor) Adhesion Al.sub.2O.sub.3—TiO.sub.2 3.86 × 10.sup.11 Ω .Math. cm activating layer sprayed film Machinable Photoveel 4,57 × 10.sup.15 Ω .Math. cm ceramic layer Device 2 Dielectric layer Al.sub.2O.sub.3—TiO.sub.2 3.86 × 10.sup.11 Ω .Math. cm sprayed film Electrode layer W sprayed film (Conductor) Adhesion Al.sub.2O.sub.3 sprayed 5.78 × 10.sup.15 Ω .Math. cm activating layer film Machinable Photoveel 4.57 × 10.sup.15 Ω .Math. cm ceramic layer Device 3 Dielectric layer Al.sub.2O.sub.3—TiO.sub.2 3.86 × 10.sup.11 Ω .Math. cm sprayed film Electrode layer W sprayed film (Conductor) — — — Machinable Photoveel 4.57 × 10.sup.15 Ω .Math. cm ceramic layer Device 4 Dielectric layer Polyimide film 9.67 × 10.sup.16 Ω .Math. cm Electrode layer Cu foil (Conductor) Insulating layer Polyimide film 9.67 × 10.sup.16 Ω .Math. cm Metal base Aluminum (Conductor) material

[0038] (Film Adhesion Force Test)

[0039] A film adhesion force was evaluated using a tensile tester for the attachment and detachment devices of the devices 1 to 3 prepared in the above. In the test, an epoxy adhesive was applied to a test area of φ8 mm of the dielectric layer forming a workpiece suction surface and fixed to the test area, and a tensile test was performed. The tensile test was performed three times for each device, and a value at which the film was peeled off was converted into an area to determine the adhesion force.

[0040] The results and positions of fracture surfaces are as shown in Table 2, and it was found that the adhesion force of the film was superior in the devices 1 and 2 as compared with the device 3. That is, it was confirmed that the adhesion force of the sprayed film was further improved by providing the adhesion activating layer.

TABLE-US-00002 TABLE 2 Attachment and Adhesion Average detachment force value device Test (MPa) (MPa) Fracture surface Device 1 First 12.3 11.8 Adhesion activating layer- machinable ceramic layer Second 10.9 Adhesion activating layer- machinable ceramic layer Third 12.1 Adhesion activating layer- machinable ceramic layer Device 2 First 12.5 12.3 Adhesion activating layer- machinable ceramic layer Second 11.3 Adhesion activating layer- machinable ceramic layer Third 13.2 Adhesion activating layer- machinable ceramic layer Device 3 First 7.4 7.6 Electrode layer-machinable ceramic layer Second 6.9 Electrode layer-machinable ceramic layer Third 8.5 Electrode layer-machinable ceramic layer

[0041] (Workpiece Dechuck Test)

[0042] A workpiece dechuck test was conducted on the devices 1 and 2 having an excellent film adhesion force to examine separation properties (dechuck properties) after sucking the workpiece. At that time, for comparison reference, the workpiece dechuck test was also performed on the device 4 using a polyimide film. As shown in Table 1 above, the device 4 uses polyimide films of 120 mm×120 mm×thickness 0.05 mm instead of the dielectric layer and the adhesion activating layer. In addition, the device 4 uses two square electrodes of 100 mm×100 mm×thickness 0.01 mm formed of a copper foil (Cu foil) as the electrode layer. Further, the device 4 uses an aluminum metal base material having a size of 120 mm×120 mm×thickness 5 mm instead of the machinable ceramic layer.

[0043] As the workpiece, a commercially available aluminum foil cut out to 80 mm×80 mm was used. Further, in order to suck the aluminum foil, a voltage of DC±300 V was applied to the electrode layers of the devices 1, 2, and 4. In the test, the aluminum foil was sucked with the workpiece suction surface facing downward in a vertical direction, and a time required for the aluminum foil to drop due to its own weight after the voltage was cut off (after turned off) was measured three times with each device.

[0044] The results are as shown in Table 3. In the devices 1 and 2, after the voltage applied to the electrode layer was cut off, the aluminum foil immediately dropped and showed good dechuck properties. On the other hand, in the device 4, the aluminum foil may not fall due to its own weight, and separation of the workpiece could not be controlled.

TABLE-US-00003 TABLE 3 Attachment and Dechuck Average detachment time value device Test (second) (second) Device 1 First ≤1 ≤1 Second ≤1 Third ≤1 Device 2 First ≤1 ≤1 Second ≤1 Third ≤1 Device 3 First 3 — Second Not peeled Third 6

[0045] (Static Elimination Property of Workpiece Suction Surface)

[0046] For the devices 1 and 2 having an excellent film adhesion force, a surface potential of the workpiece suction surface when a voltage of DC±300 V is applied to the electrode layer is measured, and the surface potential of the workpiece suction surface was measured after the voltage is turned off using a surface electrometer. At the same time, a decay time of the surface potential after the voltage was turned off was measured to evaluate static elimination properties on the workpiece suction surface.

[0047] The results are as shown in Table 4, and it was confirmed that charge on the workpiece suction surface was quickly eliminated within 1 second for all the devices.

TABLE-US-00004 TABLE 4 Measure- Measure- ment ment Attachment result result and Applied in on- in off- Decay detachment voltage state state time device Test (V) (V) (V) (second) Device 1 First +300 +320 ≤±15 ≤1 to +340 −300 −310 ≤±15 to −330 Second +300 +330 ≤±15 to +350 −300 −320 ≤±15 to −340 Third +300 +330 ≤±15 to +350 −300 −310 ≤±15 to −330 Device 2 First +300 +310 ≤±15 ≤1 to +340 −300 −330 ≤±15 to −350 Second +300 +320 ≤±15 to +350 −300 −320 ≤±15 to −350 Third +300 +310 ≤±15 to +350 −300 −320 ≤±15 to −340

[0048] (Static Elimination of Machinable Ceramic Layer)

[0049] Similarly, for the devices 1 and 2, a surface potential of the machinable ceramic layer when a voltage of DC±300 V is applied to the electrode layer was measured, and the surface potential of the machinable ceramic layer after the voltage is cut off was measured using a surface electrometer. At the same time, the decay time of the surface potential after the voltage was cut off was measured to evaluate the static elimination properties of the machinable ceramic layer.

[0050] The results are shown in Table 5, and it was confirmed that charge of the machinable ceramic layer was eliminated within 5 seconds in each device, and that the device 1 in particular had good static elimination properties. That is, all of them have good dechuck properties, and the charge on the workpiece suction surface is removed within 1 second, and thus it is considered that the dechuck properties of these devices 1 and 2 are extremely good.

TABLE-US-00005 TABLE 5 Measure- Measure- ment ment Attachment result result and Applied in on- in off- Decay detachment voltage state state time device Test (V) (V) (V) (second) Device 1 First +300 +320 +40 ≤5 to +340 to +60 −300 −310 +10 to −330 to +20 Second +300 +330 +40 to +350 to +70 −300 −320 +20 to −340 to +40 Third +300 +330 +50 to +350 to +70 −300 −310 +20 to −330 to +30 Device 2 First +300 +400 +90 ≤5 to +430 to +110 −300 −180 +100 to −220 to +120 Second +300 +380 +70 to +420 to +100 −300 −200 +90 to −230 to +110 Third +300 +390 +90 to +430 to +110 −300 −190 +100 to −220 to +120

REFERENCE SIGNS LIST

[0051] 1 Machinable ceramic layer [0052] 2 Through hole [0053] 3 Power supply terminal [0054] 4 Adhesion activating layer [0055] 5 Electrode layer [0056] 6 Dielectric layer [0057] 7 DC power supply [0058] 8 Workpiece suction surface [0059] 10 Attachment and detachment device