Optics: measuring and testing – By alignment in lateral direction – With registration indicia
Reexamination Certificate
1999-04-05
2001-12-18
Evans, F L (Department: 2877)
Optics: measuring and testing
By alignment in lateral direction
With registration indicia
C356S400000
Reexamination Certificate
active
06331891
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus and method of assembling a semiconductor device and positioning and fixing a semiconductor element to a substrate. The present invention also relates to a semiconductor device fabricated by such a method and apparatus.
2. Description of the Related Art
Many semiconductor devices have been designed in which a semiconductor element such as a photodiode or a laser diode is fixed to a substrate. To obtain such a semiconductor device, it is necessary to position and fix the semiconductor element at a certain position relative to the substrate. In the conventional method of assembling a semiconductor device, positioning marks are provided in the substrate, the semiconductor element is moved onto the substrate, and the semiconductor element is positioned relative to the substrate by moving semiconductor element in such a manner that the bottom of a side of the semiconductor element is overlaid on the positioning marks.
Such a conventional method, however, has the drawback that, when the semiconductor element comes near to a target position, the positioning marks are hidden by the semiconductor element and cannot be seen, so it is difficult to achieve the positioning of the semiconductor element with good accuracy in a short time. If the positioning mark is displaced to a position in front of the target position of the semiconductor element, the positioning mark can be easily seen but the positioning of the semiconductor element cannot be accurately attained.
Moreover, the bottom surface of the semiconductor element is not always in intimate contact with the surface of the substrate, and it is necessary to perform the positioning of the semiconductor element in a state where there is a gap between the bottom surface of the semiconductor element and the surface of the substrate. Thus, when the positioning of the semiconductor element is performed while observing the semiconductor element and the substrate, both the bottom surface of the semiconductor element and the surface of the substrate are not in focus, so it is difficult to position the semiconductor element by simultaneously observing both the substrate and the semiconductor element. Furthermore, it is difficult to quickly move the semiconductor element to a target position, so it is not possible to automatically position the semiconductor elements.
SUMMARY OF THE INVENTION
The object of the present invention is to provide an apparatus and method, for assembling a semiconductor device, by which a semiconductor element can be reliably and quickly positioned relative to a substrate.
An apparatus for assembling a semiconductor device, according to the present invention, comprises: a stage having a substrate support surface for supporting a substrate; a support member for carrying a semiconductor element to a position on or near the substrate supported by the stage; a microscope unit arranged inclined to the substrate support surface of the stage and having a coaxial illuminating unit; a counter illuminating unit arranged on the opposite side from the microscope unit with respect to a normal to the substrate support surface of the stage and inclined to the substrate support surface thereof; a camera arranged at an image forming position of the microscope unit; and an image processing unit connected to the camera.
With this constitution, it is possible to acquire an image of a positioning mark provided on the substrate and an image of a reflection of the positioning mark reflected by a side surface of a semiconductor element, to calculate the positional relationship between the semiconductor element and the substrate, and to accurately and quickly position the semiconductor element relative to the substrate.
Preferably, the stage has a heater, so that the semiconductor element can be soldered to the substrate.
Preferably, the substrate has at least one positioning mark. Further, the camera is adapted to acquire an image of at least one positioning mark and an image of a reflection of at least one positioning mark reflected by a side surface of the semiconductor element, to thereby obtain the positional relationship between the image of at least one positioning mark and the image of the reflection of at least one positioning mark. The positioning of the semiconductor element onto the substrate is performed according to the positional relationship obtained in this manner.
Preferably, the apparatus for assembling a semiconductor element further comprises: calculating means for calculating a positional relationship between the substrate and the semiconductor element from the positional relationship between the image of at least one positioning mark and the image of the reflection thereof; and moving means for moving at least one of the stage and the support member according to the calculating means.
Preferably, at least one positioning mark has a circular shape. Alternatively, at least one positioning mark has a specific shape formed in the substrate. Alternatively, at least one positioning mark is formed from a material which is different in reflectance from a material of the aforesaid substrate.
Preferably, the at least one positioning mark comprises two positioning marks. Further, the substrate has a linear structure which is different from the at least one positioning mark.
Moreover, a method for assembling a semiconductor element, according to the present invention, comprises the steps of: acquiring an image of at least one positioning mark formed on a substrate, which is supported on a stage, and an image of a reflection of at least one positioning mark reflected by a side surface of the semiconductor element arranged on or near the substrate; obtaining a positional relationship between the image of at least one positioning mark and the image of the reflection of at least one positioning mark; and positioning the semiconductor element relative to the substrate according to the positional relationship therebetween.
In this case too, the positioning of a semiconductor element relative to a substrate can be accurately and quickly achieved by obtaining an image of a positioning mark provided on the substrate and an image of a reflection of the positioning mark reflected by a side surface of a semiconductor element, and then calculating the positional relationship between the semiconductor element and the substrate.
Preferably, the step of acquiring the image of at least one positioning mark formed on the substrate comprises acquiring the image by a camera through a microscope unit, while slantingly irradiating the substrate with illuminating light from a counter illuminating unit arranged inclined to the substrate support surface of the stage, the microscope unit being arranged on the opposite side of the counter illuminating unit with respect to a normal to the substrate support surface of the stage and inclined to a substrate support surface of the stage.
Preferably, the step of acquiring an image of at least one positioning mark and an image of the reflection of at least one positioning mark reflected by a side surface of the semiconductor element, comprises a step of acquiring the images by a camera through a microscope unit, while slantingly irradiating the substrate with illuminating light from a coaxial illuminating unit provided in the microscope unit.
Preferably, the method further comprises the step of calculating a positional relationship between the substrate and the semiconductor element from the positional relationship between the image of at least one positioning mark and the image of the reflection of at least one positioning mark, and moving at least one of the stage and the support member supporting the semiconductor element, according the result of the calculation. Preferably, the method further comprises the step of computing a distance between the substrate and the semiconductor element and an angle of rotation of the semiconductor element with respect to the substrate from at least one positioning mark and the refl
Hirahara Takao
Koezuka Tetsuo
Komoriya Hitoshi
Nakamura Yutaka
Armstrong Westerman Hattori McLeland & Naughton LLP
Evans F L
Fujitsu Limited
Smith Zandra
LandOfFree
Apparatus and method for assembling semiconductor device and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method for assembling semiconductor device and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method for assembling semiconductor device and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2574808