JPS63278348A - Method and apparatus for connecting ic interconnection - Google Patents

Abstract

PURPOSE:To easily analyze a malfunction by opening a hole in an insulating film at the top of interconnections to be connected by a focused ion beam, exposing wirings, irradiating a focused laser light or an ion beam in metal compound gas, and forming wirings by metal precipitated in the hole. CONSTITUTION:An insulating film 3 (SiO2, etc.) is formed on a substrate 4 (Si, etc.), wirings (aluminum, etc.) 2a-2c are formed thereon, and a protective film (SiO2, Si3N4, etc.) 1 is formed on the uppermost part. When wirings 2a, 2c are to be electrically connected, holes 5a, 5c are opened in the film 1 above the wirings 2a, 2c, by a focused ion beam, and the part 6a of the wirings 2a and the part 6c of the wirings 2c are exposed. Thereafter, metal wirings 7 are formed in a direction for connecting the holes 5a, 5c by an ion beam induction CVD technique or laser induction CVD technique. Thus, the wirings 2a, 2c are connected through the wirings 7. Accordingly, an IC can be debugged, corrected or its defect can be analyzed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to IC wiring that connects internal wiring after a chip is completed for debugging, 11 error/failure analysis, etc. in a semiconductor integrated circuit (hereinafter referred to as IC). This invention relates to a connection method and device.

[Traditional technique princess]

In recent years, with the increasing integration and miniaturization of ICs, design and process errors have been avoided by cutting and connecting some of the internal wiring of LSI chips during the development process and debugging and correcting defective parts. It is becoming increasingly important to detect defects, perform defect analysis, and restore process conditions to improve product yield. For this purpose, examples have been reported in which IC wiring is conventionally cut using a laser or an ion beam.

That is, the first prior art is Techno, Digest Opcleo 811981, page 160 (Tech.

Digest of CLEO' 811981,
p160) l'-Laser stripe cutting system for eye debacking (La5er 5
tripe Cutting System forI
Cdebugging) J, in which an example has been reported in which wiring is cut with a laser to debug a defective location. Furthermore, as a second prior art, there is Japanese Patent Application No. 58-421275, which focuses the ion beam from a liquid metal ion source to a spot of 0.5 μm or less in order to deal with fine wiring. A technique has been proposed in which the wires are cut or holes are made using the ion beam, and the upper and lower wires are connected by vapor deposition into the holes using an ion beam.

Further, as a fifth prior art, Extended Abatruot cf 17, 17th Conference on Solids Date Devices and Materials, 1985, page 193,
thConf, on 5o11d 5tate Dev
ioea and Material 1985,
p195) "Direct Lighting Opno 1 Illi Conductive Molybdenum Lines by Laser Induced Chemical Vapor Day Position (1) ir
ect Writing of Hlghly Con
duoMo Lin@a by Laaer
There is Inauea CV D ) J.

[Problem that the invention seeks to solve]

In the first conventional technique, only a means for cutting the wires is shown, and no means for connecting the wires is shown. In addition, when using the laser processing method (the processing process is thermal, there is heat conduction to the surroundings, and processes such as evaporation and ejection are used, so fine processing of 0.5 μm or less is required. (2) Laser light is absorbed by the insulating film such as SL02゜5=iN4 and K<<, so it is absorbed by the underlying At and poLL SL wiring, etc., and when it evaporates and ejects. K. Processing of the insulating film is performed by explosively blowing away the upper insulating film.For this reason, processing is difficult if the insulating layer is thicker than 2 μm.Also, damage to the surrounding area (surroundings, upper and lower layers) may occur. Thick (causing defects). These results make it difficult to process multilayer interconnects and fine, highly integrated interconnects.

In addition, in the second prior art, means for cutting and drilling using a 11 focused ion beam and connecting upper and lower wiring using a 2f focused ion beam are shown. This method covers the problems in the first conventional technology because it is possible to process any material, and any material can be easily processed sequentially from the upper layer by sputtering.However, (
As for the means for connecting the wires at 2f, only the procedure for connecting the upper and lower wires is shown, and no mention is made of the means for connecting from one wire to the wire at another location.

In the fifth conventional technique, an ultraviolet laser is irradiated onto a S substrate coated with 5L02 in a gas of an organic compound of a metal such as Mo (Co ) 6 (molybutene carbonyl), and photothermal (phctothermal) treatment is applied. Alternatively, a photochemical laser-induced CVD process can be used to produce Fvlo(Co)
A method is shown in which metal wiring is directly drawn and formed by disassembling 6 and depositing a metal such as Mo on a substrate. However, in this case, the Mo wiring was simply formed on the insulating film, and in an actual IC, there is no way to connect the wiring under the insulating film such as the protective film or the interlayer insulating film. is not shown.

An object of the present invention is to connect the wiring underneath the insulation film to other parts by forming fine holes in the insulation film such as the protective film and the interlayer insulation film in the IC, and in particular to connect the wiring under the protection film to other parts. An object of the present invention is to provide a method and device for connecting IC wiring, which prevents short circuits between the upper wiring and the wiring above the IC, and enables debugging, correction, failure analysis, etc. of the IC.

[Means for solving problems]

The present invention uses a focused ion beam to make a hole in the insulating film above the part of the wiring to be connected, exposes the wiring, and then irradiates the metal compound gas with a focused laser beam or ion beam to deposit the precipitate in the hole. This is an IC wiring connection method in which the wiring is formed using metal.

Further, the present invention has a vacuum container, a mechanism in which an IC stage can be moved, an introduction means for introducing a metal compound gas into the vacuum container, and a high-intensity ion source installed in the vacuum container. It also has an electrostatic optical system for focusing and deflecting the ion beam, and by focusing the ion beam into a fine spot and directing it onto the sample, it is possible to process the insulating layer of an IC,
A laser optical system, an optical system, and a condensing lens are connected to the vacuum chamber through the window of the vacuum chamber, allowing a conductive film to be formed by the laser beam-induced CVD process, and a secondary electron detector is installed near the sample stage. The wiring connection device is equipped with a secondary ion content analysis tube and the like so that the sample pattern can be observed by a scanning ion image, and has an insulating film forming means such as sputtering installed in a vacuum container.

[Effect]

With this configuration, the locations of multiple wirings to be connected are detected using a scanning ion microscope using secondary electron signals or secondary ion signals from the sample, and after positioning and determining the irradiation location, the ion A beam is irradiated to remove the insulating film on the wiring in this area. In this case, since a focused ion beam is used instead of a laser, cL5μ
It is fully possible to converge and process the particles to less than m. Also, since there is no selectivity in processing depending on the material, 5LCh, 5L
An insulating film such as sNa can also be processed sequentially from the top, and a hole can be made in this to expose the wiring at the bottom. Then, an insulating material is deposited on the inner surface of this hole by sputtering or the like to prevent the upper layer wiring from being exposed. Then, metal compound gas is introduced into this vacuum container through a nozzle or piping, and the sample stage is moved relatively. Then, metal wiring is formed by a laser CVD process such that a focused laser beam is irradiated onto the location where the wiring is to be formed. As a result, the laser beam CVD gold layer film connected to the lower layer wiring and the upper layer wiring can be connected without shorting, and the internal wiring can be connected after the IC is completed, allowing debugging, correction, failure analysis, etc. of the IC.

〔Example〕

FIG. 1 is a diagram showing the basic concept of forming connection wiring to an IC according to the present invention. FIG. 1 (α) shows a portion including a cross section of a partially cut IC chip, viewed obliquely from above. Insulating film 5 on substrate 4 (S= etc.) in cross section
(5L02, etc.), and on top of that there is a wiring (At, etc.) 2
α, 2b, 2c are formed, and a protective film (5=Oz, S ha N4, etc.) 1 is further formed on the top. Now, if you want to electrically connect the wires 2α and 2C, use a focused ion beam to make holes 5α and 5c in the protective film 1 on the wires 2α and 2C.
A portion 6c of c is exposed respectively.

Then ion beam induced CVD technique or laser induced C
Holes 5α and 5C are formed using VD technology as shown in Figure 1(b).
A metal wiring 7 is formed in the direction connecting the two.

In this way, the wirings 2α and 20 are connected through the metal wiring 7.

FIG. 2 shows an example of forming metal wiring according to the first and second aspects of the present invention.

In recent years, metal wiring has become multi-layered, which is good for higher integration of devices
There are a lot of C's.

This embodiment has two layers consisting of an upper layer At80 and a lower layer At81.
A case is shown in which a layer wiring structure is used and a connection wiring is desired to be formed from only the lower layer At 1111 to wiring in another location.

In this case, in the method described above (the method shown in FIG. 2 (α)), the wiring 82 is connected to both the lower layer At81 and the upper layer
It will also be connected to. Therefore, an ion beam was used to
After drilling holes in the upper layer 5 to A/=80 as shown in Figure <b>, an insulating film 83 such as SL 02 is formed as shown in Figure 2 (C)K, and then, As shown, the interlayer insulating film 84 is further processed to expose the lower layer At 81.

The means for applying the insulating film may be normal sputter deposition, plasma CVD, or other methods (photo CVD, ion beam CVD, etc.).A normal IC has a voltage of 5V.
SL02 film (withstand voltage approx. 1
v/n, m), the required thickness is 10rLrn
That's about it. After this, laser or ion beam induced C
A wiring 85 is connected by VD to connect the lower layer AJa 81 and other wiring.

When an insulating film is formed by sputter deposition or plasma CVD, the insulating film is formed over the entire surface of the IC. For this reason, depending on the device, an insulating film is also formed on electrodes (pads, bumps, etc.) that take out signals from the IC to the outside or take in power supply voltage from the outside. The thickness of the insulating film may be 10 rLm-0.01 μm or more, and the thickness of the wiring formed by laser CVD or the like is about 0.5 μm. Therefore, by taking advantage of the difference in film thickness between the two and removing approximately 11.1 μm of the surface layer by sputter etching after forming the wiring, it is possible to remove the insulating film without damaging the wiring, as shown in Figure 6. It is possible.

FIG. 3 shows an embodiment of the wiring connection device according to the third and fourth aspects of the present invention. The reaction vessel 16 equipped with the IC chip 18 having wiring connection points is supplied with correction substances (AL(CHs)l, At(C2) via a valve 21.
H5)3, At(IC4Hp)s, Ca(CH
g)2,C(L(C2H5)2,Mo(Co)4
A correction material container 19 containing an organometallic compound (such as organometallic compound, etc.) is connected via piping to a vacuum bonder 26 via a valve 25, and to an inert gas cylinder 28 such as argon via a valve 29.

The laser beam oscillated by the laser oscillator 8cL is reflected by the dichroic mirror 94 via the shutter 50α,
The light is focused by the objective lens 23, passes through the cavity 15 provided in the summer container 16, and is irradiated to the LSI aluminum wiring correction area.
It is configured so that the correction can be performed while observing the correction area through the laser beam cut filter 11, prism 12, and eyepiece lens 13.

In addition, a preliminary gas cylinder 20 is connected to the reaction vessel 16 via a pulp 22. The IC chip is mounted on a stage 24 placed on the XY stage 17.

Next to the laser beam irradiation section, there is an electrode 100 for forming an insulating film by sputtering, and power is supplied to this from a high frequency power source 101. Since the stage 24 is movable to a position 24C directly below the sputter electrode 100 and is electrically grounded, it can form a pair with the sputter electrode 100 and generate a high-frequency discharge 102. An insulating target material 105 is attached to the sputter electrode, and an insulating film can be formed on the IC chip 18C by high frequency discharge. Vacuum vessel 3 for ion beam processing is placed next to reaction vessel 16.
9 is attached, and a vacuum container 26 for an ion beam column is attached to the upper part of the tube. Vacuum container 59
There is an XY stage 40 inside, and when the stage 17 and the stage 40 move near the gate valve 25 (when the gate valve is opened when the stage 17 and stage 40 are moved), a chuck mechanism (not shown) installed on the stages 17 and 40 Although the tray of the stage 24 can be transferred between the stages 17 and 40, the tray 24 and the IC chip 18 mounted thereon can be moved by the transfer and subsequent movement of the stage. is the top 2 of XY stage 40
It can come to positions 4α and 18α. At this position, an ion beam is ejected from a high-intensity ion source (for example, a liquid metal ion source such as a metal ion source) 27 in the ion beam column 26 at the top by an extraction pole 50 installed at the bottom. 40 passes through an electrostatic lens 61, a blanking electrode 32, a deflector-'F!L pole 35, etc., is focused and deflected, and is irradiated onto a sample 18α.

Further, a secondary particle detector 34 is installed in the vacuum container 39, which amplifies the secondary particle signal from the sample in synchronization with the deflection signal of the deflection electrode power source 67, and displays a scanning ion microscope image of the sample on the monitor 6B. The image is projected to obtain an enlarged image of the sample and the sample is detected.

It is now possible to align. A vacuum pump 36 is connected to the vacuum container via a pulp 55 for evacuation. The vacuum container 16.59 is provided with a preliminary evacuation chamber 43 for loading and unloading the sample.

That is, when the gate valve 41 is opened, the stage 24α on the stage 40 moves along with the IC 18α on it, 24b on the moving stage 42, 181! It can be moved to the ' position.

The preliminary exhaust pipe is then evacuated by the valve 45 and the exhaust pump 46. By opening the lid 44 to the position 44α, the sample can be replaced.

In the preliminary exhaust chamber 43, there is a t-pole 10 for sputter etching.
4 and is at ground potential. The stage 24A is electrically insulated from the chamber and is connected to a high frequency power source 10.
Power is supplied from 5. Inert gas 28 can be introduced into the pre-evacuation chamber via valve 106. With this configuration, an inert gas discharge plasma can be generated between the electrode 104 and the stage 24b. Since the stage 24b serves as a high-frequency application electrode, the IC chip placed on the stage 2Ah is bombarded with inert gas ions and is sputter-etched.

The method of operation of this device will be explained below. Open the lid 44 and
The C chip 18b is placed on the stage 24b on the stage 42. The lid 44 is closed, the valve 45 is opened, and the sample exchange chamber 46 is evacuated by the exhaust pump 46. Thereafter, the gate pulp 41 is opened and the stage is moved to the position 24b. After closing the gate valve 41 and thoroughly evacuating the air, the ion beam is focused while moving on the stage 40, and a scanned ion image is observed on the monitor 58 to detect the location on the IC to be connected. Thereafter, as shown in FIG. 2(b), the ion beam is irradiated only to the portions to be connected to process the interlayer insulating film 84 up to the middle. If multiple holes need to be drilled, perform the same process for all holes. Next, the gate valve 25 is opened and the stage is moved to the 2AC position. At this point, while evacuating the chamber 16, the pulp 29 is opened and an inert gas such as argon is flowed in, and the pressure is adjusted to a pressure suitable for causing discharge (10 to 10 Torr).
) Adjust the valve 25 so that After this, high frequency power supply 1
Power is supplied to the electrode 100 from 01 to generate plasma discharge, and the target material 103 is sputtered with argon ions to form a 5=02 film on the IC chip. The IC chip is now in the state shown in FIG. 2(C).

Next, the gate valve 25 is opened again and the stage is moved to the position 24α. The ion beam is irradiated to the location to be connected using the same procedure as described above, and the lower layer wiring 81 is exposed as shown in FIG. 2(d). The same processing is performed for all of the multiple processing required locations.

After that, the gate pulp 25 is opened and the stage is moved to the position 24.

The LSI is placed at the laser beam irradiation position using the X-Y table 17.
Move the chip and align the wiring correction location.

Thereafter, the pulp 21 and valve 29 are opened, and the correcting substance and inert gas are adjusted to an appropriate mixing ratio while watching a flow meter (not shown) until the total pressure reaches several tens to hundreds of Torr. Adjust pulp 25 so that After this,
The shutter '50a is opened, a laser beam is irradiated to the wiring correction location, and the shutter 60α is closed after a certain period of time. By this laser irradiation, the organometallic gas in the vicinity of the laser irradiated area is decomposed and a metal thin film of At, Ca, Mo, etc. is precipitated, and the wiring is repaired. Correct all aluminum wiring correction points in the LSI chip as necessary. Next, valve 2
5 is opened, the inside of the reaction vessel 16 is sufficiently evacuated, and then the sample is transferred to the chamber 59 and further to the preliminary evacuation chamber 43.

In the preliminary evacuation chamber 46, an appropriate pressure for sputter etching is obtained by turning on the vacuum pump 46 and adjusting the opening degree of the pulp 45 while introducing an inert gas. Then, power is supplied from the high frequency power supply 105 to the stage 24h to generate plasma to sputter-etch the surface of the IC chip. As a result, the insulating film 83 shown in FIG. 2(e) is removed.

As mentioned above, in order to remove the insulating film 83, the depth is 0.1.
Etching on the order of μm may be performed. Since the wiring film thickness by CVDK is about 0.5μm, etching
There is no problem even if it becomes m, and the shape shown in FIG. 2 (J) can be obtained.

The K for carrying out the present invention only needs to have the functions of ion beam processing, insulating film formation, wiring formation, and insulating film etching. Therefore, the following can be considered as other embodiments of the device configuration.

In FIG. 4, the insulating film is formed by sputtering as in the example in FIG. 3, but the sputtering film forming machine W1106 is used in an ion beam processing vessel. This is an example where it is installed at +9. In this way, the ion beam column 26 is moved during sputter film formation (pressure 10'
Forr or more), it must be maintained at 10'forr, so it is necessary to add a differential pumping system 107. However, since sputter film formation is not performed in a container 16 contaminated by CVD as in the case of FIG. 3, a film of good quality can be obtained. The sputter etching mechanism 108 is installed in the preliminary exhaust chamber 45.

FIG. 5 shows the ion beam processing apparatus shown in (α) and the ion beam processing apparatus shown in (b).
) This is an embodiment in which the laser CVD apparatus shown in FIG.

The ion beam processing apparatus (tL) includes an ion beam column 26 and its differential pumping system 107, and a sputtering film forming mechanism 106 is installed in an ion beam processing container 59. Further, a preliminary exhaust chamber 39 is provided in connection with the ion beam chamber 39. Cb) laser CVD equipment is
A preliminary exhaust chamber 43 is connected to the laser CVD reaction vessel 16. A sputter etching mechanism 108 is provided in the preliminary exhaust chamber 43. In the configuration shown in FIG. 5, the IC chip is temporarily taken out of the ion beam processing apparatus into the atmosphere after the lower layer wiring 81 is exposed as shown in FIG. 2(d).

After that, insert the laser CVD device KIC' chip.

However, once exposed to the atmosphere, a natural oxide film with a thickness of 1 to 2 nm is formed on the exposed lower layer wiring 81. Therefore, the natural oxide film is removed using a sputter etch mechanism 108. After this, the process of creating wiring using laser CVD is as follows:
As mentioned above.

Separating the two devices has disadvantages such as an increase in the area occupied by the devices, but has advantages such as improved reliability because each device has a simpler configuration.

In the above embodiments, a sputtering method was used as a means for forming an insulating film, but the method is not limited to this, and plasma CVD
It is obvious that other methods such as the law may also be used.

Also, although we have shown an example of using laser CVD for wiring formation,
It is obvious that the present invention is not limited to this, and that other energy beams such as ion beam CVD may be used.

Furthermore, in the above embodiments, the functions of processing, insulating film formation, wiring formation, and insulating film removal were separated into multiple containers, but these functions are limited to those shown in Figures 3 to 5. It's not a thing.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to arbitrarily connect wires located at different locations in a highly integrated, multilayered IC, and thereby facilitate failure analysis in LSI design, prototyping, and mass production processes. This has the effect of shortening the development process, shortening the start-up period for mass production, and improving yield.

[Brief Description of the Drawings] Fig. 1 is a diagram for explaining the basic concept of the connection method between the wirings of an IC according to the present invention, and Fig. 2 is a diagram for explaining the basic concept of the connection method between the wirings of an IC according to the present invention. Explanatory diagrams for connecting wiring and removing an insulating film, FIGS. 3 to 5 are I according to the present invention.
It is a figure showing the wiring connection device of C. 1.60...protective film, 2α~2e, 62, 80
, 84... Wiring, 5, 61, 84... Insulating film,
4... Substrate, 6,71°85, 87, 89...
Wiring, 72, 85, 88, 90...protective film, 8
α, Bb...Laser oscillator, 16...Reaction container,
17, 40... XY stage, 19... Correction material container, 27... Ion source, 28... Inert gas cylinder, 51... Electrostatic lens, 39... Vacuum container for ion beam processing , 100 Varnish Batter Film Forming Electrode, 104
Electrode for varnish etch, 101, 105: High frequency power source, 106: Sputter film forming mechanism, 107: Differential pumping system, 108 varnish etch mechanism. Akira 2 Figure 3 Figure 10 A Figure 5

Claims (1)

[Claims] 1. Holes are formed in an IC having multiple layers of wiring by processing with an energy beam such as a focused ion beam up to the insulating film layer immediately above the wiring layer to be connected. Then, an insulating film is applied to this hole or a wide area including this hole by sputtering or CVD, and then the interlayer insulating film between the upper layer and the lower layer is processed to expose the lower layer wiring, and then this part is coated with an insulating film. I characterized in that the wiring is formed by an energy beam-induced CVD method such as a laser beam.
How to connect C wiring. 2. For ICs with multiple layers of wiring, holes are created by processing with an energy beam such as a focused ion beam up to the insulating film layer immediately above the wiring layer to be connected, and then An insulating film is applied to a wide area including this hole by sputtering or CVD, and then the interlayer insulating film between the upper layer and the lower layer is processed to expose the lower wiring, and then an energy beam such as a laser beam is applied to this part. A method for connecting IC wiring, characterized by forming the wiring by an induced CVD method and etching the IC surface to remove an insulating film attached to the external connection surface. 3. A vacuum container is provided, which includes a high-intensity ion source such as a liquid metal ion source, an electrostatic optical system and deflection electrode for focusing and deflecting the ion source into a fine spot, a stage for moving the sample, and a sample. a detection means for detecting secondary particles from the IC, a deposition means for depositing an insulator on the IC, a laser oscillator, and an optical system for focusing and irradiating a laser beam emitted from the laser oscillator into the container through the window. , wiring material gas such as organometallic gas and carrier gas such as inert gas are added to the container.
An IC wiring connection device characterized in that it is equipped with an introduction means for introducing gas. 4. A vacuum container is provided, which includes a high-intensity ion source such as a liquid metal ion source, an electrostatic optical system and deflection electrode for focusing and deflecting the ion source into a fine spot, a stage for moving the sample, and a sample. a detection means for detecting secondary particles from the IC, a deposition means for depositing an insulator on the IC, a laser oscillator, and an optical system for focusing and irradiating a laser beam emitted from the laser oscillator into the container through the window. , wiring material gas such as organometallic gas and carrier gas such as inert gas are added to the container.
1. An IC wiring connection device characterized in that it is equipped with an introduction means for introducing a gas, and an etching means for removing an insulating material.