United States Patent [I91
`Nakajima et al.
`
`[ill Patent Number:
`[451 Date of Patent:
`
`5,675,174
`Oct. 7, 1997
`
`[54] METHOD FOR USING FUSE STRUCTURE IN
`SEMICONDUCTOR DEVICE
`
`r/5]
`
`Inventors: Hirofumi Nakajima; Takanori Hitomi,
`both of Kyoto, Japan
`
`[73] Assignee: R o b Co., Ltd., Japan
`
`[21] Appl. No.: 547,278
`Oct. 24, 1995
`
`[22] Filed:
`
`Related U.S. Application Data
`
`4,692,190 911987 Komatsu ................................. 2571529
`4,740,485 411988 SharpeGeisler ........................ 2571529
`4,748,491 511988 Takagi ..................................... 2571529
`4,764,800 811988 Sander .................................... 2571529
`5,025,300 611991 Billig et al. ............................. 2571529
`5,329,152 711994 Janai et al. .............................. 2571529
`5,374,590 12/1994 Batdorf et al. .......................... 4371173
`FOREIGN PAlXN'I' DOCUMENTS
`
`58-60560 411983 Japan.
`2-33949 a1990 Japan ..................................... 2571529
`Primary Examiner-J. Carroll
`Attorney, Agent, or Fim-Merchant, Gould. Smith, Edell,
`Welter & Schmidt. PA.
`
`1631 Continuation of Ser. No. 177,930, Jan. 6, 1994, abandoned.
`POI
`Foreign Application Priority Data
`Japan .................................... 5-000470
`Jan. 6, 1993
`[JP]
`Japan .................................... 5-111764
`May13,1993
`[JP]
`Japan .................................... 5-111792
`May13,1993
`[JP]
`..................................................... HOlL 29/00
`~
`1
`[51] Int. ~
`.
`
`...........................
`1521 U.S. C1.
`257J529; 4371173; 4371922
`..................................... .,,,.,, ,,, a conseauence of a first laser beam awlication. However. a
`[58] Field of Search
`2571529, 209;
`4 3 I I l I 3 , Y L L
`
`[571
`
`ABSTRACT
`This invention provides a semiconductor device wherein a
`fuse structure can be formed of a nonnal metal wiring
`material and the fuse structure can be cut easily and surely.
`three times to the fuse structure
`A laser beam is
`cOm~Osed of anA1 wiring 22 and a passivation "Irn 24 to cut
`the fuse. The A1 wiring 22 is sublimated to be almost cut as
`
`part of sublimated aluminum is cooled and solidified to
`possibly hinder the cutting of the fuse. In order to cope with
`the above phenomenon, second and third laser beam appli-
`cations are effected on a point of coordinates P2 (P3) so that
`the area S2 (S3) is completely damaged
`
`15 Claims, 10 Drawing Sheets
`
`[561
`
`References Cited
`U.S. PATENT DOCUMENTS
`............................
`4,383,165 511983 Smith et al.
`2571529
`4,413,272 1111983 Mochizuki et al. .................... 2571529
`4,590,388 511986 Qemons et al. ........................ 2571529
`
`IPR2015-01087 - Ex. 1021
`Micron Technology, Inc., et al., Petitioners
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`1. FIELD OF THE INVENTION
`The present invention relates to a fuse structure in a lo
`semiconductor device, and more particularly to a simple and
`secure fuse structure and a method of cutting of the same.
`2. DESCRIPTION OF THE PRIOR
`Japanese Patent Laid-Open Publication No. SHO
`58-60560 discloses a semiconductor memory in which, 15
`when a defective portion is found in testing the device. the
`portion can be disconnected by a fuse structure. In the
`semiconductor memory, a plurality of redundancy circuits
`are connectedvia the fuse structure with which the defective
`portion is disconnected by the fuse structure and removed. 20
`The fuse structure has a laminate film structure in which a
`polysilicon film is covered with a molybdenum film. The
`cutting of the fuse is effected in the following manner.
`First. a laser beam. the energy being adjusted to an
`appropriate level, is applied to the fuse. With the above- 25
`mentioned operation, at the portion to which the laser beam
`is applied, the polysilicon film and the molybdenum film are
`heated to fuse and react with each other to form molybde-
`num silicide.
`When the fuse surfaceis subsequently thermally oxidated, 30
`an oxidation film having a thickness greater than that of the
`molybdenum silicide is formed on the surface of the molyb-
`denum. This is because the molybdenum silicide has an
`oxidation rate lower than that of the molybdenum.
`Then by selectively etching the molybdenum silicide by
`an etching method having a low etching rate with respect to
`molybdenum oxide and silicon oxide (e.g., chemical dry
`etching). the fuse is cut.
`By cutting the fuse, the defective portion is eliminated to 40
`compensate for the reduction of yield resulting in increasing
`integration density of semiconductor devices.
`With this method, the fuse is cut not by means of a laser
`beam but by fusing, and therefore the output of the laser
`beam can be suppressed. With the above-mentioned 45
`arrangement, the possible thermal influence of the fuse on its
`peripheral devices is reduced.
`However. the use of etching in the fuse structure described
`above results in the problem that the fuse cutting process is
`troublesome.
`Furthermore, in the above-mentioned method. a polysili-
`con film having a superior characteristic of cutting by a laser
`beam is required to be wired in order to form the fuse
`structure. Therefore. in a semiconductor device where no
`polysilicon film is used as a structural body, it is required to
`purposely form apolysilicon film specially for the formation
`of the aforementioned fuse structure.
`
`1
`METHOD FOR USING FUSE STRUCTURE IN
`SEMICONDUCTOR DEVICE
`
`'This is a continuation of application Ser. No. 081177,
`930, filed Jan. 6. 1994 abandoned".
`
`BACKGROUND OF THE INVENTION
`
`SUMMARY OF THE INVFBTION
`Accordingly, an object of the present invention is to solve
`the abovementioned problem and provide a fuse structure
`of a semiconductor device capable of being surely cut
`without complicating the manufacturing process and the
`method for using.
`A fuse structure in a semiconductor device comprises:
`a substrate;
`
`2
`a metal wire which has aportion to be cut as formed above
`the substrate; and
`a coating film to be coated on the metal wiring.
`A method for cutting the fuse having a substrate. a metal
`5 wire which has a portion to be cut as formed above the
`substrate, and a coating film to be coated on the metal
`wiring, comprises steps of:
`a first application step for applying a laser beam to a
`portion to be cut of the metal wiring, the application
`step resulting in a condition where a section surface and
`another section surface of the metal wiring are con-
`nected with each other by residual metal; and
`a second application step for applying a laser beam to the
`portion at least one time to remove the residual metal
`produced in the first application step.
`A fuse structure in a se&nductor
`device comprises:
`a substrate;
`a first metal wiring which has a portion to be cut as formed
`above the substrate and a first end and the other end;
`a first insulating portion adjacent to the first end of the first
`metal wiring;
`a second metal wiring insulated from the first metal
`wiring by the first insulating portion;
`a first region formed in the substrate below the first
`insulating portion;
`a first connecting portion for electrically connecting the
`first region with the first metal wiring;
`a second connecting portion for electrically connecting
`the first region with the second metal wiring; and
`a coating film for coating at least the first metal wiring.
`A method for cutting a fuse structure comprises steps of:
`a first application step for applying a laser beam to a
`portion to be cut of the metal wiring, the application
`step resulting in a condition where a section surface and
`another section surface of the metal wiring are con-
`nected with each other by residual metal; and
`a second application step for applying a laser beam to the
`portion at least one time to remove the residual metal
`produced in the first application step,
`said fuse structure comprising:
`a substrate;
`a first metal wiring which has a portion to be cut as
`formed above the substrate and a first end and the
`other end;
`a first insulating portion adjacent to the first end of the
`first metal wiring;
`a second metal wiring insulated from the first metal
`wiring by the first insulating portion;
`a first region formed in the substrate below the first
`insulating portion;
`a first connecting portion for electrically connecting the
`first region with the first metal wiring;
`a second connecting portion for electrically connecting
`the first region with the second metal wiring; and
`a coating film for coating at least the first metal wiring.
`The above, and other objects. features and advantages of
`the present invention will-become apparent from the fol-
`60 lowing description read in conjunction with the accompa-
`drawings, in which like reference numerals designate
`the ,,,
`elements.
`BRIEF DESCRIPTION OF THE DRAWINGS
`65 FIG. 1 is a view showing a method for manufacturing a
`fuse structure in accordance with an embodiment of the
`present invention;
`
`50
`
`'J &'
`J J
`
`12
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`5,675?
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`25
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`3
`14 and a p--type active base 16 are formed. Openings are
`FIG. 2 is a view showing a fuse structure in accordance
`formed at the oxidated insulating film 12 on the p--type
`with an embodiment of the present invention;
`active base 16 and the oxidated insulating film 1 2 on the
`FIG. 3 is a view of an exemplified circuit employing the
`n+-type diffusion region 8, and phosphorus is diffused into
`fuse structure;
`the openings to thereby form an n+-type emitter 18 in the
`FIG. 4A is a plan view for explaining a laser beam
`p--type active base 16.
`application portion of the fuse structure; FIG. 4B is a
`Subsequently. an A l wiring is formed between elements.
`sectional view taken along the line IVB-lVB in FIG. 4A;
`First. in a manner as shown in FIG. 2, the entire wafer
`FIG. 5A is a view showing the state of the fuse structure
`surface including the fuse structure formation region H1 is
`before laser beam application; FIG. 5B is a view showing lo
`covered with an insulating film 20 by the CVD method.
`the state of the fuse structure after a first laser beam
`Then the insulating film 20 is selectively etched by means of
`application;
`a resist to provide contact holes for drawing out wires.
`FIG. 6A is a view showing the state of the fuse structure
`Al is then sputtered onto the entire surface of the struc-
`after a second laser beam application; FIG. 6B is a view
`tural body including the fuse structure formation region H1
`showing the state of the fuse structure after a third laser 15
`to form a wiring pattern composed of a 0.5 pn-thick Al
`beam application;
`wiring 22. In order to protect the Al wiring 22, a silicon
`FIG. 7A and 7B are views showing a fuse structure in
`nitride film is deposited to a thickness of 1 pn by the CVD
`accordance with a second embodiment of the present
`method to be a passivation film 24.
`invention, wherein FIG. 7B is a plan view of the fuse
`Through the above-mentioned steps. a bipolar transistor is
`structure viewed from above a surface of a substrate, and 20
`formed in the transistor formation region TI. On the other
`FIG. 7Ais a sectional view taken along the line VIIA--VIIA
`hand, a fuse structure that has the Al wiring 22 as a metal
`in FIG. 7B;
`wire and the passivation film 24 as a coating film is formed
`FIG. 8 is a sectional view of an essential portion of a fuse
`in the fuse structure formation region HI.
`structure in accordance with a third embodiment of the
`Note that the functions and performance of the LSI are
`present invention;
`tested when the semiconductor device manufacturing pro-
`FTG. 9 is a sectional view of an essential portion of a fuse
`cess draws to a close. When the specifications of the
`structure in accordance with a fourth embodiment of the
`objective electric characteristic items are out of the ranges of
`present invention;
`the intended specifications, the fuse structure is cut to tune
`FTG. 10 is a sectional view of an essential portion of a fuse
`the defective specifications of the electric characteristic
`structure in accordance with a fifth embodiment of the 30
`items. For examole. in a circuit as shown in FIG. 3. the
`present invention;
`tuning is achieved by cutting any fuse (F1 to F4) connected
`FIG. 11A is a sectional view of an essential portion of a
`in pardel with resistors (R2 to R5) so that the fi distribution
`fuse structure in accordance with a sixth embodiment of the
`f d s within the range of the intended specifications.
`present invention; and FIG. 11B is a sectional view of an 35 me following describes a cutting
`of the fuse
`essential portion of a fuse structure in accordance with a
`structure based on FIGS. 4 through 6. FIG. 4Ais a top view
`seventh embodiment of the present invention.
`of a portion to which a laser beam is applied in the fuse
`structure. FIG. 4B is a sectional view of the fuse structure
`DESCRIPTION OF THE PFSFERRED
`taken along the line IVB-IVB in FIG. 4A (referred to as the
`EMBODIMENT
`40 "widthwise direction of the fuse" hereinafter) (including the
`The following describes a fuse structure for trimming in
`n-type silicon layer 6, oxidated insulating film 12, interlayer
`accordance with an embodiment of the present invention
`insulating film 20, Al wiring 22 and passivation film 24).
`with reference to the attached drawings. FIGS. 1 and 2 are
`Note that FIG. 2 is a sectional view of the fuse structure
`views showing a method for manufacturing a fuse structure
`taken along the line II-IT
`in FIG. 4A.
`in accordance with an embodiment of the present invention. 45
`~ i r s t , in order to cut the wiring 22 in the widthwise
`The fuse structure is fabricated with a bipolar transistor in
`direction of the fuse, a first laser beam application, i.e., the
`the Process of manufacturing an LSI- In s m +
` a fuse
`first application step is effected. The point of coordinates to
`structure is formed in a fuse StrUChKe formation region HI,
`is applied is determined to be the center
`which a laser
`and a bipolar transistor is formed in a transistor formation
`p l i, the widthwise direction of the fuse. The laser beam
`region TI.
`50 energy, beam size, and beam pulse are adjusted so that the
`First. in a manner as shown in FIG. 1. arsenic is diffused
`A1 wiring 22 is damaged throughout its entire width (width
`in a p-type silicon substrate 2 using an oxide film (not
`L1) at and around the center point P 1 (area S1) and so that
`shown) as a mask to form an n+-type diffusion layer 4.
`the damage does not reach the n-type silicon layer 6 and the
`Further, an n-type silicon layer 6 is formed on an upper
`oxidated insulating film 12.
`surface of the p-type silicon substrate 2 through epitaxial 55 Note that, in the present embodiment, LR2E manufac-
`growth.
`tured by NIKON was used as a laser repairing apparatus and
`the operation condition was such that the laser was Nd YLE
`After fonning a thermal oxidation Nm (not shown) on the
`semiconductor laser, the wavelength was 1047 nm, the
`wafer surface to form openings. n-type and p-type impurities
`intensity of energy was 4 to 8 JLJ, and the beam spot was a
`are successively diffused to form an n+-type diffusion region
`8 and a p+-type diffusion region 10. Note that the p+-type 60 6 to 10 pm square. The width of the employed fuse was not
`greater than 7 pm, and the thickness was 0.5 pn to 1.5 pn.
`W s i o n region 10 is an isolation diffusion layer for elec-
`trically isolating each transistor on the LSI chip.
`The passivation film 24 ensures cutting of fuse. The
`After removing the thermal oxidation film on the wafer
`passivation film 24 is covering the Al wiring 22. Therefore,
`when the energy of the laser beam is given to the A1 wiring
`surface by etching, the wafer surface is thermally oxidized
`again to form an oxidated insulating film 12. Then. boron 65 22 and Al is sublimated in the passivation film 24, the
`sublimated Al inflates in volume, with which the Al wiring
`ions are implanted into a region to be the base of the
`22 is burst and spattered together with the passivation film
`transistor. By dEusing the boron ions, a pf-type outer base
`
`13
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`24. With the above-mentioned operation, the fuse is almost
`embodiment, another semiconductor device may be formed
`cut in the laser beam application region as shown in FIG. 5B. instead. The present invention may be utilized in tuning in
`conformity to the intended electric standards by connecting
`In contrast to the above, when the passivation film 24 is
`a circuit element such as a capacitor or a resistor with the
`not provided, by applying a laser beam from above the fuse
`structure as shown in FIG. 5A, the energy of the laser beam j fuse structure.
`is given to the Al wiring 22, with which Al is sublimated
`Although the aluminum wiring film is used as the metal
`momentarily. The sublimated Al is liquefied near the cut
`wiring film in the present embodiment, tungsten may be
`portion by being cooled to be subsequently solidified. With
`used instead, or an aluminum alloy such as AlSi, AlSiCu. or
`the above-mentioned actions, the fuse is not cut.
`AlCu may be used as the wiring film.
`Although no sufficient theoretical corroboration is pro- lo Although the silicon nitride filmis used as the coating film
`vided for the operation of the passivation film 24, the
`to be coated on the metal wiring film in the present
`inventor considers it as described above.
`embodiment, a silicon oxide film or the like may be used
`Note that a part of aluminum burst spattered together with
`instead.
`the passivation film 24 is possibly solidified near the cut
`Note that the film thicknesses of the metal wiring film and
`portion creating an aluminum fragment 26 when it is cooled
`the coating film as well as the areas S1 through S3 to be
`When such an aluminum fragment 26 is existing, the fuse is
`damaged by a laser beam are not limited to those described
`possibly not completely cut depending on the adherence
`in the above-mentioned embodiment.
`condition of the fragment. In anticipation of the above-
`Although three times laser beam applications are effected,
`mentioned condition. second and third laser beam applica-
`two or not less than four times laser beam applications may
`tions are subsequently effected. In the present embodiment,
`be effected
`the second and third laser beam applications correspond to 20 Although the wiring 22 is cut throughout the entire
`the second application step.
`width thereof (width L1) in the first laser beam application
`process in the present embodiment, a part of the entire width
`The second laser beam application sets its target at a point
`of the Al wiring 22 may be cut off in the first time and the
`of coordinates F'2 located slightly outside of theAl wiring 22
`remaining portion may be removed in any of the second and
`on the passivation film 24. The laser beam energy, beam
`size, and beam pulse are adjusted so that only an edge 25 subsequent laser beam application processes.
`portion of the Al wiring 22 will be damaged (area S2) at and
`According to the fuse structure and the circuit cutting
`around the point of coordinates F'2. When a laser beam is
`method of the present invention, the metal wiring film is
`applied from above as a second application in the condition
`coated with a coating film. Therefore, the metal wiring film
`as shown in FIG. 5B where the first application has been
`is effectively sublimated in comparison with the case where
`effected, a residual aluminum fragment 26a is sublimated to 30 no coating film is providing when a laser beam is applied to
`the fuse structure in the first application step, with which the
`thereby obtain a section surface as shown in FIG. 6A.
`fuse is almost cut throughout the entire width thereof.
`In the third time, the laser beam application sets its target
`at a point of coordinates P3 on the side opposite from the
`When a part of the sublimated metal wiring film is cooled
`target point in the second time. In the above time, the laser 3j and solidified again near the edge portions of the metal
`wiring film, the fuse can be completely cut because the
`beam energy, beam size, and the beam pulse are adjusted so
`remaining metal wiring film is removed in the second laser
`that an area S3 is damaged at and around the point of
`coordinates P3. In the present embodiment. the second and
`beam application step. Therefore, the defective portion of
`third laser beam applications are effected by adjusting the
`the semiconductor device can be disconnected easily and
`beam size at the same laser energy. By changing the beam 40 surely at the portion of the fuse structure to allow the yield
`size in a manner described as above, the quantity of heat per
`to be increased.
`unit area can be increased. Therefore, when the width L1 of
`Furthermore, circuit elements such as a capacitor or a
`the Al wiring 22 is great, the portions which tend to be
`resistor can be made to conform to the intended specifica-
`bridged can be concentratedly cut.
`tions easily and surely by the fuse trimming.
`When a laser beam is applied from above as a third 4j Furthermore, according to the fuse structure of the present
`application in the condition as shown in FIG. 6A where the
`invention, the metal wiring film is formed of aluminum,
`second application has been effected, a residual aluminum
`aluminum alloy, or tungsten. Therefore, the fuse structure
`fragment 26b is sublimated to thereby obtain a section
`can be fo-d
`of the metal material employed in a semi-
`surface as shown in FIG. 6B. By thus effecting the first
`conductor device such as a semiconductor memory or in the
`through third laser beam applications. the fuse can be cut. 50 process of manufacturing a circuit element such as a capaci-
`The fuse can be completely cut without damaging the
`tor or a resistor. Therefore, it is not required to prepare
`n-type silicon layer 6 and the oxidated insulating film 12.
`another material exclusively for the formation of the fuse
`Three times laser beam applications are effected by adjust-
`structure, meaning that a metal wiring film can be easily
`ing the laser beam energy, beam size, and beam pulse in the
`formed
`laser beam application process so that damage does not jj
`Since the coating film is composed of a silicon oxide film
`reach the n-type silicon layer 6 and the oxidated insulating
`or a sacon nitride film in the fuse structure of the present
`film 12.
`invention, the coating film can be formed of a passivation
`When the width L1 of the Al wiring 22 is narrow, the areas
`film or a silicon oxide film employed in the process of
`S2 and S3 may each have the same area as that of the area
`manufacturing a semiconductor device such as a semicon-
`S1. The above is because, when the width L1 of the Al 60 ductor memory. The above-mentioned arrangement allows
`wiring 22 is narrow, the fuse can be completely cut even
`the coating film to be easily formed.
`when the quantity of heat per unit area is small. There may
`FIGS. 7A and 7B show a fuse structure for triwning in
`be adjusted not only the beam size but also either one or both
`accordance with a second embodiment of the present inven-
`of the beam pulse and the laser energy according t~ the
`tion. The fuse structure has a region C1 and regions B1 and
`thickness of the Al wiring, coating film. or the like to be cut. 65 B2 provided on opposite sides of the region C1. FIG. 7A is
`Although a bipolar transistor is formed as a semiconduc-
`a sectional view taken along the line VIIB-VDB
`in FIG.
`tor device connected to the fuse structure in the present
`7B.
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`surface of the film. The corrosion which has started from the
`The region C1 is a region for cutting an Al wiring by
`section surface advances via the contact 34 to the n+-type
`applying a laser beam to the film. As a substructure of the
`diffusion region 36. However, no corrosion takes place
`region C1, there is provided a n--type epitaxial growth layer
`inside the n+-type diffusion region 36 and the corrosion stops
`37 as surrounded by a pt-type diffusion layer 40. In the
`region C1. there are further provided in order a cutting-use 5 there.
`wiring 43 as a first metal wire and a passivation film 24 as
`Note that the n--type epitaxial growth region 37 is fo-d
`a coating film. The ~assivation film 24 is formed of a silicon
`as a substructure of the region C1 so that it is surrounded by
`nitride film.
`the p+-type region 40 in the second embodiment (refer to
`FIGS. 7A and 7B). Therefore, even if the insulating film 32
`The regions B1 and B2 prevent the possible corrosion of
`aluminum from advancing toward the semiconductor device 10 is damaged and the cutting-use Al wiring 43 is short-
`from the section surface of the cutting-use Al wiring 43 cut
`circuited with the silicon substrate. the electric potential at
`the cutting-use Al wiring 43 can be stabilized.
`by laser beam application. When the section surface of the
`cutting-use Al wiring 43 is exposed to air, aluminum is
`The above is because the cutting-use Al wiring 43 is
`oxidated to corrode. It is possible that the corrosion will not
`connected to a positive bias, and therefore the n--type
`stop near the section surface to advance to the semiconduc- 15 epitaxial growth region 37 becomes positive when the
`tor device dong the cutting-use wiring 43 as time elapses
`cutting-use Al wiring 43 is short-circuited with an n--type
`to damage the device. For the above reason, the region B1
`epitaxial growth region 37. On the other hand, the p-type
`stops the advancing of the corrosion of aluminum
`silicon substrate 2 and the p+-type region 40 are connected
`The following describes a substructure of the region B1.
`to a ground bias, and therefore the n--type epitaxial growth
`An n+-type diffusion layer 36a as a difFusion layer is 20 region 37 and the pt-type region 40 form a p-n junction to
`provided in n--type layer 28. At a first end 43a of the
`be biased backward. Consequently, there is formed no
`cutting-use Al wiring 43 is adjacently provided a first
`current between the n--type epitaxial growth region 37 and
`insulating portion 55. The first insulating portion 55 is also
`the p+-type region 40, for which the cutting Al wiring 43
`adjacent to a first connection-use A1 wiring 42a as a
`receives no influence from the substrate potential.
`connection-~se metal wiring. The first co~nection-~se Al 25 Although the nP-type layer 28 is provided on the p-type
`wiring 4 k and the cutting-use wiring 43 are insulated
`silicon substrate 2 and the n+-type diffusion region 36 is
`from each other by the first insulating portion 55. Note that
`formed on the n--type layer 28 in the aforementioned second
`the wiring 4% is connected to the semiconductor device.
`embodiment, a region may be provi&d inside the p-type
`The cutting-use Al wiring 43 and the n+-type diffusion
`silicon substrate 2. FIG. 8 shows a third embodiment where
`layer 36a are connected with each other by way of a contact 30 an n--type region 46a and 46c and an n-type region 48a and
`48b are provided in the ptype silicon substrate 2. Note that
`34u as a first connecting portion. The connection-use Al
`wiring 42u and the n+-type diffusion layer 36a are connected
`the structure shown in FIG. 8 does not have the backward
`with each other by way of a contact 34b as a second
`bias construction.
`connecting portion.
`FIG. 9 shows a fourth embodiment. In the present
`The following describes a substructure of the region B2.
`embodiment, a two-layer Al wiring is provided. In a region
`An n+-type diffusion layer 36c as a diffusion layer is
`C1 of the fuse structure, a cutting-use Al wiring 43 and a
`passivation film 24 are formed in order on an insulating film
`provided in the n--type layer 28. At a second end 43c of the
`cutting-use Al wiring 43 is adjacently provided a second
`32 via an interlayer insulating film 50. The cutting-use Al
`insulating portion 57. The second insulating portion 57 is 40 wiring 43 is connected to a contact-use Al wiring 52 at a
`also adjacent to a comection-use Al wiring 42c as a third
`lower layer portion. When the cutting-use Al wiring 43 in an
`metal wire. The connection-use Al wiring 42c and the
`upper layer portion is cut by a laser beam, the corrosion of
`cutting-use Al wiring 43 are insulated from each other by
`aluminum advances from the section surface of the cutting-
`way of the second insulating portion 57. Note that the
`use Al wiring 43 toward the contact-use Al wiring 52,
`connection-use Al wiring 42c is connected to the semicon- 45 however, the corrosion stops at the n+-type diffusion region
`36. With the above-mentioned arrangement. the corrosion of
`ductor &vice.
`the metal wiring taking place in the region can be prevented
`The cutting-use wiring 43 and the n+-type diffusion
`from advancing toward a c~nnection-use metal wiring as a
`layer 36c are connected to each other by way of a contact
`3 4 ~ as a third connecting portion. The connection-use Al wiring of a semiconductor element. Therefore, the yield in
`wiring 4zc and the n+-type diffusion layer 3(jc are connected 50 manufacturing the semiconductor device can be increased.
`with each other by way of a contact 34d as a fourth
`Instead of the abovementioned arrangement, the region
`B1 may be composed of the npn structure (not shown).
`connecting portion.
`Although the fuse structure is fabricated with the semi-
`The above-mentioned fuse structure is fabricated together
`conductor device in the above-mentioned embodiment, the
`with semiconductor devices (not shown) on both sides
`thereof, and the functions and performance of each semi- 55 present invention may be utilized in tuning in conformity to
`conductor device are tested at the time the manufacturing
`the intended electric standards by connecting a circuit ele-
`process draws to a close. 'When the specifications of the
`ment such as a capacitor or aresistor with the fuse structure.
`Although the comection-use Al wiring 42 is provided on
`objective electric characteristic items are out of the ranges of
`both sides of the region C1. the connection-use Al wiring 42
`the intended specifications through a test, the cutting-use Al
`wiring 43 is cut to tune the specifications of the electric 60 may be provided on one side of the region C1 as connected
`with the semiconductor device or the like, and the other end
`characteristic items. The method for cutting the fuse struc-
`of the region C1 may have another structure.
`ture is the same as in the first embodiment, and therefore no
`description therefor is provided herein.
`There is further provided a diffusion layer in the silicon
`In applying the laser beam, a part of the passivation film substrate. The diffusion layer electrically connects the
`24 spatters away simultaneously with the sublimation of Al 65 cutting-use metal wiring with the connection-use metal
`in a manner as described above. The cutting-use Al wiring
`wiring. and after the metal wiring is cut by a laser beam, it
`43 is exposed. Therefore. corrosion starts from the section
`prevents the corrosion of the metal wiring from advancing
`
`35
`
`15
`
`

`
`5,675,174
`
`10
`9
`from the section surface. Therefore, the corrosion of the
`Consequently, there is formed no current between the short-
`metal film can be prevented from advancing toward the
`circuited n--type epitaxial growth layer 29 and the p+-type
`connection-use metal wiring film as a wiring of a semicon-
`region 41, for which the cut Al wiring 22 receives no
`ductor element.
`influence from the substrate potential.
`Furthermore, since aluminum or the like is used for the 5
`FIG. 11B shows a fuse structure in accordance with a
`metal wiring and a passivation film or the like can be used
`seventh embodiment. In the present embodiment. no epi-
`for the coating film, the fuse structure can be formed of the
`taxial growth layer is formed, and a p--type region 56 and
`material common to the circuit elements such as the semi-
`an n-type region 58 are directly formed in an n-type silicon
`substrate 54.