JPH027537A - Moving device and shape measuring device - Google Patents

Abstract

PURPOSE:To realize the high speed of measurement and control to lessen the vibration of a driving part even if acceleration is large by offsetting the reaction at the time of the accelerating to provide a means for controlling vibration. CONSTITUTION:The surface condition of a work 22 is detected by a reflected light detector 25 through a lens 27 by the use of the reflected light from the work 22, further transmitted light 23 of the work 22 is condensed by a lens 23 to make a transmitted light detector 24 incident and the lateral deformation of the work 22 is detected. An XY stage 11 moves a height measuring part 10 in the directions of X and Y, and driving mechanisms of both the directions are approximately the same. A weight 41X and the weight of a weight plate 40 are approximately the same as the weights of the XY stage 11 and the height measuring part 10 and a weight 41Y and the weight of a weight plate 40Y are approximately the same as the weights of the height measuring part 10 and a moving member 50. Thus, if linear driving mass of both the side mechanisms seen from motors 30X, 30Y is equal, the reaction is eliminated because the value of the reaction is equal and reverse when the motors 30X, 30Y are accelerated.

Description

[Detailed Description of the Invention] Purpose of the Invention: (Industrial Application Field) This invention provides an 8-motion device with extremely low vibration and an 8-motion device with extremely low vibration.
The present invention relates to a shape measuring device that measures and inspects three-dimensional shapes, such as three-dimensional shape measurement of IC lead frames and IC pin bending measurements, by applying the same.

(Prior art) A lead frame is made by processing a metal plate with a thickness of 100 to 300 μm into the shape shown in Fig. 4 by etching or pressing. A semiconductor chip is attached (die bonding) to the island 1 of this lead frame, and the tip of the inner lead 2 and the electrode of the semiconductor chip are plated with a thin metal such as gold or aluminum. Semiconductor devices are manufactured by connecting with wires (wire bonding). In addition, in FIG. 4, 3 indicates a dam, 4 indicates an outer lead, 5 indicates an outer frame, and 6 indicates a partially plated area.

The above is an explanation of the lead frame, but as mentioned above, the lead frame itself has a small plate thickness, and the inner lead 2
Since the width of each part is as narrow as 100 to several 100 μm, deformation may occur during manufacturing, and malfunction of manufacturing equipment may cause poor positioning accuracy of the partial plating area 6. Some defective products may be mixed in. If such defective products are used, it may cause defects in the die bonding or wire bonding process and reduce the reliability of the completed semiconductor device.
It is essential to inspect lead frames after manufacturing them to eliminate defective products.

Conventionally, such lead frame inspections have been carried out visually with the naked eye or using a microscope, but it requires a large amount of manpower to inspect a large number of products, and it is difficult to perform sensory tests. This caused problems in terms of testing accuracy and reliability.

In order to solve such problems, for example, a method for inspecting lateral deformation of a lead frame is to use a video signal obtained by photographing a lead frame under transmitted illumination using an ITV.
There is a method of detecting deformation by comparing the signal obtained by photographing a reference pattern or an adjacent pattern in the same way, and when inspecting a partially plated part, similar processing is performed using reflected illumination to determine the position of the plated part. Various methods have been proposed for detecting defects, including a method using an optical non-contact height measuring device for vertical deformation inspection.

However, although each of these methods can individually achieve its purpose, the inspection process is complicated because a different method must be used for each inspection item. ml becomes sloppy and IT again
In the method using V, there are cases where dust or scratches attached to the lead frame, which do not cause a defect, are detected and determined to be defective. Furthermore, the method using a non-contact height measuring device has many reliability problems such as unstable measurement values when the measurement point is on the edge of the pattern, making it difficult to put it into practical use. Ta.

As a lead frame inspection method that solves these drawbacks, there is a method disclosed in Japanese Patent Application Laid-Open No. 61-2521i53 by the present applicant. This scans the surface of the lead frame to be inspected with a light spot, detects the lateral deformation of the lead frame based on the transmitted light and scanning position, and detects the surface condition of the lead frame based on the amount of light reflected by the lead frame at this time. Optical triangulation is performed by detecting the image of the light spot on the lead frame at this time and then projecting and forming the image in a direction oblique to the irradiation optical axis of this light spot and the displacement of the image formation position. The vertical deformation of the lead frame is detected by measurement based on the method.

(Problems to be Solved by the Invention) However, in the case of the above-mentioned Japanese Patent Application Laid-Open No. 61-252653, if the lead frame is moved by an XY stage, the XY stage becomes large and high-speed operation is difficult.
■The lead frame vibrates and does not allow accurate measurements.■
If the lead frame is fixed so that it does not move, it will deform.
In addition, if the height measuring section is moved using a normal The disadvantage is that the vibration of the parts increases, which affects the measurement system and workpiece. Vibration can be reduced by increasing the weight and rigidity of each part, but the effect is not sufficient.
It also increases design constraints.

This invention was made due to the circumstances mentioned above,
The purpose of the present invention is to provide a moving device that can achieve high speeds and exhibits small vibrations even when acceleration increases, and to apply the above-mentioned moving device to perform measurements without being subject to excessive design restrictions. The object of the present invention is to provide a shape measuring device that can perform the following.

Structure of the Invention; (Means for Solving the Problems) The above objects of the present invention are achieved by providing means for suppressing vibration by offsetting reaction force during acceleration. Also,
light source means for irradiating a light spot perpendicularly to the surface of the workpiece (for example, a lead frame) whose surface condition is to be inspected;
a light receiving means located on the optical axis of a light spot extending on the opposite side of the light source means with the workpiece in between; and a light receiving means located on the optical axis of a light spot that extends on the opposite side of the light source means with the workpiece in between; an imaging optical means for forming an image at a predetermined position in a predetermined angular direction less than or equal to comprising a scanning means for relatively moving the optical axis of the spot along the surface of the workpiece, and a measuring means for detecting the relative movement amount by the scanning means,
Deformation in the surface direction of the workpiece is detected by the output signal of the light receiving means and the output signal of the measuring means, and deformation perpendicular to the surface direction of the workpiece is detected by the output signal of the one-dimensional light incident position detection means. The present invention relates to a shape measuring device configured to detect deformation in the direction and surface condition, and the above object of the present invention is to scan the light spot by driving the lens in the X and Y directions. This is achieved by making

(Function) In conventional equipment, when the lead frame is moved by an xY stage, the stage becomes large and high-speed operation is difficult, and the lead frame vibrates, making accurate measurement impossible.
There were problems such as deformation if the lead frame was fixed so that it would not move. Furthermore, although it is possible to increase the speed by moving the height measurement section using a normal XY stage, there is also the drawback that when the acceleration becomes large, the vibration of the drive section becomes large, which affects the measurement system and the workpiece.

In contrast, in the present invention, the movable member is provided with a means for suppressing vibration by offsetting the reaction force during acceleration, and by applying this moving device, a height measuring section is provided on the XY stage, and the xY
The light spot is scanned by driving the stage. Therefore, it is possible to realize high-speed measurement and to suppress vibrations of the drive unit to a small level even when the acceleration is increased.

(Embodiment) In this invention, as shown in FIG.
By placing it on the stage 11 and driving it, the light spot 2
The work 22 is scanned in step 1, and the light transmitted through the work 22 is incident on a transmitted light detector 24 through a lens 23. That is, the light emitted from the light source 20 is irradiated onto the workpiece 22 as a light spot 21 via the lens 26, and the reflected light from the workpiece 22 is sent via the lens 27 to the reflected light detector 25, which detects the surface condition of the workpiece 22. It is now detected. In addition, the transmitted light 23 of the work 22 is transmitted through a lens 23.
The light is focused and incident on the transmitted light detector 24, and the light is transmitted to the workpiece 22.
Lateral deformation of is detected.

Incidentally, the XY stage 11 is driven by a drive mechanism as shown in FIG. 2, and is configured to move the height measuring section 1O in the X direction and the Y direction. The driving mechanisms in the X direction and the Y direction are almost the same, and the details of the driving mechanism in the X direction are shown in FIG. 3, for example. That is, the XY stage 11 is driven by motors 30X and 30Y, and
Couplings 31X and 30Y are attached to both end shafts, respectively.
32X, 31Y, and 32Y are installed, and coupling 3
1X and 31Y each have a left-handed ball screw 33X.
and 33Y are installed, and couplings 32X and 32Y are installed.
are fitted with right-handed ball screws 34X and 34Y, respectively. Ball screw 33X is mounted on frames 35 and 36X
The XY stage 11 is mounted between them and is screwed to the XY stage 11, so that the XY stage 11 moves in the X direction according to the rotation of the ball screw 33X. Further, the ball screw 34X is mounted between the frames 37X and 38X, and the weight plate 40X on which the weight 41X is mounted
41X and weight plate 40
The weight of is almost the same as the weight of the XY stage 11 and the height measurement unit IO. Since the screw of the ball screw 34X is opposite to that of the ball screw 33X, the motor 3
The XY stage 11 and weight plate 40 are driven by 0X.
B shifts in the opposite direction to X.

On the other hand, the ball screw 33Y is screwed to a moving member 50 for moving the XY stage 11 in the Y direction, and the ball screw 33Y is mounted between the mounting stands 37'f and 38Y.
Y is screwed to a weight plate 40Y on which a weight 41Y is placed. Then, the weight 41Y and the weight plate 40Y f) The weight is transferred to the XY stage 11. The weight is almost the same as the weight of the height measurement unit IO and the moving member 50.

Since the screw of the ball screw 33Y is opposite to that of the ball screw 34Y, the XY
The stage 11 and the weight plate 40Y move eight times in opposite directions. In this way, if the linear drive mass of the mechanisms on both sides as seen from the motors 30X and 30Y is equal, then the motor 30X
, 30Y, the reaction forces are equal in magnitude and in opposite directions, so the reaction forces cancel each other out and are eliminated. Although the rotational inertia of the shaft is not eliminated, the radius is small and there is no problem.The rotational moment caused by the mismatch between the center of gravity of the driven part and the linear drive shaft can be canceled by determining the mounting positions of the weights 41X and 41Y.

Even with structures other than the above, equivalent results can be obtained by selecting the pitch and weight of the ball screw so that the acceleration x mass is equal.

Effects of the invention: As described above, according to the shape measuring device of the present invention, it is possible to improve the measurement efficiency by increasing the scanning speed of the light spot.
c, the time to move 10++++a is approximately 80a
sec, and 10m when measuring lead frame pin bending.
The time required to scan m is 0.32 sec.

Further, a drive device having a vibration isolating means like the XY stage of the present invention has a great effect on devices that require both high precision and high acceleration, such as wire bonders, steppers, PGs, etc.

screw, 40X, 40Y... weight plate, 41X, 4
1Y...Eight.

Claims (1)

[Scope of Claims] 1. A moving device characterized by comprising means for suppressing vibration by offsetting reaction force during acceleration. 2. Consisting of a drive section, a moving member connected to one side of the drive section, and a balancer connected to the other side of the drive section, the balancer absorbs the reaction force when the moving member is accelerated. A moving device characterized by being configured to offset each other. 3. A moving device comprising a set of the drive unit and balancer according to claim 2 provided in the XY directions with respect to the moving member. 4. A light source means for irradiating a light spot perpendicularly to the surface of the workpiece whose surface condition is to be inspected; and a light receiving means located on the optical axis of the light spot extending on the opposite side of the light source means across the workpiece. , an imaging optical means for forming an image of the light spot irradiated onto the workpiece at a predetermined position in a predetermined angle direction of less than 90 degrees with respect to the irradiation optical axis of the light spot; and this imaging optical means. a one-dimensional light incident position detecting means located near the imaging position of the image of the light spot; a scanning means for relatively moving the optical axis of the light spot along the surface of the workpiece; measuring means for detecting a relative movement amount, detecting deformation in the surface direction of the workpiece based on the output signal of the light receiving means and the output signal of the measuring means, and detecting the one-dimensional light incident position. 4. A shape measuring device configured to detect the deformation and surface condition of the work in a direction perpendicular to the surface direction of the work using an output signal of the moving device according to claim 1, 2 or 3. A shape measuring device, characterized in that a height measuring section is provided on a moving member, and the light spot is scanned by driving the moving device. 5. The shape measuring device according to claim 4, further comprising means for suppressing vibration by offsetting reaction force during acceleration in the XY directions.