TW201721305A - Exposure device, adjustment method and program of exposure device especially for correction of position deviation of a substrate equipped with a large number of patterns - Google Patents

Abstract

In a substrate equipped with a large number of patterns, it is also adjusted quickly and correctly. The exposure device according to the present invention includes a exposure device for correcting a camera 29 and a DMD 22 and capable of forming patterns according to FO-WLP having a plurality of semiconductor chips SC collected in the field of view and photographing, extracting the outline of each of the semiconductor chips SC from said image, and the image of the comparison area TA extracted as a mark and connected to the welding pad CP is compared with the template image for the detection of position deviation of each of chips.

Description

Exposure device, alignment method of the exposure device, and program

The present invention relates to an exposure apparatus for forming a pattern on a substrate or the like, and more particularly to the alignment of a substrate having a plurality of patterns arranged in a row.

In recent years, an exposure method in which a plurality of circuit patterns (semiconductor wafer patterns, etc.) are drawn on one substrate has been utilized. For example, in a wafer level package (WLP) for performing an IC package process in a wafer state, a fan-out wafer level package (FO-WLP) is known.

Therefore, a plurality of semiconductor wafers cut out from the wafer are arranged on the support substrate (referred to as a pseudo wafer), and after rewiring is formed by pattern exposure in the gap of the semiconductor wafer, the dummy wafer is cut to obtain a package. (The process shown above is referred to as Mold first (Chip-first) type FO-WLP).

In the FO-WLP, in order to embed a semiconductor wafer on a malleable resin supporting substrate, a random inherent positional shift occurs in each semiconductor wafer, and it is necessary to correct the position of the rewiring pattern by adjustment.

In the correction method, the imaging range is matched with the scanning bandwidth (bandwidth) of the projection area obtained by the optical modulation element array (DMD or the like), and the camera is scanned, and the entire wide area in which the images are connected is obtained. portrait. Then, the positions of the alignment marks or the terminal pads formed in the respective wafers are detected, and the positional shift amount of each wafer is detected by the template matching method (see Patent Document 1).

On the other hand, in the case where a multilayer substrate is formed by patterning by laminating into a plurality of layers, the circuit pattern is also superimposed on the first layer to expose the film, and therefore adjustment must be performed. In the method of detecting the positional shift amount, for example, the positional shift can be detected by using the alignment mark or the wafer shape (grain shape) (refer to Patent Document 2).

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2013-58520

[Patent Document 2] Japanese Patent Publication No. 2013-520828

In a large-sized resin substrate different from a wafer or the like, the number of patterns is extremely large (for example, 10,000 or more), and it takes time and a limit to acquire an entire wide-area image while imaging an area along the scanning zone. As a result, it takes time to adjust the calculation, and the productivity of the substrate is lowered. On the other hand, if the pattern alignment is performed for each layer, it is difficult to accurately detect the positional shift amount if the shape of the wafer itself is not characteristic.

Therefore, in a substrate provided with a plurality of patterns, it is also necessary to perform the adjustment quickly and accurately.

The exposure apparatus of the present invention is an exposure apparatus capable of patterning a substrate in which a plurality of patterns (hereinafter referred to as a lower layer pattern) are arranged. For example, patterning of rewiring can be performed on a support substrate formed by FO-WLP. Especially this According to the exposure apparatus of the present invention, it is possible to adjust the alignment of a rectangular substrate having a larger number (for example, 10,000 or more) of the lower layer pattern arranged in a matrix over the entire area. The lower layer pattern here includes a semiconductor package (wafer), and also includes a circuit pattern in which a glass substrate or a printed substrate is regularly arranged.

An exposure apparatus according to the present invention includes: an imaging unit; a measurement unit that measures a position of each of the lower layer patterns; and a correction unit that calculates a positional shift amount of each of the lower layer patterns by template matching, and corrects the drawing material. For example, the imaging unit includes a camera that can move in the main scanning direction or the like, and by driving the camera, the imaging area can be scanned intermittently or continuously on the substrate.

In the present invention, the imaging unit performs imaging by grasping a plurality of lower layer patterns in the field of view by adjusting the imaging magnification or the like. For example, imaging may be performed with a field of view frame larger than the scanning bandwidth due to the array of light modulation elements. Further, it may be accommodated in the field of view frame in the number of the plurality of lower layer patterns along the main scanning direction and the sub-scanning direction.

Next, the measurement unit performs template matching based on the comparison target image from which the feature marks belonging to at least a part of each of the lower layer patterns are extracted, and detects the positional shift. The plurality of lower layer patterns are simultaneously photographed, and at least a part of the lower layer pattern is used as a comparison object for template matching, and is formed as a comparison object image extracted as a feature mark by a connection pad or the like formed there, thereby enabling rapid comparison Correction and correction.

In the lower layer pattern in which the wiring pattern is complicated, it is difficult to individually recognize the lower layer pattern by being accommodated in the adjacent lower layer pattern of the field of view frame. Therefore, the measurement unit can extract the comparison object image after detecting the contours of the lower layer patterns.

If there are many feature marks randomly in one lower layer pattern, It takes time to sign the extraction process. Therefore, the measurement unit may be configured to arbitrarily set an area in which the comparison target image is arbitrarily set. For example, a part of the area of the lower layer pattern may be set as the comparison object image.

The measurement unit is configured to refer to the positional shift amount of the adjacent lower layer pattern in order to suppress the adjustment adjustment time for the lower layer pattern in which the positional shift detection is not possible. Thereby, it is also possible to perform adjustment adjustment which is effective as information adjacent to the lower layer pattern to a certain extent. Alternatively, the lower layer pattern in which the measurement unit cannot perform the positional shift detection may determine the positional shift amount of the lower layer pattern in accordance with the extraction of the lower layer pattern contour according to the operator's operation. For example, by the contour detection assisting function, the operator can support contour detection on the screen and detect the position offset based thereon.

In the multi-package region composed of the lower layer pattern of two or more, the measurement unit may detect the position shift amount of the lower layer pattern in the region after all the lower layer patterns in the region have been imaged.

The method of modulating an exposure apparatus according to the present invention is a method of aligning a substrate-patterned exposure apparatus in which a plurality of lower layer patterns are arranged, and among the plurality of lower layer patterns, imaging is performed so as to grasp a plurality of lower layer patterns in a field of view, and each measurement is performed. The lower layer pattern position is calculated by template matching to calculate the positional shift amount of each lower layer pattern, and the exposure method for correcting the drawing material is performed, and the template matching is performed based on the comparison object image of the feature mark extracted from at least a part of each of the lower layer patterns, and the detection is performed. Position offset.

The program of the present invention is an imaging device that patterns a substrate in which a plurality of lower patterns are arranged, and an imaging device that captures a plurality of lower layers in a field of view in a plurality of lower patterns; and measures each lower pattern bit. The measurement means for calculating the positional shift amount of each lower layer pattern by template matching, and correcting the correction means of the drawing material to function, based on the comparison object of the feature mark extracted from at least a part of each of the lower layer patterns In the image, the template matching is performed, and the method of detecting the positional shift is used as a measuring means.

According to the present invention, it is possible to quickly and appropriately adjust the adjustment of the substrate on which the plurality of patterns are formed.

10‧‧‧Exposure device

12‧‧‧Drawing platform

15‧‧‧ platform drive mechanism

18‧‧‧Exposure head

20‧‧‧Light source

21‧‧‧Light source drive department

22‧‧‧DMD

23‧‧‧Image Optics

24‧‧‧DMD drive circuit

26‧‧‧Grating conversion circuit

27‧‧‧Measurement circuit (measurement department)

29‧‧‧Camera (camera)

30‧‧‧ Controller (measurement unit, camera unit)

31‧‧‧Exposed control department (camera department)

32‧‧‧ memory

BA‧‧‧With area

CP‧‧‧ connection pad

PC‧‧‧ contour

RM‧‧‧Resin mold area

SC‧‧‧Semiconductor package (semiconductor wafer)

TA‧‧‧Comparative target area

TA1‧‧‧Comparative object area

TI‧‧‧ portrait

VF‧‧· camera vision

W‧‧‧Substrate

Fig. 1 is a block diagram of an exposure apparatus of the present embodiment.

Fig. 2 is a view showing an example of a support substrate (temporary substrate) formed in the FO-WLP.

Fig. 3 is a view showing a flowchart of the adjustment adjustment and drawing processing.

Fig. 4 is a view showing the imaging range of the camera.

Figure 5 is a diagram showing the extraction of features of a semiconductor wafer.

Fig. 6 is a view showing a part of a region of a semiconductor wafer as a comparison target region.

Fig. 7 is a view showing the correction of data at the time of rewiring formation.

Figure 8 is a diagram showing a multi-wafer.

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

Fig. 1 is a block diagram of an exposure apparatus of the present embodiment.

The exposure device 10 can form a circuit by irradiating light to the substrate W. The patterned unmasked exposure apparatus includes an exposure head 18 provided with a DMD (Digital Micro-mirror Device) 22. The substrate W is mounted on the drawing platform 12, and the X-Y coordinate system is defined on the drawing platform 12 along the main scanning direction (X direction) and the sub scanning direction (Y direction).

The exposure head 18, along with the DMD 22, includes an illumination optics and an imaging optics (not shown). The light emitted by the light source 20 (laser or discharge lamp, etc.) provided by the exposure device 10 is guided to the DMD 22 by the illumination optical system.

The DMD 22 is a light modulation element array in which a minute rectangular micromirror (here, several μm to several tens of μm) is arranged in a matrix in a matrix, and is composed of, for example, a 1024×768 micromirror. Each of the micromirrors is positioned such that the first posture (ON state) in which the light beam from the light source 20 is reflected toward the exposure surface of the substrate W and the second posture (OFF state) reflected in the direction outside the exposure surface are positioned. Switch the gesture according to the control signal (exposure data).

In the DMD 22, each micromirror is selectively ON/OFF controlled, and light reflected on the micromirror in the ON state is transmitted through the imaging optical system and irradiated onto the substrate W. Therefore, the light irradiated on the substrate W is composed of a light beam of light selectively reflected by each micromirror, and becomes pattern light corresponding to a circuit pattern to be formed on the exposure surface.

When all the micromirrors are in an ON state, an exposure region which is a rectangular projection region having a predetermined size is defined on the substrate W. For example, if the magnification of the imaging optical system 23 is 1 time, the size of the exposed area coincides with the size of the DMD 22. While the drawing platform 12 is moved in the X direction by the stage driving mechanism 15, the exposure area is relatively moved (scanned) on the substrate W, thereby exposing Substrate W.

Among them, the exposure head 18 is disposed such that the exposure region obtained by the DMD 22 is inclined at a predetermined minute angle with respect to the scanning direction. As a result, the trajectory of the minute projection area of the micromirror arranged along the main scanning direction is shifted by a slight distance along the sub-scanning direction.

In the exposure operation, since the multiple exposure is performed, the exposure pitch (exposure operation time interval) is set so that the minute projection regions of the respective micromirrors overlap each other. As a result, the exposure area is shifted by the minute distance by the main scanning direction, whereby the center point (exposure point) of the minute projection area at the time of exposure shooting is distributed in one small projection area (cell). As a result, the pattern is formed by the resolution below the cell size.

The accompanying exposure region is relatively continuously or intermittently moved on the substrate W along the main scanning direction (X direction), and the pattern is formed on the substrate W along the main scanning direction. When the multiple exposure operation along one scanning tape ends from one end to one end of the substrate W, a multiple exposure operation along the next scanning zone is performed. The drawing process is completed by exposing the entire substrate W.

The controller 30 connected to an external workstation (not shown) controls the drawing process, and outputs a control signal to the DMD drive circuit 24, the read address control circuit (not shown), the light source drive unit 21, and the like. The program for controlling the exposure operation is stored in advance in a ROM (not shown) in the controller 30.

The pattern data transmitted by the workstation as CAD/CAM data is used as vector data of the coordinate data, and the raster conversion circuit 26 converts the vector data into raster data. The raster data represented by the binary data of 1 or 0 determines the position of each micromirror to be in an ON state or an OFF state. Generated grating The material is sent to the DMD drive circuit 24 in conjunction with the exposure operation. The raster data read and write timing is controlled by the read address control circuit.

Since thermal deformation or the like occurs on the substrate W, the adjustment adjustment is performed before the multiple exposure is performed. The camera 29 is arranged to image the substrate W on the drawing platform 12, and the imaging magnification of the imaging target can be changed by the built-in focus lens. The exposure control such as the imaging magnification, the AF processing, and the aperture adjustment in the camera 29 is executed by the exposure control unit 31.

The controller 30 controls the stage drive mechanism 15 to control the scanning speed and the like while the substrate W is being imaged by the camera 29. The measurement circuit 27 detects the position of a feature point such as a correction mark based on the image data captured by the camera 29. In addition, the plurality of cameras may be arranged at predetermined intervals, and may be photographed while being moved in parallel during the adjustment adjustment.

The controller 30 performs the adjustment adjustment based on the difference between the position of the detected feature point and the ideal (designed) reference position, that is, the positional shift amount. Specifically, the drawing position (drawing timing) of the pattern is corrected in accordance with the calculated position shift amount.

Fig. 2 is a view showing an example of a support substrate (temporary substrate) formed in the FO-WLP.

In the support substrate (hereinafter, the same reference numeral B as in FIG. 1), a semiconductor package (hereinafter referred to as a semiconductor wafer) SC is arranged in a matrix at a predetermined pitch, and is displayed on the 125 × 160 semiconductor wafer SC. Although the cells are arranged in a state in which the resin-made support substrate W is embedded, in actuality, the semiconductor wafer SC of 20,000 or more is arranged. The semiconductor wafer SC having a support substrate W of, for example, 5 mm or less is arranged at a pitch of 10 mm or less.

In the FO-WLP, it is necessary to pattern the rewiring of the resin portion that abuts against the gap of the adjacent semiconductor wafer SC. However, the semiconductor wafer SC has a random positional shift amount due to the resin ductility, and if the actual position of the connection pad of the semiconductor wafer SC is shifted from the design position, the wiring of the resin portion is not formed at the time of pattern formation. The state in which the semiconductor wafer SC is connected.

Therefore, the adjustment adjustment is performed before the drawing to correct the drawing data. In the present embodiment, when detecting a positional shift amount of each of a large number of semiconductor wafers SC, it is performed by imaging and template matching using a wide range of fields of view. This is explained below.

Fig. 3 is a view showing a flowchart of the adjustment adjustment and drawing processing. Fig. 4 is a view showing the imaging range of the camera. Figure 5 is a diagram showing the extraction of features of a semiconductor wafer.

When the substrate W is loaded on the drawing platform 12, the imaging magnification of the camera 29 or the like is controlled, and the drawing platform 12 is intermittently moved, thereby performing camera scanning (S101). At this time, the imaging magnification is set such that the plurality of semiconductor wafers SC are received in the camera field of view VF.

In Fig. 4, the imaging magnification is set so that the imaging of the six semiconductor wafers SC can be performed as the entire wafer. The camera field of view VF is different from the range of the band area BA which is the scanning area of the exposure area of the DMD 22, and is larger than the width of the band area BA. When the imaging of the six semiconductor wafers SC is completed, the next six semiconductor wafers SC are imaged once and repeated. In addition, the scanning speed is adjusted according to the complexity of the pattern.

While moving the drawing platform 12 to perform camera scanning, The image data sent from the camera 29 is taken, and the area to be compared in the template matching is extracted, and as shown in FIG. 5, the connection pad CP having a circular shape in the semiconductor wafer SC is extracted as a mark. The extraction (image recognition) of the connection pad CP is performed by a well-known image recognition process (S102, S103). At this time, after extracting the outline of the semiconductor wafer SC received in the camera field of view VF, an area (hereinafter referred to as a comparison target area) TA of the template matching target is extracted.

In Fig. 5, the outline PC of the semiconductor wafer SC is depicted, but the outline PC is only the boundary line between the support substrate W and the resin portion. Therefore, it is impossible to judge that the image data sent to the measurement circuit 27 is formed. The wire of the wire, or the edge of the wafer. Therefore, the outline of the semiconductor wafer SC is extracted by edge detection or the like based on the wafer size information or the like which is input in advance.

Next, the connection pad CP of the semiconductor wafer size is set to extract the image TI of the comparison target area TA as a mark as a comparison target for template matching. In order to increase the speed of the correction processing, the partial area may be extracted as a comparison target area.

Fig. 6 is a diagram in which a part of the area is set as a comparison target area. Here, the comparison target area TA1 is set in such a manner that template matching is performed on the image of the right corner portion of the comparison target area TA. Since the size of the comparison target area TA1 is small, the number of connection pads CP is reduced, and the processing time for template matching can be shortened. The controller 30 can arbitrarily set the size and position of the comparison target area TA1 by the input operation of the operator or the like in accordance with the complexity of the pattern.

When the comparison target area TA (or TA1) exhibiting the positional relationship of the connection pads CP is extracted, a well-known template matching process is performed according to the template pattern of the semiconductor wafer SC prepared in advance, and the position of the connection pad CP is biased. The amount of positional shift of the semiconductor wafer SC is calculated by the amount of shift (S104, S105).

In terms of the positional shift amount, the displacement and the amount of rotation in the X and Y axis directions are detected here and stored in the memory 32. When the positional shift amount is detected, the pattern data is corrected in accordance with the position of each semiconductor wafer SC (S106). When a semiconductor wafer in which the position shift amount cannot be detected is generated, the position shift amount is obtained by referring to the adjacent pattern.

Further, in other processing methods in which a semiconductor wafer in which the positional shift amount cannot be detected is generated, the positional shift amount can be determined by an operator of the exposure apparatus by manual operation. The operator, while viewing the image data of the monitoring screen displayed on the outside, uses the contour detection assisting function provided by the controller 30 to teach the measuring circuit 27 the outline of the semiconductor wafer in which the positional shift amount cannot be detected. The measurement circuit 27 measures the positional shift amount of the semiconductor wafer in which the positional shift amount cannot be detected from the input contour. This processing can also be performed collectively for the semiconductor wafer in which the positional shift amount cannot be detected after the position shift detection (S105) of all the semiconductor wafers of the substrate is completed.

Fig. 7 is a view showing the correction of data at the time of rewiring formation. Since the semiconductor wafer SC is located at a randomly rotated position, the position of the connection pads is also shifted by the design position. Therefore, the gap of the wafer is divided as shown in FIG. 7 to calculate the positional shift amount of the resin portion, and the pattern position is corrected to match the wiring and the connection pad CP. By correcting the camera scan and the pattern data in parallel, if the adjustment adjustment of the entire support substrate W is completed, the drawing processing is executed (S107). Among them, in the camera scan, the scanning speed can be increased for the non-patterned section.

As described above, with this embodiment, a plurality of semiconductor wafers SC are used. The image is taken in the field of view, and the outline of each of the semiconductor wafers SC is extracted from the image, and the image of the comparison target area TA from which the connection pad CP is extracted is compared with the template image, and the positional shift amount of each wafer is detected. Once the plurality of wafers are imaged to perform template matching for each wafer, the alignment process can be quickly performed on the substrate on which a large number of wafers are loaded.

In the present embodiment, a single wafer type alignment method in which one semiconductor wafer is mounted in one package is described. However, the multi wafer in which a plurality of semiconductor wafers are mounted in one package can be similarly adjusted. positive.

Figure 8 is a diagram showing a multi-wafer. In the case of a multi-wafer, the position shift amount of all the semiconductor wafers forming one package pattern is detected, and then the correction correction amount of the entire package is calculated. Therefore, when the imaging of the semiconductor wafer constituting the multi-wafer cannot be performed once, the image shift amount is calculated after the imaging of all the wafers is completed. Further, at the time of the correction correction, the data correction amount is calculated with respect to the resin mold region RM between the wafers.

In the present embodiment, the alignment processing for the substrate used in the FO-WLP is shown, but it is also effective in the case where the pattern is laminated. Further, the feature marks required for the template matching may be elements, parts, wirings, and the like other than the connection pads.

Claims (11)

An exposure apparatus that patterns a substrate in which a plurality of lower layer patterns are arranged, and includes an imaging unit that performs image capturing so as to grasp a plurality of lower layer patterns in a field of view among the plurality of lower layer patterns; and a measuring unit And measuring a position of each of the lower layer patterns; and correcting a portion, wherein the positional shift amount of each of the lower layer patterns is calculated by template matching, and the drawing data is corrected, and the measuring unit extracts the feature mark according to at least a part of the regions belonging to the lower layer pattern. The comparison object image is subjected to template matching, and the positional deviation is detected. The exposure apparatus according to claim 1, wherein the measurement unit detects the contour of each of the lower layer patterns and extracts the comparison target image. The exposure apparatus according to claim 1 or 2, wherein the measurement unit can arbitrarily set an area of the comparison target image. The exposure apparatus according to any one of claims 1 to 3, wherein the measurement unit refers to a positional shift amount of the adjacent lower layer pattern for the lower layer pattern in which the positional shift cannot be detected. The exposure apparatus according to any one of claims 1 to 3, wherein the measurement unit determines the position of the lower layer pattern according to the extraction of the lower layer pattern according to the operator's operation for the lower layer pattern in which the positional shift cannot be detected. Offset. The exposure apparatus according to any one of claims 1 to 5, wherein the measuring unit has a plurality of package regions formed of two or more lower patterns, After the entire imaging of the lower layer pattern in the area is completed, the positional shift amount of the lower layer pattern in the area is detected. The exposure apparatus according to any one of claims 1 to 6, wherein the measuring unit extracts a connection pad as a feature mark. The exposure apparatus according to any one of claims 1 to 7, wherein the substrate has a rectangular shape, and a plurality of lower layer patterns are arranged on the entire substrate. The exposure apparatus according to any one of claims 1 to 8, wherein the substrate is a support substrate formed according to FO-WLP. A method of aligning an exposure apparatus, wherein a substrate on which a plurality of lower layer patterns are arranged is patterned, wherein among the plurality of lower layer patterns, imaging is performed so that a plurality of lower layer patterns are grasped in a field of view, and positions of the respective lower layer patterns are measured. The positional shift amount of each lower layer pattern is calculated by template matching, and the exposure method for correcting the drawing material is performed, and template matching is performed based on the comparison target image from which the feature marks belonging to at least a part of each of the lower layer patterns are extracted, and the positional shift is detected. A program characterized in that an exposure apparatus for patterning a substrate in which a plurality of lower layer patterns are arranged functions as an imaging means for grasping a plurality of lower layer patterns in a field of view among the plurality of lower layer patterns Method for performing imaging; measuring means for measuring the position of each lower layer pattern; The correction means calculates the positional shift amount of each of the lower layer patterns by template matching, corrects the drawing material, and performs template matching based on the comparison object image in which the feature marks of at least a part of the regions belonging to the lower layer pattern are extracted. The method of detecting the positional shift functions as the above-described measuring means.