The above and other features and advantages of the present invention will become more apparent through the following detailed description of exemplary embodiments thereof, made with reference to the attached drawings, in which:
Various preferred embodiments of the present invention will now be described in detail, examples of which are illustrated in the accompanying drawings. The invention may, of course, be embodied in many different forms and should not be construed as being limited to the various preferred embodiments set forth herein. Rather, these exemplary embodiments are provided only by way of example so that this disclosure will be thorough and complete, and will convey the inventive concepts to those skilled in the art. Like reference numerals refer to like elements throughout the drawings.
According to various principles of the present invention, a system for sensing a shape of a chip may use a lower lighting unit. The chips whose shapes are sensed using the embodiments described herein are not limited to those used for processing an electrical signal but may include any number of a variety of chip types. For example, the chip may be provided with a pattern for processing electrical signals, such as a semiconductor memory device. Alternatively, however, the chip may lack such a pattern. The specific details of the chip are therefore relevant only with regards to the sensing of its shape..
A process for picking up a chip during a semiconductor manufacturing process will be discussed by way of example to describe the various embodiments of the present invention. However, the system is not limited to the picking-up process and may be applied to any process in which a shape of the chip is to be identified. In the picking-up process, a picker picks up the chip and transfers it to another device, such as a sorter. Before picking up the chip, a process for sensing a shape of the chip may be desirable.
Referring to
The chip 122 may have a deformed shape within an allowable range. For example, the chips produced through a singulation process, where individual chips are cut and divided apart from their original wafer, may either be flat or somewhat bent. These variations in the shapes of the chips 122 may be considered when setting an allowable error range within which the shape of the chip is regarded as capable of being accurate sensed. The allowable error may vary in accordance with a process property, a shape of the chip, and the like.
The chip 122 may be mounted or attached, as discussed above, on the support plate 120 in a conventional method. The support plate 120 is preferably formed of a transparent or a semitransparent material so that light 130 can pass through the support plate 120. For purposes of this disclosure, the terms “transparent” and “semitransparent” mean that at least some portion of incident light is able to pass through the support plate 122. “Transparent” means that at least slightly more light is able to pass through as compared to “semitransparent.”The optical sensing unit 140 is preferably configured to sense light having an intensity equal to or greater than a predetermined threshold value. The predetermined threshold value may vary in accordance with the process, the shape of the chip 122, a type of the support plate 120, and other factors. The support plate 120 is preferably formed of a material that can transmit light 130 from the lower lighting unit 112 with an intensity equal to or higher than the threshold value. The support plate 120 may be constructed in a variety of forms, such as a film, a sheet, or other forms. The support plate 120 may, for example, be formed of a polymer film.
The lower lighting unit 112 preferably includes a light emission surface. A light source 114 may be used as the lower lighting unit 112 itself. Alternatively, the lower lighting unit 112 may include a waveguide layer 116 housing the light source 114. The light source 114 may, for instance, be selected from the group consisting of a light emitting diode (LED), a halogen lamp, a fluorescent lamp, an incandescent lamp, an organic LED, or other light sources. The number and arrangement of light sources 114 in the lower lighting unit 112 may vary as needed. To uniformly emit the light 130, however, the light sources 114 are preferably arranged spaced apart from each other by an equal interval, or facing each other along a circumference of the lower lighting unit 112.
The lower lighting unit 112 may be configured to sense one or more chips 122, and is not limited to any particular structure or shape. For example, the lower lighting unit 112 may comprise a flat plate form or may be formed by a plurality of light sources 114 separated and gathered in island-like groups. The lower lighting unit 112 may directly contact the support plate 120 or it may be spaced apart from the support plate 120 by a predetermined distance.
The waveguide layer 116 may also be formed of a transparent or a semitransparent material, for instance such as Teflon resin or acryl resin. The particular style of support 110 may be selected considering the handling purpose of the chip 122. For example, the support 110 may comprise a plunger, as will be described in detail later.
A method of sensing the shape of the chip 122 will now be described according to another aspect of the present invention. Again referring to
As illustrated in
Since the light 130 has known directionality, it is suitable for transferring an image corresponding to the boundary portion 124 of the support plate 120 to the optical sensing unit 140. Accordingly, using the sensing system 100 of this exemplary embodiment, the boundary portion 124 may be sensed by the optical sensing unit 140, and the shape of the chip 122 can thereby be accurately determined. In this manner, the problems experienced by the prior art, including inaccurate shape determination due in large part to unclear boundary portions 124, can be solved. It should be noted that although an image of the chip 122 having a rectangular shape is shown in
While the light 130 emitted from the lower lighting unit 112 may be slightly refracted or diffracted while passing through or exiting the support plate 120, as long as a size of the image sensed by the optical sensing unit 140 is within an allowable range (when compared with an actual size of the chip 122), the identification of the shape of the chip 122 is possible. In addition, even when the chip 122 is deformed or bent, the shape of the chip 122 can still be sensed if the light 130 emitted from the lower lighting unit 112 is within the allowable range.
It is sometimes desirable to determine a location of a center of the chip 122. This can also be readily accomplished using the principles of the present invention. Referring still to
Other features and aspects of the present invention will now be further described. Referring again to
In an alternative embodiment, an upper lighting unit (not shown) may also be provide to emit light toward the chip 122 from above. The upper lighting unit may perform a different function than that of the lower lighting unit 112. For example, the upper lighting unit may be used to generally observe a wafer having a plurality of chips 122. The upper lighting unit may also be used to measure or inspect chips 122 having a relatively small deformation, or to detect chip deformations.
The support 240 may be formed of a transparent or a semitransparent material, for example, such as Teflon resin or acryl resin, that permits light to pass through it. The support 240 may be arranged at an upper portion of the lower lighting unit 200, with a plurality of holes 250 formed therethrough to receive pins 220 of a plunger 210. The pins 220 of the plunger 210 may slide through the holes 250 to push the chip 122 upward. Electric wires 260 may be inserted in a side portion of the support 240. The electric wires 260 may be connected by a connection terminal 270 to a control unit 280. Electric power supplied to the light sources 230 may thereby be controlled using the control unit 280.
The support 240 may be formed of a transparent or a semitransparent material that permits the light from the light sources 230 to pass through it. The support 240 is again provided at an upper portion of the lower lighting unit 200. In this case, the support 240 includes an opening through which a plunger 310 can move to push the chip 122 upward. Electric wires 260 may be inserted in a side portion of the support 240 and connected to a control unit 280 through a connection terminal 270. The plunger 310 in this embodiment is preferably formed in a pyramid shape to push the chip upward. The plunger 310 itself may be formed of a transparent or a semitransparent material, for instance, such as Teflon resin or acryl resin, so that the light can pass through it.
In this embodiment, however, the support 240 can include a vacuum shutter 410 arranged at an upper portion thereof to hold the support plate 120 (see
The vacuum shutter 410 is preferably configured to open and close the vacuum holes 420 to supply and cut off the vacuum force to the support plate 120. The vacuum shutter 410 may open or close the vacuum holes 420, for example, by sliding across the support 240. The chip 122 and the support plate 120 can thereby be selectively held or released from the support 240 by controlling the vacuum shutter 410. The vacuum shutter 410 may be formed of a transparent or a semitransparent material such as Teflon resin or acryl resin so that the light can pass through it.
As can be seen from the above description of various preferred embodiments, according to the principles of the present invention, a system can accurately sense the shape of a chip by utilizing a lower lighting unit emitting light towards the chip from below. Using a system and method according to these principles, the shape of the chip can be reliably sensed even when the chip is thin and deformed or warped. In particular, the use of a binary image, for instance, can aid in the accurate sensing of chip shape.
While the present invention has been particularly shown and described with reference to various exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that changes in the form and details of those embodiments may be made without departing from the spirit and scope of the present invention as defined by the following claims.
Number | Date | Country | Kind |
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2006-0048307 | May 2006 | KR | national |