WO2008120883A1

WO2008120883A1 - Apparatus for inspection of semiconductor device and method for inspection using the same

Info

Publication number: WO2008120883A1
Application number: PCT/KR2008/001637
Authority: WO
Inventors: Ssang-Gun Lim; Sang-Yun Lee; Yeong-Su Shin
Original assignee: Intekplus Co., Ltd
Priority date: 2007-03-30
Filing date: 2008-03-24
Publication date: 2008-10-09
Also published as: KR20080088938A; KR100862883B1

Abstract

An apparatus for inspection of an external appearance of a semiconductor device received in a tray includes a controller, a lighting unit having at least two illuminators which are sequentially turned on and off according to control signals of the controller to illuminate light on an upper surface of the semiconductor device at a specific angle, an imaging unit which captures at least two images reflected from the surface of the semiconductor device according to selective light il¬ lumination of the lighting unit, an image processor which respectively removes shadows from the images captured by the imaging unit and combines the images into a single image, and an image inspection unit which compares the single image combined by the image processor with a reference image to determine whether there is a defect.

Description

APPARATUS FOR INSPECTION OF SEMICONDUCTOR DEVICE AND METHOD FOR INSPECTION USING THE SAME

Technical Field

[1] The present invention relates to an apparatus for inspection of a semiconductor device and a method for inspection using the same, and more particularly to an apparatus for inspection of a semiconductor device and a method for inspection using the same capable of more accurately inspecting the semiconductor device by illuminating light on the semiconductor device received in a tray in various directions to acquire images without shadows. Background Art

[2] Generally, semiconductor devices manufactured through a manufacturing process should undergo accurate inspection before shipping.

[3] Since the semiconductor device requires high accuracy, an even small defect occurring in an inner element or an outer shape of the device causes a critical influence on performance of the device.

[4] Accordingly, it is necessary to inspect not only an electrical operation of the semiconductor device, but also an outer shape thereof.

[5] In a method for inspection of an outer shape of the semiconductor device, the outer shape of the semiconductor device is photographed using a vision camera and the photograph is analyzed to inspect whether a defect is generated in, for example, a marking formed on one surface of the semiconductor device and a ball or lead in contact with one surface of the semiconductor device.

[6] Specifically, as shown in FIGS. 8 and 9, semiconductor devices undergo various inspections while the devices are disposed in a rectangular tray made of plastic and moved.

[7] In this case, after a semiconductor device 200 disposed in a tray 100 is picked up by a holder and placed in a specific position of a tester, the electrical inspection is performed on the semiconductor device 200.

[8] Further, as for the inspection of an outer shape, in a state where the semiconductor device is disposed in the tray 100, that is, in an in-tray state, light is illuminated on the semiconductor device using a lighting unit. Then, the outer shape of the semiconductor device is photographed by the vision camera, and the image is analyzed.

[9] In the conventional in-tray method, an outer frame 110 is formed at a periphery of the tray 100, and partition walls 130 are formed to define receiving grooves 120 in order to receive a number of semiconductor devices in the tray 100. [10] However, since there is height difference between the surfaces of the semiconductor devices received in the receiving grooves 120 and the outer frame 100 and the partition walls 130, a shadow is formed according to the light illumination direction when light is illuminated for vision inspection, thereby causing an inspection error due to the shadow.

[11] In other words, the shadow is formed due to the outer frame and the partition walls formed in the tray according to the light illumination direction. The shadow may be considered as a surface spot, and it may be analyzed that the lead or ball is inferior.

[12] Meanwhile, the method for inspection of an outer shape of a semiconductor device is filed by the present applicant and disclosed in Korean Patent Registration No. 10-617619, entitled "Apparatus for inspection of a semiconductor device and method for inspection using the same."

[13] According to the disclosed method, light is illuminated on the upper surface of the semiconductor device at inclined angles from a plurality of light sources to produce a plurality of distinguishable shadows. Then, the shadow images are combined to detect an outline of the semiconductor device, thereby inspecting the size of the semiconductor device.

[14] That is, in a case of acquiring an unclear image of the semiconductor device and the tray, since an external appearance (i.e., outline) of the semiconductor device cannot be accurately obtained, it is difficult to inspect the size of the semiconductor device, but it is possible to overcome the problem by the disclosed method. In this method, only the size of the semiconductor device is inspected by illuminating light to facing edges of the semiconductor device, producing shadows in the facing edges and neighboring sides of the semiconductor device, and combining the shadow images. In this case, since the shadow images are combined, it is difficult to inspect whether there is a defect in the surface of the semiconductor device due to the shadow images. Disclosure of Invention Technical Problem

[15] Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide an apparatus for inspection of a semiconductor device and a method for inspection using the same, wherein light is illuminated on the semiconductor device received in a tray in various directions to acquire a number of images reflected from the surface of the semiconductor device according to light illumination, shadows are removed from the acquired images to combine the images without the shadows into a single image, and the combined single image is compared with a reference image to determine whether there is a defect of the semiconductor device, thereby reducing inspection errors due to a shadow image. Technical Solution

[16] In accordance with an aspect of the present invention, there is provided an apparatus for inspection of an external appearance of a semiconductor device received in a tray, the apparatus comprising: a controller; a lighting unit having at least two illuminators which are sequentially turned on and off according to control signals of the controller to illuminate light on an upper surface of the semiconductor device at a specific angle, an imaging unit which captures at least two images reflected from the surface of the semiconductor device according to selective light illumination of the lighting unit an image processor which respectively removes shadows from the images captured by the imaging unit and combines the images into a single image; and an image inspection unit which compares the single image combined by the image processor with a reference image to determine whether there is a defect.

[17] In this case, the lighting unit may include first to fourth illuminators which are disposed in four directions of front, rear, left and right directions with respect to the semiconductor device.

[18] Further, the lighting unit may include first illuminators which are disposed in a first direction and in a second direction adjacent to the first direction with respect to the semiconductor device and second illuminators which are disposed in a third direction facing the first direction and in a fourth direction facing the second direction.

[19] Further, the lighting unit may include first illuminators which are disposed in a first direction and in a third direction facing the first direction with respect to the semiconductor device and second illuminators which are disposed in a second direction adjacent to the first direction and in a fourth direction facing the second direction.

[20] In accordance with another aspect of the present invention, there is provided a method for inspection of an external appearance of a semiconductor device received in a tray, the method comprising: sequentially turning on and off illuminators disposed in at least two divided regions with respect to the semiconductor device and acquiring respective images reflected from a surface of the semiconductor device removing shadows from the acquired images; combining the respective images without the shadows into a single image; and comparing the combined single image with a reference image to determine whether there is a defect.

[21] In this case, the step of sequentially turning on and off illuminators includes selectively turning on and off the illuminators in four directions of front, rear, left and right directions with respect to the semiconductor device.

[22] Further, the step of sequentially turning on and off illuminators includes alternately turning on and off first illuminators, which are disposed in a first direction and in a second direction adjacent to the first direction with respect to the semiconductor device, and second illuminators, which are disposed in a third direction facing the first direction and in a fourth direction facing the second direction with respect to the semiconductor device.

[23] Further, the step of sequentially turning on and off illuminators includes alternately turning on and off first illuminators, which are disposed in a first direction and in a third direction facing the first direction with respect to the semiconductor device, and second illuminators, which are disposed in a second direction adjacent to the first direction and in a fourth direction facing the second direction with respect to the semiconductor device. Brief Description of the Drawings

[24] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[25] FIG. 1 illustrates a configuration of an apparatus for inspection of a semiconductor device according to the present invention

[26] FIGS. 2 to 4 illustrate various arrangement structures of a lighting unit shown in

FIG. 1

[27] FIGS. 5 to 7 illustrate conceptional diagrams for explaining a method for inspection of a semiconductor device according to embodiments of the present invention and

[28] FIGS. 8 and 9 illustrate conceptional diagrams for explaining a conventional method for inspection of a semiconductor device. Best Mode for Carrying Out the Invention

[29] FIG. 1 illustrates a configuration of an apparatus for inspection of a semiconductor device according to the present invention, which includes a controller 11, a supporting table 14 which supports a tray 13 for receiving a semiconductor device 12, a lighting unit 15 which includes at least two illuminators 151 to illuminate light on the semiconductor device 12 at inclined angles, an imaging unit 16 which captures at least two images reflected from the surface of the semiconductor device 12 according to the selective light illumination of the lighting unit 15, an image processor 17 which combines a number of images captured by the imaging unit 16into a single image, and an image inspection unit 18 which compares the combined single image with a reference image to determine whether there is a defect of the semiconductor device 12.

[30] FIGS. 2 to 4 illustrate various arrangement structures of the lighting unit shown in

FIG. 1.

[31] Referring to FIG. 2, the lighting unit 15 includes first to fourth illuminators Rl, R2,

R3 and R4, which are disposed in four (front, rear, left and right) directions with respect to the semiconductor device 12. The lighting unit 15illuminates light at inclined angles in four directions with respect to the semiconductor device 12 received in the tray.

[32] That is, the lighting unit 15 includes a first illuminator Rl corresponding to the front side of the semiconductor device 12, a second illuminator R2 corresponding to the right side thereof, a third illuminator R3 corresponding to the rear side thereof, and a fourth illuminator R4 corresponding to the left side thereof. Each illuminator may include a number of LEDs.

[33] In this case, divided regions of the first to fourth illuminators Rl, R2, R3 and R4 may be modified through various embodiments without being limited to the case shown in FIG. 2.

[34] Referring to FIG. 3, the lighting unit 15 may include first illuminators Rl which are disposed in a first direction and in a second direction adjacent to the first direction with respect to the semiconductor device, and second illuminators R2 which are disposed in a third direction facing the first direction and in a fourth direction facing the second direction.

[35] Referring to FIG. 4, the lighting unit 15 may include first illuminators Rl which are disposed in the first direction and in the third direction facing the first direction with respect to the semiconductor device, and second illuminators R2 which are disposed in the second direction adjacent to the first direction and in the fourth direction facing the second direction.

[36] FIGS. 5 to 7 illustrate conceptional diagrams for explaining a method for inspection of a semiconductor device according to embodiments of the present invention. In the present invention, an external appearance of the semiconductor device is inspected while the semiconductor device is received in the tray.

[37] Referring to FIG. 5, the method according to a first embodiment of the present invention includes sequentially turning on and off the illuminators disposed in the four divided regions (front, rear, left and right regions) with respect to the semiconductor device and acquiring respective images reflected from the surface of the semiconductor device removing shadows from the acquired images; combining the respective images without the shadows into a single image; comparing the combined single image with a reference image to determine whether there is a defect of the semiconductor device.

[38] That is, first to fourth images are acquired by capturing images reflected from the surface of the semiconductor device whenever the illuminator lights up while the first to fourth illuminators Rl to R4 are turned on and off in a certain order.

[39] In this case, since each illuminator illuminates light at an angle inclined to any side, if a partition wall or an outer frame formed in the tray 13has a height difference with the surface of the semiconductor device 12, a shadow is formed by a side adjacent to the light illumination direction. [40] Accordingly, the shadows are removed from the respective images acquired according to sequential light illumination.

[41] Then, four images without the shadows are combined into a single image. The combined single image is compared with the reference image to determine whether there is a defect of the semiconductor device.

[42] In this case, although the illuminators are disposed in four directions with respect to the semiconductor device and four images are acquired in the present invention, illuminators may be installed in five or more divided regions to acquire images as the number of the illuminators.

[43] Referring to FIG. 6, the method according to a second embodiment of the present invention includes turning on illuminators disposed in first and second directions adjacent to a tray loading position to acquire a first image turning on illuminators disposed in third and fourth directions to acquire a second image removing shadows of the first image and the second image; combining the first image and the second image without the shadows into a singe image; and comparing the combined single image with a reference image to determine whether there is a defect of the semiconductor device.

[44] That is, first illuminators Rl disposed in the first and second directions are turned on and an image reflected from the semiconductor device 12 is captured to acquire the first image.

[45] Then, the first illuminators Rl are turned off and second illuminators R2 disposed in the third and fourth directions opposite to the first and second directions are turned on. The image reflected from the semiconductor device 12 is captured to acquire the second image.

[46] In this case, since each illuminator illuminates light at an angle inclined to any side, if a partition wall or an outer frame formed in the tray 13has a height difference with the surface of the semiconductor device 12, a shadow is formed by sides adjacent to the light illumination direction.

[47] Accordingly, the shadows are respectively removed from the first and second images.

[48] Then, the first and second images without the shadows are combined into a single image. The combined single image is compared with the reference image to determine whether there is a defect of the semiconductor device.

[49] Referring to FIG. 7, the method according to a third embodiment of the present invention includes turning on first illuminators Rl disposed in a first direction adjacent to a tray loading position and in a third direction facing the first direction to acquire a first image turning on second illuminators R2 disposed in second and fourth directions to acquire a second image removing shadows from the first image and the second image; combining the first image and the second image without the shadows into a singe image; and comparing the combined single image with a reference image to determine whether there is a defect of the semiconductor device.

[50] That is, the first illuminators Rl disposed in the first direction and the third direction facing the first direction are turned on and the image reflected from the semiconductor device 12is captured to acquire the first image.

[51] Then, the first illuminators Rl are turned off and the second illuminators R2, which are disposed in the second direction adjacent to the first direction and in the fourth direction facing the second direction, are turned on. The image reflected from the semiconductor device 12 is captured to acquire the second image.

[52] Then, the shadows are removed from the first and second images, respectively.

[53] Then, the first and second images without the shadows are combined into a single image. The combined single image is compared with a reference image to determine whether there is a defect of the semiconductor device. Industrial Applicability

[54] According to the present invention, light is illuminated on the semiconductor device received in the tray in various directions to acquire a number of images reflected from the surface of the semiconductor device according to the light illumination. Then, shadows are removed from the acquired images and the images without the shadows are combined into a single image. Then, the combined single image is compared with a reference image to determine whether there is a defect of the semiconductor device. Therefore, it is possible to improve reliability of inspection by reducing inspection errors due to a shadow image.

[55] Although the preferred embodiment of the present invention has been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

[1] An apparatus for inspection of an external appearance of a semiconductor device received in a tray, the apparatus comprising: a controller; a lighting unit having at least two illuminators which are sequentially turned on and off according to control signals of the controller to illuminate light on an upper surface of the semiconductor device at a specific angle, an imaging unit which captures at least two images reflected from the surface of the semiconductor device according to selective light illumination of the lighting unit an image processor which respectively removes shadows from the images captured by the imaging unit and combines the images into a single image; and an image inspection unit which compares the single image combined by the image processor with a reference image to determine whether there is a defect.

[2] The apparatus according to claim 1, wherein the lighting unit includes first to fourth illuminators which are disposed in four directions of front, rear, left and right directions with respect to the semiconductor device.

[3] The apparatus according to claim 1, wherein the lighting unit includes: first illuminators which are disposed in a first direction and in a second direction adjacent to the first direction with respect to the semiconductor device and second illuminators which are disposed in a third direction facing the first direction and in a fourth direction facing the second direction.

[4] The apparatus according to claim 1, wherein the lighting unit includes: first illuminators which are disposed in a first direction and in a third direction facing the first direction with respect to the semiconductor device and second illuminators which are disposed in a second direction adjacent to the first direction and in a fourth direction facing the second direction.

[5] A method for inspection of an external appearance of a semiconductor device received in a tray, the method comprising: sequentially turning on and off illuminators disposed in at least two divided regions with respect to the semiconductor device and acquiring respective images reflected from a surface of the semiconductor device removing shadows from the acquired images; combining the respective images without the shadows into a single image; and comparing the combined single image with a reference image to determine whether there is a defect.

[6] The method according to claim 5, wherein the step of sequentially turning on and off illuminators includes selectively turning on and off the illuminators in four directions of front, rear, left and right directions with respect to the semiconductor device.

[7] The method according to claim 5, wherein the step of sequentially turning on and off illuminators includes alternately turning on and off first illuminators, which are disposed in a first direction and in a second direction adjacent to the first direction with respect to the semiconductor device, and second illuminators, which are disposed in a third direction facing the first direction and in a fourth direction facing the second direction with respect to the semiconductor device.

[8] The method according to claim 5, wherein the step of sequentially turning on and off illuminators includes alternately turning on and off first illuminators, which are disposed in a first direction and in a third direction facing the first direction with respect to the semiconductor device, and second illuminators, which are disposed in a second direction adjacent to the first direction and in a fourth direction facing the second direction with respect to the semiconductor device.