JPH08159721A - Method and device for measuring height of protruding part - Google Patents

Abstract

PURPOSE: To accurately measure an object with improved reliability by performing modulation so that light intensity can be increased when scanning a protruding part in advance when scanning the object to be measured with laser beams. CONSTITUTION: A modulation circuit 89 is made not to be operated and a laser source 61 emits laser beams with a constant intensity. The frequency of an oscillator 82 is linearly increased and laser beams are passed through bumps 12-1 and 12-2 between positions Q1 and Q2 on a semiconductor chip 11 by a light deviation element 81. Then, the information is stored in a circuit 89, modulation is made so that the light intensity of a part with a small light intensity can be increased, a chip 11 is scanned similarly, and the height dimensions of the bumps 12-1 and 12-2 can be calculated according to the triangulation principles based on the information from the element 22A. A display 87 shows the result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection height measuring method and apparatus, and more particularly to a method and apparatus for measuring the height of bumps formed on a semiconductor chip. In recent years, semiconductor devices have become large in scale, and bumps are often used as I / O means.

FIG. 7 shows a semiconductor device 10 having bumps. The semiconductor device 10 includes a back surface 11 of the semiconductor chip 11.
A large number of bumps 12 are arranged in a grid on a. Each bump 12 is provided on the electrode 13 on the back surface 11a of the semiconductor chip 11, as shown in an enlarged view in FIG. As shown in FIG. 9, the semiconductor device 10 is mounted face down with the bumps 12 joined to electrodes (not shown) on the wiring board 14.

Here, if the height h of the bump 12 (the size from the back surface 11a of the semiconductor chip 11 to the top of the bump 12) varies, there will be spots where bonding is insufficient or spots where bonding is not performed. It causes the mounting failure. Therefore, before mounting the semiconductor device 10, it is necessary to measure the height of the bump for each bump and inspect the degree of the variation.

[0004]

2. Description of the Related Art Initially, an inspector visually inspected bump height variations. However, in the present situation that the bumps have a small diameter of about 100 μm and the intervals are closely arranged with about 200 μm, visual inspection is becoming difficult. Therefore, as an alternative to the visual inspection, the height dimension of the bump can be determined by using a one-dimensional position detection element (PSD: Position S
A device that uses the principle of triangulation has been proposed.

FIG. 10 schematically shows a conventional measuring device 20. Reference numeral 21 is an image forming lens, and 22 is a position detecting element.
The laser light 23 is incident at a predetermined incident angle i and is scanned in the direction perpendicular to the paper surface of FIG. During scanning, the reflected laser light 24 reflected by the top 12 a of the bump 12 is moved by the imaging lens 21 to a position 25 on the position detection element 22.
Then, an image is formed as a light spot 26. Semiconductor chip 1
The reflected laser light 27 reflected at the portion indicated by the reference numeral 11b ₋₁ on the surface 11b of No. 1 is also spotted on the position 28 on the position detecting element 22 by the imaging lens 21.
The image is formed as

The position detecting element 22 includes light spots 26 and 2
9 and 9 are arranged at positions that are formed symmetrically with respect to the center line CL. The position detecting element 22 is shown in FIG.
As shown in FIG. 3, the light-receiving surface 40 has strip-shaped electrodes 41 and 42 on both sides of the light-receiving surface 40. Here, the direction in which the electrodes 41 and 42 face each other (the width direction of the position detection element 22) is defined as the U ₁ direction. The direction in which the electrodes 41 and 42 extend (the length direction of the position detection element 22) is defined as the U ₂ direction.

When the laser light 23 is scanned, the light spot of the laser light reflected by the semiconductor device 10 on the light receiving surface 40 is swung in the direction of arrow U ₁ and moved as shown by arrow 30 in FIG. While proceeding in the direction of arrow U ₂ . When a light spot is formed on the light receiving surface 40, the light receiving surface 40 performs photoelectric conversion, and the electrodes 41 and 42 output photocurrents I ₁ and I ₂ according to the positions of the light spots. Here, the electrodes 41, 4
A is the dimension between 2 and CL is the center line between the electrodes 41 and 42.
And

The light spot 45 extends from the center line CL to the electrode 4
It is assumed that it is formed at a position displaced by the dimension X _A toward the 2 side.
The above dimension X where the photocurrents at this time are I ₁ and I _2
A is

[0009]

[Equation 1]

It can be obtained by Therefore, in FIG. 10, the dimension B (the amount of movement of the light spot in the U ₁ direction) between the position 25 and the position 28 is obtained based on the above equation (1). In practice, the optical currents I _1, I _2, was amplified by the amplifier circuit 50, a current - converted into a voltage V _1, V ₂ voltage conversion circuit 51, the voltage V _1, V
₂ is added, subtracted, multiplied, and divided.

In FIG. 13, position 27 _-1 and bump top 12a
A dimension obtained by multiplying the dimension between and by the optical magnification m determined by the imaging lens 21 in FIG. 10 is equal to the dimension B described above. On the other hand, as shown in FIG. 13, the height dimension h of the bump 12 is
It is expressed by the following equation (2). h = B · sin θ / m · sin α (2)

It should be noted that α = 180 ° -2θ. Figure 10
The middle / height calculation circuit 52 performs the calculation of the above equations (1) and (2). The height dimension data of the height dimension h of the bump 12 is output from the circuit 52.

[0013]

On the surface 11a of the semiconductor chip 11, due to the difference between the reflectance of the surface 11a of the semiconductor chip 11 and the reflectance of the top portion 12a of the bump 12 and the difference in the shapes of the surface 11a and the top portion 12a. Reflected laser light 2
There is a difference between the light intensity of No. 7 and the light intensity of the reflected laser light 24 reflected by the top 12 a of the bump 12. The light intensity of the reflected laser light 24 is extremely lower than the light intensity of the reflected laser light 27.

In the scanning locus of FIG. 12, the thickness of the line represents the light intensity, thick means that the light intensity is high, and thin means that the light intensity is low. Three
Reference numeral 1 is a scanning locus portion of the reflected laser light 27 having high light intensity reflected by the surface 11a of the semiconductor chip 11. 32
Is a scanning locus portion of the reflected laser light 24 having a small light intensity reflected by the top 12 a of the bump 12.

The reflected laser light 24 having a small light intensity is easily affected by noise or the like. Therefore, according to the conventional measuring device 20 shown in FIG. 10, the moving dimension B of the light spot in the U ₁ direction cannot be accurately obtained, and as a result, the height dimension h of the bump 12 is accurately measured. Was difficult. In addition, the light intensity of the reflected laser light 27 and the reflected laser light 2
Since the difference in the light intensities of 4 is considerably large, the position detecting element 22
As a result, it has been necessary to use a large dynamic range, that is, an expensive one.

Therefore, according to the present invention, the scanning locus portion 32 in FIG. 12 is made thick as shown by the chain double-dashed line.
An object of the present invention is to provide a method and apparatus for measuring the height of a protrusion, which solves the above problems.

[0017]

FIG. 1 shows the principle configuration of the present invention. As shown in FIG. 1, the protrusion height measuring device 60
Is a laser source 61, a laser beam scanning unit 62, a reflected laser beam intensity / reflected laser beam incident position detection unit 63, a modulation unit 64, a protrusion height calculation unit 65, and a control unit 6.
6 and.

The laser source 61 emits an unmodulated laser beam 67 _-1 whose light intensity is constant or a modulated laser beam 67 _-2 whose light intensity changes. The laser light scanning unit 62 scans the measurement object 68 with the laser light 67 ₋₁ (67 ₋₂ ).
The measurement object 68 has a structure in which the protrusion 70 is provided on the substrate 69. 71 _-1 is an unmodulated laser beam for scanning, 71 _-1
-2 is the modulated laser beam scanning.

The detecting means 63 is a scanning non-modulated laser beam 71.
_-1 is the reflected laser light 7 reflected on the measurement object 68
2 _-1 , or the reflected laser light 72 _-2 reflected by the scanning modulation laser light 71 _-2 on the measurement object 68 is received, and the intensity of the reflected laser light and the incident position of the reflected laser light are detected. The control means 66 controls the operation timing of the laser light scanning means 62, and when the non-modulated laser light 67 _-1 scans, the control means 66 provides information complementary to the reflected laser light intensity change information from the detection means 63. The modulation means 64 is supplied.

The modulation means 64 operates the laser source 61 according to this information. The laser source 61 emits a modulated laser beam 67 _-2 . When the modulated laser beam 67 _-2 scans a portion of the reflected laser beam 72 _-1 , where the light intensity is weak,
It is modulated to increase the light intensity. Further, the control means 66 supplies the reflected laser light incident position information from the detection means 63 to the protrusion height calculation means 65 when the modulated laser light 67 _-2 scans.

The projection height calculation means 65 calculates the reflected laser light incident position information based on the principle of triangulation shown in FIGS. 10 and 13 to calculate the height dimension of the projection 70. .

[0022]

The control means 66 and the modulation means 64 act so that the reflected laser light 72 _-2 has no portion with a low light intensity. Control means 66 and projection height calculation means 65
Acts so that the height of the protrusion is calculated based on the information less affected by noise.

[0023]

FIG. 2 shows a projection height measuring device 80 according to an embodiment of the present invention. In the figure, parts corresponding to those shown in FIGS. 1, 10 and 11 are designated by the same reference numerals. The protrusion height measuring device 80 includes a laser source 61 and an optical deflector 8.
1, an oscillator 82, relay lenses 83 and 84, an objective lens 85, an imaging lens 21, and a position detection element 22A.
And a stage 86, a measurement result display device 87, and a microcomputer 88.

A modulation circuit 89 is provided in association with the laser light source 61. The position detection element 22A has a characteristic that the dynamic range is narrower than that of the position detection element 22 shown in FIG. The reason why a device having a narrow dynamic range is sufficient will be described later.
In addition, the amplifier circuit 50, the current-voltage conversion circuit 51, and the analog-digital conversion circuit 9 are associated with the position detection element 22A.
5 is provided.

The one electrode 41 of the position detecting element 22A is used.
By adding the photocurrent I ₁ extracted from the photocurrent I ₂ and the photocurrent I ₂ extracted from the other electrode 42, the light intensity of the reflected laser light at each time is obtained. A stage moving mechanism 90 that moves the stage 86 in the X direction is provided in association with the stage 86.

The microcomputer 88 has a CPU 91.
1 and a memory 92, which constitutes a control means 66 and a protrusion height calculation means 65 in FIG.
Control the overall behavior. Optical deflection element 81 and oscillator 82
Constitute the laser beam scanning means 62 in FIG.

The light deflection element 81 has a T
eO ₂ acousto-optic medium 100, transducer 101
And the sound absorbing material 102 is attached. Oscillator 8
When the signal from No. 2 is applied to the transducer 101, the ultrasonic traveling wave 103 propagates in the acousto-optic medium 100, and the incident laser beam 67 _-1 (67 _-2 ) is deflected by diffraction, that is, angle-modulated. , Y-direction scanning laser light 71 _-1 (71 _-2 ) is emitted.

The electrodes 41, 4 of the position detecting element 22A are
The intensity of the reflected laser light 66 is obtained by adding the currents output from the two. Therefore, the position detecting element 2
2A outputs information on the position where the reflected laser light 66 is incident and information on the light intensity of the reflected laser light 66. Therefore, in FIG. 2, the position detection element 22A, the amplification circuit 50, the current-voltage conversion circuit 51, and the analog-digital conversion circuit 95 are
The reflected laser light incident position detecting means 63 having the reflected laser light intensity in FIG. 1 is configured.

The laser source 61, the light deflection element 81, the relay lenses 83 and 84, and the objective lens 85 are arranged so that the laser light is incident on the stage 86 at a predetermined incident angle and the laser light is directed in the Y direction. It is arranged to scan.
The imaging lens 21 and the position detection element 22A are used for the stage 8
Reflected laser light 72 reflected by the semiconductor device 10 on 6
It is arranged to receive _-1 (72 _-2 ). The position detection element 22A is provided so that the electrodes 40 and 41 extend in the Y direction.

Next, the operation when measuring the height dimension of the bump of the semiconductor device by using the projection height measuring device 80 having the above structure will be described. First, the semiconductor device 1
As shown in FIG. 2, the bumps 12 are fixed on the stage 86 in the direction in which the bumps 12 face upward, and the stage 86 is appropriately rotated with respect to the vertical axis so that the rows of the bumps 12 are aligned with the Y direction. Let

Thereafter, the device 80 operates under the control of the microcomputer 88, and the height dimension of each bump 12 is measured. In the first scanning step described below, the laser light scans from point Q ₁ to point Q ₂ , and in the second scanning step, the laser light also starts scanning from the same point Q ₁ as described above. , Scan to point Q ₂ .

Given this, the first scan gives
The positions of the bumps 12 _-1 , 12 _-2 are obtained as a temporal position from the scanning start time, and the bumps 12 _-1 and 12 _-2 are calculated during the second scanning.
It is possible to increase the light intensity of laser light when scanning _-1 , 12 _-2 . 4 is shown in FIG.
A procedure for measuring the height dimension of two bumps 12 _-1 and 12 _-2 arranged in the Y direction will be described.

First scanning step 120 The modulation circuit 89 is not operating, the laser source 61 is not modulated, and the light intensity is constant (S _{1 as} shown by the line I ₋₁ in FIG. 5A). The non-modulated laser beam 67 _-1 is emitted. Here, the light intensity S ₁ of the unmodulated laser light 67 _{-1 is set so that} the light intensity of the laser light reflected by the surface 11a of the semiconductor chip 11 becomes lower than the saturation level of the detection characteristic of the position detection element 22A. Stipulated in.

On the other hand, the oscillation frequency of the oscillator 72 is as shown in FIG.
(B) It is changed so as to increase linearly, as indicated by the median line II _-1 . As a result, the non-modulated laser beam 67 _-1 is oscillated in the Y direction by the light deflection element 81 and becomes the non-modulated laser beam 71 _-1 for scanning as shown in the diagram on the left side of FIG. 5C. Along the locus 110 from the position Q ₁ to the position Q ₂ , the tops of the bumps 12 _-1 , 12 _-2 and the semiconductor chip 1
The first surface 11a is sequentially scanned.

Bump Position Detection Step 121 The reflected laser light 72 ₋₁ from the semiconductor device 10 in the first scanning step 120 passes over the position detection element 22A as shown in FIG.
Scanning is performed as indicated by arrow 130 in the diagram on the left side of (D).
131 _-1 is a portion scanned by the reflected laser light from the chip 11.

[0036] 132 _-1 is a part reflected laser beam is scanned from the top of the bump 12 _-1 or 12 _-3. Here,
The thickness of the lines indicating the scanned portions 131 _-1 , 132 _-2 represents the light intensity, as in the case shown in FIG. 12, the thick line indicates the high light intensity, and the thin line indicates the low light intensity. It represents each.

From the diagram on the left side of FIG.
It can be seen that the laser light reflected at the tops of 2 _-1 , 12 _-2 has a small light intensity. Each electrode 41 of the position detection element 22A,
By adding the currents output from 42, the light intensity information shown by the line III _-1 in FIG. 5 (E) is obtained. 133
_-1 is a portion representing the light intensity S ₁₀ of the reflected laser light from the chip 11, and 134 _-1 is a portion representing the light intensity S ₁₁ of the reflected laser light from the tops of the bumps 12 _-1 , 12 _-2. Is. The light intensities S ₁₀ and S ₁₁ have a large difference.

Information on the change in the light intensity is provided to the circuits 50, 51,
After passing through 95, it is stored in the memory 92. The positions of the bumps 12 _-1 , 12 _-2 are stored in the memory 92 as temporal information by the times T ₁ , T ₂ from the time t ₀ when the first scan is started until the portion 134 _-1 appears. It

Second Scanning Step 122 The information of the light intensity change stored in the memory 92 is taken out and added to the modulation circuit 89. The laser source 61 is modulated by the modulation circuit 89 so as to increase the light intensity in a portion where the light intensity is low, that is, complementary to the change in the light intensity indicated by the line III- ₁ in FIG. 5D. As a result, the laser source 61 emits the modulated laser light 67 _-2 whose light intensity changes as shown by the line I _-2 in FIG. 5A. Modulated laser light 6
7 _-2 changes so that the light intensity of the portion corresponding to the low light intensity of the reflected laser light 72 _-1 is high. That is, the modulated laser beam 67 _-2 changes so that the light intensity increases just when scanning the top of the bump 12 _{-1 and} the top of the bump 12 _-2 .

On the other hand, the oscillation frequency of the oscillator 72 is as shown in FIG.
In (B), as indicated by the line II _-2 , it is changed so as to increase linearly as in the case of the step 120 described above. The stage 86 is stationary. As a result, the modulated laser light 67 _-2 is swung in the Y direction by the light deflection element 81 to become the scanning modulated laser light 71 _-2 , which is shown in FIG.
As shown in the diagram on the right side of (C), as in the case of the above step 120, between the positions Q ₁ and Q ₂ the above trajectory 100
The tops of the bumps 12 _-1 , 12 _-2 and the surface 11 a of the semiconductor chip 11 are sequentially scanned along the same locus 100 as in the above.

Since the second scan is exactly the same as the first scan, with reference to the start time t ₁₀ of the second scan,
By modulating the laser source 61, the scanning modulated laser beam 71 _-2, when the light intensity becomes larger, just to scan the top portion of the top and the bump _12-2 of the bump 12 _-1. Bump height dimension calculation step 123 The reflected laser light 72 _-2 from the semiconductor device 10 in the second scanning step 122 passes over the position detection element 22A as shown in FIG.
Scanning is performed as indicated by an arrow 130 in the diagram on the right side of (D).

Each electrode 4 of the position detecting element 22A at this time
Based on the information extracted from 1, 42, the calculation is performed on the principle of triangulation. Bump 1 obtained by calculation
The display device 87 displays the measurement results of the height dimensions of 2 ₋₁ and 12 ₋₂ . With the above, the bump height measurement is completed.

Next, the effects and the like of the above bump height measuring method will be described. In the diagram on the right side of FIG.
31 _-2 is a portion scanned by the reflected laser light from the chip 11, and 132 _-2 is a portion scanned by the reflected laser light from the tops of the bumps 12 _-1 , 12 _-2 . Light intensity of the reflected laser light from the chip 11 is the same as in the first scanning step 120, the thickness of the line portion 131 _-2, part 1
It is the same as the line thickness of 31 _-1 . But bump 1
Since the light intensity of the laser light incident on the tops of the 2 ₋₁ and 12 ₋₂ is increased, the light intensity S ₂₁ of the reflected laser light from the tops of the bumps 12 ₋₁ and 12 ₋₂ is the first scan. It is higher than the light intensity S ₁₁ in the case of step 120.

The light intensity information obtained by adding the currents output from the electrodes 41 and 42 of the position detecting element 22A is as shown by line III- ₂ in FIG. 5 (E). That is, the level S _{21 of the} portion 134 _-2 representing the light intensity of the reflected laser light from the tops of the bumps 12 _-1 , 12 _-2 is the chip 1
The level is the same as the level S _{20 of the} portion 133 _-2 representing the light intensity of the reflected laser light from No. 1.

Therefore, the light intensity S ₂₁ of the reflected laser light from the tops of the bumps 12 _-1 , 12 _-2 is the same as the light intensity S ₂₀ of the reflected laser light from the chip 11. Correspondingly, in the right drawing of FIG. 5 (D), the the thickness of the line portion 132 _-2, is represented equal to the thickness of the line portion 131 _-2. The light intensity S ₂₀ of the reflected laser light from the chip 11 and the light intensity S ₂₁ of the reflected laser light from the bumps 12 _-1 , 12 _-2 are both at a saturation level that saturates the detection characteristics of the position detection element 22A. Lower and position detection element 22A
Has a value sufficiently higher than the noise influence level that is affected by noise.

As a result, the following two effects can be obtained. (i) bumps 12 _-1, for the reflected laser beam from the top of the 12 _-2, and it minimizes the effects of noise, the bumps 12 _-1, the height dimension of 12 _-2 accuracy as compared with the conventional Well measured. (ii) The difference between the light intensity S ₂₁ of the reflected laser light from the bumps 12 _-1 , 12 _-2 and the light intensity S ₂₀ of the reflected laser light from the chip 11 is reduced to be smaller (in the embodiment, Since the difference in light intensity is substantially zero), the bump height can be measured even when using a position detection device having a characteristic that the dynamic range is narrow because the difference in light intensity is small. This position detecting device is less expensive than a device having a wide dynamic range.

Since the operation of the CPU 91 is substantially the same as the above description, the description thereof will be omitted. Although in the above-mentioned embodiment, the light intensity of the reflected laser light from the top of the bump in the second scanning step is made substantially equal to the light intensity of the reflected laser light from the chip,
The present invention is not limited to this. That is, the second
The light intensity of the reflected laser light from the top of the bump in the scanning step 122 may be increased so as to approach the light intensity of the reflected laser light from the chip to reduce the difference in light intensity between the two. By this, the height dimension of the bump is
It can measure more accurately than before.

In addition, the first scanning step 120 is performed a plurality of times, the light intensity difference of the reflected laser light obtained each time is averaged, and the second scanning step 122 is performed based on this average. Good. Next, a modified example of the present invention will be described.
FIG. 6 shows a modification of the present invention.

Since the device 80 of FIG. 2 uses the optical deflecting element 81 as the laser beam scanning means, the scanning mode of the laser beam can be changed by changing the program of the CPU 91. This modification is based on this. In the second scanning step, the laser light scans the bump top portion at a slower speed than the chip portion, and the laser light scans the bump top portion. Is taken for a longer time than that of the chip portion to obtain more detailed information on the top of the bump so that the bump height dimension can be measured more accurately.

To explain this modification, the measurement procedure is the same as in the above embodiment. The first scanning step 120 and the bump position detecting step 121 are performed in the same manner as in the above embodiment. In the second scanning step 122A, the laser source 61 is modulated by the modulation circuit 89, and the light intensity is changed to the line I in FIG.
_-2a emits a modulated laser beam 67 _-2a, and the oscillation frequency of the oscillator 82 is changed to that shown in FIG.
In the middle, the modulation laser beam 71 _-2a is changed stepwise as shown by the line II _-2a so that the portion of the chip 11 scans quickly and the positions of the bumps 12 _-1 , 12 _-2 scan slowly. Do it.

As a result, from the position detecting element 22A,
In FIG. _6E , information on the light intensity of the reflected laser light shown by line III- _2a is obtained. Information on the light intensity of the reflected laser light from the bumps 12 _-1 , 12 _-2 is obtained over a time t ₀ which is several times longer than that of the above-described embodiment. Therefore, the bump height calculation step 123A calculates the height dimension near the tops of the bumps 12 _-1 , 12 _-2 at more positions than in the above embodiment.

As a result, the bumps 12 _-1 , 12 _-2
The height can be measured more accurately than in the above embodiment. Next, another modification of the present invention will be described. In the second scanning step, by appropriately changing the oscillation frequency of the oscillator 82, the mode of scanning the laser light by the optical deflector can be appropriately determined.

For example, the scanning speed for the tops of the bumps is the same as in the above-described embodiment, and the portion of the surface of the chip 11 between the adjacent bumps may be scanned at a higher speed than for the bumps. . By doing so, the time required for the second scanning step is shortened, and the time required for measuring the bump height of one semiconductor device can be shortened.

It is also possible to perform the second scanning step by scanning when the laser beam returns from Q ₂ to Q ₁ . Further, the object to be measured by the height measuring device of the present invention is not limited to the bump of the semiconductor device, and may be any object having a protrusion on the substrate.

[0055]

As described above, according to the first aspect of the invention, the position of the protrusion is obtained by the first scanning step, the laser source is modulated, and the second scanning step is performed.
A laser beam having a high light intensity is applied to the protrusion to increase the light intensity of the reflected laser light from the protrusion, and the height dimension of the protrusion is calculated based on the information at this time. Therefore, it is less likely to be affected by noise,
The height dimension of the protrusion can be measured more reliably and accurately than in the conventional case.

Further, of the measurement object, the light intensity of the reflected laser light from the substrate and the light intensity of the reflected laser light from the protrusions can be reduced, whereby the dynamic range is narrower than the conventional one. Even if an inexpensive position detector is used, the height dimension of the protrusion can be accurately measured. According to the second aspect of the present invention, it is possible to increase the number of measurement points for the protrusions, and thus it is possible to measure the height dimension of the protrusions with higher accuracy.

The invention of claim 3 has the same effect as the effect of the invention of claim 1. According to the invention of claim 4, since the light deflection element is used, the laser beam can be scanned in an arbitrary manner. Therefore, by appropriately determining the scanning mode of the laser light, the height dimension of the protrusion can be accurately measured, and the time required to measure the height dimension of all or the protrusion can be shortened.

According to the fifth aspect of the present invention, it is possible to increase the number of measurement points on the protrusion by slowing down the scanning speed for the protrusion. Therefore, the height of the protrusion can be measured more reliably and accurately. It can be measured.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of a protrusion height measuring device of the present invention.

FIG. 2 is a diagram showing a protrusion height measuring device according to an embodiment of the present invention.

FIG. 3 is a diagram showing a light deflection element in FIG.

FIG. 4 is a diagram showing a method for measuring the height of a protrusion using the apparatus of FIG.

FIG. 5 is a diagram for explaining the measuring method of FIG.

FIG. 6 is a diagram showing a modification of the measuring method.

FIG. 7 is a diagram showing a semiconductor device which is an example of an object to be measured.

FIG. 8 is a perspective view showing a part of FIG. 7 in an enlarged manner.

9 is an enlarged perspective view showing a part of FIG. 7. FIG.

FIG. 10 is a diagram schematically showing a conventional bump height measuring device.

11 is a diagram showing a position detection element in FIG.

12 is a diagram showing a scanning locus of the reflected laser light on the position detecting element in FIG.

FIG. 13 is a diagram illustrating the principle of triangulation.

[Explanation of symbols]

10 semiconductor device 11 semiconductor chip 12 bump 13 electrode 14 wiring board 21 imaging lens 22A position detection element 40 light receiving surface 41 electrode 42 electrode 50 amplification circuit 51 current-voltage conversion circuit 60 protrusion height measuring device 61 laser source 62 laser light Scanning means 63 Reflected laser light intensity / reflected laser light incident position detection means 64 Modulation means 65 Projection height calculation means 66 Control means 67 _-1 Non-modulated laser light with constant light intensity 67 _-2 Modulated laser light 68 Measurement target object 69 substrate 70 protrusion 71 _-1 scanning unmodulated laser beam 71 _-2, 71 _-2a scanning modulated laser beam 72 _-1, 72 _-2, 72 _-2a reflected laser beam 80 lens 81 light deflector 82 oscillator 83, 84 Relay lens 85 Objective lens 86 Stage 87 Microcomputer 88 Measurement result display device 89 Modulation circuit 9 Stage moving mechanism 91 CPU 92 Memory 95 analog - digital converter 100 TeO ₂ acousto-optic medium 102 sound absorbing material 103 ultrasonic traveling wave 110 scanning locus 120 first scanning step 121 bumps position detecting step 122,122A second scanning step 123 , 123A Bump height calculation step 130 Arrows showing how the reflected laser light scans the position detecting element 131 _-1 , 131 _{-2 The} part scanned by the reflected laser light from the chip 132 _-1 , 132 _{-2 From the} top of the bump _Scanned portion of the reflected laser light 133 _-1 , 133 _-2 , portion representing the light intensity of the reflected laser light from the 133 _-2a chip 134 _-1 , 134 _-2 , 134 _-2a Reflected laser light from the top of the bump Light intensity

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoji Nishiyama 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor Fumiyuki Takahashi 1015, Kamedotachu, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor Gotoshi Ando 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited

Claims (5)

[Claims] 1. An object to be measured having a protrusion on a substrate,
A method of scanning the laser beam emitted from a laser source, receiving the reflected laser beam with a position detection element, and using the output signal of the position detection element, and measuring the height of the protrusion by the principle of triangulation. In the first scanning step of scanning the measuring object with unmodulated laser light, and the output signal of the position detecting element receiving the reflected laser light from the measuring object in the first scanning step. When detecting the position of the protrusion based on the step of detecting the position of the protrusion, and the position of the protrusion detected by the step of detecting the position of the protrusion, the laser source is modulated to scan the protrusion. A second scanning step of scanning the measurement object with a modulated laser beam that is modulated so that the light intensity increases, and a reflection laser from the measurement object in the second scanning step. Using the output signal of the position detecting element that receives the light, the projection height calculation step of calculating the height of the projection based on the principle of triangulation is used. How to measure the height of the protrusion. 2. The second scanning step is characterized in that the modulated laser light is scanned with respect to the protrusion at a speed slower than a speed with which the substrate is scanned. The method for measuring the height of the protrusion as described. 3. A laser source for emitting a laser beam, a modulation means for modulating the laser source, and a laser beam scanning for scanning a laser beam from the laser source on an object to be measured having a protrusion on a substrate. And a reflected laser light intensity / reflected laser light incident position detection means for receiving the reflected laser light from the measurement object and outputting information on the light intensity of the reflected laser light and information on the position at which the reflected laser light is incident. Means and the laser scanning means for performing a first scan for scanning a laser beam having a constant light intensity, the position of the protrusion is detected by the information from the detecting means at this time, and the detected protrusion A second laser scanning means for scanning the modulated laser light, the light intensity of which is modulated so as to increase the light intensity when scanning the protrusion, in accordance with the position of the portion; Control means for performing scanning, and projection height calculation means for obtaining the projection height by supplying information from the detection means during the second scanning and performing calculation based on the principle of triangulation. A protrusion height measuring device having the following configuration. 4. The laser beam scanning means comprises a light deflection element for angularly modulating the laser light by frequency modulation, and an oscillator for oscillating a signal applied to the light deflection element. 3. The protrusion height measuring device according to 3. 5. The laser beam scanning means comprises an optical deflecting element for angularly modulating the laser beam by frequency modulation, and an oscillator for transmitting a signal to be applied to the optical deflecting element, and the control means for the second scanning. 4. The projection height measuring device according to claim 3, wherein the oscillator is controlled so that the scanning speed of the laser beam with respect to the projection is slower than that of the substrate.