JPH1040380A - Method and device for inspecting mark - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and accurately recognize a mark and to execute an inspection within limit time by inspecting a mark to be inspected by using a mark position, a mark range and a reference mark pattern. SOLUTION: A picture signal obtained by photographing a reference IC package from its upper surface is outputted from a video camera 12 and sent to a picture processing unit 11, various picture processing for the picture signal is executed and the processed result is sent to a monitor device. Consequently the picture obtained by photographing the reference IC package from its upper surface is displayed on the screen of the device 15. An window for retrieving a printing mark and the existing position and range of a 1st pin mark is set up from the picture of an initial IC package. The picture pattern of a mark included in a position and a range corresponding to the mark position and the mark range is teached as a reference mark pattern and a mark to be inspected is inspected by using the mark position, the mark range and the reference mark pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mark inspection method and apparatus for inspecting marks such as characters and symbols drawn on the surface of an IC package or the like by using image processing.

[0002]

2. Description of the Related Art Conventionally, ICs (integrated circuits) and LSIs have been used.
When manufacturing (large-scale integrated circuits) and the like, the product name is placed on the surface of a resin-sealed package (hereinafter simply referred to as an IC package) in which these IC elements and LSI elements are sealed with resin, that is, the surface of the mold resin. And various characters such as lot numbers, manufacturer names or trade names, numbers, and symbols are printed. Hereinafter, these characters and the like to be printed are referred to as print marks. Further, on the surface of the mold resin of the IC package, there are formed depressions, ie, index marks, for designating the position where the first lead terminals are arranged, the direction of the IC package, and the front and back sides. Hereinafter, the index mark of this depression is referred to as a first pin mark.
Note that there are two types of print marks on the IC package: a case formed by engraving with a laser beam and a case formed by stamping with ink.

When the manufactured IC package is stored in a storage container such as a stick or a tray, it is necessary to check whether or not different types of IC packages are mixed. Further, for example, a case where a plurality of IC packages taken out from a plurality of storage containers such as the stick-shaped or tray-shaped storage containers are re-stored in another large-capacity storage container, for example, a tape-shaped storage container made of embossed tape or the like. In addition, it is necessary to inspect whether different types of IC packages are mixed. Further, when the IC package is stored in the stick-shaped, tray-shaped or tape-shaped storage container, it is determined whether the first pin mark is at a correct position in order to store the IC package in a correct direction. That is, it is necessary to check whether the IC package is oriented correctly.

In an inspection apparatus for performing these inspections, a reference print mark and a first pin mark pattern are stored in advance, and the print mark and the first pin mark actually formed on the IC package are stored. By comparing the pattern obtained by photographing with a video camera or the like with the pattern of the reference print mark or the first pin mark, whether or not the above-described different types of IC packages are mixed is determined. And an inspection of whether the orientation of the IC package is correct. In the following description, the pattern of the reference print mark is referred to as a reference print pattern, and the pattern of the reference first pin mark is referred to as a reference first pin pattern. A pattern obtained by photographing a print mark actually formed on the IC package with a video camera is referred to as a print pattern to be inspected, and a first pin mark similarly formed on the IC package is photographed. The obtained pattern is referred to as a first pin pattern to be inspected.

[0005] As a result of the inspection by the inspection apparatus, for example, when the reference print pattern and the inspection target print pattern coincide with each other, there is no mixing of different types of IC packages. It can be determined that the IC package has been mixed. When the reference first pin pattern and the first pin pattern to be inspected match, the direction of the IC package is correct, and when they do not match, it can be determined that the direction of the IC package is incorrect. In the reference print pattern and the inspection target print pattern, each of the print characters constituting the print mark is handled as an individual pattern, or a group of a plurality of print characters is handled as one pattern, or There are cases where these are handled in combination.

[0006] By the way, in order to realize the inspection by the pattern comparison as described above, the above inspection apparatus must be
It is necessary to previously capture and store the reference print pattern and the reference first pin pattern as images. The reference print pattern and the reference first pin pattern stored in the inspection device are formed from an image obtained by photographing a printed mark actually printed or a first pin mark actually formed by a video camera. ing. Thus, the reference printing pattern and the reference first
Importing the pin pattern image and storing it
This is generally called teaching or teaching, and is usually performed by a human operating the inspection apparatus.

Here, especially when the print mark is composed of, for example, characters, the shapes of all characters are already generally known, and the characteristic amount of each character is also known. Therefore, when inspecting a print mark composed of the character, the reference print pattern that is prepared in advance does not necessarily need to be generated by the teaching, and may be created by calculation or the like from the characteristic amount of the character. It is possible. However, the print mark drawn on the IC package often includes special characters and symbols other than general characters, or special logo (font) characters. Therefore, in the conventional inspection apparatus, teaching is always performed prior to the above-described inspection.

[0008]

However, the types of the ICs are extremely large, and if the differences in the production lot number and the version (for example, the difference in the operation speed) are included, the print marks printed on the IC package are made. The number of types of reference print patterns prepared in correspondence with the pattern to be inspected composed of these print marks also becomes enormous.

However, as described above, it is very troublesome to perform the above-described teaching on the inspection apparatus through human intervention every time the type, manufacturing lot, version, etc. of the IC to be inspected changes. This leads to longer inspection times and higher costs due to labor costs.

For this reason, the type of IC, the production lot,
It is also possible to create a plurality of reference print patterns that can cope with all the differences between versions and the like in advance by the above-mentioned teaching and store them in the inspection device. Large-capacity storage means for storing all print patterns is required,
The cost of the inspection device increases.

When a new IC is developed,
New print marks will also appear, and in order to generate a reference print pattern corresponding to these new print marks, further teaching is required, and conversely, if there is an IC that has been discontinued Requires erasing the reference print pattern corresponding to the IC whose production has been discontinued.

Further, at the time of the above-mentioned inspection, the difference between the previously stored reference print pattern and the print pattern to be inspected is compared. In some cases, correct judgment cannot be made due to a defect of a print mark or the like. For example, in the case of similar print marks such as the numbers 0 and 8, 1 and 7, 6 and 8, etc., there is a possibility that an erroneous judgment may be made due to some defects of these print marks. More specifically, for example, in the case where the center of the number 0 appears to be connected by dust or the like, the 0 may be recognized as 8, and conversely, the line at the center of the number 8 may be recognized. Is printed faintly or is not printed, the 8 may be recognized as 0, etc.

As described above, a mere overall pattern comparison between the inspection target print pattern and the reference print pattern is not sufficient.
The reliability of the inspection when the print mark includes the similar characters as described above becomes low.

In order to solve this problem, conventionally, when the inspection result of a mark to be inspected is ambiguous, that is, when the inspection device cannot judge correctly, the image of the print mark to be inspected is divided into a plurality of areas, and each image is divided into a plurality of areas. An inspection is performed by comparing the pattern in the divided area with the corresponding part of the reference print pattern to ensure the reliability of the inspection. For example, a case where a print mark composed of one character is used as an inspection target print pattern will be described as an example.If the inspection result is ambiguous, the inspection apparatus uses the image of the inspection target print mark and a reference print pattern. The inspection is performed by dividing the image of the print mark to be inspected into a plurality of areas, and comparing the pattern image in each of the divided areas of the image of the print mark to be inspected with the pattern in each of the divided areas corresponding to the reference print pattern. I try to ensure the reliability. In addition, as a region division method here, a method of equally dividing into two in the vertical and horizontal directions,
For example, there is a method of dividing the image into fixed areas.

However, when the inspection is performed for each of the divided areas as described above, for example, when the pattern of the print mark is included in the boundary part at the time of the area division, the pattern width of the print mark at the boundary part is changed. In some cases, it is detected as a width different from the actual pattern width.
The ratio of the pattern width in the divided area is largely different from the original ratio, and the reliability of the inspection is impaired. More specifically, when the print mark is, for example, a character, and when a part of the character is included in a boundary portion at the time of the area division, the line width of the character at the boundary portion is equal to the actual line width. May be detected as a different width, and if such a wrong line width is detected, the character cannot be correctly recognized.

On the other hand, the inspection time is generally limited.
Therefore, the inspection algorithm for performing the above-described inspection must be completed within the time limit.

As described above, the print mark on the IC package may be formed by engraving with a laser beam or may be formed by imprinting with ink. A print mark formed by being stamped using the above-described method is likely to have, for example, variations in the thickness of the mark line (eg, the thickness of a character line) and a shift in a printing position due to a variation in the stamping. Even if the line thickness changes or the printing position shifts as described above, if an inspection algorithm that can tolerate these changes (hereinafter referred to as a high allowable amount inspection algorithm) is used, the print marks on the IC package can be printed. Can be recognized.

However, in the above-mentioned high tolerance inspection algorithm, a large amount of execution time is required because a change in the line thickness of the print mark and a shift in the print position are absorbed. For this reason, conventionally, an inspection algorithm (hereinafter, referred to as a low-permissible-amount inspection algorithm) in which the permissible amount of the change in the line thickness or the deviation of the printing position is set to be small so that the inspection is completed within the time limit. Is used. However, even if the above-described high tolerance inspection algorithm can recognize the print mark on the IC package, the low tolerance inspection algorithm may fail to recognize it. That is, in the inspection apparatus using the low tolerance inspection algorithm, even if the inspection result should be normally determined to be good, it is often determined to be defective, and the yield of quality determination at the time of inspection is deteriorated. .

Therefore, the present invention has been made in view of such a situation, and even if there are many types of ICs or a new IC is developed, a print mark or a first pin mark on an IC package is obtained. To provide a mark inspection method and apparatus capable of easily and accurately recognizing a mark, performing an inspection within a time limit, improving the yield of pass / fail judgment, and suppressing an increase in cost. And

[0020]

SUMMARY OF THE INVENTION A mark inspection method and apparatus according to the present invention performs mark inspection by using image processing, teaches a mark position and a mark range, and at least marks and an image around the mark. By taking in, instructing the image pattern of the mark within the position and range corresponding to the mark position and mark range as a reference mark pattern, and inspecting the mark to be inspected using the mark position and mark range and the reference mark pattern To solve the above-mentioned problem.

That is, according to the present invention, the teaching of the mark position and the mark range and the teaching of the reference mark pattern are separately performed, so that a plurality of types of marks existing in the same mark position and the same mark range can be obtained. It is possible to easily teach a plurality of types of reference mark patterns corresponding to the respective types.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the overall configuration of a mark inspection apparatus for inspecting a print mark and a first pin mark formed on an IC package as one embodiment of a portable device for implementing the mark inspection method of the present invention. ing.

That is, the mark inspection apparatus according to the embodiment of the present invention shown in FIG. 1 is capable of printing characters such as a product name, a lot number, a manufacturer name or a trade name, various characters, numerals, symbols, etc., formed on an IC package 14. An illumination device 19 for illuminating the IC package 14, wherein the illumination device 19 illuminates the IC package 14;
4, a video camera 12 for photographing a print mark or a first pin mark formed on the surface of the monitor 4, a monitor device 15 for displaying an image, An image processing unit 11 that performs image processing for displaying and performs image processing for realizing an inspection function to be described later; image signal, reference print pattern, reference first pin pattern data, and coordinates for setting various windows. Value, IC package 1
4, a storage device 18 for storing various information such as position and range information indicating the inspection area at the time of the mark inspection, and a window instruction to be described later and other various operation inputs from the operator can be processed by the mark inspection device. Panel 16 as a man-machine interface for converting signals into various signals, and a host computer 1 for controlling each part according to a program.
7 is provided.

In the mark inspection apparatus of this embodiment, when the IC package 14 is stored in the stick-shaped, tray-shaped or tape-shaped storage container, for example, it is determined whether or not different types of IC packages 14 are mixed.
Whether the IC package 14 has been stored in the correct orientation in these storage containers is determined based on the mark inspection result, and the quality of the IC package 14 is determined.

In the following description, a plurality of IC packages 14 taken out of the plurality of stick-shaped or tray-shaped storage containers are transferred to a tape-shaped storage container (eg, embossed tape 13) as another large-capacity storage container. In the case where it is stored again, the I stored on the embossed tape 13
An example in which the mark inspection apparatus of the present invention inspects whether the type of the C package 14 is correct and whether the direction of the IC package 14 is correct will be described. FIG.
In the example, while the embossed tape 13 containing the IC package 14 is transported by a transport system (not shown), the IC package 1 stored on the embossed tape 13 is transported.
4 illustrates a configuration in the case where inspections of No. 4 are sequentially performed.

Here, before describing the specific operation of the configuration of FIG. 1, the inspection function of the IC package 14 in the mark inspection apparatus of the present embodiment will be described.

The inspection function of the IC package 14 in the mark inspection apparatus of the present embodiment includes the above-described IC package 1 of a different type on the embossed tape 13 as described above.
And a function of checking whether or not the IC package 1 is contained in the embossed tape 13.
There is a function to check whether or not 4 is stored in the correct orientation.

The mixing inspection function of the different types of IC packages 14 is realized by recognizing a print mark printed on the IC package 14.
The inspection function of the orientation at the time of storage is realized by recognizing the position of the first pin mark formed on the IC package 14.

The recognition of the print mark is performed by checking whether the pattern of the print mark actually printed on the IC package 14, that is, the print pattern to be inspected is the same as the reference print pattern registered in the teaching process described later. Is determined. When determining whether or not the reference print pattern and the inspection target print pattern are the same, for example, a so-called template matching process is used for each character, and a determination is made based on a score indicating the degree of matching, which will be described later.

The recognition of the first pin mark is based on the fact that the pattern of the first pin mark formed as a depression on the IC package 14, ie, the first pin pattern to be inspected, is the reference first pin registered in the teaching process described later. This is performed by determining whether the pattern is the same as the pattern. To determine whether the first reference pin pattern is the same as the first pin pattern to be inspected, a determination process based on a template matching process is used as in the case of the inspection of the print mark. Here, the first pin mark has a circular or semicircular shape as described later, and the first pin mark is formed as a depression on the IC package 14 as described above. Further, the surface of the mold resin of the IC package 14 is matte, but the first pin mark is a mirror surface. Therefore, as described later, for example, by illuminating from the lateral direction, the first pin mark portion looks darker than the other portions. In the inspection of the first pin mark, the difference in brightness between the first pin mark portion and other portions, that is, the IC package 14 is attached to the video camera 1
The determination process is performed by the template matching process using the difference in the gray value of the image captured in step 2. At this time, the matching position is ignored, and it is determined whether or not the first pin mark exists based on a score indicating the degree of matching. Further, at the time of the determination, an image in the inspection area, which will be described later, is binarized, and a determination process using the ratio of the area of the area of the first pin pattern to be inspected to the area of the other areas is added. By selectively using these determination processes by the IC package 14, it is possible to cope with the case where the front and back of the IC package 14 need to be determined.

Note that the template matching process is a process in which a small region in an image serving as a reference is used as a template, and a region most similar to the template in the other image is searched for, that is, the matching is determined. Therefore, in the mark inspection apparatus of the present embodiment, the reference print pattern or the first reference pin pattern is used as a template, and the matching with the print pattern to be inspected or the first pin pattern to be inspected in the inspection area described later is determined.

The score is a value indicating the degree of matching in the template matching process. In this embodiment, a non-defective score, a defective score, and an intermediate score are set as scores for a print mark. A first pin score is set for a mark. The non-defective score is a threshold value for determining that the IC package to be inspected is non-defective, and the value of the degree of matching obtained by performing the template matching process for each character or the like forming a print mark is When all the values are equal to or larger than the threshold value, the IC package is determined to be non-defective. The above-mentioned defective product score is defined as the IC to be inspected.
This is the threshold for determining that the package is defective,
When there is a character whose matching degree value obtained by performing the template matching process for each character or the like is less than the threshold, the IC package is determined to be defective (an IC of a different type). The above-mentioned intermediate score is a value that is less than the above-mentioned good product score and is not less than the defective product score. As a result of the inspection using the above-mentioned good product score and defective product score, it is not defective,
When it is difficult to determine that the package is a non-defective product, a threshold value is used to divide the image pattern of the mark for one character, perform matching processing for each divided region, and determine the acceptability of the IC package as described later. is there. For this reason, the intermediate score can also be referred to as a division score, and the value of the degree of matching for each of the divided regions into which each of the characters or the like is divided is equal to or greater than the threshold or less than the threshold. This IC package is determined to be good or defective depending on whether or not it exists. Further, the first pin score is a threshold value when the first pin mark of the IC package to be inspected is inspected, and the degree of matching obtained by performing the template matching process on the first pin mark Is determined based on whether the value is equal to or more than the threshold value or less than the threshold value. Each score is set, for example, according to an operation of the operation panel 16 by an operator. Further, even if the IC package is good, for example, if the print mark is thin, it may be determined that the IC package is defective. In this case, the brightness of the illumination device 19 is adjusted as described later, and Can be inspected.

Next, in order to realize the above-described inspection function, the mark inspection apparatus according to the embodiment of the present invention performs inspection in the following steps. That is, in the mark inspection apparatus of the present embodiment, the teaching step of storing the reference print pattern and the reference first pin pattern, the reference print pattern and the reference first pin pattern obtained in the teaching step, and the actual IC package The inspection function described above is performed by a normal inspection process by comparing the inspection target print pattern and the inspection target print pattern on 14 and a retry inspection process of performing an inspection again when the normal inspection process is determined to be NG, that is, a defect. Is feasible.

The teaching process includes two teaching processes, an offline teaching process performed by an operator as a first teaching process according to the present invention, and an online teaching process automatically performed by the mark inspection apparatus as a second teaching process. There is a process.

In the offline teaching process by the operation of the operator, a reference IC package (hereinafter referred to as a reference IC package) is used.
The upper surface of the package is photographed by the video camera 12,
In an online teaching process to be described later, a print mark and a first pin mark on the IC package are searched, and a position and a range for registering the reference print pattern and the reference first pin pattern are set and stored as windows.
The image of the first pin mark photographed by the video camera 12 is simultaneously stored and loaded as file data when the position and range data obtained by the teaching are saved in the storage device 18. Sometimes they are read at the same time.

Here, even if the IC packages are of different types, if the IC packages have the same shape, the positions and ranges of the print marks and the first pin marks are considered to be the same. A search range for registering a reference print pattern and a reference first pin pattern in an online teaching process described later is set in advance as a window. With this, even if different types of ICs are in the same shape IC package, when performing teaching of the reference print pattern or the reference first pin pattern to each of these various ICs, the type of the IC is changed. There is no need to reset the window each time it changes. Further, in the offline teaching step, a score, which will be described later, when determining the degree of matching in the template matching process is set and stored. Hereinafter, the window set during the offline teaching is referred to as an offline teaching window.

Next, in the automatically performed online teaching process, the first IC package 14 supplied to the mark inspection apparatus is assumed to be good, and the upper surface of the first IC package 14 is placed on the video camera 12. And the position and range corresponding to the offline teaching window are set in the first IC package 1.
Search out from the image of No. 4 by automatic search. Further, in the online teaching process, the image pattern of the print mark in the window searched by the automatic search is stored as a reference print pattern, and the image pattern of the first pin mark in the window also searched is used as the reference first pin. Store as a pattern. In the teaching of the first pin mark, an image itself of the first pin mark taken by the video camera 12 is stored. The operation of storing the reference print pattern and the reference first pin pattern in the online teaching process will be hereinafter referred to as master registration.

Here, in the online teaching process, when the character string of the print mark is searched for from the image of the IC package 14 photographed by the video camera 12, the printing on the reference IC package used in the offline teaching process is performed. Since the position of the mark and the position of the print mark on the first IC package 14 may be different, the size of the window for searching for the character string is larger or smaller than the size of the on-fly teaching window. For example, the width is 1.5 times larger, and the left and right are larger by the width obtained by adding the upper and lower widths. The window used in the online teaching process is hereinafter referred to as an online teaching window. In the online teaching process, a character string searched in the online teaching window is separated for each character, and each character is registered as a template image, that is, a reference print pattern.
A search area for inspecting the C package, that is, an inspection area is set and stored. This inspection area is an area larger for one character at each of the left and right ends of the character string than for other characters. The reason for this is that when actually inspecting the IC package, first, the characters at the left and right ends of the character string are searched, and when these left and right characters are found, the position of the IC to be inspected is determined based on their positional relationship. This is because the inclination of the entire package is calculated, and the actual inclination and position of the character string are corrected in accordance with the obtained inclination and position. Further, when separating each character of the character string as described above, master registration is not performed without using a horizontally long and vertically short character such as "-".

In the online teaching process, when the master registration fails, the image processing unit 11 displays on the monitor screen that the teaching has failed. Further, when the lot of the IC supplied by the embossed tape 13 is switched during the execution of the mark inspection, the quality of the characters of the print mark changes, and an inspection error frequently occurs. Then, the mark inspection device is temporarily stopped and the master registration (on-line teaching) is performed again.

Next, the normal inspection process is performed after performing the master registration operation in the teaching process, and the reference print pattern and the reference first pin pattern obtained in the teaching process are compared with the actual IC package 1.
4 is compared with the print pattern to be inspected and the print pattern to be inspected obtained by photographing No. 4 to check whether or not different types of IC packages are mixed and stored on the embossed tape 13; IC on 13
Inspect the package for correct orientation.

Further, in the mark inspection apparatus of the present embodiment,
In addition to the normal inspection process described above, there is the retry inspection process. In the retry inspection process, as described above, when the IC package is determined to be NG, that is, defective in the normal inspection process, it is reconfirmed that the IC package is not determined to be defective although it is good. This is a re-inspection process for performing

That is, for example, when the print mark is stamped with ink, the thickness of the character may change or the print position may shift due to the variation in the pressing force at the time of the stamp. In such a case, it may be determined that the product is defective although it is originally good. For this reason, in the mark inspection apparatus according to the present embodiment, even if it is determined as NG once in the above-described normal inspection process, re-confirmation is performed by the retry inspection, and when it is determined as NG again in the retry inspection, Only the IC package is determined to be defective.

In the above-described ordinary inspection process, it is possible to perform an inspection that can cope with a change in the thickness of the character or a shift in the printing position. However, in this case, a long processing time is required for the inspection. Become. On the other hand, changes in the thickness of these characters and misalignment of the printing position occur at a low frequency, and spending a large amount of inspection time in a normal inspection process due to such a low frequency of occurrence causes an increase in inspection cost. Is not preferred.

For this reason, in the mark inspection apparatus of the present embodiment, in the above-described normal inspection process, the processing corresponding to the change in the thickness of the character and the deviation of the printing position is omitted, and the defective product is once judged in the normal inspection process. By performing the retry inspection only when it is determined that the IC package is defective, it is possible to shorten the overall inspection time and to prevent an erroneous determination as a defective product despite the fact that the IC package is originally good. We are improving the yield of inspection.

Further, in the retry inspection process, compared with the inspection in the normal inspection process, the range for searching for the print mark on the IC package is set wider, and the line width of the print mark (for example, characters) Inspection is performed by changing the thickness. Note that this retry inspection step is performed particularly at the time of inspecting a print mark, but can also be applied to inspection of a first pin mark. However, in the case of the first pin mark, unlike the print mark, the thickness and position of the mark hardly change, so that a retry inspection is not necessarily required when inspecting the first pin mark.

The inspection time can be obtained, for example, by the following equation.

[0048] _{t total = t 1pin + t mark1} + t mark2 t mark1 = t pos1 + t ch1 * in _{n 1 t mark2 = t pos2 +} t ch2 * n 2 above formulas, t _total is the total inspection time, t _1pin
Inspection time of the first pin marks, t _MARK1 the inspection time, for example, product name of the print mark, t _mark2 the inspection time of the print mark for example lot number, t _pos1 the correct positioning and inclination of the print mark of the product name T _pos2 is the time required for positioning and rotation correction of the factor mark of the lot number, t _ch1 is the inspection time of one character of the print mark of the product name, and t _ch2 is the printing of the lot number. 1 character inspection time of the mark, n ₁ is the number of characters in the print mark of the product name, t _ch2 is the number of characters in the print mark of the lot number. These inspection processing times vary greatly depending on the type of IC package, the size of characters, the size of the first pin mark, and the like. Generally, when the height or width of a character is n times, n ² times of processing time is required.

Next, detailed contents of the teaching process, the normal inspection process, and the retry inspection process in the mark inspection apparatus according to the embodiment of the present invention will be described in order.

First, among the teaching steps, the off-line teaching step is specifically performed according to a procedure shown in a flowchart of FIG. FIG. 2 shows the overall flow of the offline teaching.

In the flowchart of FIG. 2, first, in step ST1, the reference IC package is set in front of the video camera 12. The setting of the reference IC package may be performed by an operator or automatically by the transport system. From the video camera 12, an image signal obtained by photographing the reference IC package from above is output, sent to the image processing unit 11, and subjected to, for example, filtering and various image processing for display on a monitor screen, which will be described later. It is sent to the device 15. Thereby, the monitor device 15
On the monitor screen, an image of the reference IC package photographed from above is displayed.

In the next step ST2, the offline teaching window is set on the image of the reference IC package displayed on the monitor screen. That is, in the step ST2, the first IC package 14 is used in the online teaching process performed later.
A window for retrieving the position and range where the print mark and the first pin mark are present from the image is set. In step ST2, the score is set when the degree of matching is determined in the template matching process. The setting of the position and range of these windows and the setting of the score are performed by the operator using the operation panel 16.
Is performed in accordance with the operation of.

In step ST3, step ST2
The information on the position, range, and score of the offline teaching window set in the step (1) is stored in the storage device 18. In step ST3, the photographed reference IC
The image information of the first pin mark on the package is also stored in the storage device 1.
8 is stored.

The setting of the position and range of the offline teaching window in step ST2 is performed as shown in FIGS. 3 to 9 below.

FIG. 3 shows a top image of the reference IC package 24 photographed by the video camera 12 and displayed on a monitor screen. In addition, for example, “ABCDEF”, “abcd”
efgh "" 11100000111 "" -αβγσθ
It is assumed that each character string and numeral string of "-" are formed as print marks, and the first pin mark 23 is arranged at the lower left corner as a position corresponding to the first lead terminal.

In the example of FIG. 3, among the print marks on the reference IC package 24, the character string “abcdefgh” is surrounded by the off-line teaching window 21, and the first pin mark 25 is placed on the off-line teaching window 23. Surrounding. The portion surrounded by the above-mentioned offline teaching window 21 is a range for registering the reference print pattern as a master at the time of the later online teaching, and the portion surrounded by the above-mentioned offline teaching window 23 is the later online teaching. This is the range for registering the reference first pin pattern as a master during teaching.

Here, when the off-line teaching window 21 surrounding the print mark is set, the entire character string of the print mark to be master-registered as a reference print pattern at the time of the subsequent offline teaching is set. At this time, since the number of characters in the horizontal direction of the print mark varies depending on the type of IC, when setting the off-line teaching window 21, the entire character string in one horizontal line is surrounded. It should be noted that up to four windows 21 for offline teaching can be set.
However, if many characters or the like are inspected at one time, the inspection time will be long at the time of the subsequent mark inspection. Therefore, the mark inspection apparatus of the present embodiment registers only the character string necessary for the inspection of the print mark.

When the offline teaching window 25 surrounding the first pin mark 25 is set, the whole of the first pin mark 25 is similarly surrounded.

The offline teaching windows 21 and 25 are moved and changed in size according to the operation of the operation panel 16 by the operator. The operation panel 16 includes the windows 21 and 25.
For example, a mouse or a trackball is provided as a means for inputting and setting the movement and size of the mouse. Therefore, the windows 21 and 25 are provided on the monitor screen in accordance with the operation of the mouse or the trackball by the operator. It moves to the position and is set to an arbitrary size. Information indicating the positions and sizes of the windows 21 and 25 on the monitor screen, such as coordinate information, is stored in the storage device 18. However, at this stage of the offline teaching process, windows 21 and 2
Only the position and size of No. 5 are set, and the teaching of the print mark and the first pin mark in the windows 21 and 25 is not performed.

In the example of FIG. 3, "abcdefgh"
In the above offline teaching window 2
Although surrounded by 1, if there are characters or the like that are not desired to be registered as the reference print pattern in the subsequent online teaching process, an area including these characters or the like that should not be registered can be set as a prohibited area. In FIG.
An example in which the prohibited area is set is shown. Note that FIG. 4 also shows an upper surface image of the reference IC package 24 as in FIG.

In FIG. 4, the prohibited area in the portion surrounded by the offline teaching window 21 in the example of FIG.
Set with. Since the prohibited area is for setting an area in the window 21 that is not desired to be registered as a reference print pattern, the window 22 is set within the range of the window 21. The window 22 for setting the prohibited area is also provided by the operator with the operation panel 1.
The size is changed while moving according to the operation of No. 6. Window 2 on the monitor screen
Information indicating the position and the size of No. 1 is also stored in the storage device 18.

By the way, the first pin mark is shown in FIG.
In addition to those arranged at the corners of the reference IC package 24 as shown in FIG. 5, for example, semicircular marks 27 as shown in FIG. In some cases, for example, there are two large and small circle marks 28 and 29 as shown in FIG. That is, in the case of the IC package 26 of FIG. 5, the first lead terminal exists on the side where the semicircle mark 27 is located, and in the case of the IC package 30 of FIG. Exists. Therefore, for example, in the case of the IC package 26 as shown in FIG.
By setting an off-line teaching window surrounding the semicircle mark 27 as shown in a window 33 shown in FIG. 7, the semicircle mark 27 can be registered as a reference first pin pattern at the time of online teaching later.

The semicircle mark 27, the small circle mark 28, and the large circle mark 29 in FIGS. 5 and 6 serve not only as the first pin mark but also to indicate the front and back of the IC package. I have. That is, in the IC package, there are two kinds of bending directions of the lead terminals, the forward vent and the reverse vent. In order to distinguish between the forward vent and the reverse vent, the marks 27 and 28 shown in FIGS. , 29 are formed. The IC package 26 provided with the semicircle mark 27 as shown in FIG. 5 is a regular vent, and the IC package 26 provided with two large and small circle marks 28 and 29 as shown in FIG.
The C package 30 is a reverse vent.

Here, when the top images of the IC packages 26 and 30 are displayed on the monitor screen, the semicircle mark 27 and the two large and small circle marks 28 and 29 have the same grayscale value, respectively. . Further, as can be seen from FIGS. 5 and 6, a semicircular mark 27
And the half of the great circle mark 29 indicating the reverse vent are very similar in shape and very close in area.

Therefore, when inspecting the first pin mark at the time of the mark inspection to be described later, there is a possibility that the half circle mark 27 and half of the large circle mark 29 are erroneously recognized. . For this reason, in the mark inspection apparatus of the present embodiment, when inspecting the first pin mark, the semicircle mark 27 and the half of the great circle mark 29 are not erroneously recognized from each other. With respect to the IC package 26 of the front vent, another window is set in addition to the window 33 for the offline teaching.

That is, for example, as shown in FIG. 7, when the semicircle mark 27 as the first pin mark is surrounded by the offline teaching window 33 with respect to the image of the IC package 26 of the front vent as shown in FIG. And another window 34 is set. The area where the window 34 is arranged corresponds to the position where the great circle mark 29 is to be arranged on the reverse vented IC package 30 shown in FIG.

As described above, the positive vent IC package 2
If the two windows 33 and 34 are provided to the IC card 6, the IC package 26 of the front vent will be provided later.
When the IC package 30 of the reverse vent is mistakenly mixed when the inspection of the first pin mark (semicircle mark 27) is performed, an inspection area described later which is provided corresponding to the two windows 33 and 34 will be provided. At the same time, a mark having the same gray level and the same shape (half of the mark in the case of a great circle mark) is detected, which is the first pin mark inspection of the IC package 26 of the above-described positive vent. Sometimes this should not be possible. Therefore, it is possible to detect that the IC package is defective, that is, that the IC package is not the IC package 26 of the above-described vent. Note that the size of the window 34 does not need to be accurate, and the size of the window 34 can be detected in a later mark inspection so that the presence of any mark in an inspection area to be provided corresponding to the window 34 can be detected. Any size is acceptable. The windows are set so as not to protrude to the lead terminal side.

On the other hand, the reverse vent IC shown in FIG.
In the package 30, as shown in FIG. 9, a window surrounding the whole of the great circle mark 29 is set as the window 35 for offline teaching. In the case of the reverse vented IC package 30, the actual first lead terminals are arranged on the side on the small circle mark 28 side, but in any case, the side opposite to the side on the large circle mark 29 side. Since it is known that the first lead terminal is provided on the side, the great circle mark 29 side may be used as a window for off-line teaching. In other words, the mark inspection apparatus uses the offline teaching window 35.
When the great circle mark 29 is detected in the inspection area to be described later, which is provided corresponding to
It can be known that the first lead terminal exists on the side opposite to the side on the side of the ninth side.

Here, the IC package 3 of the reverse vent is used.
With respect to 0, two windows are not provided as in the case of the above-mentioned normal vent, and only one window 35 is provided. This is because, when the inspection of the great circle mark 29 of the IC package 30 of the reverse vent is performed, the IC package 26 of the normal vent is erroneously mixed.
Even if the semicircular mark 27 of the IC package 26 of the regular vent enters the inspection area provided corresponding to the window 35, the inspection area having a size surrounding the great circle mark 29 has This is because the score of the semicircle mark 27 is lower than that of the great circle mark 29, so that it can be detected that the IC package 26 is different from the reverse vented IC package 30.

Each of the offline teaching windows 33, 34 and 35 described with reference to FIGS. 7 to 9 also moves and changes size according to the operation of the operation panel 16 by the operator. Information indicating the position and size of each window 33, 34, 35 on the monitor screen is also stored in the storage device 18.

Next, the procedure for setting the window for offline teaching in the above-described offline teaching process will be described with reference to the flowchart of FIG. Note that the flowchart of FIG. 10 describes step ST2 and step ST3 of the flowchart of FIG. 2 in more detail. When the offline teaching window is set, the operator operates the operation panel 16 to set the offline teaching window. From the window
Further, the teaching processing for resetting the optimal offline teaching window is described.

In FIG. 10, in step ST11, each pixel constituting an image in the window set by the operator operating the operation panel 16 is binarized, and the obtained binarization is performed.
A labeling process for assigning individual labels to each connected component in the value image is performed. As a result, when there is a mark such as a character in the window, for example, the same label is assigned to each line or each pixel in the plane constituting the mark such as the character. In other words, the same label is assigned to each connected line or surface among the lines or surfaces constituting a mark such as a character.

In step ST12, the label in contact with the window set by the operator is removed. In step ST12, a noise component is also removed by performing a file ring described later on the image signal.

In step ST13, the individual labels are classified in the window set by the operator. That is, classification is performed for each pixel to which the same label is assigned in the window. In other words, in step ST13, when there is, for example, a character or the like in the window set by the operator as described above, the same label is assigned to each pixel of each line constituting the character. Classification is performed for each label, that is, for each character.

In the next step ST14, it is determined whether or not a label remains in the window set by the operator. That is, that a label remains in the window indicates that characters and the like exist in the image in this window, and that no label remains means that there is a character and the like in the image in the window. It does not. If it is determined in step ST14 that a label remains, the process proceeds to step ST15.
To step ST if it is determined that there is no remaining
Proceed to 18.

In step ST15, of the labels in the window set by the operator, only the labels arranged in a horizontal example are left, and the other labels are deleted. That is,
In this step ST15, if there is an image composed of, for example, a plurality of characters arranged in a horizontal line in the window, only the labels corresponding to these character strings are left, and labels not arranged in the horizontal line are deleted. Do that.

At step ST16, at step ST16
The outermost shape of each of the labels arranged in the horizontal line remaining at 15 is stored in the storage device 18 as a window automatically set, that is, a window for offline teaching, instead of the window set by the operator.

At step ST17, the automatically set off-line teaching window is displayed on the monitor screen.

On the other hand, in step ST18, the window set by the operator is stored as an off-line teaching window, and in the next step ST19, the window is displayed on the monitor screen. That is, the determination of NO in step ST14 is a case where a character string or the like is not correctly enclosed in the offline teaching window.
As shown in step 8 and step ST19, the window set by the operator is stored and displayed as it is.

As described above, in the processing of the flow chart of FIG. 10, a mark such as a character string in the window set by the operator is detected, and an optimal offline teaching window is determined based on the detected mark such as the character string. Is automatically set again, the automatically set offline teaching window is stored, and the automatically set window is displayed on the monitor screen.

In the description of this embodiment, an example in which characters and the like are arranged in a horizontal line is given. However, even when characters and the like are arranged in a vertical direction, window setting and the like are performed in the same manner as described above. It is possible. That is, in the present embodiment, when a long window is set at the time of offline teaching, it is interpreted that characters and the like are arranged side by side,
When a vertically long window is set, it is interpreted that characters and the like are arranged vertically. In the present embodiment, the operation when a vertically long window is set is equivalent to the operation when a horizontally long window is set.

Next, the online teaching process, which is automatically performed in the teaching process, that is, the master registration for storing the reference print pattern and the reference first pin pattern is specifically described in FIGS. 11 and 12. This is performed according to a procedure as shown in the flowchart. Note that FIG.
FIG. 1 shows a flow of storing a reference print pattern.
2 shows a flow when the reference first pin pattern is stored.

In the online teaching process, as described above, it is assumed that the first IC package 14 supplied to the mark inspection device is a non-defective product, and the offline teaching window stored in the offline teaching process is used to further determine the IC package 14. A window for online teaching is generated, an image pattern of a print mark in the window for online teaching is stored as a reference print pattern, and an image pattern of the first pin mark is also stored as a reference first pin pattern.

First, in FIG. 11, which shows a flowchart for registering the reference print pattern, step ST20
Then, a window larger than the window for offline teaching set in the offline teaching is set. For example, a window whose size is 1.5 times higher and lower than the size of the on-fly teaching window and whose left and right sides are further increased by a width obtained by adding up and down widths is set as the online teaching window.

At step ST21, at step ST21
Each pixel constituting the image in the online teaching window set in step 20 is binarized, and a labeling process for assigning an individual label to each connected component in the obtained binary image is performed. As a result, when there is a mark such as a character in the window, for example, the same label is assigned to each line or each pixel in the plane constituting the mark such as the character.

In step ST22, the label in contact with the online teaching window is removed. In step ST22, a noise component is also removed by performing a later-described file ring on the image signal.

In step ST23, the individual labels are classified in the online teaching window. That is, classification is performed for each pixel to which the same label is assigned in the window.

In the next step ST24, it is determined whether or not a label remains in the online teaching window. That is, to say that a label remains in the window indicates that characters and the like exist in the image in this window, and to say that there is no label means that there is no character and the like in the image in the window. It represents that. In the step ST24,
If it is determined that the label remains, step ST2
Go to step 5, if it is determined that there is no remaining, step S
Proceed to T27.

In step ST25, of the labels in the online teaching window, only the labels arranged in a horizontal example are left, and the other labels are deleted. That is, in this step ST25, when there are images consisting of a plurality of characters arranged in a horizontal line in the window, only the labels corresponding to these character strings are left, and the labels not arranged in the horizontal line are left. Do delete.

In step ST26, the above-mentioned step ST
At 25, the original image and coordinates and the search range are stored for each of the remaining labels. In other words, in step ST26, the image of the mark such as the character existing in the online teaching window and its coordinates, that is, the reference print pattern is stored, and the mark such as the character described above is searched in the window. Information for specifying a range, that is, an inspection area at the time of an actual mark inspection is stored in the storage device 18. Note that the search range, that is, the inspection area is a range for designating the area for searching for a mark. Usually, the range is, for example, 30 pixels. Pixels. However, when the inspection area (search range) is enlarged, the inspection time is extended.

On the other hand, in step ST27, error processing is performed. That is, that no label remains in step ST24 means that a mark such as a character does not exist within the range set in step ST20, and the reference print pattern cannot be stored in the online teaching. Therefore, error processing is performed.

As described above, in the processing of the flowchart of FIG. 11, the online teaching window is set at a position corresponding to the offline teaching window previously set in the offline teaching step and is larger than the position. In the first image of the IC package 14 supplied to the inspection device, each pattern of the print marks in the online teaching window is registered as a reference print pattern, and when the mark inspection is actually performed from the online teaching window. Is set and registered.

Next, referring to FIG. 12 showing a flowchart for registering the reference first pin pattern, step ST
At 70, a template matching process of an image in the window is performed using an offline teaching window corresponding to the first pin mark set in the offline teaching.

In step ST71, the value obtained by the matching (hereinafter referred to as a matching score) is compared with the first pin score. If the matching score is larger than the first pin score, the process proceeds to step ST72; Proceed to step ST74.

If it is determined in step ST71 that the matching score is larger than the first pin score, it is possible to determine that the image in the window is the first pin mark.
The pattern of the pin mark is registered as a master first pin pattern.

In the next step ST73, a display for confirming that the master registration of the first pin pattern has been completed is performed on, for example, a monitor device.

On the other hand, in step ST74, which is performed when it is determined in step ST71 that the matching score is smaller than the first pin score, error processing is performed. That is, determining that the matching score is smaller than the first pin score in step ST71 means that the first pin mark does not exist in the window subjected to the matching process in step ST70. Since the reference first pin pattern cannot be stored in online teaching, error processing is performed.

As shown in the flowchart of FIG. 12, in the mark inspection apparatus of the present embodiment, a search position for registering the reference first pin pattern at the time of online teaching later by the offline teaching is set in advance. By doing so, even if the type of IC changes, if the position of the first pin mark is the same in the IC package, the teaching of the reference first pin pattern can be automatically performed without an operator in the online teaching process. It is possible to perform it.

Next, the above-described ordinary inspection process performed after the above-described offline teaching process and online teaching process is performed according to a procedure as shown in the following flowcharts of FIGS. Note that the flowchart of FIG. 13 shows a flow for inspecting the entire print mark in which characters and the like are arranged in a line, for example, and the flowchart of FIG. 14 shows one mark such as a print mark for each character or a first pin mark. Only shows the flow when inspecting.

First, in the flowchart of FIG.
In step ST30, the IC to be inspected stored on the embossed tape 13, which is the tape-shaped storage container of FIG.
From the image obtained by photographing the package 14 with the video camera 12, the print marks arranged in a line in the inspection area set in the above-described online teaching step, for example, the characters at both ends in the character string are searched. Note that the search referred to here is based on the same position as the position of the template in the reference image, and the similarity determination is performed at all pixel positions within a predetermined size range, and the region having the highest similarity is determined. When the search is performed in the mark inspection apparatus of the present embodiment, a pattern similar to the stored reference print pattern is searched for in the inspection area by template matching.

In step ST31, affine transformation is performed as the above-described inclination and position correction processing from the position and angle of the character string found by the search.

At step ST32, 1 in the character string
Inspect for each character. That is, in the step ST32, for each character in the character string, an inspection is performed to search for a matching pattern in the reference print pattern by the template matching process.

In step ST33, it is determined whether or not the inspection in step ST32 has been completed for all the characters in the character string. If not, the process returns to step ST32;
Proceed to T34.

In step ST34, as a result of performing the template matching processing on all the characters in the character string, the pattern of all the characters in the character string matches the corresponding pattern in the reference print pattern. It is determined whether or not. If it is determined in step ST34 that they do not match, the process proceeds to step ST34.
Proceeding to 36, the IC package is determined to be defective, that is, a different type of IC. On the other hand, if it is determined in step ST34 that they match, the process proceeds to step ST35, where the IC package is a non-defective product.
That is, it is determined that the IC is correct.

Next, the flow of processing for inspecting only one mark such as a print mark for each character or a first pin mark will be described with reference to the flowchart of FIG. In addition,
The flowchart of FIG. 14 can be applied to both the case of inspecting one mark such as the first pin mark and the inspection of one character in step ST32 of the flowchart of FIG. The example of FIG. 14 shows a flow in the case of inspecting one character of a print mark. In the case of inspecting the first pin mark, one character in the flowchart of FIG.
In other words, it can be inspected as a similar process in other words.

In FIG. 14, in step ST40, the template matching process for comparing the one-character pattern printed on the IC package with the reference print pattern is performed.

In step ST41, it is determined whether or not the value of the degree of matching in the template matching process is less than the above-mentioned good item score. When it is determined that the value of the degree of matching is less than the non-defective score, the process proceeds to step ST42, and when it is determined that the value is not less than the non-defective score, that is, when it is determined that the value is not less than the non-defective score, the process proceeds to step ST48. In step ST48, it is determined that the pattern of the one character matches the reference print pattern.

In step ST42, it is determined whether or not the value of the degree of matching in the template matching process is less than the above-mentioned defective product score. Here, when it is determined that the value of the degree of matching is not less than the defective product score, that is, when it is determined that the value is equal to or more than the defective product score, the process proceeds to step ST43.
Go to 7. In step ST47, it is determined that the pattern of the one character does not match the reference print pattern.

In the step ST43, as a result of the judgments in the steps ST41 and ST42, the value of the degree of matching is less than the good score and not less than the bad score, and it is difficult to judge the character. In order to inspect a character in detail, the character is divided as described above, and a determination process is performed by matching for each divided region. In the mark inspection apparatus of this embodiment, the number of divisions at the time of division is divided into three in the horizontal and vertical directions as shown in FIG. By dividing into nine parts in this manner, for example, lines constituting a character are less likely to straddle the divided area, and the reliability of the inspection is improved. Therefore, in the processing of step ST43 performs the template matching process for each of the divided regions B ₁ .about.B ₉ that the 9 divided. FIG. 15 shows an example in which, for example, the numeral 8 is used as one character.

In the next step ST44, it is determined whether or not each value obtained by the matching processing of the divided areas B _{1 to} B ₉ is equal to or larger than the above-mentioned intermediate score, that is, the divided score. When it is determined that the value of the degree of matching in each of the divided areas B _{1 to} B ₉ is not equal to or more than the above-described division score, that is, when it is determined that the value is less than the division score, the process proceeds to step ST46, and it is determined that the value is equal to or more than the division score. Sometimes, the process proceeds to step ST45. In step ST46, it is determined that the one-character pattern does not match the reference print pattern. In step ST45, it is determined that the one-character pattern matches the reference print pattern.

Next, as a result of the inspection performed in the normal inspection process as described above, when it is determined that the inspection is NG, that is, a defect, the retry inspection is performed. The flow is performed as shown in FIG.

In FIG. 16, step ST50 is performed.
Is the normal inspection step. Next, step ST5
In step 1, pass / fail judgment is made. Here, the above step S
When it is determined that the result of the normal inspection process at T50 is good, the process proceeds to step ST59, and when it is determined that the result is bad, the process proceeds to step ST52. In step ST59, the IC package is determined to be non-defective.

In step ST52, which proceeds when it is determined to be defective in step ST51, an inspection corresponding to the print mark to be inspected, that is, for example, the thickness of a character line is performed. There are two types of print marks formed on the IC package 14, a mark imprinted with a laser beam and a mark imprinted with ink. The thickness of characters or the like is always constant in the print mark engraved by the laser beam, but the thickness of the characters or the like in the print mark formed by the ink stamp is easily changed (for example, chipped or blurred). Therefore, in particular, in the case of a print mark formed by the above-described ink stamping, an inspection corresponding to a change in thickness of a character or the like, bleeding, chipping, or the like is required. For this reason,
At the time of retry inspection of the print mark by the ink stamping, the character is changed in thickness and re-inspected.

In the next step ST52, pass / fail is determined again. Here, when the result of the inspection in step ST52 is determined to be good, the process proceeds to step ST58, and when it is determined to be bad, the process proceeds to step ST54. In step ST58, the IC package is determined to be non-defective.

In step ST54, which proceeds when it is determined that there is a defect in step ST53, an inspection corresponding to a print position shift of a print mark to be inspected, that is, a character is performed. Specifically, in step ST54, the inspection is performed by setting a wide search range for the print mark.

In the next step ST55, pass / fail is determined again. Here, when the result of the inspection in step ST54 is determined to be good, the process proceeds to step ST57, and when it is determined to be defective, the process proceeds to step ST56. In step ST57, the IC package is determined to be non-defective, and in step ST56, the IC package is determined to be defective.

In the normal inspection process, the inspection range for one character is 30 pixels × 30 pixels, the search size can be changed, and the change in the character line width cannot be dealt with. In the inspection process, the inspection range for one character is a fixed size of 40 pixels × 40 pixels, and the character line width of the reference print pattern is increased or decreased for the change of the character line width, and the inspection is performed again. Therefore, in the retry inspection process, the processing time is, for example, about five times as long as that in the normal inspection process.

The retry inspection can also be performed in the online teaching process. However, the retry inspection in this case refers to the inspection corresponding to the thickness of the mark line in step ST52 and the printing position in step ST54 when it is determined in step ST51 that it is defective after the normal inspection in step ST50. Inspection corresponding to the deviation is performed, and a print mark obtained by these inspections is used as the reference print mark.

Incidentally, when inspecting the print mark and the first pin mark on the IC package 14 as described above, the illumination conditions on the IC package 14 are extremely important. That is, when performing the mark inspection based on an image photographed on the IC package 14 by the video camera 12, the image of the print mark and the first pin mark formed on the IC package 14 and other mold resin surface portions If the contrast between the image (hereinafter referred to as a non-mark portion) and the non-mark portion is not high, the difference between the print mark and the first pin mark and the other non-mark portions cannot be detected, and the reliability of the mark inspection can be reduced. Sex will be worse. Therefore, the illuminating device 19 increases the contrast between the image of the print mark and the first pin mark on the IC package 14 captured by the video camera 12 and the image of the other non-mark portions. It must realize the state.

Therefore, the illumination device 19 of the mark inspection apparatus of the present embodiment illuminates the IC package 14 from a position as close as possible and illuminates the IC package 14 from a direction parallel to the upper surface thereof. Thus, an illumination state in which a high-contrast image is obtained is realized. That is, in the lighting device 19, the position of the light emitting unit that generates the illumination light is arranged at a position close to the upper surface of the IC package 14 and at a low position so that illumination can be performed from the lateral direction. An illumination state in which a high-contrast image can be obtained is realized.

As described above, lowering the position of the light emitting portion with respect to the upper surface of the IC package 14 and reducing the illumination angle on the upper surface of the IC package 14 are different from those of the upper surface of the IC package 14. When the illumination angle is increased by increasing the position of the light emitting unit with respect to
This is because the contrast of the image obtained by photographing the print mark and the first pin mark on the package 14 decreases. In particular, in the case of a mark such as the first pin mark in which the mark portion is specular and depressed, when the illumination angle on the IC package 14 is increased, the contrast is lowered and the first pin mark portion is reduced. Since it is difficult to distinguish the image from other parts, the illumination angle is reduced to stabilize the mark inspection. The print marks formed on the IC package 14 include:
As described above, there are two types of marks: a mark imprinted by a laser beam and a mark imprinted by ink. The density of the print mark formed by the above-described ink stamping is slightly changed but is dark. There is not much change. On the other hand, the density of the print mark imprinted by the laser beam becomes thinner than the print mark formed by the ink printing. Therefore,
When the print mark on the IC package 14 is a print mark engraved with the laser beam, the position of the light emitting unit is set as close as possible to the print mark to stabilize the mark inspection. .

As described above, in the illumination device 19 for illuminating the IC package 14, the quality of the illumination condition greatly affects the reliability of the mark inspection.

The illumination device 1 for realizing such an illumination state
9 has a structure as shown in FIG.

The lighting device 19 shown in FIG. 17 has a hollow rectangular box-shaped casing 51 whose upper and lower sides are open.
And a plurality of light-emitting units 50 provided on the respective inner surfaces of the four surfaces of the rectangular box-shaped housing 51, and the illumination device 19 itself can be moved in the vertical direction. Is what it is. Although illustration of a mechanism for moving the lighting device 19 in the vertical direction is omitted, the mechanism includes, for example, a support portion for fixing and supporting the housing 51 and a longitudinal side having the vertical direction. And a fixing mechanism that moves the support unit up and down on the rail and then fixes the support unit at that position. It is also possible to provide a drive mechanism for moving the support section in the vertical direction on the rail, and to control the drive mechanism in accordance with the illumination state of the IC package, so that the illumination device 19 can be moved up and down. It is also possible to automatically change the arrangement position in the direction.

Here, each of the light emitting sections 50 is formed of an LED array unit in which, for example, ten LED (light emitting diode) elements are arranged in a straight line.
Each inner surface of the four surfaces of the housing 51 has 3
Therefore, a total of 12 LED array units are used on the four surfaces in the lighting device 19. The housing 51
The three LED array units respectively corresponding to the above four surfaces are arranged in a three-parallel state in which the long sides of these LED array units are made parallel and the long side ends are aligned. It is arranged at a position above the embossed tape 13, that is, at a position near the lower part of the housing 51. Note that the illumination device 19 of the mark inspection device of the present embodiment.
Then, the inner surface of the housing 51 is provided with the LED so as to have a height of about 15 mm from the surface of the IC package 14.
Arrange the array unit group.

Further, the brightness of the LED array units of the light emitting section 50 can be individually adjusted for each unit. In the mark inspection apparatus of the present embodiment, since the reliability of the mark inspection of the IC package 14 greatly affects the illumination state of the illumination device 19, each of the LED array units is adjusted before the teaching. In the adjustment, the brightness (light amount) is adjusted so that the contrast between the non-mark portion of the IC package 14 and the print mark and the first pin mark is sufficiently high, and the illumination unevenness in the IC package 14 is eliminated. Light emission adjustment.

Note that each LED array unit (light emitting unit 5
0), the illumination angle on the IC package 14 is
It is desirable that the angle be small as described above. However, as shown in FIG. 17, the LED array units provided on each inner surface of the housing 51 are arranged in parallel with the three rows in the up-down direction of the housing 51. For this reason,
Of the three rows of LED array units, the brightness is separately adjusted for the LED array unit closest to the IC package 14, the LED array unit farthest from the IC package 14, and the LED array unit at the intermediate position. It is desirable. In the lighting device 19, the LED array unit closest to the IC package 14 is adjusted to be the brightest, the LED array unit located farthest to the darkest, and the LED array unit at the intermediate position is adjusted to have the intermediate brightness. Thus, the reliability of the mark inspection in the mark inspection apparatus is improved.

Here, the adjustment of the brightness of each LED array unit and the confirmation of whether or not the mark inspection can be performed satisfactorily with the adjusted brightness as described above can be performed, for example, by the host computer 17 displaying on the monitor screen. The adjustment is performed on a light amount adjustment menu which is one of a plurality of inspection item setting menus displayed as menu items, and the light amount adjustment is performed, for example, before the teaching.

That is, the host computer 17
Before the teaching, a plurality of inspection item setting menus are displayed on the monitor screen for the initial setting of the mark inspection apparatus. At this time, the operator views the operation panel while watching the monitor screen. When the light amount adjustment menu is selected by operating the button 16, the mark inspection apparatus shifts to a light amount adjustment mode.

The host computer 17 of the mark inspection apparatus that has shifted to the light amount adjustment mode displays an IC on the monitor screen.
In addition to displaying the image of the package, a confirmation frame having a size of, for example, 20 pixels × 20 pixels is set on the image of the IC package, and the grayscale value of the image in the confirmation frame is displayed on the monitor screen. The confirmation frame can be arbitrarily set as a window different from the offline teaching window, or can be set as the same window as the offline teaching window.

At this time, the operator designates an image portion whose contrast is actually to be checked by the operator using the operation panel 16.
By operating the host computer 17
Moves the confirmation frame on the monitor screen in response to the operation of the operation panel 16 by the operator, and displays the gray value of the image in the confirmation frame.

Note that the actually displayed value is:
The average value of the gray value of the mark part in the above-mentioned confirmation frame, the ratio of the mark part in the above-mentioned confirmation frame, the average value of the gray value of the non-mark part other than the mark in the above-mentioned confirmation frame, and the non-mark in this confirmation frame There is a ratio of the portion occupied, a difference between the average value of the gray value of the marked portion and the average value of the gray value of the non-mark portion, and the like. The larger the difference between the average values of the gray values of the mark portion and the non-mark portion, the higher the contrast and the higher the reliability of the mark inspection. Therefore, the light amount of the illumination device 19 is adjusted based on the difference between the average values of the gray values of the marked portion and the non-marked portion.

Whether the contrast is suitable for the mark inspection is determined when the operator looks at the numerical value displayed as the gray value, or when the mark inspection apparatus itself sets the reference gray value set in advance as the reference value. Either the case where the comparison is made with the actually measured density value can be used. Therefore, when it is determined that the contrast is not suitable for the mark inspection, the host computer 17 uses the illumination device 19 based on a comparison result between the reference gray value and the actual measured gray value.
Or the operator adjusts the light amount of the illumination device 19 by operating the operation panel 16 based on the gray value displayed on the monitor screen.
Note that, even when the operator operates the operation panel 16 to adjust the light amount, the host computer 17 actually adjusts the light amount of the illumination device 19 according to the operation amount of the operation panel 16.

However, when the operator adjusts the light amount of the illuminating device 19 based on the gray value displayed on the monitor screen, the host computer 17 also compares the reference gray value with the actual measured gray value. When the host computer 17 determines from the result of the comparison that the light amount of the illuminating device 19 is small and is not suitable for the mark inspection, the host computer 17 indicates so, and the host computer 17 determines that the light amount is a limit value at the time of performing the mark inspection. Yes, when it is judged that it is better to increase the light amount a little more, it is judged that the light amount is the amount necessary for the mark inspection, and it is judged that the light amount is sufficient for the mark inspection. When this is done, the fact is displayed on a monitor screen to assist the operator in determining the amount of light. In addition, as a display example when it is determined that the light amount of the lighting device 19 is small and not suitable for the mark inspection, a character display such as “BAD” is displayed, and the light amount is a limit value at the time of performing the mark inspection. The display example when it is determined that there is
BAD "," GOOD "is a display example when it is determined that the light amount is sufficient for the mark inspection, and" GREAT "is a display example when it is determined that the light amount is an amount sufficient for the mark inspection. Is displayed. Therefore, the operator displays, for example, “BA
When "D" is displayed, it can be recognized that the light amount of the illumination device 19 must be adjusted to be larger. For example, when "NOT BAD" is displayed, the light amount becomes slightly larger. Can be recognized as having to be adjusted, for example, "GOOD"
Or "GREAT", it can be recognized that there is no need to adjust the light amount.

On the other hand, the cause of the uneven illumination in the IC package 14 may be, for example, poor mounting of the LED array unit or brightness of each LED array unit mounted on the four inner surfaces of the housing 51. It is conceivable that the four inner surfaces of the housing 51 are not targeted at the top, bottom, left and right. When the illumination unevenness occurs, the brightness of the IC package image displayed on the monitor screen changes between left and right or up and down. If the illumination unevenness becomes extremely large, the teaching and the master registration will fail. In particular, since the print marks are arranged side by side on the IC package, the inspection of the print marks is strongly affected by illumination unevenness in the horizontal direction of the screen.

In the mark inspection apparatus of this embodiment, the confirmation of the presence or absence of such illumination unevenness and the adjustment of the light amount corresponding to the illumination unevenness are also performed on the light amount adjustment menu before teaching, as described above. That is, the illumination unevenness is confirmed and the light amount is adjusted on the light amount adjustment menu among the inspection item setting menus displayed on the monitor screen by the host computer 17.

That is, in the mark inspection apparatus of this embodiment,
When checking the illumination unevenness and adjusting the light amount, an image of the IC package is displayed on the monitor screen, and among the images of the print marks on the IC package, for example, the print marks at the left and right ends are displayed in the same check frame as described above. The light and dark values of the print mark portion and the non-mark portion at these left and right ends are obtained so as to check the illumination unevenness at the left and right ends based on these values, and adjust the light amount according to the check result. To do.

More specifically, in order to check the illumination unevenness in the left-right direction, first, for example, the leftmost print mark is surrounded by the check frame, and the average of the grayscale values of the print marks in the check frame is determined. The value and the average value of the gray values of the non-mark portions other than the print mark are obtained, and the difference between the average values of the gray values of the leftmost print mark and the non-mark portion is obtained. next,
Surround the right end print mark with the above confirmation frame, find the average value of the gray value of the print mark in the confirmation frame and the average value of the gray value of the non-mark part other than the print mark, and The difference between the average value of the gray value and the non-mark portion is determined. Furthermore, the average value of the gray value of the non-mark portion when the print mark on the left end is surrounded by the confirmation frame and the average value of the gray value of the non-mark portion when the print mark on the right end is surrounded by the check frame Find the difference between

The presence or absence of illumination unevenness is confirmed from the difference between the grayscale values of the left and right ends thus obtained, and the light amount is adjusted. That is, when the difference between the average values of the grayscale values of the print mark at the left end and the non-mark portion is smaller than the allowable value for obtaining the contrast required for the mark inspection, the value of the difference at the left end is equal to the allowable value. The light amount is adjusted to be equal to or greater than the value, and when the difference between the average values of the gray values of the print mark and the non-mark portion at the right end is less than the allowable value, the value of the difference at the right end is The light amount is adjusted so as to be equal to or more than the allowable value. Further, when the difference between the average value of the gray value of the non-mark portion at the left end and the average value of the gray value of the non-mark portion at the right end is larger than the non-permissible value that is not allowable as illumination unevenness, The light amount is adjusted so that the difference between the average value of the gray value of the non-mark portion at the left end and the right end is equal to or less than the non-permissible value.

The display of each of the above-mentioned gray-scale values on the monitor screen and the display for allowing the operator to recognize the presence of uneven illumination can be performed in the same manner as described above. The light amount adjustment is performed in the same manner as described above.

In addition, the lighting device 19 includes the L
It is also possible to provide a diffusion plate for diffusing light from the ED array unit. If this diffusion plate is provided, light of each LED element constituting the LED array unit can be diffused, and illumination unevenness on the IC package 14 can be reduced.

Using the lighting device 19 described above, the IC package 14 housed on the embossed tape 13 is placed inside the open lower side of the housing 51, and the upper surface of the IC package 14 is The light is illuminated laterally and from the vicinity so as to be surrounded by the light emitting unit 50, and the upper surface of the IC package 14 is moved from the open upper center of the housing 51 by the video camera 12 in the direction of the arrow V in FIG. To shoot. Thus, the video camera 12 can obtain an image with high contrast between the print mark and the first pin mark on the IC package 14 and other non-mark portions.

In the above description, the example in which the host computer 17 controls the lighting device 19 is described. However, the image processing unit 11 may control the lighting device 19. That is, in this case, the image processing unit 11 controls the lighting device 19 described above, which was performed by the host computer 17.

Next, the above-described image filtering will be described.

As described above, since the surface of the mold resin of the IC package 14 has a satin shape, the density value of an image obtained by photographing with the video camera 12 is not uniform. Therefore, even if the mark on the IC package 14 is printed or imprinted well, there is a tendency that the score value of the matching process tends to be low, and it is difficult to distinguish different marks. In the mark inspection apparatus of the present embodiment, in order to improve this, as a pre-process of the mark inspection, the image taken by the video camera 12 is subjected to a smoothing process by the image processing unit 11, and the IC package is processed. The non-marked portion and the marked portion of 14 are made uniform in their grayscale values to stabilize the matching process.

Here, as the smoothing process, the image signal from the video camera 12 is filtered twice by a 3 × 3 median filter. FIG. 18 shows the gray value distributions before and after the median filter processing. In FIGS. 18A and 18B, the vertical axis indicates the number of pixels, and the horizontal axis indicates the gray level (glayva).
lue). FIG. 18A shows the gray value distribution of the non-mark portion before and after the median filter processing, and FIG. 18B shows the gray value distribution of the print mark portion before and after the median filter processing as the mark portion. ,
The solid lines in FIGS. 18A and 18B show the gray value distribution curves of the image from the video camera 12, ie, the original image before the median filter processing, and the broken lines in the figures show the gray value values of the image after the median filter processing. The distribution curve is shown.

As can be seen from FIG. 18, it is understood that the gray value distribution of both the non-mark portion and the mark portion falls within a narrower range after the median filter processing than before the processing.

That is, in the matching processing, even if the gray level changes uniformly as a whole, it does not affect the result of the matching processing, but the change in the gray level of each pixel greatly affects the score. As described in, if the change in the gray value in each of the non-mark part and the mark part is reduced by the median filter processing,
The stability and accuracy of mark inspection are improved.

As described above, in the mark inspection apparatus according to the embodiment of the present invention, the teaching process is divided into an offline teaching process and an online teaching process, so that IC packages having the same shape (marks at the same positions) can be obtained. Can set the master print position of the reference print pattern and the reference first pin pattern at the time of online teaching by one offline teaching. Therefore, in the mark inspection apparatus of this embodiment, it is not necessary to store teaching data of many types of IC packages, and the storage capacity may be small. Also,
At the time of online teaching, the print mark and the first pin mark, for example, on the first IC package actually stored on the embossed tape 13 are stored as the reference print pattern and the reference first pin pattern. Of the print mark and the pattern of the first pin mark.

In the mark inspection apparatus of this embodiment, 1
By dividing a character into nine parts and comparing and inspecting the character with a reference print pattern, a stable mark inspection can be performed even when the line width of a character or the like changes.

Further, in the mark inspection apparatus of this embodiment,
By changing the processing algorithm of the normal inspection process in the retry inspection, even if a defect is determined when the line width of a character or the like changes, it can be remedied by the retry inspection. Therefore, according to the mark inspection apparatus of the present embodiment, even an IC package in which the mark position is shifted can be determined as a non-defective product, and erroneous determination of a non-defective product as a defective product can be prevented.

[0152]

As is apparent from the above description, in the mark inspection method and apparatus of the present invention, the mark position and the mark range are taught, and at least the image of the mark and its surroundings are taken in. Teach the image pattern of the mark within the corresponding position and range as a reference mark pattern, and inspect the mark to be inspected using the mark position and the mark range and the reference mark pattern. Even if there are many types of ICs or new ICs are developed, the printed marks and first pin marks on the IC package can be easily and accurately recognized, and the inspection can be performed within the time limit. The yield can be improved, and the increase in cost can be suppressed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a mark inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a flow of an offline teaching process.

FIG. 3 is a diagram used to explain a window set for inspecting a print mark and a first pin mark on an IC package.

FIG. 4 is a diagram used to describe a prohibited area.

FIG. 5 is a diagram used for explaining a normal vent.

FIG. 6 is a diagram used for explaining a reverse vent.

FIG. 7 is a diagram used to explain a window set for inspecting a first pin mark on a front vent IC package.

FIG. 8 is a diagram used to describe a window that is set so that a forward vent IC package is not erroneously determined to be a reverse vent IC package.

FIG. 9 is a diagram used to explain a window set for inspecting a first pin mark of an IC package of a reverse vent.

FIG. 10 is a flowchart showing a flow of setting an offline teaching window.

FIG. 11 is a flowchart illustrating a flow of an online teaching process for performing master registration of a reference print pattern.

FIG. 12 is a flowchart illustrating a flow of an online teaching process for performing master registration of a reference first pin pattern.

FIG. 13 is a flowchart illustrating a flow of an inspection process for inspecting one line of a print mark.

FIG. 14 is a flowchart illustrating a flow of an inspection process for inspecting one character of a print mark and a first pin mark.

FIG. 15 is a diagram used to describe a character division area.

FIG. 16 is a flowchart showing a flow of a retry inspection process.

FIG. 17 is a diagram illustrating a specific configuration of a lighting device.

FIG. 18 is a diagram used to explain the effect of image processing by filtering.

[Explanation of symbols]

11 image processing unit, 12 video camera, 1
3 Embossed tape, 14 IC package, 15
Monitor device, 16 operation panel, 17 host computer, 18 storage device, 19 lighting device

Claims (11)

[Claims] 1. A mark inspection method for performing a mark inspection using image processing, comprising: a first teaching step of teaching a mark position and a mark range; an image capturing step of capturing at least an image of a mark and its surroundings; A second teaching step of teaching, as a reference mark pattern, an image pattern of a mark within a position and a range corresponding to the mark position and the mark range, and using the mark position and the mark range and the reference mark pattern, A mark inspection method, comprising: inspecting a mark. 2. The method according to claim 1, wherein the inspection step includes a division inspection step of dividing the image of the mark to be inspected into a plurality of areas and inspecting each of the plurality of divided areas.
The mark inspection method described. 3. The mark inspection according to claim 2, wherein in the division inspection step, the image of the mark to be inspected is inspected for each of nine divided regions obtained by dividing the image of the mark to be inspected into three in the horizontal and vertical directions. Method. 4. When a mark is determined to be defective in the inspection step, a fine mark inspection is performed on the mark determined to be defective in such a manner that the thickness of a line forming the mark and the deviation of the mark position are corrected. 2. The mark inspection method according to claim 1, further comprising a retry inspection step. 5. A mark inspection apparatus for performing mark inspection using image processing, wherein: first teaching means for teaching a mark position and a mark range; image capturing means for capturing at least a mark and a peripheral image thereof; Second teaching means for teaching, as a reference mark pattern, an image pattern of a mark within a position and a range corresponding to the position and the mark range; and storage for storing information on the mark position and the mark range and information on the reference mark pattern. An inspection apparatus for inspecting a mark to be inspected using the information on the mark position and the mark range stored in the storage means and the information on the reference mark pattern. 6. The mark according to claim 5, wherein the inspection unit divides the image of the mark to be inspected into a plurality of regions and performs a division inspection for inspecting each of the plurality of divided regions. Inspection equipment. 7. The division inspection according to claim 6, wherein the inspection is performed for each of nine divided areas obtained by dividing the image of the mark to be inspected into three in the horizontal and vertical directions. Mark inspection device. 8. When the mark is determined to be defective, the inspection means performs a fine mark inspection on the mark determined to be defective by correcting the thickness of a line forming the mark and the deviation of the mark position. 6. The mark inspection apparatus according to claim 5, wherein a retry inspection is also performed. 9. The mark inspection apparatus according to claim 5, further comprising illumination means for illuminating the mark to be inspected and its periphery. 10. The mark inspection apparatus according to claim 9, wherein the illumination means has a plurality of light emitting units, and each light emitting unit is capable of adjusting a light emission amount. 11. The mark inspection device according to claim 9, wherein the illumination device includes illumination position changing means for changing an illumination position.