JP2013200163A - Projection height measuring method and projection height measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for accurately locating positions of crown portions of bumps which are a plurality of projecting portions distributed on a substrate plane and obtaining heights of the bumps from positional coordinates of the crown portions.SOLUTION: A projection height measuring method comprises the steps of: irradiating a substrate plane 10 with first illuminating light R having a predetermined wavelength emitted in a vertically downward direction as well as second illuminating light G having a different wavelength from the first illuminating light R emitted in an obliquely downward direction; taking, with a first color image taking unit, images of first reflected light mirror-reflected from projecting portions 11 among the first illumination light R as well as second reflected light reflected from the projecting portions 11 among the second illumination light G; extracting a first illumination light component as well as a second illumination light component through light wavelength resolution of obtained images; creating an approximation line from luminance distribution for each illuminating light; and obtaining a first luminance point as well as a second luminance point which are peaks of a plurality of luminance values which appear at predetermined intervals. The projection height measuring method also comprises: identifying the projecting portions 11 by obtaining the luminance points corresponding to the crown portions of the projecting portions 11 using the two luminance points; and obtaining a height of each identified luminance point using a positional coordinate thereof.

Description

  The present invention provides a plurality of protrusions such as various substrates such as semiconductors having bumps such as BGA (Ball Grid Array) and CSP (Chip Size Package) and chips mounted with bumps such as CoC (Chip on a Chip). The present invention relates to a protruding portion height measuring method and a protruding portion height measuring apparatus that measure the height of the protruding portion in which the portions are distributed.

  With recent downsizing and higher performance of electronic devices, particularly portable electronic devices, electronic components mounted inside have been mounted at higher density. Among them, IC packages are also miniaturized, and bump bonding type packages such as BGA and CSP are rapidly spreading. Furthermore, a method of stacking and mounting chips on which bumps are mounted, such as CoC, has been proposed and implemented.

  In the case of such a bump bonding type package, a bump is formed by placing a solder ball on the terminal on the back of the package, the back of the package is brought into contact with the mounting target substrate, and the bump (ball-shaped solder) is reflowed or the like. Mounting is performed by heating and soldering the wiring land portion on the mounting target substrate.

  A large number of bumps are formed on the package, but the process margin when forming the bumps is small, and it is difficult to form bumps having a uniform height. For this reason, bumps or hemispheres having different heights may be formed in irregular shapes. Under such circumstances, if some bumps are extracted and the height is measured and the heights of other bumps are estimated, an inappropriate case occurs. In order to solve the case, it is required to measure the height of all the bumps. In addition, the number of bumps per chip and wafer is increasing due to the density of bumps, but the processing time for measuring the bumps applied to the wafer is required to be as short as possible.

  Therefore, a stereo camera method has been proposed and implemented as a method for measuring the height of the bump. For example, the bumps are irradiated with light from different angles from two alignment illumination devices, and the reflected light from the top of the bumps is imaged by two imaging devices arranged at different angles. The image acquired by each imaging device is a binary image of white and black, and a point of a white bright luminescent spot is obtained from both images as a coordinate of the top of the bump. The height of each bump is obtained using the two coordinates (see Patent Document 1).

  As another example, light is irradiated perpendicularly to the bump from one of the first lighting devices, and reflected light that is regularly reflected by the bump and returns coaxially is imaged by the first imaging means. The other second illumination device irradiates the bumps with light from an oblique direction, and the reflected light that is regularly reflected is imaged by the second imaging means arranged at a predetermined angle. The height of the bump is obtained using the stereogram method based on the coordinates of one bright spot reflected in each image acquired by both imaging means (see Patent Document 2).

JP-A-11-230718 Japanese Patent Publication No. 2001-124523

  However, the conventional method has the following problems. That is, the light irradiated toward the bumps is reflected also on the surface of the substrate other than the bumps. Therefore, when the bump shape distributed on the substrate is small and the pitch between adjacent bumps is narrow, the reflected light from the substrate and the reflected light from the top of the bump appear in the captured image with high brightness. It is crowded. Therefore, when a portion having high luminance is extracted from the binary image with a predetermined threshold, reflected light from the substrate is also extracted, and the substrate surface is erroneously detected as a bump.

  In addition, the bumps include irregular shapes having irregularities on the surface. When the irregular bump is imaged, a plurality of bright spots appear despite the fact that the bump is a single bump, and the position of the top of one head cannot be accurately detected for each bump. is there.

  The present invention has been made in view of such circumstances, and accurately extracts the position of the top of each protrusion distributed on the substrate plane, and the protrusion based on the position coordinates. The main object of the present invention is to provide a protrusion height measuring method and a protrusion height measuring apparatus capable of measuring the height of the top of the head in a short time and with high accuracy.

In order to achieve such an object, the present invention has the following configuration.
That is, the present invention is a projection height measuring method for measuring the height of projections distributed on a substrate plane,
An irradiation process of irradiating a first illumination light having a predetermined wavelength from the first direction toward the substrate plane and a second illumination light having a wavelength different from that of the first illumination light from the second direction;
A first imaging process in which the first color image imaging unit captures the first reflected light that is regularly reflected from the protruding portion of the first illumination light and the second reflected light from the protruding portion of the second illumination light; ,
A first extraction step of performing optical wavelength decomposition on the image acquired in the first imaging step and extracting a first illumination light component and a second illumination light component;
A first luminance value calculation step of creating an approximate line from the luminance distribution of the first illumination light component extracted in the first extraction step and obtaining a first bright point that becomes a peak of a plurality of luminance values appearing at predetermined intervals;
A second bright spot calculation step of creating an approximate line from the luminance distribution of the second illumination light component extracted in the first extraction step and obtaining a second bright spot at which a plurality of luminance values appearing at predetermined intervals peak;
Obtaining a candidate for the first bright spot corresponding to the reflected light from the top of the same protrusion for each second bright spot on the basis of the second bright spot, and a first protrusion specifying process for specifying the protrusion;
A second imaging process in which the second color image pickup unit images the first reflected light from the protruding portion of the first illumination light and the second reflected light that is regularly reflected from the protruding portion of the second illumination light; ,
A second extraction step of performing optical wavelength decomposition on the image obtained in the second imaging step and extracting a first illumination light component and a second illumination light component;
A first luminance value calculation step of creating an approximate line from the luminance distribution of the first illumination light component extracted in the second extraction step and obtaining a first bright point that becomes a peak of a plurality of luminance values appearing at predetermined intervals;
A second bright spot calculation step of creating an approximate line from the luminance distribution of the second illumination light component extracted in the first extraction step and obtaining a second bright spot at which a plurality of luminance values appearing at predetermined intervals peak;
Obtaining a second bright spot candidate corresponding to the reflected light from the top of the same protrusion for each first bright spot on the basis of the first bright spot, and specifying a protrusion;
A coordinate calculation process for obtaining coordinates of the first bright spot determined in the first protrusion specifying process and the second bright spot determined in the second protrusion specifying process;
A height calculating step of calculating the coordinates of the first bright spot and the second bright spot and obtaining the height of the protrusion specified based on the two coordinates.

  (Operation / Effect) According to this method, an image of a predetermined region of the substrate including light of different wavelengths reflected from the substrate is captured by the first color image capturing unit. The acquired image is subjected to optical wavelength decomposition to extract light components of the two wavelengths, thereby displaying two different color high-luminance parts. That is, the first illumination light component of the first illumination light that is regularly reflected from the substrate extracted in the first extraction process appears as a high luminance distribution on the substrate surface around the protrusion and in the protrusion. The second illumination light component of the other second illumination light appears as a bright spot only in the protrusion.

  By obtaining approximate lines individually from the luminance distributions of these two illumination light components, two different sine waves are created, and a plurality of first bright spots and second peaks that are peaks of each illumination light component from each sine wave. Bright spots can be obtained. Here, since the first luminescent spot includes reflected light from the substrate surface that causes erroneous detection, the first luminescent spot is located in the same protrusion with respect to the second luminescent spot that does not include reflected light from the substrate surface. A candidate for a bright spot is obtained, and a protrusion is specified from the candidate.

  Similarly, in the second extraction process using the image picked up by the second color image pickup unit, the second illumination light component of the second illumination light specularly reflected from the substrate is the substrate surface around the protrusion and the protrusion. Appears as a high brightness distribution. The first irradiation component of the other first illumination light appears as a bright spot only in the protrusion.

  By obtaining approximate lines individually from the luminance distributions of these two illumination light components, two different sine waves are created, and a plurality of first bright spots and second peaks that are peaks of each illumination light component from each sine wave. Bright spots can be obtained. Here, since the second bright spot includes reflected light from the substrate surface that causes erroneous detection, the first bright spot located in the same protruding portion with reference to the first bright spot not including the reflected light from the substrate surface. A candidate point is obtained, and a protrusion is specified from the candidate.

  The position coordinates of the pair of first bright spot and second bright spot for each protrusion obtained in the first extraction process and the second extraction process are obtained, and each protrusion is obtained using the coordinates of the same protrusion obtained at different angles. The height of the part is required.

  That is, out of two bright spots of different colors appearing on the protrusion, the protrusion is specified for each image based on the bright spot of one illumination light appearing in the protrusion, and the brightness of the top of the protrusion is determined. Since the candidate is obtained, it is possible to avoid erroneous detection as a protruding portion by reflected light from the substrate surface. Therefore, it can obtain | require with the height precision of a protrusion part.

  In the above method, it is preferable that the approximate line obtained in the first luminance value calculation process and the second luminance value calculation process is obtained by fitting the actual luminance value with a normal distribution.

  According to this method, even if there are minute irregularities on the surface of the protrusion and a plurality of bright spots appear, the bright spot is narrowed down to one point by theoretical calculation. Therefore, it is possible to avoid erroneous detection due to the unevenness of the surface of the protrusion.

In the above method, the first projecting part specifying step obtains a candidate for the first bright spot at the top of the head along the traveling direction of the second illumination light,
In the second projecting portion specifying process, it is preferable to obtain a candidate for the second bright spot at the top of the head along the direction opposite to the traveling direction of the second illumination light.

  According to this method, since the positional relationship of the bright spot at which the top of the protrusion appears is determined by the direction of light irradiation, it is adjacent to the reference bright spot along the light irradiation direction or the opposite direction. By obtaining the bright spot, a bright spot that is a candidate for the top of the protrusion can be easily obtained.

  In the above method, the first projecting part specifying process and the second projecting part specifying process include a predetermined reference distance between the first bright spot and the second bright spot in which the candidates for the first bright spot and the second bright spot are determined in advance. It is preferable to obtain from within the range.

  According to this method, since the range in which the bright spot corresponding to the top of the protrusion appears is specified, it is possible to avoid erroneous detection at a position deviating more than necessary. Also, the processing load can be reduced.

  The present invention has the following configuration in order to achieve such an object.

That is, a protrusion height measuring device that measures the height of protrusions distributed on a substrate plane,
A holding table for holding the substrate;
A first illumination unit that emits first illumination light having a predetermined wavelength from a first direction toward the substrate plane;
A second illumination unit that irradiates second illumination light having a wavelength different from that of the first illumination light from the second direction;
A first color imaging unit disposed at a position where the first illumination light is regularly reflected from the substrate surface;
A second color imaging unit arranged at a position where the second illumination light is regularly reflected from the substrate surface;
A first light component extraction unit that performs light wavelength decomposition on an image captured by the first color imaging unit, and extracts a first illumination light component and a second illumination light component reflected in the image;
An approximate line is created from the luminance distribution of the first illumination light component extracted by the first light component extraction unit, and first bright points that are peaks of a plurality of luminance values appearing at predetermined intervals are obtained and extracted second. A first bright spot calculation unit that creates an approximate line from the brightness distribution of the illumination light component and obtains a second bright spot at which a plurality of brightness values appearing at predetermined intervals peak;
Obtaining a candidate for the first bright spot corresponding to the reflected light from the top of the same protrusion for each second bright spot on the basis of the second bright spot, a first protrusion specifying part for specifying the protrusion; and
A second light component extraction unit that performs light wavelength decomposition on an image captured by the second color imaging unit, and extracts a first illumination light component and a second illumination light component reflected in the image;
An approximate line is created from the luminance distribution of the first illumination light component extracted by the second light component extraction unit, and first bright points that are peaks of a plurality of luminance values appearing at predetermined intervals are obtained and extracted second. A second bright spot calculation unit that creates an approximate line from the luminance distribution of the illumination light component and obtains a second bright spot at which a plurality of brightness values appearing at predetermined intervals peak;
Obtaining a second bright spot candidate corresponding to the reflected light from the top of the same protrusion for each first bright spot with reference to the second bright spot, a second protrusion specifying part for specifying the protrusion; and
And a height calculation unit for calculating the coordinates of the first bright point and the second bright point and calculating the height of the protrusion specified based on the two coordinates.

  According to this configuration, the above method can be suitably implemented.

  According to the protrusion height measuring method and the protrusion height measuring apparatus of the present invention, the height of the top of each protrusion in which a plurality of protrusions are distributed on the substrate plane can be set in a short time and It can be measured with high accuracy. As a result, if the present invention is applied to the measurement of solder bumps, it is possible to prevent the occurrence of solder defects (short-circuit between adjacent electrodes or poor conduction).

It is a perspective view of a protrusion height measuring device. It is the front of a protrusion part height measuring apparatus. It is a block diagram which shows the structure of a protrusion part height measuring apparatus. It is the flowchart which showed the process by the Example apparatus. It is the schematic diagram at the time of the imaging using an Example apparatus. It is the image imaged by the 1st observation part. It is the image displayed about each component of the 1st illumination light and the 2nd illumination light from the image imaged by the 1st observation part. It is a figure which shows the fitting process based on the luminance distribution of the image imaged with the 1st observation part. It is the image imaged by the 2nd observation part. It is the image displayed about each component of the 1st illumination light and the 2nd illumination light from the image imaged by the 2nd observation part. It is a figure which shows the fitting process based on the luminance distribution of the image imaged by the 2nd observation part. It is a schematic diagram for calculating | requiring the height of a protrusion part. It is a mimetic diagram for deriving a formula of a modification. It is an enlarged view of the part enclosed with the dashed-dotted line of FIG.

  An embodiment of the present invention will be described below with reference to the drawings.

  FIG. 1 is a perspective view showing an example of an embodiment according to the protrusion height measuring method of the present invention. FIG. 2 is a front view showing a schematic configuration of the embodiment apparatus. Hereinafter, in each figure, the three axes of the orthogonal coordinate system are X, Y, and Z, the XY plane is the horizontal plane, and the Z direction is the vertical direction. In particular, in the Z direction, the direction of the arrow is represented as the top, and the opposite direction is represented as the bottom.

  As shown in FIG. 1, the protrusion height measuring device 1 includes a substrate moving unit 2, a first observation unit 3, a second observation unit 4, and a control unit 5. Hereinafter, each part is explained in full detail.

[Substrate moving part]
The substrate moving unit 2 includes a Y-axis stage 21 placed on an apparatus base (not shown) of the protrusion height measuring device 1, an X-axis stage 22 attached on the Y-axis stage 21, and an X-axis stage 22. It is comprised from the holding table 23 attached on the top.

  The Y-axis stage 21 is configured such that the X-axis stage 22 can be reciprocated horizontally at a predetermined speed in the Y direction along a guide provided on the upper surface.

  The X-axis stage 22 is configured to be capable of horizontally reciprocating the holding table 23 in the X direction at a predetermined speed along a guide provided on the upper surface.

  The table 23 is a chuck table that holds the substrate 10 placed on the surface by suction. The chuck table is communicatively connected to a vacuum source installed outside via an opening / closing control valve. The table 22 corresponds to the holding table of the present invention.

[First observation section]
As shown in FIG. 2, the first observation unit 3 includes a first illumination device 31 and a first color image imaging unit 32. The first lighting device 31 is provided in communication with the side surface of the lens barrel 34 attached to the tip of the first color camera 33 that constitutes the first imaging device 31. The first lighting device 31 is equipped with a first filter 35 that transmits light of a predetermined wavelength. In the present embodiment, the first filter 35 uses one of the three primary colors RGB that transmits light having a red wavelength.

  The first color camera 33 is oriented perpendicularly to the holding table 23. In addition, optical elements such as a beam splitter and a lens are incorporated in the lens barrel 34 attached to the tip of the first color camera 33. Therefore, the first illumination light irradiated from the first irradiation device 31 is reflected vertically downward by the beam splitter, and is regularly reflected on the surface of the substrate 10 placed and held on the holding table 23 to return coaxially. Is transmitted through a beam splitter, and the transmitted light is imaged on an image sensor of the first color camera 33 through a lens.

[Second observation section]
The second observation unit 4 includes a second illumination device 41 and a second color image capturing unit 42. One second lighting device 41 is arranged in a tilted posture with a predetermined angle toward the holding table 23. In the other second color image capturing unit 42, the second color camera 43 receives the reflected light obtained by regular reflection of the second illumination light emitted from the second illumination device 41 by the bump through the lens tube 44 attached to the tip. In order to be able to do so, it is deployed in an inclined posture of a predetermined angle.

  The second illumination device 41 is equipped with a second filter 45 that transmits light of a predetermined wavelength. In the present embodiment, the second filter 45 uses one of the three primary colors RGB that transmits light having a green wavelength.

  An optical element such as a lens is incorporated in the lens barrel 44 attached to the tip of the second color camera 43. Therefore, the second illumination light irradiated from the second irradiation device 41 is directed to the protruding portion of the substrate 10 at a predetermined angle with an oblique inclination, and the reflected light regularly reflected by the protruding portion is allowed to pass through the lens barrel 44. An image is formed on the image sensor of the second color camera 43 through the optical element.

  The first and second color cameras 33 and 43 and the first and second illumination devices 31 and 41 are attached to a base frame (not shown) of the protrusion height measuring device 1.

[Controller unit]
FIG. 3 is a block diagram showing the control unit 5. As shown in FIG. 3, an input operation unit 51, an information output unit 52, a storage unit 53, a device control unit 54, an image processing unit 60, and the like are included.

  The input operation unit 51 includes a keyboard, a mouse, a touch panel, a switch, and the like, and sets various conditions.

  The information output unit 52 includes an image display display and a lamp.

  The storage unit 53 includes a semiconductor recording medium such as a memory card and a data disk, a magnetic recording medium, a magneto-optical recording medium, and the like, and image data and devices captured by the first color camera 33 and the second color camera 43. The setting conditions are stored.

  The device control unit 54 is connected to the substrate moving unit 2, the first observation unit 3, and the second observation unit 4, and drives and controls each component unit. For example, the image is acquired by changing the position of the holding table 23 so that the first and second color cameras 33 and 43 can acquire an image in a predetermined field of view in an arbitrary region on the substrate.

  In addition, the device control unit 54 can individually adjust the light amounts of the first lighting device 31 and the second lighting device 41. For example, the device control unit 54 adjusts the voltage and current applied to the light amount adjustment units provided in both the lighting devices 31 and 41, and adjusts the application time of the voltage and current.

  The image processing unit 60 includes a first light component extracting unit 61, a coaxial bright spot calculating unit 62, a protruding part specifying unit 63, a second light component extracting unit 64, an oblique axis bright point calculating unit 65, a protruding part specifying unit 66, and a high A height calculating unit 67 is provided. Each of these parts will be described in detail in the following description of the operation of measuring the height of the protruding part by the implementation / separation device. The coaxial bright spot calculating unit 62 is a first bright spot calculating unit of the present invention, the protruding part specifying unit 63 is a first protruding part specifying part, and the oblique axis bright spot calculating part 65 is a second bright spot calculating part. The protrusion specifying part 66 corresponds to the second protrusion specifying part.

  FIG. 4 is a flowchart showing the process of measuring the height of the protrusions distributed on the substrate using the apparatus of this embodiment. Hereinafter, the protrusion height measurement process will be described in detail along the flowchart.

<Step S <b>1> Condition Setting The substrate 10 is placed and held on the holding table 23, and the imaging condition of the protruding portion on the substrate is set. For example, the imaging range of the substrate 10, the light amount of each lighting device, and the like are set by operating the input operation unit 51.

<Step S2> When the setting of the irradiation start condition is completed, the apparatus is operated to irradiate light from the first lighting device 31 and the second lighting device 41 toward the substrate 10 simultaneously. Here, as shown in FIG. 2 and FIG. 5, the first illumination device 31 irradiates the red first illumination light R vertically toward the substrate 10, and the second illumination device 42 emits the green second illumination. Light G is irradiated toward the substrate 10 from an oblique direction. As the substrate 10 is irradiated with light, each of the first color camera 33 and the second color camera 43 starts imaging the substrate 10. Thereafter, image processing captured by the color cameras 33 and 43 is executed in parallel. First, the processing of the image acquired by the first color camera 33 will be described.

<Step S3A> Image Acquisition As the substrate 10 is irradiated with light, the first color camera 33 images the substrate 10 in the field of view. The acquired image is irradiated vertically downward by the first irradiation device 31, is regularly reflected by the surface of the substrate 10 and the protrusions 11 distributed on the substrate 10, and has the same optical path (coaxial) as the illumination optical path. The reflected light of the first illumination light R returning from the second illumination light G and the second illumination light G, which is the scattered light irradiated from the second illumination device 31 and irregularly reflected on the substrate, are reflected. That is, as shown in FIG. 6, the first illumination light R regularly reflected by the surface of the substrate 10 and the top of the protrusion 11 is reflected around the protrusion 11 and at the center of the protrusion 11. Further, the second illumination light G is reflected only in the protrusion 11.

<Step S <b> 4 </ b>A> First Light Component Extraction Processing The first light component extraction unit 61 decomposes the acquired image into light wavelengths of RGB three primary colors, and only the light wavelength components of the first illumination light R and the second illumination light G are obtained. Extract. FIG. 7 shows an image reproduced for each extracted light wavelength component. That is, in an image obtained by extracting only one main component of the first illumination light R, a high brightness area on the surface of the substrate 10 and the first bright spot RP in the protrusion 11 are displayed. In the image obtained by extracting only the other component of the second illumination light G, only the second bright spot GP is displayed.

<Step S5A> Coaxial Bright Spot Calculation Processing The coaxial bright spot calculation unit 62 performs real wavelength along the X-axis or Y-axis direction for each of the components of the first illumination light R and the second illumination light G that have undergone optical wavelength decomposition. An approximate line is obtained from the luminance distribution according to the luminance level. For example, the luminance distribution is subjected to a fitting process with a normal distribution along the Y-axis direction. FIG. 8 shows a sine wave obtained in the region including the two protrusions 11 along the Y axis. A plurality of peak values on the sine wave are obtained for each illumination light, and each main peak value of the first illumination light R is set as first bright spots RP1, RP2, RP3 in order along the axial direction. Each peak value of the other second illumination light G is set as second bright spots GP1 and GP2 in order along the axial direction.

<Step S6A> Protrusion Part Determination Process Here, in the image in which the arrangement of the protrusion parts 11 is reflected, three first bright spots RP are obtained, whereas two second bright spots GP are obtained. . That is, it means that the first illumination light R that is the reflected light from the surface of the substrate 10 is included in the image captured by regular reflection. Therefore, the protrusion specific part 63 does not include the component of the reflected light from the unnecessary substrate 10, and the second bright spot GP reflected only in the protrusion 11 is the first bright spot RP indicating the top of the protrusion 11. Make it a standard for seeking candidates.

  The protrusion specifying unit 63 uses the candidate and specifies each protrusion 11 as follows, for example. First, when the second bright spot GP1 is used as a reference, the first bright spot RP1 that appears first after searching in the traveling direction of the second illumination light G from the reference position is a bright spot existing in the same protruding portion 11. Identify. Next, similarly for the second bright spot GP2, a search is made in the traveling direction of the second illumination light G with the position as a reference to obtain the first bright spot that appears first. In this case, the first bright spot RP3 is obtained. That is, the first bright spot RP2 that is not a candidate means a bright spot generated by the reflected light from the substrate 10.

  The calculation method functions effectively because the positions where the bright spots of the first bright spot RP and the second bright spot GP appear in the projecting portion 11 are determined from the positional relationship between the first lighting device 31 and the second lighting device 41. Can be made.

  When a pair of the first bright spot RP and the second bright spot GP is obtained for each protrusion 11, the pair portion is identified as the protrusion 11, and the position coordinates of both bright spots are associated and stored in the storage unit 53. .

  Next, processing of an image acquired by the second color camera 43 will be described.

<Step S3B> Image Acquisition As the substrate 10 is irradiated with light, the second color camera 43 images the substrate 10 in the field of view. The acquired image is irradiated obliquely downward from the second irradiation device 41, and the second illumination light G that is regularly reflected by the surface of the substrate 10 and the protrusions 11 distributed on the substrate 10, and the first illumination device The first illumination light R, which is scattered light irradiated from 31 and diffusely reflected on the substrate, is reflected. That is, as shown in FIG. 9, the second illumination light G regularly reflected by the surface of the substrate 10 and the top of the protrusion 11 is reflected around the protrusion 11 and the protrusion 11. Further, the first illumination light R is reflected only in the protruding portion 11.

<Step S <b> 4 </ b>B> Second Light Component Extraction Processing The second light component extraction unit 64 decomposes the acquired image into light wavelengths of RGB three primary colors, and only the light wavelength components of the first illumination light R and the second illumination light G are obtained. Extract. When the image is reproduced for each extracted light wavelength component, it is as shown in FIG. In other words, in the image in which only one main component of the second illumination light G is emitted, the high brightness area of the substrate 10 and the second bright spot GP in the protrusion 11 are displayed. In the image obtained by extracting only the component of the other first illumination light R, only the first bright spot RP is displayed.

<Step S5B> Oblique-Axis Bright Spot Calculation Processing The oblique-axis bright spot calculation unit 65 follows the X-axis or Y-axis direction for each component of the first illumination light R and the second illumination light G that have undergone optical wavelength decomposition. An approximate line is obtained from the luminance distribution according to the actual luminance level. A fitting process using a normal distribution is applied to the luminance distribution under the same conditions as in step S5A. That is, when a sine wave is obtained in a region including two protrusions 11 along the Y axis, the result is as shown in FIG. A plurality of peak values on a sine wave are obtained for each illumination light, and each peak value of one main second illumination light G is set as second bright spots GP1, GP2, GP3 in order along the axial direction. The peak values of the other first illumination light R are set as first bright spots RP1 and RP2 in order along the axial direction.

<Step S6B> Protrusion Part Determination Process Here, in the image in which the arrangement of the protrusion parts 11 is reflected, three second bright spots GP are obtained, whereas two first bright spots RP are obtained. . That is, it means that the second illumination light G that is reflected light from the surface of the substrate 10 is included in the image captured by regular reflection. Therefore, the protrusion specific part 66 does not include the component of the reflected light from the unnecessary substrate 10, and the first bright spot RP reflected only in the protrusion 11 is the second bright spot GP indicating the top of the protrusion 11. Make it a standard for seeking candidates.

  The protrusion specifying unit 66 uses the candidate and specifies each protrusion as follows in the same manner as in step S6A. When the predetermined first bright spot RP is used as a reference, the second bright spot GP is searched in the direction opposite to the traveling direction of the second illumination light G from the reference position. That is, in FIG. 11, when the first bright spot RP1 is used as a reference, the search is performed in the left direction. As a result, the second bright spot GP1 is obtained. Next, when a search is performed based on the first bright spot RP2, a second bright spot GP3 is obtained. That is, the second bright spot GP2 that is not a candidate means a bright spot generated by the reflected light from the substrate 10.

  When a pair of the first bright spot RP and the second bright spot GP is obtained for each protrusion 11, the pair portion is identified as the protrusion 11, and the position coordinates of both bright spots are associated and stored in the storage unit 53. .

<Step S7> Height Calculation Processing The height calculation unit 67 uses the stereogram method to set the height of each protrusion as follows based on the bright spot coordinate pairs obtained in Step S6A and Step S6B. Ask.

  FIG. 12 is a front view showing an example of a form for calculating the height of the protruding portion 11 by the stereogram method, and is a view of FIG. 5 seen from the arrow direction of the X axis.

  The positions d1 to d3 indicating the positions of the first bright spots RP at the tops of the protrusions 11b1 to 11b3 captured by the first color camera 33 do not change even if the heights of the protrusions 11b1 to 11b3 vary. On the other hand, d′ 1 to d′ 3 indicating the positions of the first bright spots RP at the tops of the protrusions 11b1 to 11b3 imaged by the second color camera 43 vary when the protrusions 11b1 to 11b3 have different heights. It changes in proportion to the variation of the height.

Here, when the respective heights of the protruding portions 11b1 to 11b3 are H1 to H3, the variations thereof are denoted by Δh ₁ to Δh ₃ . That is, the height of the n-th protrusion is defined as H _n and the variation thereof is defined as Δh _n .

12, the height H1-H3 = h of the protrusion 11B1～11b3, a state in which a = h-Δh ₃ 'height H3 of the' protrusion 11b3 is shown. That is, the protruding portion 11b3 is, 'as in the case height Delta] h ₃ only low protrusions 11b3' protruding portion 11b3 indicated by a broken line reflected light shown by the dashed line is reflected at the top portion of the variation in height If not, it is shifted by Δd _{3 in the} Y ′ direction as compared with the reflected light indicated by the solid line.

The angle θ1 formed between the surface of the substrate 10 and the reflected light of the first illumination light R is 90 degrees, and the angle difference between the angle θ2 formed between the surface of the substrate 10 and the reflected light of the second illumination light G and the angle θ1 is an angle θ. Then, a variation Delta] h _n height of the n-th protruding portion, between the shift amount [Delta] d _n which is calculated on the basis of the image observed its top portion, the following relationship is established.

Based on the relational expression, Δh _n can be calculated. That is subtracted in the case where the height of the protrusions 11 meets specified height, since the shift amount [Delta] d _n of the protruding portion 11 varies the height of the defined is obtained, the amount of deviation from the prescribed height Thus, the height of the protrusion 11 is obtained.

  In addition, when applying to a present Example, the protrusion part 11 of the board | substrate 10 is divided into a predetermined imaging range suitably, and it images simultaneously with the 1st observation part 3 and the 2nd observation part 4 for every divided imaging range (step S8). ). And the dispersion | variation in height and height of the top part of each protrusion part are computable from each luminescent point information obtained by the said process from the imaged image.

  According to the above-described embodiment apparatus, by simultaneously irradiating the substrate 10 with different wavelengths of light at different angles, and imaging the substrate 10 with the two first and second color cameras 33 and 43 arranged at different angles, Two bright spots are reflected in each protrusion 11 distributed on the substrate. By dividing the image into light wavelengths by RGB, an image in which a red region and a green region are separated can be obtained. Further, a luminance distribution is obtained for each light wavelength component, and a sine wave is created by a footing process using a normal distribution, and a first bright spot RP and a green second bright spot GP for each reflected light are obtained from the sine wave. Can do.

  Here, in both images, the reflected light of the scattered light does not include the reflected light from the surface of the substrate 10, and only the reflected light reflected by the protruding portion 11 is reflected. Therefore, by obtaining the bright spot reflected in the image of the same protrusion 11 based on the bright spot obtained from the scattered light, the reflected light from the surface of the substrate 10 is reflected as the bright spot of the protrusion 11. Detection can be avoided, and the bright spot at the top of each head 11 can be accurately obtained. Therefore, the height of the protrusion 11 can be accurately obtained by using the bright spot obtained for each protrusion 11.

  The present invention is not limited to the embodiment described above, and can be modified as follows.

  (1) In the above-described embodiment, the range for searching for bright spots is not specified in the protrusion specifying process in steps S6A and S6B. However, the search may be performed only within a predetermined range. For example, the projecting portion 11 having a normal shape has a specific position on the curved surface deviated from the top of the projecting portion 11, as shown in FIG. 13, with the first illumination light R emitted from the first lighting device 31. The reflection angle changes, and the reflected light is irregularly reflected and reflected on the second color camera 43. At this time, in the image obtained by imaging with the first color camera 33, X is within a range up to a distance du between the optical axis of the reflected light that is regularly reflected by the first illumination light R and the optical axis of the reflected light that is irregularly reflected. By searching for the coaxial bright spot along the axial direction, the bright spot generated by the reflected light from the substrate 10 can be avoided, and only the first bright spot RP at the top of the protrusion 11 can be obtained.

  On the other hand, in the image captured by the second color camera 43, the distance between the optical axis of the reflected light that is regularly reflected by the second illumination light G and the optical axis of the reflected light that is reflected by the first illumination light R reflected irregularly. If the oblique axis bright spot is searched along the X-axis direction in the range up to dt, the bright spot generated by the reflected light from the substrate 10 is avoided, and only the first bright spot RP at the top of the protrusion 11 is obtained. be able to.

  Here, the distance du and the distance dt can be set as follows. That is, since the reflected light of the first illumination light R diffusely reflected by the protrusion 11 is captured by the second color camera 43, it is the same as the angle θ1 of regular reflection of the second illumination light G.

  The position where the first illumination light R is reflected at the angle θ1 is estimated as follows. First, when it is assumed that the protrusion 11 does not exist, the position of the substrate 10 at which the optical axis of the first illumination light R that is regularly reflected arrives is defined as the origin (0, 0). A condition of an angle θ2 that bisects the angle formed by the optical axis of the first illumination light R and the reflected light at the angle θ1 until reaching the position of irregular reflection is obtained by a broken line extending from the origin. The angle θ2 can be obtained by the following equation.

  Therefore, the position coordinates at which the reflected light forms θ1 can be obtained from the equation as follows.

  Here, Z is the distance from the origin of the substrate 10 to the top of the protrusion 11. The distance Z is measured or specified in advance.

  When the coordinates are obtained, as shown in FIG. 14, the distance L from the coordinates to the coordinates of the top of the head can be obtained by the following equation.

  Therefore, the distance dt of the search range for obtaining the bright point on the oblique axis can be set by the following equation.

  The search range distance du for obtaining the coaxial bright spot can be set by the following equation.

  Thus, by setting the search range for obtaining the bright spot in advance, the calculation load can be reduced and the processing speed can be increased.

  (2) In the above-described embodiment device, R and G of RGB are used as the light irradiated from the first lighting device 31 and the second lighting device 41, but it is not limited to the combination. In other words, any combination that has a light wavelength in a band where two reflected lights can be separated when the two reflected lights are decomposed into light wavelengths may be used.

  (3) In the above-described embodiment device, the first and second filters 35 and 45 are used to irradiate light of a predetermined wavelength from the first lighting device 31 and the second lighting device 41. However, the filters are used. If a light source (for example, LED) that can irradiate light having a predetermined wavelength is used, the filters 35 and 45 can be omitted.

  (4) In the above-described embodiment apparatus, the first color camera 33 is vertically arranged. However, the first color camera 33 is not limited to this form, and the first color camera 33 is configured at a different angle from the second color camera 43. It can be realized even if there is.

  (5) Coaxial luminescent spot calculation process (step S5A) and oblique axis luminescent spot calculation process of the above embodiment (in step S5B, fitting with a normal distribution is used to obtain an approximate line from the luminance distribution according to the level of the actual luminance value. Although processing is performed, fitting processing may be performed by a least square method.

DESCRIPTION OF SYMBOLS 1 ... Projection part height measuring apparatus 2 ... Board | substrate moving part 10 ... Board | substrate 11 ... Projection part 31 ... 1st illumination device 32 ... 1st color image imaging unit 33 ... 1st color camera 35 ... 1st filter 41 ... 2nd illumination Apparatus 42 ... 2nd color image pick-up unit 43 ... 2nd color camera 45 ... 2nd filter 60 ... Image processing part 61 ... 1st light component extraction part 62 ... Coaxial luminescent point calculation part 63 ... Projection part specific | specification part 64 ... 2nd Light component extraction part 65 ... Oblique axis bright spot calculation part 66 ... Projection part specifying part 67 ... Height calculation part

Claims (5)

In the protrusion height measurement method for measuring the height of the protrusion distributed on the substrate plane,
An irradiation process of irradiating a first illumination light having a predetermined wavelength from the first direction toward the substrate plane and a second illumination light having a wavelength different from that of the first illumination light from the second direction;
A first imaging process in which the first color image imaging unit captures the first reflected light that is regularly reflected from the protruding portion of the first illumination light and the second reflected light from the protruding portion of the second illumination light; ,
A first extraction step of performing optical wavelength decomposition on the image acquired in the first imaging step and extracting a first illumination light component and a second illumination light component;
A first luminance value calculation step of creating an approximate line from the luminance distribution of the first illumination light component extracted in the first extraction step and obtaining a first bright point that becomes a peak of a plurality of luminance values appearing at predetermined intervals;
A second bright spot calculation step of creating an approximate line from the luminance distribution of the second illumination light component extracted in the first extraction step and obtaining a second bright spot at which a plurality of luminance values appearing at predetermined intervals peak;
Obtaining a candidate for the first bright spot corresponding to the reflected light from the top of the same protrusion for each second bright spot on the basis of the second bright spot, and a first protrusion specifying process for specifying the protrusion;
A second imaging process in which the second color image pickup unit images the first reflected light from the protruding portion of the first illumination light and the second reflected light that is regularly reflected from the protruding portion of the second illumination light; ,
A second extraction step of performing optical wavelength decomposition on the image obtained in the second imaging step and extracting a first illumination light component and a second illumination light component;
A first luminance value calculation step of creating an approximate line from the luminance distribution of the first illumination light component extracted in the second extraction step and obtaining a first bright point that becomes a peak of a plurality of luminance values appearing at predetermined intervals;
A second bright spot calculation step of creating an approximate line from the luminance distribution of the second illumination light component extracted in the first extraction step and obtaining a second bright spot at which a plurality of luminance values appearing at predetermined intervals peak;
Obtaining a second bright spot candidate corresponding to the reflected light from the top of the same protrusion for each first bright spot on the basis of the first bright spot, and specifying a protrusion;
A coordinate calculation process for obtaining coordinates of the first bright spot determined in the first protrusion specifying process and the second bright spot determined in the second protrusion specifying process;
A projection height measurement comprising: calculating a coordinate of the first bright spot and the second bright spot, and calculating a height of the projection specified based on the two coordinates. Method. In the protrusion height measuring method according to claim 1,
An approximate line obtained in the first luminance value calculation process and the second luminance value calculation process is obtained by fitting an actual luminance value with a normal distribution. In the protrusion height measuring method according to claim 1 or 2,
The first protrusion specifying process determines a candidate for the first bright spot at the top of the head along the traveling direction of the second illumination light,
The method of measuring the height of the protrusion, wherein the second protrusion specifying process is to obtain a candidate for the second bright spot at the top of the head along the direction opposite to the traveling direction of the second illumination light. In the protrusion height measuring method according to claim 3,
The first protrusion specifying process and the second protrusion specifying process are performed within a predetermined range of a reference distance between the first bright spot and the second bright spot, in which candidates for the first bright spot and the second bright spot are determined in advance. A method for measuring the height of a protrusion, characterized in that A projection height measuring device for measuring the height of projections distributed on a substrate plane,
A holding table for holding the substrate;
A first illumination unit that emits first illumination light having a predetermined wavelength from a first direction toward the substrate plane;
A second illumination unit that irradiates second illumination light having a wavelength different from that of the first illumination light from the second direction;
A first color imaging unit disposed at a position where the first illumination light is regularly reflected from the substrate surface;
A second color imaging unit arranged at a position where the second illumination light is regularly reflected from the substrate surface;
A first light component extraction unit that performs light wavelength decomposition on an image captured by the first color imaging unit, and extracts a first illumination light component and a second illumination light component reflected in the image;
An approximate line is created from the luminance distribution of the first illumination light component extracted by the first light component extraction unit, and first bright points that are peaks of a plurality of luminance values appearing at predetermined intervals are obtained and extracted second. A first bright spot calculation unit that creates an approximate line from the brightness distribution of the illumination light component and obtains a second bright spot at which a plurality of brightness values appearing at predetermined intervals peak;
Obtaining a candidate for the first bright spot corresponding to the reflected light from the top of the same protrusion for each second bright spot on the basis of the second bright spot, a first protrusion specifying part for specifying the protrusion; and
A second light component extraction unit that performs light wavelength decomposition on an image captured by the second color imaging unit, and extracts a first illumination light component and a second illumination light component reflected in the image;
An approximate line is created from the luminance distribution of the first illumination light component extracted by the second light component extraction unit, and first bright points that are peaks of a plurality of luminance values appearing at predetermined intervals are obtained and extracted second. A second bright spot calculation unit that creates an approximate line from the luminance distribution of the illumination light component and obtains a second bright spot at which a plurality of brightness values appearing at predetermined intervals peak;
Obtaining a second bright spot candidate corresponding to the reflected light from the top of the same protrusion for each first bright spot with reference to the second bright spot, a second protrusion specifying part for specifying the protrusion; and
A projection height measurement comprising: a height calculation unit that calculates the coordinates of the first bright spot and the second bright spot and obtains the height of the projection specified based on the two coordinates apparatus.

Images