Source: https://patents.google.com/patent/JP4861051B2/en
Timestamp: 2020-08-12 19:34:15
Document Index: 331631925

Matched Legal Cases: ['art 212', 'art 212', 'art 212', 'art 212', 'art 214', 'art 142', 'art 142']

JP4861051B2 - Semiconductor device and electrical fuse cutting method - Google Patents
Semiconductor device and electrical fuse cutting method Download PDF
JP4861051B2
JP4861051B2 JP2006130702A JP2006130702A JP4861051B2 JP 4861051 B2 JP4861051 B2 JP 4861051B2 JP 2006130702 A JP2006130702 A JP 2006130702A JP 2006130702 A JP2006130702 A JP 2006130702A JP 4861051 B2 JP4861051 B2 JP 4861051B2
JP2006130702A
JP2007305693A (en
岳洋 上田
2006-05-09 Application filed by ルネサスエレクトロニクス株式会社 filed Critical ルネサスエレクトロニクス株式会社
2006-05-09 Priority to JP2006130702A priority Critical patent/JP4861051B2/en
2007-11-22 Publication of JP2007305693A publication Critical patent/JP2007305693A/en
2012-01-25 Publication of JP4861051B2 publication Critical patent/JP4861051B2/en
239000004065 semiconductors Substances 0.000 title claims description 68
239000004020 conductors Substances 0.000 claims description 82
239000002184 metals Substances 0.000 claims description 54
The present invention relates to a semiconductor device and a method for cutting an electric fuse, and more particularly to a semiconductor device including an electric fuse and a method for cutting an electric fuse.
Conventionally, a technique is known in which a fuse is mounted on a semiconductor device, and a resistance value used in the semiconductor device is adjusted by cutting the fuse or a defective element is separated and replaced with a normal element. Yes.
As a method of cutting the fuse, a method of cutting the fuse by irradiating a part of the fuse with a laser or a method of cutting the fuse with an electric current is used.
Patent Documents 1 to 3 disclose an electrical fuse that is cut using a phenomenon in which a material constituting the fuse moves due to electromigration.
Japanese Patent Application Laid-Open No. 2005-39220 discloses a fuse that can be cut with a smaller current. In Patent Document 1, the conductor constituting the fuse is formed in a shape that is bent back multiple times. FIG. 9 is a plan view showing the fuse disclosed in Patent Document 2. FIG. Here, the fuse 1100 is folded twice.
The fuse 1100 includes a current inflow terminal 1101, a current outflow terminal 1102, and a first forward straight line portion 1103, a backward straight line portion 1104, and a second forward straight line portion 1113 between the two terminals. The fuse 1100 further includes a first right angle connecting portion 1106 that connects the first forward straight line portion 1103 and the return straight line portion 1104, and a second right angle connecting portion 1107 that connects the second forward straight line portion 1113 and the return straight line portion 1104. In the fuse 1100 configured as described above, when a predetermined current flows from the current inflow terminal 1101 to the current outflow terminal 1102, the heat generated in the hatched portion 1108 outside the fuse 1100 is transferred to the hatched portion 1109 inside the fuse 1100. Added to the generated heat, the cutting of the return straight line portion 1104 sandwiched by the shaded portion 1109 is accelerated. Thereby, the fuse 1100 is easily cut.
Further, in Patent Document 3 (Japanese Patent Laid-Open No. 2005-57186), by enclosing a portion to be cut of a fuse with a plate, heat generated in the cut portion of the fuse when a current is passed through the fuse is detected in the fuse. A configuration in which confinement or accumulation in the vicinity of the cut portion is disclosed.
In Patent Document 4 (Japanese Patent Laid-Open No. 2004-186590), a conductive layer and an insulating film are formed in this order in or on a semiconductor substrate, and a connection hole that penetrates the insulating film and reaches the upper surface of the conductive layer is provided. A semiconductor device is disclosed. The semiconductor device has a flat portion formed on the insulating film, a bend defining a cavity portion formed continuously on the side surface and bottom surface of the connection hole on the insulating film, and having a shape whose diameter is reduced upward. A wiring layer including a portion. Here, the shape of the wiring layer formed in the connection hole is bent and thinned at the lower part of the connection hole. The structure is a fuse element structure, and the thin portion has a high resistance. Therefore, the minimum current value that can cut the electrical connection between the lower wiring layer and the upper wiring layer can be reduced. With such a configuration, it is said that a fuse element structure and a multilayer wiring structure that can be easily cut even at a low current density can be formed with good consistency.
US Patent No. 4064493 JP-A-2005-39220 JP 2005-57186 A JP 2004-186590 A
However, the technique described in Patent Document 4 forms a cavity in the connection hole in a state before the fuse element is cut. Therefore, a special process is required to form such a cavity. In addition, it is necessary to form an insulating film on the cavity under the condition that the cavity is not filled, so that the formation of the insulating film is limited. Further, such a fuse element structure cannot be manufactured simultaneously with a dual damascene multilayer wiring structure in which vias and wirings are formed simultaneously.
Further, as described in Patent Documents 1 to 3, when the fuse is cut using a phenomenon in which the material constituting the fuse moves due to electromigration, when the semiconductor device is subjected to heat treatment after the fuse is cut, the material becomes There is a possibility that re-migration occurs due to electromigration and reconnection occurs at the cut point. If such reconnection occurs, the correct result cannot be obtained when detecting whether or not the electrical fuse to be cut is cut even if the electrical fuse to be cut is cut. Become.
The possibility of reconnection as described above is not so high, and it is considered that there is no problem with the amount used for normal operation, but when the reliability of semiconductor devices is very high or under severe conditions For example, when the electric fuse is used in the above, it is necessary to further improve the holding characteristic that the cut electric fuse holds the cut state.
The present inventor has found a new method different from the conventional fuse cutting method in the method of cutting the fuse by current.
An electrical fuse formed on the semiconductor substrate and composed of a conductor;
In a state before cutting, including a first wiring formed in different layers, a via connected to the first wiring, and a second wiring connected to the via,
In the cut state, an outflow portion is formed in which the conductor flows out from the second wiring, and a gap is formed between the first wiring and the via or in the via. A semiconductor device is provided.
The inventor controls the configuration of the electrical fuse and the method of applying voltage to the electrical fuse to forcibly cause the conductor constituting the electrical fuse to flow out to the outside when the electrical fuse is cut. And found a new cutting method for electrical fuses that breaks the balance between the movement and supply of materials to form large cuts in other parts. Thereby, the cut state of the cut electric fuse can be kept good.
The electric fuse of the present invention is different from the conventional electric fuse in that an “outflow portion” is formed in the cut state. Here, “outside” can be outside the region where the second wiring was formed in the state before cutting, for example, outside the wiring groove where the second wiring was formed. Can do. By setting it as such a structure, the space | gap part used as a cutting location can be formed largely. In addition, since the gap is provided at a location different from the outflow portion, the possibility that the cut electrical fuse is reconnected can be greatly reduced.
Further, according to the semiconductor device of the present invention, in the state before cutting, the electrical fuses are formed in different layers, the vias connected to the first wirings, and the vias connected to the vias. Second wiring. By applying excessive power to the electric fuse having such a configuration, an outflow portion is formed in a wiring portion having a large area in the in-plane direction of the semiconductor substrate, and a via having a small area in the in-plane direction of the semiconductor substrate. A gap can be provided in the portion. That is, the outflow part and the gap part can be easily formed by configuring the electric fuse with a connection structure between the wiring and the via. Moreover, the cut state of the cut electric fuse can be kept good.
An electric circuit including a first wiring formed on a semiconductor substrate and made of a conductor and formed in a different layer, a via connected to the first wiring, and a second wiring connected to the via A method of cutting a fuse,
A predetermined voltage is applied between the first wiring and the second wiring to cause a current to flow through the electrical fuse, causing the conductor to flow out of the second wiring and the via and A method for cutting an electric fuse is provided which forms a gap between a first wiring and the via.
According to the method for cutting an electric fuse of the present invention, in the cut state, the conductor constituting the electric fuse is caused to flow outward from the second wiring to form the gap portion. Can be formed. Further, since the gap is provided at a location different from the location where the conductor has flowed out, the possibility of reconnecting the cut electrical fuse can be greatly reduced. Thereby, the cut state of the cut electric fuse can be kept good.
In addition, according to the present invention, there is provided a method for manufacturing a semiconductor device, including a step of selecting a fuse to be cut and a step of cutting the electric fuse to be selected by the method for cutting the electric fuse.
According to the present invention, the cut state of the cut electric fuse can be kept good.
In the embodiment of the present invention, the electric fuse can be constituted by a laminated structure of wiring, vias and wiring. These wirings and vias can each be formed in an insulating film. Further, the conductor constituting the wiring and the via can be composed of a copper-containing metal film containing copper as a main component. Further, the side walls and bottom surfaces of the wiring and vias can be covered with a barrier metal film. In addition, a barrier insulating film may be formed on the wiring surface.
In the present embodiment, the electric fuse having such a configuration is cut in the following procedure.
(1) An excessive power is applied to the electric fuse, and, for example, electrons are excessively injected from the upper layer wiring, thereby heating the wiring and the via.
(2) The conductor constituting the heated wiring and via expands, and a crack is generated in the surrounding insulating film and barrier metal film. At this time, a crack is generated around a wiring having a large area in the in-plane direction of the semiconductor substrate (that is, a wiring having a large volume).
(3) The conductor flows out into the crack of the insulating film or the barrier metal film, and the density of the conductor constituting the electric fuse is lowered.
(4) Along with this, the conductor in the via portion having a small area in the in-plane direction of the semiconductor substrate (that is, the via portion having a small volume) is sucked up in the direction in which the conductor flows out. As a result, a cut portion is generated in the via portion, and the electric fuse is cut.
The method for cutting an electric fuse by the above method is called “crack assist type”. First, the operation when the electric fuse is cut with the crack assist type will be described.
FIG. 1 is a diagram showing a state when an electric fuse is cut by a crack assist type.
The electric fuse 200 has a conductor 206 and a first terminal 202 and a second terminal 204 provided at one end and the other end, respectively. The conductor 206 constitutes a wiring or a via. Here, it is shown as a straight line for ease of explanation. The electric fuse 200 is an electric fuse (E fuse) in which the conductor 206 is cut by passing a current between the first terminal 202 and the second terminal 204. The electric fuse 200 can be formed on a semiconductor substrate (not shown). Here, when the electric fuse 200 is cut, the first terminal 202 is set to a high voltage (for example, Vcc) and the second terminal 204 is set to a low voltage (for example, ground). As a result, a current flows from the first terminal 202 to the second terminal 204. Therefore, electrons move from the second terminal 204 toward the first terminal 202. When a current exceeding a predetermined current value flows between the first terminal 202 and the second terminal 204, an outflow portion 212 is formed in which the conductor 206 flows out to the outside. In addition, along with the formation of the outflow portion 212, the conductor 206 suddenly moves in the direction of the outflow portion 212, and the cut portion 214 is formed.
When the cut portion 214 occurs in the conductor 206, no current flows through the conductor 206, and the conductor 206 is gradually cooled. At this time, for example, as shown in FIG. 1A, when the outflow portion 212 is formed on the second terminal 204 side of the cutting portion 214, the cutting portion is between the outflow portion 212 and the cutting portion 214. The tension during cooling acts from 214 to the outflow portion 212, and the conductor 206 moves in the direction of the outflow portion 212. In addition, between the cut portion 214 and the first terminal 202, the conductor 206 is not connected to the first terminal due to the influence of electron movement when a current flows between the first terminal 202 and the second terminal 204. Move in the direction of the terminal 202. As a result, the conductors 206 move in opposite directions on both sides of the cut portion 214, so that the cut portion 214 can be formed sufficiently large.
For example, as shown in FIG. 1B, when the outflow portion 212 is formed closer to the first terminal 202 than the cutting portion 214, the cutting portion 214 is between the cutting portion 214 and the outflow portion 212. The tension at the time of cooling acts in the direction of the outflow part 212 to the outflow part 212, and the conductor 206 moves in the direction of the outflow part 212. At this time, the conductor 206 is disconnected between the cut portion 214 and the second terminal 204 due to the influence of electron movement when a current flows between the first terminal 202 and the second terminal 204. Move in the direction of location 214. However, the amount by which the conductor 206 moves in the direction of the cut portion 214 is smaller than the amount by which the conductor 206 moves in the direction of the outflow portion 212. In the present embodiment, when the electric fuse 200 is cut, a large amount of the conductor 206 flows into the outflow portion 212, and the cut portion 214 can be enlarged. Thereby, the cutting location 214 can be kept sufficiently large.
Further, for example, as shown in FIG. 1C, outflow portions 212 are formed at two places between the cut portion 214 and the first terminal 202 and between the cut portion 214 and the second terminal 204. In this case, the tension during cooling acts in the direction of the two outflow portions 212, and the conductor 206 moves in the direction of the two outflow portions 212. As a result, the conductors 206 move in opposite directions on both sides of the cut portion 214, so that the cut portion 214 can be formed sufficiently large.
Next, a method for applying a voltage to the electric fuse 200 will be described.
As described above, in the present embodiment, excessive power is applied to the electric fuse 200 to form the outflow portion 212 in the conductor 206 and cause the cut portion 214 to occur. In the present embodiment, a voltage of about 2 to 5 V, for example, is applied between the first terminal 202 and the second terminal 204. Thereby, the outflow part 212 and the cutting part 214 can be formed in the electric fuse 200.
FIG. 2 is a diagram illustrating a circuit configuration including the electric fuse 200.
The first terminal 202 of the electric fuse 200 is connected to the power supply line 222, and the second terminal 204 is connected to one of the source and drain of the transistor 220. The other of the source and drain of the transistor 220 is grounded. Although not shown here, a plurality of electrical fuses 200 are formed on the semiconductor substrate, and the plurality of electrical fuses 200 are connected to the power supply line 222. Therefore, the stray capacitance 224 is added to the power supply line 222. A procedure for cutting the electric fuse 200 in the circuit thus configured will be described.
In this embodiment mode, the power supply line 222 is turned on and the transistor 220 is turned on, whereby the power supply voltage VCC is applied to the first terminal 202 and the second terminal 204 is grounded. Current flows through 206. As a result, a cut portion is generated in the conductor 206. Here, when voltage is applied to the electric fuse 200, the transistor 220 can be turned on after the power supply line 222 is turned on.
FIG. 3 is a diagram illustrating the on-timing of the transistor and the voltage value applied between the first terminal and the second terminal of the electric fuse.
In the figure, the lower solid line shows the on / off state of the transistor 220, and the upper solid line shows the state of the potential applied to the first terminal 202 of the electric fuse 200. The timing at which the transistor 220 is turned on is indicated by a dashed line in the figure. When the transistor 220 is turned on after the power supply line 222 is turned on, an instantaneous voltage drop occurs at the timing when the transistor 220 is turned on, but the potential immediately becomes VCC . Therefore, when the transistor 220 is turned on, the voltage value Vcc is applied to both ends of the electric fuse 200, and excessive power is applied to the electric fuse 200. Thereby, the conductor 206 can be flowed outward to form the outflow portion 212 and the large cut portion 214 can be formed.
FIG. 4 is a diagram illustrating another example of the circuit configuration of the semiconductor device 100 including a plurality of electrical fuses 200.
Here, the first terminal 202 can be connected to a circuit having a capacity capable of storing a charge amount sufficiently larger than the charge amount that is reduced by cutting the electric fuse 200. The power supply line 222 is connected to the external power supply 302 via the external terminal 300. The power supply line 222 is connected to a circuit having a sufficiently large capacity, such as an external capacitor 304 or an ESD protection circuit 306. The external capacitor 304 can be configured to be provided outside the chip such as a probe card. The power supply line 222 can be configured to be connected to both the external capacitor 304 and the ESD protection circuit 306, or can be configured to be connected to one of them.
Here, for example, the capacitance of the stray capacitance 224 is C 0 , and the capacitance of the external capacitance 304 and the ESD protection circuit 306 connected to the power supply line 222 is C 1 . Further, when the voltage supplied from the external power source 302 and V CC, a charge amount Q before electrical fuse 200 cut is stored in the semiconductor device 100,
Q = (C 0 + C 1 ) × V CC
Assuming that the current that flows when the electric fuse 200 is cut is I cut , and the time taken to cut the electric fuse 200 is T cut , the amount of charge that is reduced by cutting the electric fuse 200 is
ΔQ = I cut × T cut
In the present embodiment, C 0 and C 1 can be set so that ΔQ / Q <0.01 (formula 1). Thereby, as shown in FIG. 3, a voltage drop that occurs for a moment when the transistor 220 is turned on can be suppressed. In the case where a large number of electric fuses 200 are connected to the power supply line 222 and Equation 1 is satisfied with only the capacitance C 0 of the stray capacitance 224, the external capacitor 304 and the ESD protection circuit 306 are not connected to the power supply line 222. You can also. Further, when Expression 1 is satisfied with only one of the capacitor C 0 , the external capacitor 304, and the ESD protection circuit 306, only one of the external capacitor 304 and the ESD protection circuit 306 is connected to the power supply line 222. can do.
The semiconductor device 100 is configured as described above, and the conductor 206 is cut with excessive power by applying a voltage according to the procedure described with reference to FIG. As a result, the conductor 206 is allowed to flow outward to form the outflow portion 212 and a large cut portion 214 can be formed.
Next, a specific configuration of the electric fuse 200 in the present embodiment will be described. In the present embodiment, the electric fuse 200 is configured with a multilayer wiring structure.
FIG. 5 is a schematic top view showing the configuration of the electric fuse 200 in the present embodiment.
Here, the first terminal 202 and the lower layer wiring 122 (first wiring) are formed in the lower layer. The second terminal 204 and the upper layer wiring 134 (second wiring) are formed in the upper layer. The lower layer wiring 122 and the upper layer wiring 134 are electrically connected by a via 128 formed in a layer between the upper layer and the lower layer.
Fig.5 (a) is a figure which shows the state before a cutting | disconnection. In the present embodiment, the lower layer wiring 122 and the upper layer wiring 134 can be formed asymmetrically so as to have different volumes. For example, the lower layer wiring 122 and the upper layer wiring 134 can be formed to have different areas in the planar arrangement in the in-plane direction of the semiconductor substrate. In this way, when a current is passed between the first terminal 202 and the second terminal 204, the wiring having a larger volume expands more, and an outflow portion is selectively formed in the wiring. Can do.
The first terminal 202 and the second terminal 204 can be formed wider than the lower layer wiring 122 and the upper layer wiring 134. As an example, the width of the lower layer wiring 122 and the upper layer wiring 134 can be 0.1 μm, and the width of the first terminal 202 and the second terminal 204 can be 0.3 μm. However, since it is easy to dissipate heat if the wiring width is widened, if the wide first terminal 202 or the second terminal 204 is provided in the vicinity of the wiring for forming the outflow portion, it is difficult to form the outflow portion, There is a possibility that the fuse 200 is difficult to be cut. Therefore, when the first terminal 202 and the second terminal 204 are formed wider than the lower layer wiring 122 and the upper layer wiring 134, the first terminal 202 and the second terminal 204 are separated to some extent from the outflow portion and the cut portion. Can be provided in position. In addition, the first terminal 202 and the second terminal 204 can be formed to have the same width as the lower layer wiring 122 and the upper layer wiring 134.
In the example shown in FIG. 5, the upper layer wiring 134 is formed to have a larger area in the planar arrangement in the in-plane direction of the semiconductor substrate than the lower layer wiring 122. Here, the lower layer wiring 122 and the upper layer wiring 134 have substantially the same film thickness. In this way, the volume of the upper layer wiring 134 becomes larger than the volume of the lower layer wiring 122. In such a configuration, when excessive power is applied between the first terminal 202 and the second terminal 204, a current flows through the electric fuse 200, and the lower layer wiring 122, the via 128, and the upper layer wiring 134 are connected. The constituent conductor is heated and expands. Here, in the upper layer wiring 134 having a large volume, the force exerted on the periphery by the heated conductor is the largest.
As a result, the conductor easily flows out to the outside in the upper layer wiring 134, and an outflow portion 142 is formed in the upper layer wiring 134 as shown in FIG. Further, when the outflow portion 142 is formed in the upper layer wiring 134, the conductor moves in the direction of the outflow portion 142, and the conductor constituting the via 128 is sucked up in the direction of the outflow portion 142. As a result, a gap is formed in the via 128 portion.
FIG. 6 is a diagram illustrating an example of a cross-sectional view taken along the line AA ′ of FIG.
6A is a cross-sectional view illustrating the configuration of the semiconductor device 100 before cutting, and FIG. 6B is a cross-sectional view illustrating the configuration of the semiconductor device 100 after cutting. Here, a wiring structure of a single damascene structure is shown.
As shown in FIG. 6A, a semiconductor device 100 includes a semiconductor substrate (not shown), a first etching stop film 102, and a first interlayer insulating film 104 formed on the semiconductor substrate in the following order. The first protective film 106, the second etching stop film 108, the second interlayer insulating film 110, the third etching stop film 112, the third interlayer insulating film 114, the second protective film 116, and the fourth An etch stop layer 118 is included.
In the state before cutting, electric fuse 200 includes lower layer wiring 122, via 128 electrically connected to lower layer wiring 122, and upper layer wiring 134 electrically connected to via 128. Here, the lower wiring 122 is formed in the first etching stop film 102, the first interlayer insulating film 104, and the first protective film 106. The via 128 is formed in the second etching stop film 108, the second interlayer insulating film 110, and the third etching stop film 112. The upper wiring 134 is formed in the third etching stopper film 112, the third interlayer insulating film 114, and the second protective film 116.
The lower layer wiring 122, the via 128, and the upper layer wiring 134 are configured by a conductor corresponding to the conductor 206 in FIG. The conductor can be composed of a copper-containing metal film containing copper as a main component. The copper-containing metal film can contain silver. Furthermore, the copper-containing metal film is one or more selected from Al, Au, Pt, Cr, Mo, W, Mg, Be, Zn, Pd, Cd, Hg, Si, Zr, Ti, or Sn. It can also be set as the structure containing a different element. The copper-containing metal film can be formed by, for example, a plating method. Further, the surface of the copper-containing metal film can be configured such that, for example, a silicide film is formed.
Further, the first and second barrier metal films 120, 126 provided on and in contact with the side and bottom surfaces of the lower layer wiring 122, the via 128, and the upper layer wiring 134, respectively, A third barrier metal film 132 is formed. The barrier metal film can include a refractory metal. The first barrier metal film 120, the second barrier metal film 126, and the third barrier metal film 132 can be made of, for example, Ta, TaN, Ti, TiN, W, WN, or the like.
That is, the second barrier metal film 126 is provided in contact with the lower layer wiring 122 and the via 128 in a state before cutting. A third barrier metal film 132 is provided between and in contact with the via 128 and the upper wiring 134.
The first interlayer insulating film 104 and the third interlayer insulating film 114 can be composed of a low dielectric constant film such as SiOC. As the low dielectric constant film, in addition to SiOC, polyhydrogensiloxane such as HSQ (hydrogensilsesquioxane), MSQ (methylsilsesquioxane), or MHSQ (methylated hydrogensilsesquioxane), Aromatic-containing organic materials such as polyaryl ether (PAE), divinylsiloxane-bis-benzocyclobutene (BCB), or Silk (registered trademark), SOG, FOX (flowable oxide), Cytop, or BCB (Bencyclic cyclone) It can also be used. These porous films can also be used as the low dielectric constant film. The first interlayer insulating film 104 and the third interlayer insulating film 114 may be made of the same material or different materials.
Further, the second interlayer insulating film 110 can be made of the same material as described above for the first interlayer insulating film 104 and the third interlayer insulating film 114. However, the second interlayer insulating film 110 is harder than the first interlayer insulating film 104 and the third interlayer insulating film 114 in relation to the first interlayer insulating film 104 and the third interlayer insulating film 114. It is preferable to use a material. For example, the second interlayer insulating film 110 can be made of a material having a higher Young's modulus than the first interlayer insulating film 104 and the third interlayer insulating film 114. With such a configuration, the outflow portion 142 can be easily formed in the wiring portion.
Note that the second interlayer insulating film 110 is not limited to such a structure, and may be formed using the same material as the first interlayer insulating film 104 and the third interlayer insulating film 114. Also in this case, since the area of the via 128 in the in-plane direction of the semiconductor substrate is very narrow compared to the wiring, the outflow portion 142 can be selectively formed in the wiring portion.
The second etching stopper film 108 and the fourth etching stopper film 118 function as an etching stopper film when forming a via hole or a wiring groove, and prevent diffusion of copper constituting the lower layer wiring 122 and the upper layer wiring 134. It has a function. In the present embodiment, it also functions as a coating film for the electric fuse 200. The second etching stop film 108 and the fourth etching stop film 118 can be made of a material harder than the first interlayer insulating film 104 and the third interlayer insulating film 114. The second etching stopper film 108 and the fourth etching stopper film 118 can be made of a material having a higher Young's modulus than the first interlayer insulating film 104 and the third interlayer insulating film 114. The second etching stop film 108 and the fourth etching stop film 118 can be made of, for example, SiCN, SiN, SiC, SiOF, or SiON.
The first protective film 106 and the second protective film 116 function to protect the first interlayer insulating film 104 and the third interlayer insulating film 114 when the lower layer wiring 122 and the upper layer wiring 134 are polished by CMP, respectively. Have The first protective film 106 and the second protective film 116 can be composed of, for example, a SiO 2 film.
The first etch stop film 102 and the third etch stop film 112 can be made of the same material as the second etch stop film 108 and the fourth etch stop film 118. Although not shown here, the first etching stopper film 102 and the third etching stopper film 112 are made of the same material as the second etching stopper film 108 and the fourth etching stopper film 118. A stacked film of the first insulating film and a second insulating film formed over the first insulating film and formed using the same material as the first protective film 106 and the second protective film 116 may be used.
The lower layer wiring 122, the via 128, the upper layer wiring 134, and the like having the above-described configuration can be formed in the same process as the normal multilayer wiring structure. Thereby, the electric fuse 200 can be formed without adding a special process.
As described above, for example, the periphery of the upper-layer wiring 134 is covered with the coating film such as the third barrier metal film 132 and the fourth etching stop film 118, and the periphery thereof is made of a material softer than the coating film. A structure in which the interlayer insulating film 114 is formed can be employed. Further, the upper layer wiring 134 has a larger area in the in-plane direction of the semiconductor substrate than the via 128 and the lower layer wiring 122.
Next, a procedure for cutting the electric fuse 200 having such a configuration will be described.
When an excessive power is applied to the electric fuse 200 by applying a predetermined voltage between the first terminal 202 and the second terminal 204, the conductor constituting the upper wiring 134 of the electric fuse 200 expands. Thus, it expands in the direction of the third interlayer insulating film 114, which is a soft film. As the conductor expands, a crack is generated in the third barrier metal film 132 and the like, and the conductor constituting the upper wiring 134 flows into the third interlayer insulating film 114 from the crack. That is, the conductor constituting the upper layer wiring 134 flows out of the wiring groove. Thereby, as shown in FIG.6 (b), the outflow part 142 is formed.
Furthermore, since the conductor rapidly moves in the direction of the outflow portion 142, the conductor is cut at a place where the movement of the conductor cannot catch up. In the present embodiment, the conductor is cut at the via 128 portion, and the gap 140 is formed. By such a mechanism, a large gap portion 140 is formed at a location away from the outflow portion 142 to some extent.
In the present embodiment, since the second barrier metal film 126 is provided between the via 128 and the lower layer wiring 122, the second barrier metal film 126 is easily peeled off from the lower layer wiring 122, and the second The gap 140 is easily formed between the barrier metal film 126 and the lower layer wiring 122.
Further, in the cut state, the conductor constituting the via 128 moves together with the second barrier metal film 126, and a gap 140 is formed between the second barrier metal film 126 and the lower layer wiring 122. Therefore, even if a heat treatment or the like is performed in the subsequent process, the conductor in which the second barrier metal film 126 is composed of the copper-containing metal film moves again and reconnection occurs with the lower layer wiring 122. Can be prevented. Thereby, the heat resistance of the semiconductor device 100 can be improved. Since the second barrier metal film 126 and the third barrier metal film 132 are formed between the outflow portion 142 and the gap portion 140, movement of the conductor can be further prevented.
If the electric fuse 200 having the structure as described in the present embodiment is cut using a phenomenon in which the conductor moves due to electromigration, the electromigration is suppressed due to the presence of the barrier metal film, and the electric fuse is made efficient. It is difficult to cut well. However, by cutting the electric fuse 200 having such a configuration with a crack assist type, when the electric fuse 200 is cut, the conductor becomes an extremely high temperature, and the barrier metal film, which is a refractory metal, also moves to make the electric fuse 200 good. In addition, the reconnection can be effectively suppressed by preventing movement in the subsequent steps.
In the present embodiment, since the electric fuse 200 is cut by the crack assist type having the above-described mechanism, the gap 140 is inevitably formed in a region different from the outflow portion 142. Thereby, reconnection of the electric fuse 200 can be prevented.
In the above, an example in which cracks occur in the third barrier metal film 132 and the like has been described. However, when the upper wiring 134 is heated and expanded, the fourth etching stopper film 118 becomes the upper wiring 134 and the second protective film. It may peel from 116 and a gap may be formed between them. In this case, the conductor constituting the upper wiring 134 flows into the gap portion, and the outflow portion 142 is formed. Even in this case, when the conductor moves in the direction of the outflow portion 142, the cut portion 214 is formed in the via 128 portion.
FIG. 7 is a diagram showing another example of the AA ′ cross-sectional view of FIG.
7A is a cross-sectional view showing the configuration of the semiconductor device 100 before cutting, and FIG. 7B is a cross-sectional view showing the configuration of the semiconductor device 100 after cutting. Here, it differs from the example shown in FIG. 6 in that the wiring structure has a dual damascene structure.
Here, the via 151 and the upper layer wiring 152 are integrally formed as a dual damascene wiring 154. Prior to cutting, the electric fuse 200 is configured by the lower layer wiring 122 and the dual damascene wiring 154 (via 151 and upper layer wiring 152) electrically connected to the lower layer wiring 122. The via 151 is formed in the second etching stop film 108, the second interlayer insulating film 110, and the third etching stop film 112. The upper wiring 152 is formed in the third etching stopper film 112, the third interlayer insulating film 114, and the second protective film 116.
The via 151 and the upper layer wiring 152 can also be made of the same material as the via 128 and the upper layer wiring 134. Further, the dual damascene wiring 154 has a configuration in which the side surface and the bottom surface are covered with the fifth barrier metal film 150. The fifth barrier metal film 150 can also be made of the same material as the second barrier metal film 126, the third barrier metal film 132, and the like. In a state before cutting, a fifth barrier metal film 150 is provided between and in contact with the via 151 and the lower layer wiring 122.
When excessive power is applied to the electric fuse 200 having the above configuration, the conductor constituting the upper layer wiring 152 expands and expands toward the third interlayer insulating film 114 which is a soft film. As the conductor expands, a crack is generated in the fifth barrier metal film 150 and the like, and the conductor constituting the upper wiring 152 flows out of the third interlayer insulating film 114. Thereby, as shown in FIG.7 (b), the outflow part 142 is formed.
Furthermore, since the conductor rapidly moves in the direction of the outflow portion 142, the conductor is cut at a place where the movement of the conductor cannot catch up. In the present embodiment, the conductor is cut at the via 151 portion, and the gap 140 is formed. In the present embodiment, since the fifth barrier metal film 150 is provided between the via 151 and the lower layer wiring 122, the fifth barrier metal film 150 is easily peeled off from the lower layer wiring 122. The gap 140 is easily formed between the barrier metal film 150 and the lower wiring 122.
Further, in the cut state, the conductor constituting the via 151 moves together with the fifth barrier metal film 150, and a gap 140 is formed between the fifth barrier metal film 150 and the lower layer wiring 122. Therefore, even if heat treatment or the like is performed in the subsequent process, the conductor in which the fifth barrier metal film 150 is formed of the copper-containing metal film moves again and reconnection occurs with the lower layer wiring 122. Can be prevented. Thereby, the heat resistance of the semiconductor device 100 can be improved.
FIG. 8 is a cross-sectional view showing a state where an electric fuse 200 having a wiring structure having a single damascene structure similar to that shown in FIG. 6 is actually formed and cut by a crack assist type.
Here, the interlayer insulating film in which the via 128 was formed was made of SiOC (Black Diamond). Further, the interlayer insulating film on which the upper layer wiring 134 was formed was composed of SiOC (Aurora). Black Diamond and Aurora are both SiOC porous films, but Aurora is a softer film having a lower relative dielectric constant and lower film density than Black Diamond.
As shown in the drawing, in the electric fuse 200, an outflow portion 142 is formed in the upper layer wiring 134, and a gap portion 140 is formed between the via 128 and the lower layer wiring 122. The electrical fuse 200 in which the outflow portion 142 and the gap portion 140 were formed was evaluated again after being placed for about 5 minutes under a temperature condition of about 300 ° C., but no reconnection occurred.
As described above, according to the semiconductor device 100 including the electric fuse 200 in the present embodiment, since the electric fuse 200 is configured by the multilayer wiring structure, it can be arranged in the stacking direction, and the area for forming the electric fuse can be reduced. Can be reduced.
Further, since the via is cut, the reconnection probability of the conductor after cutting can be reduced.
Further, when the electric fuse 200 is formed on a single plane, there is a possibility that the outflow portion 142 may be formed by bridging between the conductors that should be electrically cut. When this occurs, for example, the cut electric fuse is connected by the outflow portion 142, and the cutting yield decreases (low resistance after cutting), the resistance fluctuates after cutting (change over time), and the like. In the present embodiment, since the gap portion 140 and the outflow portion 142 which are cut portions are formed in different layers, such a problem of the bridge can also be prevented.
Further, the example in which the outflow portion 142 is formed in the upper layer wiring 134 portion and the upper layer wiring 152 portion has been described above. However, the outflow portion 142 may be formed in the lower layer wiring 122 portion. For example, by forming the area of the lower layer wiring 122 in the in-plane direction of the semiconductor substrate larger than the area of the upper layer wiring 134, the outflow portion 142 can be formed in the lower layer wiring 122 portion. In this case, the upper layer wiring 134 corresponds to the first wiring, and the lower layer wiring 122 corresponds to the second wiring. In particular, in the single damascene structure shown in FIG. 6, a barrier metal film is provided between the upper layer wiring 134 and the lower layer wiring 122 between the via 128. Therefore, even when the outflow portion 142 is formed in either the upper layer wiring 134 or the lower layer wiring 122, reconnection can be effectively prevented.
It is a figure which shows the state at the time of cut | disconnecting the electric fuse in embodiment of this invention. It is a figure which shows the circuit structure containing an electrical fuse. It is a figure which shows the ON timing of a transistor, and the voltage value applied to the 1st terminal of an electric fuse. It is a figure which shows the other example of the circuit structure of the semiconductor device containing a some electrical fuse. It is a schematic diagram which shows the structure of the electric fuse in embodiment of this invention. It is a figure which shows an example of A-A 'sectional drawing of FIG. It is a figure which shows the other example of A-A 'sectional drawing of FIG. FIG. 7 is a cross-sectional view showing a state in which an electric fuse having a wiring structure having a single damascene structure similar to that shown in FIG. 6 is actually formed and cut by a crack assist type. It is a top view which shows an example of the conventional current fuse.
DESCRIPTION OF SYMBOLS 100 Semiconductor device 102 1st etching stop film 104 1st interlayer insulation film 106 1st protective film 108 2nd etching stop film 110 2nd interlayer insulation film 112 3rd etching stop film 114 3rd interlayer insulation Film 116 Second protective film 118 Fourth etching stop film 120 First barrier metal film 122 Lower layer wiring 126 Second barrier metal film 128 Via 132 Third barrier metal film 134 Upper layer wiring 140 Void portion 142 Outflow portion 150 Fifth barrier metal film 151 Via 152 Upper layer wiring 154 Dual damascene wiring 200 Electrical fuse 202 First terminal 204 Second terminal 206 Conductor 212 Outflow portion 214 Cutting point 220 Transistor 222 Power supply line 224 Floating capacitance 300 External terminal 302 External Power supply 304 External capacitor 306 ESD protection circuit 1 00 Hughes 1101 current input terminal 1102 current output terminal 1103 first forward linear portion 1104 backward linear portion 1106 first right-angled connecting section 1107 second right-angled connecting portions 1108 outside the hatched portion 1109 inside the hatched section 1113 second forward linear portion
In the cut state, an outflow portion is formed in which the conductor flows out from the second wiring, and a gap is formed between the first wiring and the via or in the via. Semiconductor device.
The said conductor is a semiconductor device comprised by the copper containing metal film which contains copper as a main component.
The electrical fuse further includes a first barrier metal film provided between and in contact with the first wiring and the via in the state before cutting,
A semiconductor device in which the gap is formed between the first barrier metal film and the first wiring in the cut state.
The semiconductor device according to claim 2 or 3,
The electrical fuse further includes a second barrier metal film provided in contact with the second wiring on a side surface of the second wiring in the state before cutting.
In the cut state, a crack is formed in the second barrier metal film, and the outflow portion is formed by outflowing the conductor from the crack.
The semiconductor device in which the second wiring is formed to have a larger area in the in-plane direction of the semiconductor substrate than the first wiring.
The semiconductor substrate further includes an insulating layer formed around the electric fuse,
The semiconductor device in which the second wiring is formed in a wiring groove formed in the insulating layer, and the outflow portion is formed by the conductor flowing out of the wiring groove.
The insulating layer includes a first insulating layer formed around the via, a second insulating layer formed around the second wiring and having a Young's modulus lower than that of the first insulating layer; A semiconductor device including:
The insulating layer includes a first insulating layer formed around the via, a second insulating layer formed around the second wiring and having a lower film density than the first insulating layer, A semiconductor device including:
The insulating layer includes a first insulating layer formed around the via, a second insulating layer formed around the second wiring and having a dielectric constant lower than that of the first insulating layer, A semiconductor device including:
The semiconductor device according to any one of claims 7 to 9,
The semiconductor device in which the second wiring is formed in a wiring groove formed in the second insulating layer, and the outflow portion is formed by the conductor flowing out of the wiring groove.
A predetermined voltage is applied between the first wiring and the second wiring to cause a current to flow through the electrical fuse, causing the conductor to flow out of the second wiring and the via and A method for cutting an electric fuse, wherein a gap is formed between the first wiring and the via.
The method for cutting an electric fuse according to claim 11,
A method for cutting an electric fuse, wherein the conductor is caused to flow outward from the second wiring, and the conductor is moved from the via toward the second wiring to form the gap.
JP2006130702A 2006-05-09 2006-05-09 Semiconductor device and electrical fuse cutting method Active JP4861051B2 (en)
JP2006130702A JP4861051B2 (en) 2006-05-09 2006-05-09 Semiconductor device and electrical fuse cutting method
US11/797,704 US7635907B2 (en) 2006-05-09 2007-05-07 Semiconductor device with electric fuse having a flowing-out region
CN 200710101190 CN101071802B (en) 2006-05-09 2007-05-09 Semiconductor device and method for cutting electric fuse
US12/603,936 US8236622B2 (en) 2006-05-09 2009-10-22 Method for cutting electric fuse
US13/541,125 US20120267755A1 (en) 2006-05-09 2012-07-03 Semiconductor device with electric fuse having a flowing-out region
JP2007305693A JP2007305693A (en) 2007-11-22
JP4861051B2 true JP4861051B2 (en) 2012-01-25
ID=38684341
JP2006130702A Active JP4861051B2 (en) 2006-05-09 2006-05-09 Semiconductor device and electrical fuse cutting method
US (3) US7635907B2 (en)
JP (1) JP4861051B2 (en)
CN (1) CN101071802B (en)
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JP5436867B2 (en) * 2009-01-09 2014-03-05 ルネサスエレクトロニクス株式会社 Method for manufacturing a fuse element
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JP5435713B2 (en) * 2009-07-23 2014-03-05 ルネサスエレクトロニクス株式会社 Semiconductor device manufacturing method, manufacturing program, and semiconductor device
CN103633066B (en) * 2012-08-20 2016-12-07 北大方正集团有限公司 A kind of double-deck fuse and manufacture method thereof
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JP4343507B2 (en) * 2002-09-04 2009-10-14 Ｏｋｉセミコンダクタ株式会社 Trimming pattern
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JP3881660B2 (en) * 2004-02-12 2007-02-14 株式会社東芝 Semiconductor device and manufacturing method thereof
2006-05-09 JP JP2006130702A patent/JP4861051B2/en active Active
2007-05-07 US US11/797,704 patent/US7635907B2/en active Active
2007-05-09 CN CN 200710101190 patent/CN101071802B/en active IP Right Grant
2009-10-22 US US12/603,936 patent/US8236622B2/en not_active Expired - Fee Related
2012-07-03 US US13/541,125 patent/US20120267755A1/en not_active Abandoned
CN101071802B (en) 2010-06-23
US7635907B2 (en) 2009-12-22
CN101071802A (en) 2007-11-14
US8236622B2 (en) 2012-08-07
US20070262414A1 (en) 2007-11-15
US20100037454A1 (en) 2010-02-18
JP2007305693A (en) 2007-11-22
US20120267755A1 (en) 2012-10-25
US6765773B2 (en) 2004-07-20 ESD protection for a CMOS output stage
US8617914B2 (en) 2013-12-31 Method of forming semiconductor device having seal ring structure
KR101354389B1 (en) 2014-01-22 A semiconductor device and a method of increasing a resistance value of an electric fuse
JP3881660B2 (en) 2007-02-14 Semiconductor device and manufacturing method thereof
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