JP2012002619A - Laser interference bump measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply and precisely measure the height of a bump and inspect the shape of the bump without any necessity of imaging a large number of interference fringes many times with changing the length of an optical path of object light or .SOLUTION: Beat light formed by superimposing light, emitted from two light sources 21 and 22, having different wavelengths are split, one is reflected from a reference mirror 28 to be defined as the reference light, the other is applied to and reflected from a bump to be defined as object light, and interference fringes formed by superimposition and interference of the reference light and the object light are captured by a CCD 30, thereby enabling to measure the height or inspect the shape of the bump from the image of the interference fringes. The respective wavelengths λ1 and λ2 of the two light sources are set such that the wavelength Λ/2 of the beat light becomes larger than the height in the design specifications of the bump 23 to be measured.

Description

  The present invention utilizes optical interference phase shift and measures the height of fine bumps (also referred to as microbumps) in the semiconductor device mounting process or shape inspection (step, unevenness, inclination, flatness, etc.) of the bump surface. In the present specification, the present invention relates to a laser interference bump measuring instrument capable of simply performing shape inspection.

  Conventionally, bump height measurement and shape inspection in a semiconductor device mounting process are performed by a confocal laser microscope, a light cutting method, a phase modulation optical interference measuring instrument, a white light interference measuring instrument, or the like.

  In a confocal laser microscope, the light source and the light detector are optically conjugate with respect to the objective lens (the light emitted from one point of the light source is collected at one point of the detector). With a thick sample where the focal length varies by installing a pinhole at the conjugate position, selecting scattered light only from the focal position, and detecting scattered light and fluorescence only at the focused part Even if there is, an image without blur can be obtained.

  The laser scans the sample and finally obtains the entire image. If the scanning speed is slowed, a high-resolution image is obtained with less noise. Information can be collected from a plurality of focal planes by moving the microscope stage up and down. By superimposing two-dimensional images of a plurality of focal planes, a three-dimensional image of a specimen can be created by a computer (see Patent Document 1).

  In the light cutting method, a sample is irradiated with slit light from a laser light source, and a curved strip of light on the sample is photographed with a camera. From the image formation position in the image, X, Y, This is a method for obtaining the Z value.

  The phase modulation optical interferometer visualizes and measures the fine concavo-convex structure by detecting the interference fringes while modulating the phase of the light with an optical interferometer. It can be measured. Therefore, it can be applied to shape measurement of optical components such as lenses and mirrors, flatness measurement of liquid crystal panels (about 1000 mm × 400 mm), and accurate shape measurement of spacers of liquid crystal elements.

  The white light interferometer uses a white light source having a sufficiently broad spectrum distribution as a light source, forms interference fringes by the white light source, and white fringes are observed only where the reference surface optical path length difference of the sample is zero, This is a means for measuring the shape of the object by moving the position of the reference mirror along the optical axis at equal intervals, for example, 1 / 8λ, and obtaining the position where this white stripe is formed (see Patent Document 2). Such a white interference measuring instrument is widely used for three-dimensional shape inspection of various industrial products such as surface measurement of a liquid crystal display and flatness measurement of a semiconductor wafer.

JP 2000-275027 A WO 2006/068217

  In recent years, with the downsizing, thinning, and miniaturization of semiconductor devices, the height dimensions of bumps mounted on the semiconductor devices tend to be small. For example, in a semiconductor, a fine bump having a height of about 20 μm corresponding to an advanced fine pitch connection technology, a confocal laser microscope having a resolution of about 1 μm and a light spot diameter of 1 μm or more, a light cutting method, Measurement is difficult with a phase shift optical interference measuring instrument or the like. Furthermore, when these methods are applied to bump measurement, there are the following major problems.

  The confocal laser microscope moves the microscope stage up and down to superimpose multiple 2D images obtained by collecting information from multiple focal planes to obtain a 3D image of the sample. For this reason, there is a problem that it takes time to perform the operation and the shape inspection of the bump having a small height cannot be accurately measured.

  The light cutting method usually has only one slit light in the camera field of view, so there is little misidentification of data, but the mechanical system must be moved each time one line is measured with one slit light. There is a problem that the operability is poor and it takes time to measure a large number of points.

  Although the white light interferometer has a high resolution of 0.1 μm or less, the position of the reference mirror is moved along the optical axis at regular intervals, for example, (1/8) λ, and the interference fringes coincide with the measurement optical path length. Since it is a means to measure the height shape of an object by finding the position of maximum intensity, even if there is a step on the surface and the height is much larger than the wavelength, the position of the reference mirror is repeatedly moved many times. For example, height is required. However, the measurement is not only troublesome, but the measurement time takes several seconds to several tens of seconds per field of view, and high-speed measurement inspection cannot be performed.

  In a phase shift optical interferometer, a laser beam having a single wavelength of about 0.6 μm is usually used. However, in a single-wavelength optical interference, an interference fringe appears every λ / 2 with the wavelength of the light source being λ on a continuously inclined surface. However, if there is a step of λ (1/2 + n) times on the sample surface, the interference fringe Since there is no change, the level difference (and its height, position, etc.) cannot be recognized correctly. Therefore, the measurement range must be limited to λ / 2 or less. For this reason, there exists a problem that a measuring object is limited to the sample of the design specification which can measure the height even if there is a level difference.

  Therefore, the present invention aims to improve the quality of the mounting process corresponding to the fine pitch connection technology and to reduce the cost (reduction of defective rate), and is used for the height measurement and shape inspection of the bump. In view of the problems of various conventional measurement means, a laser interference bump measuring instrument that enables high-resolution and high-speed measurement inspection of the height and shape of fine bumps in the mounting process to improve semiconductor productivity. The challenge is to achieve this.

  In order to solve the above-described problems, the present invention is a laser interference bump measuring instrument including two light sources, a half mirror, a reference mirror, and a detection means, and the two light sources have light of different wavelengths. The light of different wavelengths is superimposed and beat to be used as beat light, and the half mirror divides the beat light and directs one of the divided beat lights to the reference mirror The other is directed to the bump, and one of the beat light is reflected by the reference mirror to become reference light, the other is reflected by the bump to become object light, and the detection means passes through the half mirror and the reference light from the reference mirror and the bump. An interference fringe image is detected by receiving the interference light on which the object light from is superimposed, and a bump height measurement or a bump shape inspection can be performed from the interference fringe image. Providing over interference bump instrument.

When the wavelength of the beat light is Λ and the wavelengths of the two light sources are λ1 and λ2, the wavelength Λ of the beat light is determined by the following equation.
Λ = λ1λ2 / (λ2-λ1)
However, Λ >> λ1, λ2.

  The wavelengths λ1 and λ2 of the two light sources are set so that the wavelength Λ / 2 of the beat light is larger than the height in the design specification of the bump to be measured.

  An analysis device for sending and inputting information of interference fringe images from the detection means is provided. The analysis device includes an input / output interface unit, a CPU, and a storage unit, and operates according to a shape analysis program installed in the storage unit. The CPU preferably analyzes the height shape of the bumps by analyzing the information of the interference fringe image.

  The light source preferably emits laser light, LED light, white lamp monochrome light, or bright line light source light.

  The laser interference bump measuring instrument according to the present invention is provided with two light sources that emit light of different wavelengths, superimposes light of these wavelengths to generate beat light, and uses the beat light as reference light and object light. Since the structure provided for is adopted, the following remarkable effects are produced.

  That is, it is possible to easily obtain beat light in which half the wavelength is longer than the height of the bump, and by applying such beat light to the interferometer, the optical path length of the object light is changed and many interferences are repeated many times. The troublesome operation of photographing the stripes is not required, and the bump height measurement and shape inspection can be easily and accurately performed.

It is a figure for demonstrating the general structure of an interferometer in order to explain the principle of this invention. (A) is a plan view, a side view, and a diagram showing an interference fringe of this sample having an inclined surface measured by an interferometer from above, and (b) is a side view of the sample and this separate view from above. It is a figure which shows the interference fringe of the sample which has these inclined surfaces. (A) shows a state where the lens barrel of the interferometer is moved by λ / 8, and (b) shows an interference fringe image taken every time after the movement. (A) is a top view of a sample having an inclined surface measured with an interferometer, a side view and a diagram showing interference fringes of this sample from above, and (b) shows the same inclined surface measured with an interferometer. It is a figure which shows the side view of the stepped sample which has, and the interference fringe of this sample. It is a figure for demonstrating the structure of the Example of the laser interference bump measuring device which concerns on this invention. It is a figure for demonstrating the beat light used with the laser interference bump measuring device which concerns on this invention. (A) is a figure for demonstrating the structure of the analyzer in the Example of the laser interference bump measuring device based on this invention, (b) is a functional block diagram which shows the functional means of an analyzer. It is a figure which shows typically the relationship of the beat light reflected from the bump, the substrate surface (bump bottom surface), and the beat light reflected from the upper surface of the bump.

  An embodiment for implementing a laser interference bump measuring instrument according to the present invention will be described below with reference to the drawings based on the embodiments.

(principle)
The principle of the present invention will be described below. Interferometers are well known in the art, and the problems when the interferometer is used for measuring the length and shape of the sample are as described above. However, for the convenience of explaining the principle of the present invention, there are some overlaps. Measurement of the length and shape of the sample using the interferometer and the interferometer will be described with reference to FIG.

  The interferometer 1 passes the light emitted from the light source 2 through the half mirror 3 and the objective lens 4, further divides the light into two lights by the half mirror 5, and reflects one of the lights by the reference mirror 6 (reference surface). The sample 7 is irradiated with the other light as the reference light, and the reflected light as object light passes through different optical paths, and is again superimposed (superposed) by the half mirror 5, due to the optical path difference between the two lights. The generated interference fringes are photographed by the CCD 8 serving as detection means.

  Then, the information of the captured interference fringe image is analyzed by the CPU (calculation means) in accordance with a dedicated program for analyzing the mounted interference fringe in the analysis device 9 (using a computer), and the height of the sample 5 The surface shape, transmitted wavefront shape, and the like are obtained.

  When the optical path difference between the reference light and the object light is an integral multiple of the wavelength λ, the interfered light becomes bright, and if the optical path difference is shifted from the integral multiple of the wavelength λ by half the wavelength λ, that is, λ (1 / 2 + n), the interfering light becomes dark. When the optical path difference is not constant depending on the location, bright and dark interference fringes are observed.

  In such an interferometer 1, a laser having excellent coherence is used as the light source 2, and a sample 7 (for example, a bump) having an inclined surface (may be a step) on the surface as shown in FIG. When the measurement is performed, an interference fringe image 11 showing bright and dark stripes as shown in FIG. In this case, as shown in FIG. 2B, the same interference fringe image 11 as in FIG. 2A is photographed even if the height of the inclined surface of the sample 7 is in the reverse direction.

  The bright and dark stripes of the interference fringe image 11 are contour lines, and the interval is determined by the wavelength and the incident angle of the light source 2. Usually, light is incident perpendicularly to the surface of the sample 7, and the contour line spacing at that time is half the wavelength λ (λ / 2). In short, the generated interference fringes appear at the same interval as half the wavelength of the light source 2. If the phase difference between the light reflected from the sample surface and the reference surface is φ and the height of the reference surface is h, φ = 4πh / λ.

  For example, when laser light having a wavelength λ of 600 nm is used as the light source 2, the interval between the interference fringes is λ / 2 = 300 nm, and this numerical value is the height difference of the surface of the sample 7 as it is. Therefore, by counting the number of interference fringes, it is possible to measure the inclination of the surface of the sample 7 and the height difference of the steps.

  As shown in FIG. 3 (a), the lens barrel 13 (or sample 5) of the objective lens 12 is moved at a λ / 8 pitch to change the optical path length of the object light. Then, four interference fringe images 111 to 114 as shown in FIG.

  The four interference fringe images are shown as having the interference fringes moved in one direction with respect to the reference line 13 indicated by a dotted line. If the relationship between the movement direction of the objective lens barrel 12 and the movement direction of the interference fringes is known in advance, as shown in FIGS. Even in the same case, it is possible to measure which side of the inclined surface of the sample 7 is high or low.

  As described above, since the interferometer 1 uses the wavelength of light as a ruler, it has an advantage that high-precision measurement can be performed. However, since interference fringes appear at every λ / 2, when the height difference of the step on the surface of the sample 7, the height difference of the unevenness, the height difference of the inclination, etc. are larger than the wavelength λ / 2, the height of the sample 7 is increased. In addition, the height difference of the step on the surface of the sample 7, the height difference of the unevenness, the height difference of the inclination, etc. cannot be measured, and the position of the step or unevenness on the surface of the sample 7 cannot be recognized.

  For example, when the interferometer 1 measures the sample 7 shown in FIG. 4A having an inclined surface and the stepped sample 7 having the same inclination as the sample 7 and having a step in the middle, the sample 7 4 is larger than λ (1/2 + n), the interference fringe image 11 does not change as shown in FIGS. 4A and 4B. It is impossible to measure the height difference, the height difference of the unevenness, and the like, and it is impossible to recognize the step or the position of the unevenness on the surface of the sample 7.

  For this reason, white light is used as the light source, and the maximum intensity interference fringe generated when the reference optical path length and the measured optical path length coincide with each other is obtained, and the optical path length is moved many times by using an actuator such as a piezo element. Since it is necessary to take a fringe image with a camera (CCD 8) as detection means and to measure the height and position from these many interference fringe images, it takes a long measurement time.

  Actually, in recent years, in the height and shape inspection of a fine bump of about 20 μm, which is required in a semiconductor mounting process, the wavelength of light used in a conventional white interferometer is about 0.6 μm, for example. The half, 0.3 μm, is extremely short compared to the bump height of 20 μm. For this reason, it is necessary to capture several hundred images and perform image calculation processing, and it takes a measurement tact time of several seconds to several tens of seconds for measurement.

  Therefore, in the laser interference bump measuring instrument according to the present invention, the solution is to make the contour line interval, that is, half the wavelength λ longer than the design specification dimension of the height of the bump to be measured. However, as described above, the wavelength of the laser beam is, for example, about 0.633 μm, which is extremely small compared to the bump height of 20 μm, and there is a limit to the longer wavelength of the laser beam.

  The laser interference bump measuring device according to the present invention superimposes and interferes two laser beams having different wavelengths (different frequencies) to generate an optical beat, and has an extremely long wavelength compared to the wavelengths of the two laser beams. Is used as reference light and object light. Then, several interference fringe images of the interference fringes are taken by the CCD (detection means) by the phase interference shift means, and the height measurement of the sample and the shape inspection can be performed by image processing of these interference fringe images. Features the configuration.

  An embodiment of the laser interference bump measuring device 20 according to the present invention will be described. In FIG. 5, the laser interference bump measuring instrument 20 includes two light sources, a first light source 21 and a second light source 22. As these light sources, light sources that emit light such as laser light, LED light, white lamp monochrome light, and bright line light source light are used. In this embodiment, a configuration using a laser light source will be described below.

  The laser light from the first light source 21 and the laser light from the second light source 22 will be described later, but the laser light having different wavelengths is used as beat light having beat waves generated by overlapping and interfering with each other. To do. This beat light has a very long wavelength compared to the wavelengths of the light emitted from the first light source 21 and the second light source 22, respectively.

  Such beat light will be described with reference to FIG. The wavelength of the laser beam of the first light source 21 is λ1, and its waveform is shown in FIG. Further, the wavelength of the laser light of the second light source 22 is λ2 (where λ1> λ2), and the waveform thereof is shown in FIG. When these two waves are caused to overlap and interfere with each other, beat light having a beat wave having a waveform shown by a thick inclusion line in FIG. 6C is generated. When the wavelength of this beat light is Λ, Λ >> λ1, λ2.

  The laser interference bump measuring instrument 20 includes a first half mirror 24 that emits the laser light emitted from the first and second light sources 21 and 22 toward the bump 23 that is a sample to be measured. Further, a second half mirror 25, an objective lens 26, and a third half mirror 27 are sequentially provided on the optical path from the first half mirror 24 toward the bump 23.

  A reference mirror 28 is provided on the side of the third half mirror 27. The reference mirror 28 can be moved in the direction of the arrow on the optical path by a piezo element 29 as an actuator, as shown in FIG.

  The third half mirror 27 divides beat light that passes through the second half mirror 25 and travels toward the bump 23 toward the bump 23 and the reference mirror 28 (reference surface), and reflects the light from the surface of the bump 23. The object light and the reference light reflected by the surface of the reference mirror 28 are superposed to emit light toward the objective lens 26.

  A CCD 30 (detection means) is provided on the side of the second half mirror 25. The second half mirror 25 transmits the beat light from the first half mirror 24 toward the objective lens 26, and the beat light in which the object light from the third half mirror 27 and the reference light are superimposed. Light is received and emitted toward the CCD 30.

In the laser interference bump measuring instrument 20 according to the present invention, when the laser beams having different wavelengths λ1 and λ2 emitted from the first and second light sources 21 and 22 are overlapped with each other, the wavelength λ1 is obtained based on the beat wave principle. Unlike the λ2, the beat light has a beat wavelength Λ longer than the wavelengths λ1 and λ2, as shown in FIG. This wavelength Λ is expressed by the following equation.
Λ = (λ1λ2 / λ2-λ1)
However, Λ >> λ1, λ2.

  For example, for a laser beam with λ2 = 633 nm and λ1 = 640 nm, the beat wavelength is 57.87 μm according to the above formula. In this case, since λ / 2 is 57.87 / 2 = 28.93 μm, the height of the bump 23 of 20 μm is between the contour line intervals of the interference fringes and can be measured in a short time by the phase shift interference means. Become.

  The beat wavelength Λ can be set by selecting λ1 and λ2. Therefore, depending on the specific purpose of inspecting the height of the bump 23 and the surface shape (step, unevenness, inclination, etc.) of the bump 23, the height dimension in the design specifications of the bump 23, etc. (obtained by measurement) It is only necessary to select λ1 and λ2 in advance and set the beat wavelength Λ in consideration of not the height but a predetermined design height dimension.

  For example, when the height of the bump 23 is measured and inspected, the wavelength λ1 and the second wavelength of the first light source 21 are set so that half of the beat wavelength Λ (Λ / 2) is longer than the height of the design specification. The wavelength λ2 of the light source 22 may be set.

  Information on the interference fringe image captured by the CCD 30 is input to the analysis device 40, which analyzes the interference fringe image to calculate the height of the bump 23 and inspect the shape. As the analysis device 40, for example, as shown in FIG. 7, a normal computer including a CPU 41, a memory 42, a storage unit 43, a bus 45 (data and address bus), and an input / output interface unit 46 is used. The input / output interface unit 46 is connected to the CCD 30. The input / output interface unit 46 is connected to a reference mirror piezo drive unit 31 that is a specific configuration for driving the reference mirror 28 by the piezo element 29.

  The analysis device 40 inputs information on the interference fringe image captured by the CCD 30 through the input / output interface unit 46, and the CPU 41 in accordance with a dedicated image analysis program stored in the storage unit 43. By the functional means generated by the above operation, it is possible to perform image processing and analysis to determine the height of the bump 23, surface shape inspection, or transmission wavefront shape. When the reference mirror 28 is driven, the reference mirror piezo drive unit 31 inputs data such as a drive amount (drive distance) to the analyzer 40 via the input / output interface unit 46.

  As functional means performed by the CPU 41 according to the image analysis program in the analysis device 40, for example, as shown in FIG. 7B, the following means are provided. Interference intensity acquisition means 47 for calculating the interference intensity from the information of the interference fringe image captured by the CCD 30 and input to the analysis device 40 is provided.

  Further, when measuring the height of the unevenness or the like, the reference mirror 28 is moved in the optical path direction. From the interference intensity obtained by the interference intensity acquisition means 47 at each moving position, a mathematical expression (the term of action described later) is obtained. The phase difference acquisition unit 48 calculates the phase difference between the upper surface and the lower surface of the height measurement object.

  Furthermore, it has a height acquisition means 49 for calculating the height of unevenness or the like from the phase difference obtained by the phase difference acquisition means 48 according to a mathematical formula (described in the section of action described later). The action of these functional means in the analysis device 40 will be described in an example of actually acquiring the height of the bump 23 in the section (action) described later.

(Function)
The operation of the laser interference bump measuring instrument 20 according to the present invention will be described. The first laser light having the wavelength λ1 from the first light source 21 is transmitted through the first half mirror 24 toward the second half mirror 25, and the second laser light having the wavelength λ2 from the second light source 22 is The light is reflected by the first half mirror 24 and travels toward the second half mirror 25.

  In this optical path, the first laser beam having the wavelength λ1 and the second laser beam having the wavelength λ2 are superimposed on each other to generate an optical beat as shown in FIG. Become a beat light with.

  The beat light passes through the second half mirror 25 and the objective lens 26, and then is divided by the third half mirror 27. One beat light is directed to the reference mirror 28, reflected by the reference mirror 28, and referred to. The other beat light is directed to the bump 23 and reflected on the surface of the bump 23 to become object light.

  The reference light reflected by the reference mirror 28 and the object light reflected by the surface of the bump 23 enter the third half mirror 27 and are superimposed, converged by the objective lens 26, and further converged by the second half mirror 25. The light is reflected at the CCD 30, directed toward the CCD 30, and received by the CCD 30. In the middle of such an optical path, the object beam and the reference beam interfere with each other to form an interference fringe, and this interference fringe is photographed as an interference fringe image by the CCD 30 serving as a detection means.

  Then, the reference mirror 28 is moved by ８ of the wavelength of the beat light, that is, (Λ / 8) by the piezo element 29, and an interference fringe image is taken by the CCD 30 each time after the movement, and a total of four interferences are obtained. Get a fringe image. The information of the four interference fringe images is an image in which the interference fringes are shifted from each other by Λ / 8.

  Information on the four interference fringe images photographed by the CCD 30 is input to the analysis device 40 by the input / output interface unit 46. Then, the interference fringe image information is subjected to image processing and analysis by the CPU 41 operating according to a dedicated image analysis program stored in the storage unit 43, and the bump 23 height calculation and surface shape (step, unevenness, (Inclination, flatness) inspection is possible.

  For example, the analysis device 40 can measure the height of the bump 23 by obtaining the phase difference between the upper surface and the lower surface of the bump 23 based on information of four interference fringe images.

  An example of analysis performed by the CPU according to the image analysis program in the analysis device 40 will be described. When the wavelength of the beat light is Λ, the interference fringes obtained by moving the reference mirror 28 to positions in the optical path direction having lengths of 0, Λ / 8, 2Λ / 8, and 3Λ / 8, and measuring at the respective positions. Based on the information, the interference intensity acquired by the interference intensity acquisition unit 47 is a, b, c, d.

Then, the phase difference obtaining unit 48 calculates the phase difference φ at each point in the image from the equation φ = tan ⁻¹ [(ac) / (b−d)]. Further, in the height acquisition means 49, the height h (distance) from each reference point (each point in the sample surface) in the image to the reference surface can be obtained by the equation h = φΛ / 4π as described above. .

Therefore, for the measurement of the height of the bump, the height H of the bump 23 is
H = hs−hb = (φs−φb) Λ / 4π = φhΛ / 4π.
Here, hs and hb are the height (distance) from the reference surface to the substrate surface (bump bottom surface) and the height (distance) to the bump top surface, respectively, and φs is reflected from the substrate surface and the reference surface, respectively. Is the phase difference between the two beat lights, and φb is the phase difference between the two beat lights reflected from the bump upper surface and the reference surface.

  8 schematically shows the relationship between the bump 23 having the height H, the beat light 52 reflected from the substrate surface (bump bottom surface) 51, and the beat light 54 reflected from the upper surface 53 of the bump 23. It is. φh indicates the phase difference of the beat light corresponding to the height H, that is, the phase difference between the beat light 52 and the beat light 54, and corresponds to φs−φb.

  As mentioned above, although the form for implementing the laser interference bump measuring device concerning the present invention was explained based on the example, the present invention is not limited to such an example, and is described in a claim. It goes without saying that there are various embodiments within the scope of technical matters.

  Since the laser interference bump measuring instrument according to the present invention is configured as described above, it is extremely useful for bump height measurement and shape inspection in the semiconductor device mounting process, and is also used in the semiconductor and other industrial fields. It can also be applied to height measurement and shape inspection of fine elements.

1 Interferometer
2 Light source
3 Half mirror
4 Objective lens
5 Half mirror
6 Reference mirror
7 Sample 8 CCD
9 Analysis device
10 samples
11 Interference fringe image 111-114 Interference fringe image
12 Objective lens
13 Objective lens barrel
14 Reference line 20 Laser interference bump measuring device 21 First light source 22 Second light source 23 Bump
24 First half mirror
25 Second half mirror
26 Objective lens
27 Third half mirror
28 Reference mirror
29 Piezo elements
30 CCD
31 Reference mirror piezo drive
40 Analyzer
41 CPU
42 memory
43 Memory
45 bus (data and address bus)
46 I / O interface section 47 Interference intensity acquisition means 48 Phase difference acquisition means 49 Height acquisition means 51 Substrate surface (bump bottom surface)
52 Beat light reflected from substrate surface 53 Bump upper surface 54 Beat light reflected from bump upper surface

Claims (5)

A laser interference bump measuring instrument comprising two light sources, a half mirror, a reference mirror, and a detection means,
The two light sources emit light of different wavelengths, and the light of different wavelengths are superimposed and beat to be used as beat light.
The half mirror divides the beat light, directs one of the divided beat lights to the reference mirror, directs the other to the bump, one of the beat lights is reflected by the reference mirror to become reference light, and the other is reflected by the bump Becomes object light,
The detection means receives the interference light in which the reference light from the reference mirror and the object light from the bump are superimposed via the half mirror, detects an interference fringe image, and measures the height or shape of the bump from the interference fringe image. Laser interference bump measuring instrument characterized by enabling inspection. 2. The laser interference according to claim 1, wherein when the wavelength of the beat light is Λ and the wavelengths of the two light sources are λ1 and λ2, the wavelength Λ of the beat light is determined by the following equation. Bump measuring instrument.
Λ = λ1λ2 / (λ2-λ1)
However, Λ >> λ1, λ2.   3. The laser according to claim 2, wherein the wavelengths λ1 and λ2 of the two light sources are set so that the wavelength Λ / 2 of the beat light is larger than the height in the design specification of the bump to be measured. Interference bump measuring instrument. An analysis device is provided for inputting and inputting information of the interference fringe image from the detection means,
The analysis device includes an input / output interface unit, a CPU, and a storage unit, and is configured to analyze the shape of the bump by analyzing information on the interference fringe image by a CPU that operates according to a shape analysis program installed in the storage unit. The laser interference bump measuring instrument according to any one of claims 1 to 3.   The laser interference bump measuring instrument according to any one of claims 1 to 4, wherein the light source emits laser light, LED light, white lamp monochrome light, or bright line light source light.