JPH09243692A - Static electricity distribution measuring system and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable diagnose electrification of a measuring object with ease. SOLUTION: A static electricity measuring head 4 keeps a certain distance to an IC by being fixed on a measuring head holder 5 with an abjusting mechanism to travel in the directions of an X-axis and a Y-axis. An X-Y table 7 travels on an X-Y plane under the control of a motor controller 8. The static electricity measuring head 4 is connected to a computer 1 via a measurement main body 3 and the measurement results of the electric potential of a measurement area 10 is given to the computer 1. The computer 1 processes to visually display the electric potential distribution of the surface of an IC 9 on a display 2 on the basis of the measurement results of the amount of traveling and electric potential of the X-Y table 7. In this case the relative travel of the static electricity measuring head 4 to the IC 9 is preformed by certain steps and electric potential measurement is repeated at every step. This step is smaller than the size of the measurement area 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object to be handled, especially a semiconductor integrated circuit device (hereinafter referred to as "IC").
The present invention relates to a technique for measuring static electricity generated in a minute range in a minute range and visually displaying the measured potential distribution on the surface.

[0002]

2. Description of the Related Art In a manufacturing process of an IC, particularly a process performed after encapsulating a mold resin, an internal circuit of the IC may be destroyed when static electricity generated on the IC surface is discharged.

Management of the temperature and humidity of the room being manufactured,
Although various measures against static electricity such as an earth band can be implemented relatively easily, it is necessary to specify in which part of the production apparatus the electrification occurs.

FIG. 10 is a conceptual diagram showing a conventional technique for measuring the charge amount of an IC. While keeping a predetermined distance by measuring with the ruler 20, the electrostatic measurement head 4 is manually held over the surface of the IC 9 to be measured. Measurement area 10 is IC9
Multiple are adopted above.

[0005]

However, since the electrostatic measurement head 4 is held by hand in such a measurement,
The measurement area 10 cannot be finely set on the IC 9. For example, FIG. 11 is a conceptual diagram showing a plurality of measurement regions 10 set when the measurement is performed as shown in FIG.
However, it is difficult to specify in which part of the production apparatus the electrification is occurring.

The present invention has been made to solve the above problems, and a static electricity distribution system capable of easily determining the cause of electrification by obtaining the potential distribution of a measuring object in detail and visually. Is intended to provide.

[0007]

Means for Solving the Problems Claim 1 of the present invention
What is related to, the scanning on the measurement target, the electrostatic measurement head for measuring and outputting the potential on the measurement object for each predetermined movement distance for each measurement region, and processing the output of the electrostatic measurement head, A static electricity distribution measurement system comprising: a display unit for visually displaying a potential distribution on a measurement target,
The dimension of the measurement area in the scanning direction is larger than the predetermined moving distance.

[0008] The present invention according to claim 2 includes:
(A) scanning the measurement target and setting a measurement region for the measurement target at each predetermined movement distance to obtain a potential of the measurement region; and (b) the measurement at each predetermined movement distance. A method of obtaining a potential of a region, and visually displaying a potential distribution on the measurement target, wherein the dimension of the measurement region in the scanning direction is more than the predetermined moving distance. large.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1. 1 and 2 show a first embodiment of the present invention.
It is a conceptual diagram which illustrates the structure of the static electricity distribution measuring system concerning this.

A measuring stage 6 having a guide 6a and made of a conductive resin is attached to an XY table 7 which is grounded. The IC 9 is positioned by pressing its two sides against the guide 6a, and the base point for static electricity measurement is set. The measurement head holder 5 has an adjustment mechanism that moves in the X-axis direction and the Z-axis direction, and the electrostatic measurement head 4 is fixed to this, so that a predetermined distance from the IC 9 is maintained. Since the thickness varies depending on the type of IC9, it is desirable to adjust the Z-axis direction.

The XY table 7 is controlled by the motor controller 8 to move on the XY plane. Therefore, the measurement area 10 of the static electricity measurement head 4 can relatively scan over the IC 9 as indicated by the arrow 11 while maintaining a predetermined distance between the static electricity measurement head 4 and the IC 9. The computer 1 controls the motor controller 8.
The control command such as the movement amount of the XY table 7 is processed.

The static electricity measuring head 4 is connected to the computer 1 via the measuring body 3, and the result of measuring the potential of the measuring region 10 is given to the computer 1. The computer 1 displays the potential distribution on the surface of the IC 9 based on the movement amount of the XY table 7 and the measurement result of the potential.
Performs the process of displaying the image visually.

At this time, the electrostatic measurement head 4 and the IC 9 are moved relative to each other in predetermined steps, and the potential measurement is repeated each time. There is a desirable relationship between the amount of this predetermined step (hereinafter referred to as “unit step amount”) and the size of the measurement region 10 in the scanning direction (hereinafter referred to as “region size”). Of course, when the area size is smaller than the unit step amount, the entire surface of the IC 9 cannot be measured, which is not desirable.

FIG. 3 shows a case where the unit step amount is equal to the area size L1. After the potential in the measurement area 10b is measured, the potential in the measurement area 10a is measured. However, in this case, the measurement points of the potential distribution cannot be taken sufficiently finely.

In FIG. 4, the area size L1 is the unit step amount L2.
It shows the case of larger than. After the potential in the measurement area 10d is measured, the potential in the measurement area 10c is measured. By performing the measurement in this way, the measurement points of the potential distribution can be taken sufficiently finely. In addition, since the potentials are averaged or rms-valued (1 / √2 times) inside the measurement regions 10c and 10d, the obtained values are obtained even if the measurement ranges that are continuously set overlap. Is obtained as data close to the actual surface charge distribution. For example, when the measurement area 10 is 5 mm × 5 mm (area size is 5 mm), the unit step amount can be set to 1 mm.

FIG. 5 shows an IC using a circular suction pad 12.
It is a conceptual diagram which shows a mode that the surface of 9 is adsorbed and handled.
FIG. 6 is a diagram showing a state in which the potential distribution of the IC 9 handled as shown in FIG. 5 is displayed in different colors according to the magnitude of the potential. However, the color classification is shown as different hatching in the figure. In addition, the size of the measurement region 10 is also indicated by a one-dot chain line for comparison of sizes. For example, by using the electrostatic measurement head 4 that provides the measurement area 10 of 5 mm × 5 mm, the data obtained by scanning with the unit step amount of 1 mm can be processed to realize the color-coded display as shown in FIG.

7 and 8 are graphs showing the case where the potential distribution is displayed three-dimensionally. The potential distribution in the area of 28 mm × 28 mm is shown every 1 mm, and the level of the potential is shown by peaks and valleys. Both figures show the same distribution viewed from different directions, and it can be seen that they are charged in a ring shape.

Therefore, when such a handling tool having a ring shape is used in the manufacturing process of the IC 9, the cause of charging can be specified to the handling tool.

As described above, according to the present invention, the measurement result is displayed not as a numerical value but as a color-coded display or a three-dimensional graph, so that the charge distribution can be known from the potential distribution.
It becomes easy to identify the cause of charging.

Although the IC 9 is scanned by the XY stage 7, the potential can be measured by stopping the XY stage 7 each time the unit step amount is moved, or the XY stage.
It is also possible to move the stage 7 at a constant speed without stopping it and measure the potential at regular intervals.

FIG. 9 is a conceptual diagram showing a modified construction to which the present invention is applied when the movement of the XY stage 7 is not uniform. X-Y direction of X-Y stage 7, Y direction
A drive motor 15x, which is a drive system that controls axial movement,
By attaching encoders 14x and 14y, which are position detection mechanisms, to 15y via rotation transmission shafts 16x and 16y, it is possible to obtain a timing at which the moving distance is detected and the potential is measured. By doing so, the static electricity can be measured for each unit step amount even if the XY stage 7 is continuously moved, and thus the time for performing the static electricity measurement can be shortened.

Of course, the present invention can be applied not only to obtain the charging state of individual ICs, but also to investigate the cause of charging of a substrate or the like assembled by combining semiconductor elements. As a result, such troubles due to electrostatic breakdown of the substrate can be suppressed.

[0023]

As described above, according to the present invention, the dimension in the scanning direction of the measurement area in which the static electricity measuring head measures the potential is set to be larger than the predetermined moving distance which determines the position for measuring the potential. , The measurement regions are sequentially overlapped and set, and data close to the actual surface charge distribution of the measurement target is obtained. Moreover, since the potential distribution on the measurement target is visually displayed, there is an effect that the state of charging can be easily grasped and the cause of charging can be easily specified.

[Brief description of drawings]

FIG. 1 is a conceptual diagram illustrating the configuration of a first embodiment of the present invention.

FIG. 2 is a conceptual diagram illustrating the configuration of the first embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between a unit step amount and a region size.

FIG. 4 is a diagram showing a relationship between a unit step amount and a region size.

FIG. 5 is a conceptual diagram showing how to handle the IC 9 using the suction pad 12.

FIG. 6 is a diagram showing how the potential distribution is displayed in different colors.

FIG. 7 is a graph showing a case where a potential distribution is three-dimensionally displayed.

FIG. 8 is a graph showing a case where a potential distribution is three-dimensionally displayed.

FIG. 9 is a conceptual diagram exemplifying a modified configuration of the first embodiment of the present invention.

FIG. 10 is a conceptual diagram showing a conventional technique for measuring the charge amount of an IC.

FIG. 11 is a conceptual diagram showing locations of a plurality of measurement areas 10.

[Explanation of symbols]

4 static electricity measurement head, 7 XY stage, 9 I
C, 10a to 10d measurement area, L1 area size, L2
Unit step amount.

Claims (2)

[Claims] 1. An electrostatic measurement head that scans an object to be measured and measures and outputs a potential on the object to be measured for each predetermined movement distance, and an output of the electrostatic measurement head is processed. A static electricity distribution measuring system, comprising: a display unit visually displaying a potential distribution on a measurement target, wherein a dimension of the measurement region in the scanning direction is larger than the predetermined moving distance. 2. A step of: (a) scanning an object to be measured, setting a measurement area for the object to be measured for each predetermined movement distance, and obtaining a potential of the measurement area; (b) the predetermined movement Obtaining the potential of the measurement region for each distance, and visually displaying the potential distribution on the measurement target, the dimension of the scanning direction of the measurement region is larger than the predetermined moving distance, Static electricity distribution measurement method.