JP2001267324A - Wiring correction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique, where wiring change of high performance is enabled safely in an exposed state of wiring that potential estimation with an electron beam tester is easily enabled, in wiring correction of a semiconductor circuit. SOLUTION: Wiring connection, when wiring is changed in a semiconductor integrated circuit, is conducted, by procedures which include (1) a process where a pillar structure is formed using a deposition film which uses a focusing ion beam FIB at a first connection point, (2) a process where a pillar structure is formed by using a deposition film which uses an FIB at a second connection pint, and (3) a process, where previously worked wirings are transplanted on the pillar structures, formed on the first and the second connection points and the first and the second connection points are connected electrically and mechanically.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for safely and efficiently modifying wiring of a semiconductor integrated circuit.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 61-245553 discloses a technique for correcting the wiring of a semiconductor integrated circuit using a FIB assisted deposition film. Further, as the prior art 2, a part of the device is
Japanese Patent Application Laid-Open No. 03-210803 describes a technique for extracting the IB using the IB and the manipulator in combination.

[0003]

In recent years, semiconductor integrated circuits have become more sophisticated, and device structures have been miniaturized. When developing integrated circuits, it is necessary to quickly make circuit changes that embody design changes during development, verify circuit operation, determine the final product circuit, and complete mass production masks as soon as possible. is there. From this demand, a technique for correcting wiring using a charged beam has been developed as in the prior art 1. According to this, an unnecessary wiring portion is cut by FIB processing, a conductive film is formed by assist deposition using FIB, and two points of a circuit are electrically connected. The circuit change is realized by forming an insulating film by using the assist deposition. With this method, wiring can be easily and quickly corrected. However, it has the following disadvantages.

Since the resistance of the wiring is higher than that of bulk tungsten, it is not suitable for correcting a power supply line.

When the wiring layer of the device is exposed on the outermost surface, the potential evaluation with an electron beam tester becomes easy, but in this state, the wiring formed for repair and the existing wiring are short-circuited. For this reason, the insulating film is formed by FIB assisted deposition to prevent short-circuiting of the wiring. However, the formation of the insulating film usually requires a highly toxic gas.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for safely performing high-performance wiring change even in a wiring exposed state in which potential evaluation by an electron beam tester can be easily performed.

[0007]

The above object is attained by forming a new connection branch of the exposed circuit wiring in the following procedure.

A step of forming a columnar structure at a first connection point by a deposition film utilizing FIB;

A step of forming a pillar structure at a second connection point by a deposition film utilizing FIB;

A step of implanting a pre-processed wiring on a pillar structure formed at the first and second connection points to electrically and mechanically connect the first and second connection points.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 9 shows a configuration around the ion column and the sample stage of the FIB apparatus used. The ions extracted from the liquid metal ion source emitter 100 by the extraction electrode 101 are condensed by the condenser lens 102 and the objective lens 109.
Is focused on the sample 50. A variable aperture 103, an aligner-stigma 104, a blanker 105, a blanking aperture 106, and a deflector 108 are arranged between the two lenses. When the blanker 105 operates, the beam enters the Faraday cup 107. The sample 50 is held by the sample holder 51 while the sample stage 110
Mounted on top. The metal thin film 35 is mounted on the end of the sample stage. The sample stage 110 can move the sample holder 51 in five axis directions of X, Y, Z, rotation, and tilt. Above the stage, a detector 112 for detecting secondary electrons emitted from the sample, a gas supply source 113 for blowing tungsten hexacarbonyl (W (CO) ₆ ) gas from the nozzle tip to the vicinity of the FIB irradiation point, and a manipulator 115 The mounted movable probe 30 is mounted.

FIG. 10 is a block diagram of the control system of the FIB device used in the embodiment of the present invention. The high voltage power supply 203 applies a high voltage to the ion source and the lens electrode. Aperture control power supply 204
Controls the variable aperture and allows a desired aperture diameter to be selected. The aligner-stigma control power supply 205 controls the electrode voltages of the eight poles, and performs electrical axis alignment and astigmatism correction. The beam current measuring amplifier 206 measures a beam current flowing into the Faraday cup 107 during blanking. A blanking control power supply 207 drives a blanking electrode to perform beam blanking. Deflection amplifier 208
Drives an 8-pole, 2-stage electrostatic deflector. The deflection signal is supplied from the scanner 211. The preamplifier 209 is the detector 1
12 is converted into a luminance voltage signal. The converted luminance signal is converted into a digital value, and is converted into a digital value.
2 is written. By synchronizing with the scan,
A microscope image of the sample is formed on the memory. The stage control power supply 210 works in conjunction with the exhaust control power supply 213 to load / unload the sample holder and move the stage. The gas control power supply 214 controls heating of the gas source and opening and closing of the valve, and controls the amount of gas supplied to the sample surface. The manipulator control power supply 215 controls the tip position of the movable probe 30. Each control power supply is connected to the FIB via the control bus 202.
It is totally controlled by the control computer 201. Information in the image memory 212 can be displayed on the CRT of the computer 201, and image observation, processing positioning, and monitoring during processing can be performed.

With this configuration, a FIB sputtering process, a deposition process, and a movement of the probe 30 at a desired location, and a transplantation process of a fine part combining the FIB process can be performed. The details of the technique for extracting a fine part are disclosed in a known example shown in Prior Art 2.

FIG. 1 is a flowchart showing an embodiment of the present invention. The wiring correction includes a pillar 1 forming step, a pillar 2 forming step, and a wiring transplanting step.

FIG. 2 is a circuit diagram of a semiconductor circuit modified in the embodiment. Before wiring correction

[0016]

## EQU00001 ## e = / a + b. . . . . . . . . . (Equation 1) is a logic circuit, which is formed by wiring cutting 10 and wiring forming 11

[0017]

## EQU2 ## e = / a + d. . . . . . . . . . (Equation 2)

The procedure of the wiring correction processing is shown in FIGS.

FIG. 3 is a perspective view of the device surface after cutting the wiring. The wiring 12 was cut by FIB sputtering. FIG. 4 shows a state after the columns 1 and 2 are formed using the FIB assist deposition function. FIG. 5 shows a state in which wiring for transplantation is installed on a pillar using a manipulator. The production of the transplant wiring will be described later. FIG. 6 shows a state after the transplant wiring is connected to the pillar using the FIB assist deposition film. Since the wiring is transplanted on the pillar, the wiring for transplantation 31 is the wiring 1
No wiring contact was made and the wiring could be changed without fail.

FIGS. 7 and 8 are views for explaining a method of manufacturing a transplant wiring. First, a slit 37 is formed in the metal thin film 35 by FIB processing. The metal thin film is slightly lifted from the sample holder and held on the sample stage at the end of the thin film so that a cavity is formed below the slit forming portion. FIG. 7 shows a state after the movable probe 30 is brought into contact with the vicinity of the base of the cantilever beam formed by the slit processing and both are adhered by the deposition film 32. FIG. 8 shows that the root portion 36 of the cantilever is cut by FIB processing and the wiring 31 for transplantation is cut.
Shows a state where is held by the movable probe 30. By raising the probe and moving the stage to move the beam observation field of view to the device, the state of FIG. 5 can be realized. According to the present invention, since a bulk sample can be used for a wiring for transplantation, the conductivity of the wiring is high, and high-performance wiring correction can be realized. Therefore, there is an advantage that the present invention can be applied to the correction of the wiring of the power supply line and the wiring for transmitting the high-speed signal.

In this embodiment, the height of the column 1 is slightly higher than the height of the column 2. This is because the transplant wiring is transported in a horizontal state, so that it is first brought into contact with the pillar 1 to connect them,
Next, the movable probe is lowered a little more so that the column 2 and the transplant wiring can be brought into contact and connected. There is an advantage that the contact between the transplant wiring and the pillar and the connection by the deposition film can be surely performed one by one.

[0022]

According to the present invention, even if the wiring of a semiconductor integrated circuit is exposed on the surface, there is an effect that a high-performance wiring correction can be performed safely.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a first embodiment of the present invention.

FIG. 2 is a circuit diagram of a semiconductor integrated circuit used in an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a main processing procedure of the embodiment of the present invention.

FIG. 4 is an explanatory view showing a main processing procedure of the embodiment of the present invention.

FIG. 5 is an explanatory view showing a main processing procedure of the embodiment of the present invention.

FIG. 6 is an explanatory view showing a main processing procedure of the embodiment of the present invention.

FIG. 7 is an explanatory view showing a method of manufacturing a transplant wiring used in an example of the present invention.

FIG. 8 is an explanatory view showing a method for manufacturing a transplant wiring used in an example of the present invention.

FIG. 9 is a configuration diagram around a column of the FIB apparatus used in the embodiment of the present invention.

FIG. 10 is a configuration diagram of a control system of the FIB device used in the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... pillar 1 formation process, 2 ... pillar 2 formation process, 3 ... wiring transplantation process, 10 ... wiring cutting, 11 ... wiring formation, 12, 13, 1
4. Wiring, 20 ... Pillar 1, 22 ... Pillar 2, 30 ... Movable probe, 31 ... Wiring for transplantation, 32 ... Deposition film, 35 ...
Metal thin film, 36: Root portion, 50: sample, 51: sample holder, 100: emitter, 101: extraction electrode, 102
… Condenser lens, 103… variable aperture, 104
... Arina Stigma, 105 ... Blanca, 106 ...
Blanking aperture, 107 ... Faraday cup,
108: deflector, 109: objective lens, 110: sample stage, 111: sample, 112: detector, 113:
Gas source, 115: manipulator, 200: FIB column, 201: computer, 202: control bus, 203
.., High-voltage power supply, 204, aperture control power supply, 205, aligner-stigma control power supply, 206, beam current measurement amplifier, 207, blanking control power supply, 208, deflection amplifier, 209, preamplifier, 210, stage control power supply,
211: scanner, 212: image memory, 213: exhaust control power, 214: gas control power, 215: manipulator control power.

Claims (2)

[Claims] 1. A method of modifying and modifying a wiring of a semiconductor integrated circuit, wherein a new connection branch of the circuit is formed in the following procedure. Focused ion beam (Focused Ion Bea)
m: a step of forming a pillar structure by a deposition film using FIB). Forming a pillar structure at a second connection point by a deposition film using FIB; Implanting a pre-processed wiring on a pillar structure formed at the first and second connection points, and electrically and mechanically connecting the first and second connection points. 2. The wiring according to claim 1, wherein the height of the pillar structure formed at the first connection point and the height of the pillar structure formed at the second connection point are formed at different heights. How to fix.