JP2001050726A - Ic external appearance inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a foreign substance even when defective form of an external appearance exists by detecting the position of a tie bar cut-off part connecting with a lead, masking the tie bar cut-off part, and by such constitution that a foreign substance between the leads around the cut-off part is detected. SOLUTION: A specified lead 201 part in an IC image 102 of an IC photographed by a camera is set as an image processing territory, and it is designated by a data working range window 104. The detecting range of leads is limited by a lead detecting range window 105 to extract a lead 201. The tie bar cut-off part 220 of the lead 201 in the window 104 is detected, and a tie bar cut-off part mask window 106 is set. The window 106 cuts the window 106 projecting parts of the respective leads 201, and a least square line passing through the lead 201 projecting parts is drawn to mask the tie bar cut-off parts 220. The lead edge parts are detected from the lead parts except the mask territory of the window 106, and a projection graph is drawn. The defective form part projection data 108 of the graph shows existence of IC defective form such as a foreign substance 107 between the leads 201.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC appearance inspection method for inspecting an external appearance of an IC, and more particularly to an IC appearance inspection method for inspecting the presence of foreign matter around an IC lead and resin burrs around an IC package (semiconductor device). It belongs to the IC appearance inspection method.

[0002]

2. Description of the Related Art As a conventional lead inspection apparatus, Japanese Patent Laid-Open Publication No. Hei 8-15166 discloses an apparatus for inspecting a cutting state of a diver cutting portion connecting leads of a semiconductor device. In this lead inspection apparatus, a semiconductor device is supported at a predetermined position by a support means, and a lead of the semiconductor device supported by the support means is moved from its plane direction to C.
Observe with a CD camera. Then, the diver cutting portions of the plurality of leads are detected in the width direction from the image observed by the camera to obtain detection data including the number and intervals of the center positions of the leads.

The detected data has image processing means for detecting a non-cut portion in the width direction, comparing the detected data with standard data composed of similar items, and outputting the result.

FIG. 6 shows a specific example of a conventional IC appearance inspection method.
This will be described with reference to FIGS. FIG. 6 (a)
Is an image obtained by photographing the IC image on the background image 500 with the camera based on the X axis and the Y axis. FIG. 6B shows the number of dots. FIG. 6C shows theoretical values.

The lead detection range window 602 is shown in FIG.
As shown in (a), the setting is limited to a range where the tie bar cutting portion 610 does not exist. When the foreign matter 601 and 603 exist between the leads 600, only the foreign matter 603 in the lead detection range window 602 is detected on the projection graph as the defective shape portion projection data 604 shown in FIG. 6B. The lead projection area 607 shown in FIG.
Above, only the poorly shaped projection area 606 is detected as exceeding the allowable width of the lead projection area.

Here, the foreign matter 601 near the tie bar cutting portion 610 is outside the lead detection range window 602, and is not detected in the projection graph or the lead projection area.
Reference numeral 605 in FIG. 6B indicates a projection graph determination reference level.

[0007]

However, the foreign matter 601 near the tie bar cutting portion 610 is outside the lead detection range window 602, and cannot be detected by the projection graph or the lead projection area. Therefore, in the conventional lead appearance inspection method, an IC lead shape defect near the diver cutting portion 610 cannot be detected.

It is therefore an object of the present invention to provide an IC appearance inspection method capable of easily detecting an IC shape defect or resin burr near a tie bar cut portion.

[0009]

According to the present invention, there is provided an IC appearance inspection method for inspecting the presence of foreign matter in a lead, wherein a position of a tie bar cut portion connecting the leads of the semiconductor device is detected. By masking the cut portion of the tie bar, an IC appearance inspection method can be obtained, wherein a foreign substance existing between the leads around the cut portion of the tie bar is detected.

[0010]

According to the present invention, in order to inspect the external shape of an IC, in particular, the presence of foreign matter on an IC lead, the position of the tie-bar cut portion is detected and the tie-bar cut portion is accurately masked. It is possible to detect foreign matter between leads.

[0011]

1 (a) to 1 (d) show a first embodiment of an IC appearance inspection method for inspecting the presence of foreign matter on an IC lead. FIG. 1A shows an IC image projected based on the X axis and the Y axis. FIG. 1B shows a lead detection range window. FIG. 1 (c)
Indicates the number of dots and defective shape partial projection data. FIG. 1D shows a theoretical value and a shape defective projection area.

Referring to FIG. 1A, the IC appearance inspection method according to the first embodiment employs an IC photographed image 101 photographing an IC package (semiconductor device) 100. The IC image 101 is an IC on the background image 103.
This is an image obtained by shooting the image 102 with a camera, and the IC image 102 is detected by shooting an IC with the camera. The data processing range window 104 is a window for designating a specific lead 201 portion in the IC image 102 as a region for image processing. The data processing range window 104 cuts out and extracts only a predetermined number of leads 201 from the IC image 102.

A lead detection range window 105 shown in FIG. 1 (b) is a window for designating a narrower range of the lead 201 to a detecting means such as pattern matching in a data processing range window 104 in which a range is broadly specified. The lead 201 is extracted by limiting the range to the detection range of the IC lead in the data processing range window 104.

In FIG. 1B, the tie bar cutting portion 220 of the lead 201 is detected for the lead 201 captured in the data processing range window 104, and the tie bar cutting portion mask window 106 is set. If there is a defect in the appearance of the IC, for example, the foreign matter 10 between the leads 201
7 may adhere to the lead 201. The tie bar cutting portion mask window 106 cuts out the tie bar cutting portion assumed range from each lead 201 in the lead detection range window 105, detects the tie bar cutting portion assumed center position of each lead 201, and displays the tie bar cutting portion assumed center position on all the leads 201 in one side. , A tie bar cutting portion assumed center position within a certain range is cut out, a tie bar cutting portion center least square line passing through those points is drawn, and coordinates on the tie bar cutting portion 120 center least square line passing through the intermediate point of each lead 201 are obtained. Is a window in which a mask area is generated around the tie bar center coordinates.

In FIG. 1 (c), from the IC lead image captured in the lead detection range window 105, the lead portion excluding the area masked by the tie bar cutting portion mask window 106 is read by edge extraction processing. An edge portion is detected, and a projection graph is drawn by accumulating luminance values in the Y-axis direction for each coordinate on the X-axis and forming a graph.

The defective-shape portion projection data 108 shown in FIG. 1C is obtained by performing edge extraction processing on each lead 201 excluding the area masked by the tie bar cutting portion mask window 106 in the lead detection range window 5, FIG. 6 shows a cumulative waveform of the luminance value of each lead 201 when the luminance value is accumulated in the Y-axis direction for each coordinate on the axis.

The defective shape partial projection data 108 is
In the projected graph showing the shape of each lead 201,
The projection data reflects an IC shape defect such as the foreign matter 107 between the leads 201 and indicates the existence of the defect. The projection graph criterion level value 109 indicates a threshold level for indicating a range in which a lead exists.

The lead projection area 110 shown in FIG.
Is the defective shape partial projection data 108 shown in FIG.
In FIG. 7, when a portion reaching the projection graph determination reference level value 109 is set to the logical value 1 and a portion not reaching the logical value is set to the logical value 0, the area on the X-axis of each lead is shown.

The lead projection area 110 is the lead 2
01 is defective in the projection area 1 by the lead width.
Since the output is performed with the width to which 11 is added, the presence of the lead shape defect is detected because the width exceeds the specified range.

In this manner, the tie bar cutting portion of each lead 201 is cut out, and the protruding portion of the mask window 106 is cut out, and the least square line passing through the protruding portion of each side of the lead 201 on the IC package 100 is drawn to cut the tie bar. Since the arrangement of the parts 220 is specified and the tie bar cutting parts 220 of each lead 201 are masked, even if the foreign matter 107 between the leads 201 exists around the tie bar cutting parts 220,
It can be detected as a lead shape defect.

In FIG. 1D, the lead projection area 110 shown in this graph is a portion where the data indicating each lead 201 of the projection graph shown in FIG. Is the logical value of 1 and the logical value of the portion not reached is the logical value 0, the range in which each lead 201 exists is shown from the detected logical value of the projection graph in the X-axis direction.

When the foreign matter 107 exists between the leads 201, the foreign matter 107 is represented on the graph as a part of the shape defect projection area 111 on the graph.

Next, in FIG.
From 1, when a boundary portion between the background image 103 and the lead 201 is detected, the lead edge portion 202 is detected. FIG.
3B, a dXY graph for detecting a dX component differentiated in the X-axis direction of the lead edge portion 202 is displayed. In FIG. 2 (c), a histogram diagram in which dots on the dX-Y graph are accumulated in the Y-axis direction for each coordinate of the dX-axis is drawn, and a dot peak value which is a dX value at which the number of dots on the graph becomes maximum. 203.

In FIG. 2D, dX shown in FIG.
On the −Y diagram, the plus side effective range 205 where the dX value is allowed to be on the plus side with respect to the dot peak value 203.
And only the read edge coordinates between two values of the minus effective range 204 allowed on the minus side with a width up to n are registered as effective data.

In FIG. 2E, only the read edge coordinates registered in FIG.
-A lead edge least square line 209 which is a least square line on the Y coordinate is drawn. A straight line (Y = αX + β + m) obtained by shifting this straight line (Y = αX + β) by a fixed amount to the plus side of the X axis.
, And a negative lead edge allowable width (straight line) which is a straight line (Y = αX + β−m) obtained by shifting the straight line 209 (Y = αX + β) to the minus side of the X axis by a fixed amount. 207 is set.

A region sandwiched between the allowable widths 207 and 208 of these straight lines is regarded as a linear portion in the longitudinal direction of the lead, and a tie bar cutting which is a continuous region deviating from the allowable widths (straight lines) 207 and 208 on the linear region is performed. The part assumed range 206 is regarded as an area where the tie bar cutting part 220 exists.

The detection of the linear region in the longitudinal direction of the lead and the region where the tie bar cutting portion 220 exists, which is detected in FIGS. 2A to 2E, is performed on the left and right of one lead 201. The same detection is performed for all the leads 201 in the range window 105.

Next, FIGS. 3A to 3C will be described. In FIG. 3A, a tie bar cutting portion assumed range 20 is determined based on information on the linear region in the longitudinal direction of the lead 201 and the region where the tie bar cutting portion 220 exists, which is detected in FIG.
The lead edge coordinates at the intermediate position in the Y-axis direction of No. 6 are set as the assumed center position 301 of the tie bar cutting portion. This is set for all leads 201. At this time, lead 20
Similarly, when there is a lead shape defect such as one foreign substance 107, the inter-lead foreign substance center position 302 is detected as a candidate for the tie bar cutting unit 220.

In FIG. 3B, the candidate center positions of all the tie bar cutting sections 220 detected in FIG. 3A are accumulated in the X-axis direction for each Y-axis coordinate. Plot on a graph. A portion where the continuation of the number of dots is maximum is detected on this graph, and a continuation range of the set of dots is cut out as a tie bar cutting portion assumed center position effective range 303. At this time, if the lead shape defect such as the foreign matter 107 between the leads 201 is not near the tie bar cutting portion 220, the lead shape defect is located at a position outside the tie bar cutting portion assumed center position effective range 303 on the graph shown in FIG. Is detected.

In FIG. 3C, the tie bar cutting is a least-squares straight line for all the tie bar cutting part assumed center positions 301 existing in the tie bar cutting part assumed center position effective range 303 in FIG. 3B. Part center position least squares straight line 3
Subtract 05.

A point on the X-axis of the assumed center position 301 of the left and right tie bar cutting portions on each lead 201 and a point on the least squares straight line 305 of the center position of the tie bar cutting portion is defined as a tie bar portion center coordinate 304. , All leads 20 within the detection range
Ask about 1.

The tie bar cutting portion mask window 106 in the range of x1 dot × y1 dot which is set in advance around the tie bar cutting portion center coordinates 304 on each lead 201 is set for all the target leads.

Next, FIG. 4 will be described. FIG. 1 (b)
The tie bar cutting portion mask window 106 set in the above is set as a non-detection target region, and the lead detection range window 105
The image after the edge extraction processing in FIG. 4 is obtained by performing the edge extraction processing on the lead image in FIG.

The configuration of the embodiment has been described in detail above.
FIG. 1C shows the projection processing, FIG.
The histogram conversion shown in FIG. 3C, the histogram conversion shown in FIG. 3B, and the edge extraction processing shown in FIG. 4 are well known to those skilled in the art, and are not directly related to the present invention. .

The operation of the IC appearance inspection method according to the first embodiment will be described with reference to FIGS.

FIG. 1B shows the lead detection range window 1.
Each lead captured in 05 is divided into the left and right sides of the lead in FIG. 2 (a), and the lead edge is detected. In FIG. 2 (b), the differential data of the X coordinate is detected, and the differential is detected in FIG. 2 (c). A protruding point of the amount of displacement in the X direction indicating a linear part of the lead is detected from the data.

FIG. 2D specifies a range around the projected point of the detected X-direction displacement amount, which is regarded as a linear range of the lead 201. A least-squares straight line is drawn using the data on the straight line range specified in FIG. 2E, a range that can be regarded as a straight line on the lead 201 is designated, and a portion outside the range is set as a tie bar cutting section assumed range 206. To detect.

In FIG. 3A, all candidate points of the tie bar cutting unit 220 are plotted as the assumed center position 301 of the tie bar cutting unit, and the tie bar cutting unit 220 determines the X-axis direction histogram of the dots detected in FIG. 3B. The existing position is specified as a continuous mountain of dots, and the tie bar cutting unit 220
By limiting the range in which there is, a lead shape defect that becomes another noise component is identified.

The least square straight line is drawn by using only the tie bar cutting portion assumed center position 301 within the effective range 303 of the tie bar cutting portion assumed center position previously specified in FIG. Then, the lead shape defect such as the foreign matter 107 between the leads 201 is separated. The tie bar part center coordinates 304 are specified from the tie bar cutting part center least square line and the left and right edge points of the tie bar cutting part 220,
The tie-bar cutting portion mask window shown in FIG. 1B is set on all the leads 201 within the target range with that point as the center.

After masking the cut portion of the tie bar, an edge extraction process is performed in the lead detection range window 105 in FIG. 4 to raise the outline of the lead and the defective lead shape.

The edge extracted image detected in FIG.
Accumulate in the axial direction to obtain a projection graph.

At this time, since the tie bar cutting portion 220 is masked, even if the foreign matter 107 between the leads 201 around the tie bar cutting portion 220 protrudes near the same X coordinate position as the tie bar cutting portion 220, the projection image Above.

FIG. 1D shows the detection of the projection area 110 of each lead based on whether or not the projection graph judgment reference level 109 on the projection graph has been reached.
The lead 201 is determined based on whether or not the width of the reference numeral 10 exceeds the specified range.
It is possible to detect the presence of the foreign matter 107 between them. The above process is performed for each side of the lead 201.

FIGS. 5 (a) to 5 (d) show the I of the present invention.
C shows a second embodiment of the appearance inspection method.
The basic configuration according to the second embodiment is the same as that of the first embodiment, and the configuration of the first embodiment further differs from the configuration of the first embodiment in terms of other IC lead shape defects, in particular, IC package molding. The device is designed so that the appearance of the resin burr 504 can be inspected.

In FIG. 5A, the IC package 10
IC package position detection area 503 for grasping the position of 0
Are set at the upper left and lower right positions of the package 100.
Based on the position of the IC package 100 detected by the IC package position detection area 503, the resin
5 is set. Other parts are the first described above.
This is the same as the embodiment.

Next, the operation of the IC appearance inspection method according to the second embodiment will be described with reference to FIGS.

In FIG. 5A, the IC package 10
In the case where the resin burr 504 exists at the end of the mold portion on the zero, the I registered in advance by the pattern matching process
An IC package position detection area 503 is set at a position matching the upper left and lower right model images of the C package 100, and the position of the IC package 100 is accurately detected. IC package 10 detected at upper left and lower right
The resin burr mask range 505 is set based on the position of 0, and the resin burr 504 within the mask range is set to be allowed.

In FIG. 5B, the lead detection range window 506 is set so as not to detect the area within the resin burr mask range 505. The portion of the resin burr 504 within the resin burr mask range 505 is not detected.

Further, the resin burr 504 in the tie bar cutting portion mask window 507 set in the same manner as in the previous embodiment is also excluded from detection. At this time, the resin burr 50
4 is a lead 2 whose brightness as an image is plated with solder.
Since it is lower than 01, it has no effect on the read edge detection.

In FIG. 5C, the resin burr 504 existing outside the upper two mask regions is detected in the form of defective shape part projection data 509 as in the previous embodiment.

In FIG. 5D, the lead projection area 512 where the resin burr 504 is present is
Is detected in the form of the shape-defective projection area 511, and the lead projection area for two leads is connected to one, and exceeds the allowable width of the set lead projection area.
The presence of an IC lead shape defect is detected.

As described above, in the first and second embodiments, since the resin burrs near the tie bar cutting portion and the IC package are masked, the tie bar cutting portion 220, the IC package, and the resin within an allowable range are masked. The resin burr inspection can be performed without erroneously recognizing the burr 504.

[0053]

As described above, the present invention has the following effects.

The first effect is that since the inspection is performed by masking the tie-bar cut portion, it is possible to detect even the appearance defect in the vicinity of the tie-bar cut portion.

The second effect is that the position of the tie-bar cutting portion is detected for each IC and the area to be masked is set. Inspection can be performed without erroneously recognizing a shape defect.

The third effect is that the position of the tie bar cutting portion is detected from the arrangement of the tie bar cutting portions of the entire lead arranged on each side.
Even when a lead shape defect exists, an IC lead shape defect is erroneously recognized as a tie bar portion, and the defect can be inspected without missing.

[Brief description of the drawings]

1A and 1B show a first embodiment of an IC appearance inspection method of the present invention, wherein FIG. 1A shows an IC projection image, FIG. 1B shows a lead detection window, and FIG. FIG. 3D is a diagram showing partial projection data, and FIG. 4D is a diagram showing a theoretical value and a shape-defective projection region.

2A and 2B show a first embodiment of an IC appearance inspection method according to the present invention, and FIG. 2A is a diagram showing a lead edge portion;
(B) is a projection view displaying a dX-Y graph for detecting a dX component differentiated in the X-axis direction of the lead edge portion,
(C) is a histogram diagram in which dots on the dX-Y graph are accumulated in the Y-axis direction for each coordinate of the dX-axis, and (d) is a plus-side effective range on the dXY diagram of (b). It is a figure which shows the negative side effective range, (e) is XY of (a) targeting only the lead edge coordinate registered at (d).
It is a figure which shows the lead edge least square line which is a minimum square line on a coordinate, the plus side lead edge allowable width, and the minus side lead edge allowable width.

3A and 3B show a first embodiment of an IC appearance inspection method according to the present invention, in which FIG. 3A is a diagram showing an assumed center position of a tie bar cut portion and a center position of foreign matter between leads, and FIG. (C) is a diver cutting part center position minimum 2
It is a figure which shows a square and a tie-bar part center coordinate.

FIG. 4 is a diagram illustrating an IC appearance inspection method according to the first embodiment of the present invention and illustrating an image after edge extraction processing.

5A and 5B show a second embodiment of the IC appearance inspection method of the present invention, wherein FIG. 5A shows an IC image, FIG. 5B shows a lead detection window, and FIG. FIG. 3D shows projection data, and FIG. 4D is a diagram showing a theoretical value and a shape defective projection area.

6A and 6B show a second embodiment of an IC appearance inspection method according to the present invention, wherein FIG. 6A is an image obtained by photographing an IC image on a background image by a camera based on X and Y axes, and FIG. Shows the number of dots, and (c) shows a theoretical value.

[Explanation of symbols]

 Reference Signs List 101 IC photographed image 102 IC image 103 Background image 104 Data processing range window 105, 602 Lead detection range window 106 Tie bar cut portion mask window 107, 601, 603 Foreign matter 108 Defective shape partial projection data 109 Projection graph judgment reference level value 111 Shape Poor projection area 201,606 Lead 203 Dot peak value 205 Positive side effective range 204 Minus side effective range 206 Assumed range of tie bar cutting part 207 Minus side lead edge allowable width 208 Positive side lead edge allowable width 220,610 Tie bar cutting part 301 Tie bar cutting Assumed center position of part 302 Center position of foreign matter between leads 303 Effective range of assumed center position of tie bar cutting part 304 Center coordinate of tie bar part 305 Least square straight line of center position of tie bar cutting part 503 C Package position detection region 504 resin burr 505 resin Barimasuku range 506 read the detection range window 604 defective shape partial projection data 607 read projection region

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2F065 AA02 AA03 AA12 AA17 AA49 AA51 CC27 FF04 FF42 QQ00 QQ03 QQ04 QQ13 QQ17 QQ18 QQ21 QQ25 QQ27 QQ28 QQ29 QQ32 QQ36 QQ37 QQ38 QQ43 AQA QEA EA1A EB01 EB02 EC02 ED01 ED07 ED23

Claims (6)

[Claims] In an IC appearance inspection method for inspecting foreign matter existing between leads and around a semiconductor device, a position of a tie bar cut portion connecting the leads is detected, and the tie bar cut portion is masked. And detecting the foreign matter in the vicinity of the cut portion of the tie bar. 2. The IC appearance inspection method according to claim 1, wherein, after masking the tie bar cutting portion, an edge extraction process is performed in a lead detection range window for designating an existing range of the lead, and the lead and the lead shape are formed. A lead projection area is detected based on whether or not a projection graph judgment reference level value on a projection graph on which an edge extracted image in which a defective contour portion has been detected is accumulated is detected, and the width of the projection area for each lead exceeds a specified range. Detecting the presence of the foreign matter based on whether or not the IC is present. 3. The method of claim 2, wherein the X-coordinate differential data is detected by detecting a lead edge for each of the left and right sides of the lead captured in the lead detection range window. A protruding point of the displacement in the X direction indicating a linear portion of the lead is detected from the data, and a range to be regarded as a linear range of the lead is specified with the protruding point of the detected displacement in the X direction as a center. A least-squares straight line is drawn using the data on the straight line range, a range that can be regarded as a straight line on the lead is specified, and a portion outside the range is detected as the diver cutting portion assumed range. All the candidate points of the tie-bar cutting portion are plotted as the assumed center position, and the position where the tie-bar cutting portion exists is determined from the histogram of the detected dots in the X-axis direction. The tie-bar cutting portion located within the effective range of the tie-bar cutting portion assumed center position previously specified is separated by limiting the range in which the tie-bar cutting portion is present, thereby isolating a lead shape defect that is another noise component. A least-squares straight line is drawn using only the assumed center position as an effective dot, the tie-bar cutting portion is separated from the foreign matter and the lead shape defect, and the tie-bar center coordinate is set to the tie-bar cutting portion center least-squares straight line and the tie-bar cutting portion An IC appearance inspection method characterized by specifying from left and right edge points, and setting a tie bar cut portion mask window to all leads within a target range around the point. 4. The IC appearance inspection method according to claim 2, wherein said lead detection range window is narrowly designated by a detection means such as tapan matching in a data processing range window having a wide range designated. An IC appearance inspection method, wherein the lead is extracted by limiting the range of the lead detection range in the data processing range window. 5. The IC appearance inspection method according to claim 1, wherein when the resin burr exists at an end of a mold portion on the semiconductor device, an upper left and a right of the semiconductor device registered in advance by a pattern matching process. A position detection region is set at a position matching the lower model image, and a resin burr mask range is set based on the position of the semiconductor device detected at the upper left and lower right.
C appearance inspection method. 6. The IC appearance inspection method according to claim 5, wherein the lead projection area of the portion where the resin burr is present is detected in the form of a defective shape projection region of the resin burr portion. IC appearance inspection method.