JPH08194735A - Plural pattern simultaneous measuring device - Google Patents

Abstract

PURPOSE: To arbitrarily overlap and display front, back and through patterns, to mutually collate them and to highly precisely measure dimensions on the micro pattern of a lead frame. CONSTITUTION: A plural pattern simultaneous measuring device inputs the image of the lead frame which is etching-worked, coverts the image data into CAD data and overlaps and displayed more than two CAD data. The image of the front pattern and the back pattern of the lead frame are set to be reflected images under a vertical light source and the image of the through pattern is set to be a transmission image under a downward illumination light source. The images are inputted, are raster/vector-converted and respective pieces of input image data are converted into CAD data. CAD data of the back pattern whose image pick up direction is inverse is inverted. Then, they are positioned and overlapped and they are displayed on a screen like (B), (C), and (D).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a design pattern of an etching product, an etching pattern of a product manufactured based on the design pattern, and an original plate and a plate-making pattern used during the manufacture of the product, which are optionally computer-generated. Simultaneous measurement of multiple patterns that can be used effectively for product design and quality control based on the data obtained by comparing each other by overlapping display on the screen, and can properly perform etching condition management and etching correction. Regarding the device.

[0002]

2. Description of the Related Art ICs to be mounted as etching products
There is a lead frame used to electrically connect to the (integrated circuit) chip.

FIG. 17 shows an example of a lead frame for one chip as viewed from one side. A die pad (island) 10 for mounting a chip (not shown) is located at the center of the lead frame. The die pad 10 is supported by an outer frame 12 via a tab suspension bar 14, and an inner lead 16 is arranged around the die pad 10 with its tip close to the die pad 10, and an outer lead continuous with the inner lead 16 is provided. 18 is the above-mentioned outer frame 1 via the dam bar 20 etc.
Supported by 2. Also, the inner lead 16 has
A fixing tape 22 made of plastic is attached to prevent deformation of the leads 16. The broken line in the figure is the mold line.

Taking the lead frame as an example, an outline of the steps from etching product design to product completion is shown in FIG.
It becomes like 8.

CAD of lead frame pattern design
(Computer Aided Design), first, CAD data of the same product (A) as the target product size is created in the product pattern design process of CAD1, and then the actual etching is performed in the etching correction process of CAD2. The correction allowance for the side etching, which is excessively removed from the width of the resist pattern in the process, is defined as (A) product dimension C above.
(B) Machining dimension CAD data that is the prototype of the resist pattern is created by adding it to the AD data, and this machining dimension CAD data is drawn by a laser plotter in the next pattern manufacturing process, and the drawn pattern is printed on a glass plate. (C) A glass original plate pattern is created. This original plate pattern is created for both the front and back surfaces of the lead frame.

Then, using the glass original plate as a mask, the resist coated on the metal material such as the copper plate which is the base material of the lead frame is exposed (baked),
By developing and burning (curing) (D) to form a plate-making pattern (resist pattern), etching for removing the metal material in the exposed portion is performed, and then the adhering resist is peeled off. A lead frame, or (E) product pattern is obtained.

In the manufacturing process of the lead frame,
The (E) product pattern is preferably the same as the (A) product dimension CAD data which is the design pattern. Therefore, (B) processing dimension CAD data (this is (C) glass original plate pattern, which is designed by adding a correction allowance to this (A),
The size difference between (D) the pattern having the same size as the plate-making pattern) and (E) above is large, and usually has a difference of several tens of μm.

Similarly, as another etching product to be microfabricated, there is a shadow mask for a color television. In comparison with this, the lead frame has an irregular shape and the post-process performed after the etching is complicated. It has the feature of being

Further, as a feature of the lead frame, there is a gap (space to be removed by etching) between the island 10 to which the chip is attached and the tip of the inner lead to be wire-bonded, and the etching liquid easily enters there. The etching of the tip portion of the inner lead is likely to proceed and the tip tends to be tapered, but a sufficient tip width is required for wire bonding.

As described above, the lead frame is normally formed on both front and back surfaces with symmetrical resist patterns through exposure and development, and the surface on the side of the die pad to which the IC chip is attached faces downward, as shown in FIG. Metal plate 24
And the resist pattern 26 adhered to the front surface (the lower side in the figure) and the back surface, as shown in a partially enlarged view, the etching solution is sprayed from both upper and lower directions to etch the metal plate 24A in the non-resist portion. It is formed by removing. The reason for etching with the surface on the lower side is that the upper side is more likely to be side-etched while it is necessary to secure a sufficient width on the surface for wire bonding near the tips of the inner leads.

Therefore, when the resist 26 having the pattern shown in FIG.
As indicated by 0 (B) for the front surface pattern A, the back surface pattern B, and the penetrating pattern C, an under-etching defect may occur in which the surface opening width is larger than the minimum penetrating width. Generally, the cross-sectional shape of the etching pattern is shown in FIG.
As shown in (C), the penetration width is minimized on the surface (lower surface in the figure), and the minimum penetration width and the opening width of the surface match.
= C is preferable. In an extreme case, FIG.
As shown in (D), defective lead deformation may occur due to misalignment of the front and back registration of the resist pattern 26.

Further, for example, in order to mark characters on the outer frame of the lead frame, as shown in FIG. 21A, a resist pattern 26 is formed on only one side, and a through hole as shown in FIG. 21B is formed. Not form an etching pattern D,
So-called half-etching is also performed, but a defect that the half-etched portion penetrates may occur.

The penetration pattern shown in FIG. 20 and FIG.
The inspection of the quality of the half etching pattern shown in 1 is
Conventionally, (1) a method of individually measuring the front surface, the back surface, and the penetration with a microscope or the like, and (2) a method of cutting the measurement portion to locally measure the cross-sectional shape.

[0014]

However, in the above-mentioned (1) individual measurement of each part by a microscope or the like, it is difficult to grasp the difference in the front and back dimensions of the opening width and the difference between the opening width and the penetration width under a quick glance. In addition, in the local measurement of (2), since it is not possible to look over a wide area, the positional relationship in the whole is unknown, and the position is marked on the design drawing every time measurement is performed.
It needs to be specified. There is also a dimension measuring microscope, but only the penetrating dimension can be measured. Although it is not intended for measurement, there is a double-sided simultaneous observation microscope that can display observation images on both front and back sides separately on two monitors, but it is difficult to grasp the difference in front and back dimensions.

The present invention has been made to solve the above-mentioned conventional problems. For fine patterns of etching products, the front / back and penetrating patterns are arbitrarily combined, displayed in an overlapping manner, and collated with each other. An object of the present invention is to provide a simultaneous measurement apparatus for a plurality of patterns that can measure the dimensions.

[0016]

The invention according to claim 1 is provided with image input means for inputting an image of a product pattern subjected to etching processing, and raster vector conversion means for converting the input image data into CAD data. At the same time, a plural-pattern simultaneous measuring device having a function of superposing and displaying two or more CAD data, wherein the image input means inputs the image of each of the front surface pattern and the back surface pattern of the product pattern as a reflection image under an epi-illumination light source, The above problem is solved by providing a function of converting each input image data into CAD data by the raster / vector conversion means, inverting one of the CAD data, and superimposing them on each other. is there.

According to a second aspect of the present invention, in the plural-pattern simultaneous measurement apparatus, an image input means for inputting an image of a product pattern subjected to etching processing, and a raster / vector conversion means for converting the input image data into CAD data. A multi-pattern simultaneous measurement device having a function of superimposing and displaying two or more CAD data together with
By the image input means, one of the front surface pattern and the back surface pattern of the product pattern is input as a reflection image under an epi-illumination light source, and the penetration pattern is input as a transmission image under a transmission light source, and each input image data is rasterized. By converting to CAD data by the vector converting means and inverting one of the CAD data when the image capturing directions of both patterns are opposite to each other and superimposing them on each other, Similarly, the above problem is solved.

According to a third aspect of the present invention, in the plural-pattern simultaneous measurement device, an image input means for inputting an image of a product pattern subjected to etching processing, and a raster / vector converting means for converting the input image data into CAD data. A multi-pattern simultaneous measurement device having a function of superimposing and displaying two or more CAD data together with
By the image input means, both the front surface pattern and the back surface pattern of the product pattern as a reflection image under the epi-illumination light source,
The penetration pattern is input as a transmission image under a transmission light source, each image is input, each input image data is converted into CAD data by the raster vector conversion means, and a front surface pattern or a back surface pattern whose image capturing direction is opposite to the penetration pattern is taken. CA
The above problem is similarly solved by inverting the D data so as to have a function of superimposing the three elements on each other.

[0019]

According to the first aspect of the present invention, the reflection images of the front surface pattern and the back surface pattern are respectively input as images and converted into CAD data composed of vector data, and at the same time, one of the CAD data is inverted and superimposed on each other. Therefore, it is possible to align the two patterns having the opposite image capturing directions with each other on the CAD device and accurately superimpose them.

Therefore, if it is a lead frame, 1 IC
It is possible to display on the screen a state in which both patterns are overlapped in units of chips etc., and it is possible to visually recognize the dimensional difference between the front and back side double side patterns, and it is also possible to perform zooming, scrolling, etc. Both patterns can be viewed and compared over the entire length, and dimension measurement can be performed while zooming if necessary.

According to the second aspect of the present invention, similarly, the front surface pattern or the back surface pattern, which is a reflection image, and the penetrating pattern can be accurately superimposed on the CAD device and displayed on the screen. In addition, it is possible to easily visually recognize the difference in size between the two.

According to the third aspect of the present invention, both the reflection image of the front surface pattern and the back surface pattern and the transmission image of the through pattern are converted, and the converted CAD data is inverted for the pattern whose image capturing direction is opposite. Since the three persons are superposed on the CAD device, it is possible to display these three patterns on the screen in the same manner in a precise superposition.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of a CAD system (simultaneous measurement apparatus for a plurality of patterns) according to an embodiment of the present invention.

The CAD system is a sample (actual product)
A sample mounting device 30 for mounting a sample, an optical microscope 32 for enlarging a sample set in the mounting device 30, a CCD camera 34 for receiving an image observed by the microscope 32 and converting it into a color video signal, and the CCD An image processing device 36 for processing a color video signal from the camera 34,
A TV monitor 38 capable of color-displaying image data processed by the image processing device 36, and a raster / vector conversion function for generating CAD data from image data input from the image processing device 36 in addition to a normal drawing function. Or 2
An engineering workstation (EW) that constitutes a CAD device having the functions of superposing the above CAD data, mutual positional movement (shift) between them, and dimension measurement.
S) 40.

Further, in the above CAD system, the sample mounting apparatus 30 includes a manual rotary stage 42 having a sample mounting portion (not shown), an XY stage 44 for moving the sample in the plane direction, and a sample in the vertical direction. The XY stage 44 and the Z stage 46 are configured to move, and the XY stage 44 and the Z stage 46 operate by receiving a command from the workstation 40 via the interface RS232C.
The Y stage controller 48 and the auto focus controller 50 are driven and controlled respectively. Further, a laser position detector is attached to the XY stage 44, and the position measurement in the XY directions is performed by a laser scale counter 52 which is also operated by a command from the workstation 40, and the measured value is fed back to the workstation 40. Then, the position measurement value of the XY stage 44 is corrected by the XY stage controller 48.

Further, the autofocus controller 5 described above
An image signal used for autofocus is directly input to CCD 0 from the CCD camera 34, and an autofocus monitor (not shown) separately provided with an image captured through the microscope 32. It is possible to directly view the image on the TV monitor 38 from the autofocus controller 50 by using the monochrome (B /
The video signal of W) is input.

FIG. 2 shows the mounting device 30 and the optical microscope 3.
2 is a perspective view showing the appearance of the CCD camera 34 and the CCD camera 34,
The XY stage 44 shown in FIG.
An X drive motor 54 which is composed of an A stage and a Y stage 44B and is connected to the stage controller 48.
The A and Y drive motors 54B are movable in the X and Y directions, and the rotary stage 42 for mounting the sample is mounted on the Y stage 44B so that it can be manually rotated.

Further, the X stage 44A and the Y stage 44
Scale patterns 56A and 56B each made up of a fine diffraction grating are attached to the side surface of B, and laser light is used to scale the positions of both stages 44A and 44B moved by the X drive motor 54A and Y drive motor 54B. , 56B are provided with an X position detector 58A and a Y position detector 58B for irradiating and detecting the laser scale counter 5B.
Connected to 2.

Further, the Z stage 46 is arranged below the X stage 44A, and the Z stage 46 can be moved back and forth in the vertical direction by a Z drive motor 54C. It is connected to the auto focus controller 50, and the distance between the objective lens 32A of the optical microscope 32 and the sample is increased or decreased based on a control signal from the controller 50 to perform auto focus on the microscope 32. There is.

Below the Z stage 46, a transmissive light source unit 60 which also functions as a support is arranged.
0 has a built-in transmissive light source (not shown) that projects light from below onto the microscope 32, and a transmissive light source switch 60A and a light amount adjusting volume 60B are attached to its side wall.

Further, an epi-illumination light source unit 62 is attached to the microscope 32, an epi-illumination light source (not shown) is built in the unit 62, and an epi-illumination light source switch 62A and a light quantity adjusting volume 62B are provided on a side wall of the unit 62. And are attached.

Therefore, when capturing the microscopic image of the sample with the CCD camera 34, it is possible to use at least one of the light source of transmission and epi-illumination.

Next, the image processing device 36 will be described with reference to FIG.
The features of the configuration and the processing function will be described. The processing device 36 has an image input / processing / binarization processing function, for example, S manufactured by Seiko Denshi Kogyo Co., Ltd.
V-2110 (trade name) can be used.

The image processing device 36 is a CCD camera 3
Each of the R (red), G (green), and B (blue) signals input from 4 can be stored for each screen, and 3 for R image, G image, and B image each surrounded by a rectangle are stored. Monochrome memory for storing one frame memory and Y (luminance) signal
One frame memory for W image and H obtained by processing the R, G, B signals by a 3 × 3 matrix operation unit
(Hue), S (saturation), and V (luminance) image data are stored in the three frame memories for each image of H, S, and V, and the R signal and B signal are processed by the image arithmetic operation unit. A total of eight frame memories of the RB difference image frame memory that stores the difference image data of both obtained as described above are provided.

The reason why such different color signals are used is as shown in the table of FIG. 4 for the actual sample (actual pattern).
Depending on the material used and the type of image required, the type of light source suitable for use and the optimum color signal may differ.

That is, there are two types of original patterns, one for the front side and the other for the back side of the lead frame, both of which are glass dry plates (the pattern is formed of an opaque film on the glass plate), so that a black and white transmission image is obtained. The frame memory of the B / W image is the optimum plane because it can be obtained with good contrast.

Further, since the plate making pattern is a resist pattern formed on the front and back surfaces of the lead frame,
It depends on the type of metal material and the type of resist, and it is necessary to use a reflected light source to receive the reflected image.

When casein is used as the resist, since the resist has a reddish color at the stage of heat curing after development, the 42-alloy material of silver-white is used as the optimum plane for the B image frame. Although a memory can be used, the copper (Cu) material itself has a reddish color, and the difference is not clear in the B image. Therefore, the frame memory of the V image is the optimum plane.

When a blue-based dry film is used as the resist, the R image is optimal for 42 alloy, but the frame memory for the RB difference image is optimal for copper material.

In the case of the product pattern after the etching is completed and the resist film is removed, the penetrating transmission image and the reflection images on both the front and back surfaces can be received, and the transmission image is black and white as described above. / W when the image is a reflection image, H
(Hue) The image becomes the optimum plane.

Further, among the product patterns, when the fixing tape 22 (denoted as TP in the table) made of polyimide resin is attached to the inner lead as shown in FIG. 18, the tape is red. Since the transparency is high in the system, in order to obtain a completely transparent image where the image is not input on the tape, B
The / W image becomes the optimum plane. However, it is necessary to appropriately set a threshold value for binarization described later.

On the other hand, in order to capture a transmission image including a tape, blue which is opaque to the tape is suitable, so the B image becomes the optimum plane.

Furthermore, when only the tape portion is desired to be photographed, the H image becomes the optimum plane for the reflected image using the epi-illumination light source.

As described above, when the optimum plane to be used is selected according to the object to be captured as an image, the corresponding image signal is input to the binarization processing section from the eight frame memories. Binarization processing is performed on the image data input by the binarization processing unit. The threshold value set at that time can be arbitrarily set from the gradation values of 0 to 255, for example.

Morphology processing for removing black spots or white spots on the image caused by fine roughness of the surface of the actual pattern, etc. on the image data binarized by the binarization processing section. I do. However, in the case of a transmission image, such a spot does not occur, so that it is not necessary to perform it.

Whether the spot to be removed is white or black is set, a predetermined number of morphologies is set, and the image is expanded / contracted the number of times to remove the spot.

Next, the binary image obtained by performing the above processing is the workstation 4 functioning as a CAD device.
0, where the binary image is processed by the raster / vector conversion unit and converted into CAD data. As the workstation 40, normal CAD software and actual matching CAD software (for example, CAD manufactured by Computer Vision Co., Ltd.)
It is possible to use, for example, Sparc Station 10 (trade name) of Sun Microsystems, which is activated by software Medusa (trade name).

The raster / vector conversion unit converts a general outline of CAD data and a method of converting image data in a white or black area into CAD data in a trapezoidal area, although detailed description thereof will be omitted. There is. When the signal conversion processing is performed by this raster / vector conversion unit, the RV vertex thinning coefficient for determining the accuracy of linear approximation is set. The smaller this coefficient is, the less jagged the line is in the case of the outline, and the finer the trapezoid can be extracted in the case of the trapezoid area.

Further, when either one of the above two conversion methods is selected and the trapezoidal area conversion method is selected,
It is necessary to select either white or black and determine the target area for trapezoidal area processing.

In the CAD system of this embodiment, the image input means further causes both the front surface pattern and the back surface pattern of the lead frame to be a reflection image under an epi-illumination light source, and the penetrating pattern to be a transmission image under a transmission light source. Each image is input, each input image data is converted into CAD data by the raster / vector conversion means, and the image of the penetration pattern is taken from the same direction as the front surface pattern, and the C of the back surface pattern is obtained.
It has a function of inverting AD data and superimposing them on each other. This function is provided by software in the workstation 40, and
All two patterns can be superposed and any two can be superposed.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG.

First, before starting a specific operation, basic setting and adjustment of system functions are performed. In particular, when the lens of the microscope 32 or the camera 34 is replaced, it is necessary to perform orthogonal adjustment of the camera 34 and the XY stage 44. This is done by manually rotating the camera mount. In this orthogonal adjustment, as shown in the monitor screen in FIG. 6, a small mark (may be a small dust) indicated by an X mark on the sample mounting portion is used as a reference point, and this range does not deviate from the monitor screen. If the reference point does not deviate from the reference line (horizontal line) on the monitor when it is horizontally moved in the left and right X directions, it can be performed by setting OK.

Further, in order to provide the image measuring function, it is necessary to measure the size per pixel and the screen feed pitch in advance. This is one screen size (512 × 4 in this embodiment).
In measuring the stage feed value corresponding to 80 pixels), specifically, as shown in FIG. 7 showing the screen of the monitor 38, the reference point indicated by an X mark is set to the X direction and the Y direction on the screen. In both cases, the laser scale counter 52 is moved to four points on the reference line at the positions of 1/4 and 3/4, and the stage movement distances in the X and Y directions at that time are calculated.
It is possible to measure with high accuracy by using the count value according to. In this case, the size per pixel is Xs / 2
56, Ys / 240, and the screen feed pitches in the X and Y directions are calculated as 2Xa and 2Ys. For the measurement of the above dimensions and pitch, the feeding pitch by the XY stage drive motor (step motor), for example, 1 μm may be used without using the laser scale counter.

On the premise that the above preparatory operation is completed, the sample is set in step S1. Specifically, as shown in FIG.
The sample (lead frame) is attached to a predetermined position of the sample, and the operator operates the rotary stage 42 while viewing the image of the sample taken from the camera 34 displayed on the monitor 38 to adjust the sample orthogonally. To do.

If the monitor screen displaying the horizontal edge of the sample input by the CCD camera 34 whose orthogonal adjustment with the XY stage 44 has already been completed is as shown in FIG. When the rotary stage 42 is manually rotated to a position where the above-mentioned edge does not deviate from the horizontal reference line even when largely moved in the X-axis direction,
The orthogonal adjustment between the sample and the XY stage 44 is performed.

Then, in step S2, the light source to be used is selected and its light amount is adjusted. That is, the switch 60A or 6
A transmission light source or an epi-illumination light source is selected by turning on any of 2A. The desired light source is selected, and the light amount is adjusted by the light amount volume of 60B or 62B so that the brightness signal falls within the specified range by looking at the monitor of the autofocus device. In some cases, both light sources can be used at the same time.

In the next steps S3 to S6, menus are displayed on a menu screen (each can be displayed on the same screen as a window) displayed on the monitor screen as schematically shown in FIGS. 9 to 11, for example. It is executed by selecting.

First, in step S3, the center of an island (die pad) captured as an image is designated.

In this embodiment, the island 10 is shown in FIG.
Enlarge and show the monitor screen on the right side
At the point P at the upper end of the island 10._T, And the bottom point P
_BTo match the Y-axis center of the camera input screen respectively.
By inputting each Y coordinate value Y_T, Y_B
Is calculated and the point P at the left end is calculated._LAnd the point P on the right end_RThe it
By inputting it so that it matches the center of the screen in the X direction.
X coordinate value X _L, X_RSo that
ing. Therefore, these four areas are black and white (black areas are diagonal
From the coordinate value of the edge position corresponding to the boundary (indicated by the line),
The coordinates (X, Y) of the island center, which is the alignment origin,
It is calculated by the following formula.

X = (X _R + X _L ) / 2, Y = (Y _T + Y _B ) / 2

If the CAD system has an edge detecting function, the same as the above, even if the edge portions of the left, right, upper, and lower black and white boundaries are not aligned with the centers of the X and Y coordinates on the screen, the same result is obtained. You can specify the center. By specifying the center of the island of the input image in this way,
It is possible to accurately perform the overlay display in which the center coincides with the center of the island of the design pattern of CAD data.

At the next step S4, a sampled area is designated.

In the case of photographing the lead frame for one chip, for example, shown in FIG. 17, the left and right of the lead frame input from the camera 34 and displayed on the monitor while moving the XY stage 44. The shooting area can be designated by sequentially moving the upper and lower end portions into the screen and designating respective points (four endpoints defining the rectangular area) with the cursor, for example. At that time, a plurality of areas including a partial area (for example, an inner lead bonding area) can be designated.

When the CAD data of the product design dimension is input, the dimension is read from the CAD data, and the coordinates of the four end points can be automatically set, for example, by using the dimension value, and the photographing area can be set. Can also be specified. In this case, the area can be designated in a short time, and the CAD pattern design pattern to be executed later can be easily aligned with the actual pattern input as the image.

Information about the center of the island and the shooting area on the image designated in steps S3 and S4 is stored in the setting file XY.

Then, in step S5, conditions for autofocus (AF) are set. Here, the mode is selected and the limit value is set. In this mode, one reference point (position) is determined in the Z-axis direction applied to a flat sample, and the 2WAY method in which the Z stage 46 is finely moved vertically to focus on the reference point, and a surface with large unevenness is used. Z stage 4 up to a predetermined lower position beyond the focal point to be applied
From the state where 6 is lowered, the stage 46 is gradually raised to bring the sample closer to the lens and focus 1 WAY
There is a method and a selection of a lens to be used from objective lenses (five types in this embodiment).

The limit is an approach limit distance set to prevent a collision between the lens and the sample during autofocus. In addition, here, 1 WAY is used for the product sample with severe unevenness as the mode, and 2 W when it is not.
Select AY, use a 20x objective lens as a lens to capture with a resolution of 1 μm / 1 pixel, and use a focus parameter setting file for that. 2 mm from the origin as the limit value, the maximum value of the focus working distance is 1 limit. Set a normal default value such as "/ 2". The conditions set in this step are stored in the setting file AF.

When the 2-way method is selected as the AF mode, the edge of the sample is placed on the screen and autofocus is activated or the Z stage 46 is manually moved to determine the focus origin (reference point Z coordinate value) is also set. The autofocus is executed by moving the Z stage 46 up and down slightly with reference to this position as described above.

In the next step S6, conditions for image processing are set. The contents of the selection are the selection of the input plane to be used from the eight types of image frame memories shown in FIG. 3 that use different colors, the setting of the binarization threshold value when creating a binary image, white or black. Condition and raster vector (RV) to remove unnecessary points of image from image data
It is a conversion condition. The conditions set in this step are stored in the setting file SV.

After the storage of the conditions in each setting file is completed by the above operation, the raster / vector conversion method (outline (contour) mode or trapezoidal area mode) is selected.

The batch processing of step S7 for selecting the contour mode and step S8 for selecting the trapezoidal mode is automatically executed in the workstation 40, and the raster data of the entire image-captured photographing area is converted into vector data. CAD data created by the output file LFX
The data is converted into various CAD system formats in step S9, and various collation processes are performed. This collation (overlapping) process is performed by selecting a menu on the screen of the workstation.

Next, the CAD device (workstation 4
The batch processing of steps S7 and S8 executed inside 0) will be described with reference to the flowchart of FIG.

First, in step S11, the data etc. stored by the above operation are read from the above-mentioned setting files XY, AF, SV, etc., and the cell division of the photographing area is calculated.

The contents of each setting file read here are illustrated below.

File XY-Position of four sides of island (center of island) -Number of input designated areas-Coordinate value of each rectangular area File SV-Input color plane number-Binarization threshold value-Morphology direction and number of times (+: white to black) ,-: Black to white) -RV thinning coefficient file AF (normally fixed) -cell unit execution or fixed focus selection-AF mode (2 modes for each of 5 lens types (1 or 2W)
AY))-Soft limit values (upper and lower limits of Z stage) Lens file (fixed) -Field size by lens-Actual size of 512 x 480 pixels (including non-rectangular distortion)

It should be noted that the morphology depends on the contents of the file SV.
In the direction +, the black point is removed from the white image, and-is the white point removed from the black image. Also, in the contents of the file AF, "execute in cell unit" is applied to a sample having minute unevenness such as a lead frame by executing autofocus every time an image is captured, and fixed focus is applied to a glass original plate. Applies to those with high flatness. The soft limit value is the same as the limit value set in step 5, and is the upper limit value of the Z stage movement set by the operator to prevent the sample from colliding with the lens, or the lower limit value to prevent it from lowering more than necessary. is there.

In the lens file, the field size of each of the above five types of objective lenses, the actual size corresponding to all the pixels of the CCD camera 34 used in this embodiment (the distortion due to the lens is corrected). 4 dimensions) and are stored.

Similarly, the calculation of the cell division, which is executed in step S11, is carried out, for example, when the lead frame for one chip is 4
0 mm x 40 mm, 512 x CCD camera 34
When it is assumed that the visual field size of 480 pixels is 496 μm × 464 μm, it means that the lead frame is divided into 80 × 86 units (cells), as shown in FIG. It is an input unit when sequentially moving in the Y direction to input an image of the entire lead frame, and also a feed pitch (offset amount) when feeding to the next cell. However, in practice, the offset amount is usually set to about 90% of the cell size in order to make the boundary of each captured image clear.

When the calculation of the number of cell divisions in step S11 is completed, in step S12, the XY stage controller 48 moves the XY stage 44 in response to a command from the workstation to bring the field of view of the optical microscope 32 to the first photographing position. Set. At that time, the actually measured position (corresponding to the X and Y coordinate values) actually measured by the laser scale counter 52 is fed back to the workstation 40.

Next, in step S13, autofocus is performed by the autofocus controller 50 at the camera setting position based on the instruction from the workstation 40, and the Z coordinate value of the in-focus position is read by the controller 50. Workstation 4
Send to 0.

Thereafter, in step S14, the workstation 40 issues an instruction to the image processing device 36 (SV), the image processing device 36 is activated, and an image frame is input from the CCD camera 34 to the processing device 36. , A binarized image is generated by performing binarization on the input raster image and morphological processing for removing unnecessary points from the image.

Next, in step S15, raster / vector conversion is executed. First, the binary image data generated in step S14 is read from the image processing device 36 into the workstation 40, converted into vector data by the RV conversion section, and transmitted to the image processing device 36 again. , While displaying it on the TV monitor 38, converting the vector data into CAD data and storing it in a file, at the same time calculating the offset amount and scaling once sent from the XY stage and moving to the next cell, Returning to step S12, the process up to step S15 is executed for the cell, and this process is repeated.

As shown by the broken line in FIG. 13, when the step S14 is completed, a command for moving to the next cell is issued to the XY stage controller 48 and the autofocus controller 50, and the preliminary preparation is performed. By doing so, the RV conversion process, the XY stage movement, and the autofocus process can be performed in parallel.

The above image capturing is performed, for example, with reference to FIG.
By executing the above for all areas, the entire lead frame for one chip can be displayed on the monitor 38 as vector data, and the CAD data of the lead frame can be generated.

When the CAD data thus created is converted into various CAD system formats as shown in step S9 of the flow chart of FIG. 5,
The product design dimension data that is originally input as CAD data on the screen of the monitor 38 and the processing dimension data in which the correction allowance is added are displayed as a graphic pattern, and these data are converted from the image input data to CA in this embodiment.
The product pattern of the lead frame converted into the D data can be displayed in an overlapping manner.

FIG. 15 shows an example of collation on the screen of one lead frame. The line drawing A on the outer side is a processing dimension pattern, and the inner line B is a product design pattern before being corrected to A. C is the actual product pattern (inner lead) obtained by actual etching. This product pattern is a through image using a frame memory for B / W images. From this FIG. 15, it can be seen that the setting of the correction margin is almost appropriate.

The present embodiment further has a superimposed display function as schematically shown in FIG. That is, FIG.
In FIG. 6A, a front surface pattern, a back surface pattern, and a penetrating pattern are each schematically shown from the left, and as the same local pattern position and direction are indicated by arrows in each pattern, the front surface pattern and the penetrating pattern are the same. Reflected images and transmitted images are taken from different directions, and the backside pattern is taken as a reflected image from the side opposite to these two patterns. Therefore, the back surface pattern has an opposite relationship to the other two patterns, and the positions of the arrows are reversed.

Therefore, in the present embodiment, the work of inputting an image of the lead frame for one chip, for example, from the CCD camera 34 at a predetermined pitch is sequentially executed for the above three patterns and captured as raster data. A process of individually converting the CAD data of the back surface pattern, which has been reversely photographed, into CAD data by converting it into vector data by the raster / vector conversion unit built in the workstation 40, After doing, overlay these three CAD data on the device,
For example, by displaying them on the screen of the monitor 38 and aligning them while looking at them, or by making their respective origins coincide with each other, it is possible to accurately superimpose them.

FIG. 16B schematically shows an enlarged pattern displayed on the screen of the monitor 38 via the image processing apparatus 36 when the above processing is executed by the workstation 40. Reference numerals A, B, and C denote the elements in FIG.
Similar to the example of the defect due to under-etching shown in (B), the patterns correspond to the front surface, the back surface, and the through patterns. or,
Reference numeral D on the upper left of FIG. 16 (B) is an example of the normal pattern of the half etching shown in FIG.

Further, FIG. 16C shows the case where the surface pattern A shown in FIG. 20C and the penetration pattern C match, and FIG. 16D shows the case shown in FIG. 20D. In the case of the misregistration shown in FIG. 3, the corresponding superposition display according to the present embodiment is schematically shown.

As described above, in this embodiment, since the three patterns can be accurately overlapped with each other, the mutual dimensional difference can be visually recognized easily and in a wide range. Can also be done accurately. Further, by using the above-mentioned measuring function, the dimensional difference can be measured with high accuracy by, for example, magnifying and displaying.

FIG. 17 is a screen display of the vicinity of the tip of the inner lead, which is also actually displayed using the overlay display function. The line drawing D on the outer side is a reflection image on the front side and E on the inner side is the back side. It is the collation example of the image which each reflected image of the side was piled up and displayed.

From this figure, it is possible to clearly understand the difference in the degree of etching on the front side and the back side, which cannot be recognized from the transmission image. As described above, the etching of the lead frame is usually performed with the surface on which the chip is mounted facing down and the etching liquid being sprayed from both upper and lower directions. The reason for making the surface side down is that it is necessary to secure a sufficient width for wire bonding on the surface of the inner lead tip portion, but etching is easier to proceed on the upper surface. From this FIG. 17, it can be clearly understood that there is a difference in etching between the front and back surfaces.

The basic features and performance of the CAD system of this embodiment described in detail above can be summarized as follows.

Since full-color image input processing is possible, it is possible to collate the resist pattern and the front and back patterns of the product with each other or with the design pattern or the like, so that it is possible to perform dimensional comparison and measurement. It is possible to objectively evaluate etching. Since it has its own automatic positioning function, the center of the island can be calculated automatically. It functions as an interface to various commercially available CAD systems such as Medusa (trade name) manufactured by Computer Vision.

As the measurement performance, the resolution is 1 μm,
Measurement accuracy: 1μm guaranteed, visual field size: 496 × 464μm
(512 × 480 pixels), measurement size: 200 mm square (expandable), measurement target: product (transmission image, reflection image by front and back),
Plate making (resist reflection image) and glass original plate (transmission image) can be mentioned.

Therefore, the CAD system of the present embodiment is used for automatic calculation of etching correction allowance, dimensional control for each manufacturing process, quality control such as dimensional inspection of products, etching simulator, etc., for providing data to research and development. Available.

As described above in detail, according to the present embodiment, the fine patterns of the lead frame are displayed in any combination of the front, back, and penetrating patterns, which are superposed on each other and collated with each other to achieve high precision. It can be dimensioned.

Further, since the etching compensation amount can be quantified by objective data, it is possible to reduce the replacement of the compensation amount by trial and error, and as a result, the delivery time can be shortened.

Further, since the tolerance determination can be performed collectively and automatically, it is possible to greatly reduce the labor of the authentication, and the oversight can be eliminated, so that the accuracy can be improved. .

Further, since the CAD pattern, the original pattern, the plate-making pattern, and the product pattern can be compared with each other, the accuracy of the production line and the quality maintenance can be performed for each process.

The present invention has been specifically described above, but the present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the scope of the invention.

For example, the sample is not limited to the lead frame, and may be a shadow mask for a color television, for example.

[0105]

According to the first aspect of the present invention, the reflection images of the front surface pattern and the back surface pattern are input as images and converted into CAD data composed of vector data, and at the same time, one of the CAD data is inverted to be mutually converted. Since the patterns are superposed on each other, it is possible to accurately align the two patterns having the opposite image capturing directions with each other on the CAD device. Therefore, the dimensional difference between the front and back patterns can be visually recognized, and zooming, scrolling, etc. can be performed, so that both patterns can be viewed and compared in a wide range in real time, and if necessary, zooming can be performed. It is also possible to measure the dimensions while applying

According to the second aspect of the present invention, similarly, the front surface pattern or the back surface pattern, which is a reflection image, and the penetrating pattern can be accurately overlapped on the CAD device and displayed on the screen. Similarly, it becomes possible to easily visually recognize the dimensional difference between the two.

According to the third aspect of the present invention, similarly, both the reflection images of the front surface pattern and the back surface pattern and the transmission image of the penetrating pattern are converted into the converted CAD for the pattern whose image capturing direction is opposite. Since the data is inverted so that the three persons are superposed on the CAD device, it becomes possible to display these three patterns on the screen in the same manner in the same manner.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a CAD system according to an embodiment of the present invention.

FIG. 2 is a CAD system sample mounting device, a microscope,
Oblique view showing a CCD camera

FIG. 3 is a block diagram showing a frame memory and a processing function of the image processing device of the CAD system.

FIG. 4 is a diagram showing an optimum input plane for each sample.

FIG. 5 is a flowchart showing the operation of the embodiment.

FIG. 6 is an explanatory diagram showing a monitor screen when the camera and the XY stage are orthogonally adjusted.

FIG. 7 is an explanatory diagram showing a monitor screen when the dimensions per pixel and the screen feed pitch are calculated.

FIG. 8 is an explanatory diagram showing a monitor screen when a sample and an XY stage are orthogonally adjusted.

FIG. 9 is an explanatory diagram illustrating a CAD system menu screen.

FIG. 10 is another explanatory diagram illustrating the menu screen of the CAD system.

FIG. 11 is still another explanatory diagram illustrating the menu screen of the CAD system.

FIG. 12 is an explanatory diagram showing an example of a method of designating the center of an island.

FIG. 13 is a flowchart showing a procedure of batch processing executed inside the CAD device.

FIG. 14 is an explanatory diagram showing a cell division calculation method.

FIG. 15 is an explanatory diagram showing an example of a screen in which a plurality of patterns are displayed in an overlapping manner.

FIG. 16 is an explanatory diagram showing a superimposing method and display examples of CAD data corresponding to a plurality of patterns.

FIG. 17 is an explanatory diagram showing another example of a screen in which a plurality of patterns are displayed in an overlapping manner.

FIG. 18 is a plan view showing an example of a lead frame.

FIG. 19 is an explanatory view conceptually showing the manufacturing process of the lead frame.

FIG. 20 is an explanatory view showing features and problems of through etching.

FIG. 21 is an explanatory diagram showing the characteristics of half etching.

[Explanation of symbols]

 30 ... Sample mounting device 32 ... Optical microscope 34 ... CCD camera 36 ... Image processing device 38 ... TV monitor 40 ... Workstation (EWS) 42 ... Rotation stage 44 ... XY stage 44A ... X stage 44B ... Y stage 46 ... Z stage 48 ... XY stage controller 50 ... Auto focus controller 52 ... Laser scale counter 54A ... X drive motor 54B ... Y drive motor 54C ... Z drive motor 56A, 56B ... Scale pattern 58A ... X position detector 58B ... Y position detector 60 ... Transmission Light source unit 60A ... Transmissive light source switch 60B ... Light intensity adjustment volume 62 ... Epi-illumination light source unit 62A ... Epi-illumination light switch 62B ... Light intensity adjustment volume

Front page continuation (72) Inventor Teruaki Iinuma 1-1-1, Ichigaya-Kagacho, Shinjuku-ku, Tokyo Within Dai Nippon Printing Co., Ltd. (72) 1-1-1 Ichigaya-Kagacho, Shinjuku-ku, Tokyo Dai Nippon Printing Co., Ltd.

Claims (3)

[Claims] 1. An image input means for inputting an image of an etched product pattern, and CA for inputting the input image data.
A multi-pattern simultaneous measuring device having a raster / vector converting means for converting into D data and having a function of superposing and displaying two or more CAD data, wherein a front surface pattern and a back surface pattern of a product pattern by an image inputting means. Has a function of inputting an image as a reflection image under an epi-illumination source, converting each input image data into CAD data by a raster / vector converting means, inverting one of the CAD data, and superimposing them on each other. A multi-pattern simultaneous measurement device characterized in that 2. An image input means for inputting an image of an etched product pattern, and CA for inputting the input image data.
A multi-pattern simultaneous measuring device having a raster / vector converting means for converting into D data and having a function of superposing and displaying two or more CAD data, wherein a front surface pattern and a back surface pattern of a product pattern by an image inputting means. One of the two patterns is input as a reflection image under an epi-illumination light source, and the penetrating pattern is input as a transmission image under a transmission light source, and each input image data is converted into CAD data by a raster / vector conversion means. When a plurality of image capturing directions are opposite to each other, one of the CAD data is inverted and the other is superposed on each other. 3. An image input means for inputting an image of an etched product pattern, and CA for inputting the input image data.
A multi-pattern simultaneous measuring device having a raster / vector converting means for converting into D data and having a function of superposing and displaying two or more CAD data, wherein a front surface pattern and a back surface pattern of a product pattern by an image inputting means. Both as a reflection image under the epi-illumination source,
The penetration pattern is input as a transmission image under a transmission light source, each image is input, each input image data is converted into CAD data by the raster vector conversion means, and a front surface pattern or a back surface pattern whose image capturing direction is opposite to the penetration pattern is taken. CA
An apparatus for simultaneously measuring a plurality of patterns, which has a function of inverting D data and superimposing the three on each other.