JP4359113B2 - Wiring board manufacturing method and wiring board - Google Patents

Description

  The present invention relates to a method for manufacturing a wiring board and a wiring board, and more particularly to a technique effective when applied to a thin wiring board used in a semiconductor device such as a COF (Chip On Film).

  2. Description of the Related Art Conventionally, a wiring substrate (tape carrier) used in a semiconductor device such as a tape carrier package has a predetermined pattern of conductor wiring provided on the surface of a film-like insulating substrate.

  As shown in FIGS. 12 and 13, the wiring board uses a tape-like insulating substrate 1 that is long in one direction, such as polyimide tape, and a plurality of semiconductor devices provided on the insulating substrate 1. A conductor wiring 201 for forming a semiconductor device is continuously provided in each of the formation regions L1. Here, FIG. 13 is a cross-sectional view taken along line F-F ′ of FIG. 12.

  Further, the insulating substrate 1 is provided with a second opening (perforation hole) 1A used for positioning and a conveyance guide when forming the semiconductor device, along the end in the longitudinal direction.

  In recent years, as the semiconductor device is made thinner, the wiring board, in particular, the insulating substrate 1 is made thinner. For example, it is used for a COF type semiconductor device such as a driver IC for driving a liquid crystal display. In the wiring board, the thickness of the polyimide tape (insulating substrate 1) has become, for example, about 25 μm to 40 μm.

  Further, as the insulation substrate 1 is made thinner, the tape breaks around the second opening 1A due to a decrease in the strength of the insulation substrate 1, and the positional accuracy is degraded due to deformation and distortion of the insulation substrate 1. For the sake of simplicity, as shown in FIGS. 12 and 13, a reinforcing conductor 202 is provided at the end of the insulating substrate 1 in the longitudinal direction, that is, in the region where the second opening 1 </ b> A is provided. The strength is ensured (for example, Patent Document 1).

  Further, since the reinforcing conductor 202 is provided in a strip shape along the longitudinal end of the insulating substrate 1, it also serves to remove static electricity generated on the wiring substrate during transport and in each process.

  A method of manufacturing a wiring board provided with the reinforcing conductor 202 will be briefly described. First, as shown in FIGS. 14 and 15, a conductor film 2 is formed on the surface of a tape-like insulating substrate 1 that is long in one direction. Form. At this time, the width of the insulating substrate 1 is wider than the width when used as the wiring substrate. For example, when the width when used as the wiring substrate in the process of forming a semiconductor device is 35 mm, the width is as follows. A 45 mm or 70 mm substrate is used. At this time, the insulating substrate 1 is used for positioning and a conveyance guide in the step of forming the wiring substrate along the longitudinal direction of the insulating substrate 1 in the region 102 outside the region 101 used as the wiring substrate. One opening (first perforation hole) 1B is formed.

  The conductor film 2 is formed by adhering, for example, an electrolytic copper foil or a rolled copper foil. At this time, the conductor film 2 is formed in the vicinity of the center of the insulating substrate 1 so as not to block the first opening 1B. And formed over the entire surface of the region 101 used as a wiring board.

  Next, as shown in FIGS. 16 and 17, the conductor film 2 is etched to form the conductor wiring 201 in the semiconductor device formation region L <b> 1 and the reinforcing conductor 202 along the end portion of the region 101 used as the wiring substrate. Form.

  At this time, the conductor wiring 201 and the reinforcing conductor 202 correspond to the patterns of the conductor wiring 201 and the reinforcing conductor 202 for forming a semiconductor device on the conductor film 2, as shown in FIG. A resist (etching resist) 3 is formed, and the conductor film 2 is formed by etching.

  In addition, after the conductor wiring 201 and the reinforcing conductor 202 are formed, for example, a solder protective film or terminal plating is formed on the conductor wiring 201 although illustration is omitted.

  Next, as shown in FIGS. 18 and 19, for example, the reinforcing conductor 202 and the insulating substrate 1 are punched out using a die, that is, a die 4 and a punch 5, and a second opening (second perforation hole) is formed. ) 1A is formed.

  Thereafter, the insulating substrate is removed by cutting off the outside of the region where the reinforcing conductor 202 is provided, that is, the region 102 where the first opening 1B is formed, and the insulating substrate 1 is removed by a predetermined width, for example, By setting the thickness to 35 mm, a wiring board as shown in FIGS. 12 and 13 can be obtained.

  The step of manufacturing a semiconductor device using the wiring substrate as shown in FIGS. 12 and 13 includes, for example, mounting a semiconductor chip in each semiconductor chip mounting region L2 on the wiring substrate, and external electrodes of the semiconductor chip. The connection portion between the (bonding pad) and the conductor wiring is sealed with a thermosetting resin, and each semiconductor device forming region L1 is cut into individual pieces.

At this time, each process is performed by a reel to reel method, and positioning is performed using the opening (second opening) 1A of the wiring board.
Japanese Patent Laid-Open No. 2-91956

  However, in the prior art, after the conductor film 2 is etched to form the conductor wiring 201 and the reinforcing conductor 202, the reinforcing conductor 202 and the insulating conductor are formed as shown in FIGS. The substrate 1 is punched to form the second opening (perforation hole) 1A. For this reason, due to the difference in shear stress between the reinforcing conductor 202 and the insulating substrate 1, foreign matter such as burrs 8 and metal debris (not shown) is likely to be generated in the second opening 1A as shown in FIG. There was a problem.

  In addition, the defective shape of the second opening 1A due to the burr 8 or the adhesion of foreign matter may cause a decrease in positioning accuracy when the semiconductor device is formed using the wiring substrate, or foreign matter may enter the semiconductor device. Since the reliability is reduced, the wiring board becomes a defective product, and the manufacturing yield of the wiring board is lowered, and the manufacturing cost of the wiring board is increased.

  Further, if the shape of the second opening is rough due to the attachment of burrs or foreign matters, the positioning accuracy when forming the semiconductor device using the wiring board is lowered, and thus the manufacturing yield of the semiconductor device is lowered. was there.

  An object of the present invention is to provide a technique capable of reducing burrs and foreign matter adhesion in the opening in a wiring board in which a reinforcing conductor is provided around a positioning opening (perforation hole) provided in an insulating substrate. There is to do.

  Another object of the present invention is to improve the manufacturing yield of a wiring board provided with a reinforcing conductor around a positioning opening (perforation hole) provided in an insulating board, and to reduce the manufacturing cost of the wiring board. It is to provide possible technology.

  Another object of the present invention is to provide a technique capable of preventing a decrease in manufacturing yield of a semiconductor device formed using a wiring board provided with a reinforcing conductor around a positioning opening provided in an insulating substrate. There is.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  The outline of the invention disclosed in the present application will be described as follows.

(1) forming a conductor film on the surface of the tape-like insulating substrate, etching the conductor film to form a conductor wiring and a reinforcing conductor along the longitudinal direction of the insulating substrate; In the method of manufacturing a wiring board in which the region where the reinforcing conductor is formed is punched to form an opening (perforation hole), the reinforcing conductor is formed so that the region where the opening is formed is opened by the etching process . Thereafter , the opening is formed by punching out an insulating substrate in a region where the reinforcing conductor is opened using a mold .

  According to the means of (1), when forming the reinforcing conductor, by opening a portion for forming the opening (perforation hole), only the insulating substrate is punched to form the opening. can do. Therefore, as compared with the conventional case where the insulating substrate and the reinforcing conductor are punched out, burrs (residues) are less likely to be generated in the opening. Further, by punching only the insulating substrate, it is possible to prevent generation of burrs and metal debris in the reinforcing conductor.

  In addition, it is possible to prevent the generation of the burrs and metal scraps in the opening and the reduction in the manufacturing yield of the wiring board due to the defective shape of the opening, thereby reducing the manufacturing cost of the wiring board.

  Further, at this time, the insulating substrate has a first opening (first perforation hole) formed along an end portion in a longitudinal direction, and the conductor film is formed inside the region where the first opening is formed. The conductive film is etched to form the conductor wiring and the reinforcing conductor, and the region where the reinforcing conductor is formed is punched to form a second opening (second perforation hole), and then the insulation The substrate is cut and removed outside the region where the second opening is formed.

(2) An opening (perforation hole) is provided along the longitudinal direction of the tape-shaped insulating substrate, a conductor wiring is provided on the surface of the insulating substrate, and the opening is formed around the opening of the insulating substrate. In the method of manufacturing a wiring board provided with a reinforcing conductor having an open top, the area of the opening of the reinforcing conductor is larger than the area of the opening of the insulating board, and the opening of the insulating board is This is a method for manufacturing a wiring board provided in an inner region of an opening of a conductor.

  According to the means of (2), since the opening of the insulating substrate is provided in the inner region of the opening of the reinforcing conductor, burrs and metal debris are formed inside the opening (perforation hole). Since it is hard to remain and there are few shape defects of an opening part, the fall of the positioning precision at the time of manufacturing a semiconductor device using the said wiring board can be prevented. Therefore, the manufacturing yield of the semiconductor device can be improved.

  In addition, since foreign matter such as metal scraps hardly remains inside the opening, when the semiconductor device is manufactured using the wiring board, the reliability of the device can be prevented from being deteriorated due to contamination of the foreign matter.

  Hereinafter, the present invention will be described in detail together with embodiments (examples) with reference to the drawings.

  In all the drawings for explaining the embodiments, parts having the same function are given the same reference numerals, and repeated explanation thereof is omitted.

  Of the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  (1) In a wiring board in which a reinforcing conductor is provided around a positioning opening (perforation hole) provided in an insulating substrate, it is possible to reduce burrs and foreign matter adhesion in the opening.

  (2) It is possible to improve the manufacturing yield of the wiring board in which the reinforcing conductor is provided around the positioning opening (perforation hole) provided in the insulating board, and to reduce the manufacturing cost of the wiring board.

  (3) It is possible to prevent a decrease in manufacturing yield of a semiconductor device formed by using a wiring board provided with a reinforcing conductor around a positioning opening provided in an insulating substrate.

(Example)
1 to 3 are schematic views showing a schematic configuration of a wiring board according to an embodiment of the present invention. FIG. 1 is a plan view of the wiring board, and FIG. 2 is an AA ′ of the wiring board shown in FIG. 3A is an enlarged plan view of a region L3 of the wiring board shown in FIG. 1, and FIG. 3B is a cross-sectional view taken along line BB ′ of FIG. .

  1 to 3, 1 is an insulating substrate, 1A is a second opening (perforation hole), 201 is a conductor wiring, 202 is a reinforcing conductor, 202A is an opening of the reinforcing conductor, L1 is a semiconductor device formation region, and L2 is The semiconductor chip mounting area, W1 is the length of one side of the opening 1A, W2 is the length of one side of the opening 202A of the reinforcing conductor, and W3 is the step width.

  As shown in FIGS. 1 and 2, the wiring board of the present embodiment is provided with a second opening (perforation hole) 1 </ b> A along the longitudinal direction of the tape-like insulating substrate 1, and the surface of the insulating substrate 1. In this wiring board, a conductor wiring 201 is provided, and a reinforcing conductor 202 having an opening on the second opening 1A is provided around the second opening 1A of the insulating substrate 1.

  At this time, the insulating substrate 1 has a tape shape that is long in one direction, and the conductor wiring 201 and the reinforcing conductor 202 are formed in a reel-to-reel method. As shown in FIG. 1, conductor wiring 201 having the same kind of pattern is provided in each of a large number of semiconductor device formation regions L1 provided in FIG.

  The wiring board is a wiring board used for a small and thin semiconductor device such as a COF (Chip On Film) type semiconductor device used for a driver IC of a liquid crystal display, for example. For example, a thin polyimide tape having a thickness of about 25 μm to 40 μm is used. Therefore, in order to prevent deformation during transport and tape breakage, the reinforcing conductor 202 is provided around the second opening (perforation hole) 1A, that is, along the end of the insulating substrate 1 in the longitudinal direction.

  Further, the area of the opening 202A of the reinforcing conductor is larger than the area of the second opening 1A of the insulating substrate, as shown in FIGS. The two openings 1A are provided in the inner region of the reinforcing conductor opening 202A. At this time, as shown in FIG. 3A, the shape of the second opening 1A of the insulating substrate is rectangular, and the length W1 of one side of the second opening (perforation hole) 1A is For example, since it is about 1.981 mm or 1.420 mm, the length W2 of one side of the opening 202A of the reinforcing conductor is formed to be slightly longer than the length W1 of one side of the second opening 1A. In addition, a step is formed between the inner wall of the second opening 1A of the insulating substrate and the inner wall 202A of the reinforcing conductor. At this time, the width W3 of the step is preferably equal on all four sides, and is set to be about 0.1 mm.

  4 to 9 are schematic views for explaining the method of manufacturing the wiring board according to the present embodiment. FIG. 4 is a plan view of a process for forming a conductor film on the surface of the insulating substrate. FIG. 5 is a plan view of FIG. FIG. 6 is a plan view of the step of forming the conductor wiring and the reinforcing conductor, FIG. 7 is a sectional view taken along the line DD ′ of FIG. 6, and FIG. FIG. 9 is a cross-sectional view taken along line EE ′ of FIG. 8.

  Hereinafter, the manufacturing method of the wiring board of the present embodiment will be described with reference to FIGS.

  First, as shown in FIGS. 4 and 5, a conductor film 2 is formed on the surface of a tape-like insulating substrate 1 that is long in one direction. At this time, the width of the insulating substrate 1 is wider than the width when used as the wiring substrate. For example, when the width when used as the wiring substrate in the process of forming a semiconductor device is 35 mm, the width is as follows. A 45 mm or 70 mm substrate is used. Further, at this time, in the region 102 outside the region 101 used as the wiring substrate of the insulating substrate 1, the first opening used for positioning when forming the wiring substrate along the longitudinal direction of the insulating substrate 1. (First perforation hole) 1B is formed.

  The conductor film 2 is formed by adhering, for example, an electrolytic copper foil or a rolled copper foil. At this time, the conductor film 2 is formed in the vicinity of the center of the insulating substrate 1 so as not to block the first opening 1B. And formed on the entire surface of the region 101 used as a wiring board.

  Next, as shown in FIGS. 6 and 7, the conductor film 2 is etched to form the conductor wiring 201 in the semiconductor device formation region L <b> 1 and the reinforcing conductor 202 along the end of the region 101 used as the wiring substrate. Form.

  At this time, the conductor wiring 201 and the reinforcing conductor 202 correspond to the patterns of the conductor wiring 201 and the reinforcing conductor 202 for forming a semiconductor device on the conductor film 2, as shown in FIG. A resist (etching resist) 3 is formed, and the conductor film 2 is formed by etching.

  At this time, the reinforcing conductor 202 forms the opening 202A larger than the area of the second opening 1A in a region where the opening (second opening) 1A is formed in a later step. The etching resist 3 on the conductor 202 is provided with an opening 3A.

  In addition, after the conductor wiring 201 and the reinforcing conductor 202 are formed, for example, a solder protective film or terminal plating is formed on the conductor wiring 201 although illustration is omitted.

  Next, as shown in FIGS. 8 and 9, the insulating substrate 1 in the opening 202A of the reinforcing conductor is punched out using a die, that is, a die 4 and a punch 5, for example, and a second opening (first 2 perforation holes) 1A is formed.

  At this time, the area of the opening 4A and the punch 5 of the die 4 is made smaller than the area of the opening 202A of the reinforcing conductor, and only the insulating substrate 1 is punched out. Therefore, as compared with the conventional case of punching the copper foil and the insulating substrate, burrs and metal debris are less likely to be generated inside the second opening 1A, and the shape defect inside the second opening 1A can be reduced.

  Thereafter, the insulating substrate is cut outside the region where the reinforcing conductor 202 is provided to remove the region 102 where the first opening 1B is formed, and the insulating substrate 1 is made to have a predetermined width, for example, 35 mm. By doing so, a wiring board as shown in FIGS. 1 and 2 can be obtained.

  In addition, before manufacturing the semiconductor device, the wiring board is subjected to, for example, a continuity inspection of the conductor wiring 201 and an inspection of electrical characteristics, and an inspection regarding a shape defect of the second opening 1A. At this time, if there are many defective shapes of the second opening 1A, the positioning accuracy in manufacturing the semiconductor device is lowered, and the manufacturing yield of the semiconductor device is lowered. For this reason, if the shape defect of the opening 1A is larger than a predetermined number (condition), the wiring board becomes a defective product, the manufacturing yield of the wiring board is reduced, and the manufacturing cost of the wiring board is increased. As in the example wiring board, the reinforcing conductor 202 is opened in advance, and only the insulating substrate 1 in the opening 202A is punched to form the second opening 1A, thereby forming the second opening 1A. Since the shape defects can be reduced, the manufacturing yield of the wiring board can be improved.

  The process of manufacturing a semiconductor device using the wiring substrate as shown in FIGS. 1 and 2 is the same as the conventional method of manufacturing a semiconductor device. For example, a semiconductor is mounted in each semiconductor chip mounting region L2 on the wiring substrate. A chip is mounted, the connection portion between the external electrode (bonding pad) of the semiconductor chip and the conductor wiring is sealed with a thermosetting resin, and each semiconductor device formation region L1 is cut into individual pieces.

  At this time, each of the steps is performed in a reel-to-reel manner, and positioning is performed using the opening (second opening) 1A of the wiring board. Therefore, like the wiring board of this embodiment, the first step is performed. By using a wiring board that is less likely to generate burrs and metal debris in the two openings 1A and has less shape defects, it is possible to improve the positioning accuracy using the second openings 1A and improve the manufacturing yield of the semiconductor device. Can do.

  As described above, according to the wiring board of this embodiment, an opening 202A is provided in a predetermined region of the reinforcing conductor 2 in advance, and only the insulating substrate 1 inside the opening 202A of the reinforcing conductor is made of gold. Since punching with a mold is less likely to generate burrs and metal debris than when punching a conventional copper foil and insulating substrate, reducing shape defects inside the opening (second opening) 1A of the insulating substrate 1 Can do.

  Moreover, since the shape defect inside the second opening 1A can be reduced, the manufacturing yield of the wiring board can be improved, and the manufacturing cost of the wiring board can be reduced.

  In addition, since the shape defect of the second opening 1A of the wiring board can be reduced, the accuracy of positioning using the second opening 1A when forming a semiconductor device using the wiring board. The manufacturing yield of semiconductor devices can be improved.

  In addition, since foreign matter such as metal scrap does not occur in the second opening 1A, it is possible to prevent the reliability of the device from being lowered due to the inclusion of foreign matter when the semiconductor device is formed using the wiring board.

  Moreover, in the said Example, as shown in FIG. 3, although demonstrated taking the case of the wiring board provided with the rectangular-shaped (square-shaped) 2nd opening part 1A, the said 2nd opening part 1A is demonstrated. Needless to say, the shape is not limited to this, and may be various shapes such as a circular shape, an oval shape, or a rectangular shape.

  FIG. 10 is a schematic view for explaining another method of manufacturing the wiring board of the embodiment, and FIGS. 10A and 10B are steps for forming the conductor wiring and the reinforcing conductor, respectively. FIG. 10A and 10B are cross-sectional views corresponding to the cross section taken along line D-D 'of FIG.

  In the method of manufacturing the wiring board of the embodiment, as shown in FIG. 7, a resist (etching resist) 3 is formed in a region where the conductor wiring 201 and the reinforcing conductor 202 are formed, and the conductor film 2 is etched. However, the present invention is not limited to this. For example, as shown in FIG. 10A, a resist (plating resist) 6 in which the regions for forming the conductor wiring 201 and the reinforcing conductor 202 are opened using the additive method. After forming the copper plating film 7 on the conductor film 2, the plating resist 6 may be removed, and the conductor film 2 may be etched using the copper plating film 7 as a mask.

  FIG. 11 is a schematic plan view showing an application example of the wiring board of the embodiment.

  In the wiring board of the above-described embodiment, as shown in FIG. 4, the case where one region 101 is used as the wiring board is shown. However, the invention is not limited to this, and a wider insulating substrate is used. Even if there are two (two) regions 101 used as a wiring board, or three (three) or more than three regions 101 as shown in FIG. Needless to say, the conductor wiring 201 and the reinforcing conductor 202 may be formed, and finally, the insulating substrate 1 may be cut along a cutting line and divided into a plurality of wiring substrates.

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

It is a model top view which shows schematic structure of the wiring board of one Example by this invention. It is a schematic diagram which shows schematic structure of the wiring board of a present Example, and is sectional drawing in the A-A 'line of the wiring board shown in FIG. FIG. 3A is a schematic diagram showing a schematic configuration of the wiring board of the present embodiment, FIG. 3A is an enlarged plan view of a region L3 of the wiring board shown in FIG. 1, and FIG. 3B is a diagram B in FIG. It is sectional drawing in the -B 'line. It is a schematic diagram for demonstrating the manufacturing method of the wiring board of a present Example, and is a top view of the process of forming a conductor film on the surface of an insulated substrate. It is a schematic diagram for demonstrating the manufacturing method of the wiring board of a present Example, and is sectional drawing in the C-C 'line | wire of FIG. It is a schematic diagram for demonstrating the manufacturing method of the wiring board of a present Example, and is a top view of the process of forming a conductor wiring and a reinforcement conductor. It is a schematic diagram for demonstrating the manufacturing method of the wiring board of a present Example, and is sectional drawing in the D-D 'line | wire of FIG. It is a schematic diagram for demonstrating the manufacturing method of the wiring board of a present Example, and is a top view of the process of forming a 2nd opening part. FIG. 9 is a schematic diagram for explaining a method for manufacturing a wiring board according to the present embodiment, and is a cross-sectional view taken along line E-E ′ of FIG. 8. FIGS. 10A and 10B are schematic views for explaining a modified example of the method of manufacturing the wiring board according to the embodiment, and FIGS. 10A and 10B are cross-sectional views of the process of forming the conductor wiring and the reinforcing conductor, respectively. . It is a schematic plan view which shows the application example of the wiring board of the said Example. It is a model top view which shows schematic structure of the conventional wiring board. It is a schematic diagram which shows schematic structure of the conventional wiring board, and is sectional drawing in the F-F 'line | wire of the wiring board shown in FIG. It is a schematic diagram for demonstrating the manufacturing method of the conventional wiring board, and is a top view of the process of forming a conductor film on the surface of an insulated substrate. It is a schematic diagram for demonstrating the manufacturing method of the conventional wiring board, and is sectional drawing in the G-G 'line | wire of FIG. It is a schematic diagram for demonstrating the manufacturing method of the conventional wiring board, and is a top view of the process of forming a conductor wiring and a reinforcement conductor. It is a schematic diagram for demonstrating the manufacturing method of the conventional wiring board, and is sectional drawing in the H-H 'line | wire of FIG. It is a schematic diagram for demonstrating the manufacturing method of the conventional wiring board, and is a top view of the process of forming a 2nd opening part. It is a schematic diagram for demonstrating the manufacturing method of the conventional wiring board, and is sectional drawing in the I-I 'line | wire of FIG. It is a schematic cross section for demonstrating the subject of the conventional wiring board.

Explanation of symbols

1 Insulating substrate 1A Opening (second opening)
DESCRIPTION OF SYMBOLS 1B 1st opening part 101 Area | region used as a wiring board 102 Area | region which forms 1st opening part 2 Conductor film 201 Conductor wiring 202 Reinforcement conductor 202A Reinforcement conductor opening part 3 Resist (etching resist)
4 Mold (die)
5 Mold (punch)
6 resist (plating resist)
7 Electrolytic copper plating film 8 Bali

Claims (2)

Form a conductor film on the surface of the tape-shaped insulating substrate,
Etching the conductor film to form a conductor conductor and a reinforcing conductor along the longitudinal direction of the insulating substrate,
In the method of manufacturing a wiring substrate, the region where the reinforcing conductor is formed of the insulating substrate is punched to form an opening (perforation hole).
The reinforcing conductor is formed so that the region for forming the opening is opened by the etching process,
In forming the opening by punching out the insulating substrate in the opening area of the reinforcing conductor using a mold ,
The area of the opening of the reinforcing conductor is larger than the area of the opening of the insulating substrate, and the opening of the insulating substrate is provided in an inner region of the opening of the reinforcing conductor. A method for manufacturing a substrate. The insulating substrate has a first opening (first perforation hole) formed along an end in the longitudinal direction,
Forming the conductor film inside the region where the first opening is formed;
Etching the conductor film to form the conductor wiring and the reinforcing conductor,
After punching the region where the reinforcing conductor is formed to form the second opening (second perforation hole),
The method for manufacturing a wiring board according to claim 1, wherein a region of the insulating substrate in which the first opening is formed is cut and removed.

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