JPH0749219A - Measuring device for ic lead height - Google Patents

Abstract

PURPOSE:To finish a measuring work at high speed by irradiating a laser beam on the lead of a semiconductor element from two different directions, and computing the height of the lead on the basis of a difference in the forward end position of images formed due to reflective light. CONSTITUTION:The light of the first laser illuminant 1 passes a mirror 20 and is condensed with a projector lens 3 for scanning the lead of a semiconductor element 4 with a laser beam over a range from an oblique angle to a parallel direction. Reflective light from the lead is inputted to a height computing circuit 14 via a condenser lens 5 and the first sensor 6. The light of the second laser illuminant 7 is incident on a mirror 80, a projector lens 9 and the laser beam from upper level vertical to the lead of the element 4 and, therefore, inputted to the circuit 14 through a half mirror 10 for allowing the transmission of the reflective light from the lead, a condenser lens 11 and the second sensor 12 to receive the laser beam. Also, a sub-scanning travel mechanism 13 causes the element 4 to move along a sub-scanning direction. The two-dimensional image of the lead is, then, formed out of output signals from the sensors 6 and 12, and the height computing circuit 14 calculates the height of a lead end from the image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC lead height measuring device, and more particularly to a lead shape IC lead height measuring device for semiconductor elements.

[0002]

2. Description of the Related Art A conventional lead height measuring apparatus for measuring the flatness of a lead of a semiconductor device scans a laser beam from below the semiconductor device onto the lead to detect a change in position of a reflected beam spot within a scanning line. The height of the lead is measured by detecting and measuring the height and mechanically moving either the semiconductor element or the height measuring optical system.

Next, a conventional lead height measuring apparatus will be described in detail with reference to the drawings. FIG. 3 is a perspective view showing an example of a conventional lead height measuring device. The lead height measuring device shown in FIG. 3 includes a laser light source 1 for emitting laser light,
The polygon mirror 2 that scans the laser light in one direction, the projection lens 3 that collects the scanned laser light and scans the laser light parallel to the lead of the semiconductor element 4 at an oblique angle, and the laser light is the lead. A cylindrical lens 15 provided so that the scanning direction of the laser beam obtained by reflection and the direction of the radius of curvature of the convex surface are orthogonal to each other, and the cylindrical lens 15 is a laser beam.
The cylindrical lens 16 provided in parallel with the scanning direction of the laser light obtained by passing through and the direction of the radius of curvature of the convex surface, and the beam spot obtained by condensing the laser light by the cylindrical lens 16 are received. A height measuring optical system including a one-dimensional sensor 17 for detecting the position of the position, a light receiving position calculating circuit 18 for calculating a height signal from an output signal of the one-dimensional sensor 17, and a height measuring optical system are moved. And a sub-scanning moving mechanism 13 for controlling the movement.

[0004]

The above-described conventional lead height measuring device uses the principle of triangulation to measure the lead height of the semiconductor element, and is generally used as a one-dimensional sensor in PSD. Is used. Since the PSD has a slow response speed, it has a drawback that the scanning speed cannot be increased and the inspection time cannot be shortened.

[0005]

An IC lead height measuring apparatus according to the present invention comprises a first laser light source for emitting a first laser beam and a first mirror for scanning the laser beam in one direction. A first light projecting lens for converging the scanned laser light and scanning the laser light parallel to the leads of the semiconductor element at an oblique angle; and a laser obtained by reflecting the laser light on the leads. A first condenser lens that condenses light, a first sensor that receives the condensed laser light, a second laser light source that emits a second laser light, and the laser light in one direction. A second mirror for scanning, a second light projecting lens for converging the scanned laser light and making it parallel at the same time, and for irradiating the parallel-scanned laser light onto the leads of the semiconductor device from vertically above. The laser beam is bent by the lead while bending the optical path. A half mirror that transmits the laser light obtained by irradiation, a second condenser lens that condenses the laser light, a second sensor that receives the condensed laser light, and a semiconductor element in the sub-scanning direction. A sub-scanning moving mechanism for moving the head to a vertical direction, and a height calculation circuit for forming a two-dimensional image of the lead from the output signals of the first sensor and the second sensor and calculating the lead tip height from the image. Composed.

[0006]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is an optical path diagram showing an embodiment of the present invention. The IC lead height measuring apparatus shown in FIG. 1 collects a first laser light source 1 that emits a first laser light, a first mirror 20 that scans the laser light in one direction, and a scanned laser light. A first light projecting lens 3 which emits light and scans the laser light parallel to the lead of the semiconductor element 4 at an oblique angle, and a first light collecting lens 3 which collects the laser light reflected by the lead
Condensing lens 5, a first sensor 6 for receiving the condensed laser beam, a second laser light source 7 for emitting the second laser beam, and a second mirror for scanning the laser beam in one direction. 80
A second light projecting lens 9 for condensing the scanned laser light and making it parallel at the same time; and for bending the optical path so as to irradiate the leads of the semiconductor element 4 with the laser light scanned in parallel from above vertically. A half mirror 10 for transmitting a laser beam obtained by being reflected by a lead, a second condenser lens 11 for condensing the laser beam, a second sensor 12 for receiving the condensed laser beam, and a semiconductor A two-dimensional image of the lead is made from the output signals of the sub-scanning moving mechanism 13 for moving the element 4 in the sub-scanning direction and the first sensor 6 and the second sensor 12, and the lead tip height is calculated from the image. And a height calculation circuit 14 that operates.

Next, the operation of the embodiment will be described with reference to FIG.
An explanation will be given using (b). Sub-scanning moving mechanism 1 shown in FIG.
Sub-scanning is performed by 3 and the tip of the lead of the semiconductor element is moved to 2
An image of the lead tip portion by the output signal from the first sensor 6 in the case of two-dimensional scanning is shown in FIG.
An image of the tip of the lead due to the output signal from is shown in FIG. 2 (b). The difference in height between the lead A and the lead B can be obtained by the following formula when the first laser beam is irradiated obliquely downward from 45 °. Here, x is the difference in the tip position obtained from the image of the lead tip portion by the output signal from the first sensor 6, and y is the tip position obtained from the image of the lead tip portion by the output signal from the second sensor 12. Is the difference. Height difference between lead A and lead B = xy By performing this calculation on all the leads, the height of the leads of the semiconductor element can be measured.

[0008]

According to the lead height measuring apparatus of the present invention, instead of using the principle of triangulation using PSD to measure the lead of the semiconductor element, the lead of the semiconductor element is irradiated with laser light from two different directions. Since the lead height is calculated from the difference in the tip position of the image due to the reflected light, there is an effect that the measuring time for measuring the lead of the semiconductor element can be shortened.

[Brief description of drawings]

FIG. 1 is an optical path diagram showing an embodiment of the present invention.

2A and 2B are diagrams for explaining the operation of an embodiment of the present invention.

FIG. 3 is a perspective view showing a conventional example.

[Explanation of symbols]

 1 Laser Light Source 2 Polygon Mirror 3 Light Emitting Lens 4 Semiconductor Element 5 Condenser Lens 6 Sensor 7 Laser Light Source 8 Polygon Mirror 9 Light Emitting Lens 10 Half Mirror 11 Condenser Lens 12 Sensor 13 Sub-scanning Moving Mechanism 14 Height Calculation Circuit 15, 16 Cylindrical lens 17 One-dimensional sensor 18 Light receiving position calculation circuit

Claims (3)

[Claims] 1. A first laser light source that emits a first laser light, a first mirror that scans the laser light in one direction, and the scanned laser light is condensed to form a semiconductor device. A first projecting lens for scanning the laser beam parallel to the lead at an oblique angle; a first condensing lens for condensing the laser beam obtained by the laser beam being reflected by the lead; The first sensor for receiving the laser light, the second laser light source for emitting the second laser light, the second mirror for scanning the laser light in one direction, and the scanned laser light. A second light projecting lens which condenses light and makes it parallel is obtained, and an optical path is bent to irradiate the parallel-scanned laser light onto the leads of the semiconductor element from vertically above, and the laser light is reflected by the leads. With a half mirror that transmits the generated laser light A second condensing lens that condenses the laser light, a second sensor that receives the condensed laser light, a sub-scanning moving mechanism that moves the semiconductor element in the sub-scanning direction, and a first An IC lead height measuring device comprising: a sensor and a height calculation circuit that forms a two-dimensional image of the lead from the output signals of the second sensor and calculates the height of the tip of the lead from the image. 2. The IC lead height measuring apparatus according to claim 1, wherein the first laser light is irradiated from obliquely below the lead. 3. The IC lead height measuring apparatus according to claim 1, wherein the oblique angle is about 45 degrees.