JPS6079746A - Semiconductor device and modification of function thereof - Google Patents

Abstract

PURPOSE:To enable to easily perform modification of the function of a semiconductor device by a method wherein at least parts of the signal lines of the semiconductor device, which is constituted by forming plural conductive wiring layers, are constituted as the uppermost layers of the conductive wiring layers. CONSTITUTION:Input signal lines 3 and 7 have been respectively connected to lowest-layer conductive layers 10 and 11 and intermediate-layer conductive layers 12 and 13 through contact holes. The conductive layer 3 on one side has been connected to a conductive layer 15, which is another intermediate layer, through conductive layers 14 and 14' formed in a bridge form. That is, this means that the signal lines 3 and 7 have been constituted in such a way that parts of each of the signal lines are used as the uppermost-layer conductive layers. Accordingly, in case the function of the semiconductor device is modified, the modification has only to cut one part of the uppermost-layer wiring or to anew provided an uppermost-layer wiring.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a semiconductor device and a method for changing functions, in which functions can be easily changed by changing wiring patterns.

[Background technology]

Generally 10. When manufacturing semiconductor devices such as LSIs, e) 13 lithography technology is used, and elements and interconnections to be formed on the main surface of a semiconductor wafer are formed at temperatures along the pattern of a photomask.

By the way, in recent years semiconductor devices have become more diverse in small quantities,
Attempts have been made to change the function of a semiconductor device by changing the wiring no. and turns of a semiconductor device having the same element pattern. For this reason, a master slicing type semiconductor device has been proposed in which an optimal photomask is prepared for each type of semiconductor device, and the required wiring pattern can be obtained according to the demand.

However, according to the studies of the present inventors, it is difficult with this method to respond to requests for changing a part of the circuit of a semiconductor device, which has been formed up to the wiring, or changing its function. To force this, the wiring must be formed again, which requires a lot of time and effort, especially remaking photomasks and repeating the same process, which increases design change time and reduces efficiency. This causes a decrease in the temperature.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor device in which the functions of a semiconductor device including wiring layers can be changed easily and locally.

Another object of the present invention is to provide a function changing method that can easily change the function of a semiconductor device formed up to the wiring layer.

The above and other objects and novel features of the present invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

'In other words, by configuring at least part of the signal lines connected to the elements of the semiconductor device as the top layer of multiple conductor layers, the wiring can be cut or connected at this top layer, thereby changing the function of the device. It is designed so that it can be carried out easily.

Further, in the present invention, the function can be changed easily and with high reliability by cutting the wiring in the uppermost layer with a laser and forming a pattern of partial wiring in other parts to make connections.

〔Example〕

1 to 4 show one embodiment of the present invention, and FIGS. 1 and 2 show part of the logic circuit of FIG. 3. In other words, as shown in Figure 3 (5), the logic circuit consists of two NAN
It has D gates 1 and 2, and input signal lines 3, 4 .
5 and 6.7.8, and also the output signal line 9 of gate 1.
is connected to the input signal line 6. A, B, 0 are input terminals. As shown in FIGS. 1 and 2, the input signals W43 and W7 are input to the bottom conductor layer io, respectively.
, ii. After connecting to the middle conductor layer 12.13 through the contact hole, one conductor layer 3 is connected to the other middle conductor layer 15 (input terminal) by the top conductor layer 14.14' formed in a bridge shape. AVc connection). In other words, part of the signal lines 3 and 7 is configured as the F-most conductive layer. In the figure, 16.17
19 is a semiconductor region as a source and drain region of a semiconductor element such as a MISFET formed on the main surface of the semiconductor substrate 18, 19 is a Si film, and 20.21 is a PSG.
It is an interlayer insulating film consisting of etc. Note that FIG. 1 is a cross section taken along the line AA in FIG. 2 before the A/wiring 24 is formed.

When changing the function of the semiconductor device having the above configuration, for example, as shown in FIG. is the input signal 82 newly connected to input terminal A.
2 is connected. This modification method will be explained with reference to FIGS. 4(4) to 4(a), which show cross sections corresponding to the cross section along the line A--A in FIG. 2 for each process.

First, as shown in the figure, the top conductor layer 14 of the input signal line 3 is
Laser beam As a result, the uppermost conductor layer 14' is burnt out by the laser energy, the input signal line 3 is selectively cut, and the conductor layers 3 and 14' are selectively cut.
is in a non-conducting state.

Next, as shown in the figure (■), a photoresist film 23 is formed on the entire surface, and then ultraviolet rays or electron beams
The photoresist film 23a in that area is selectively removed by exposure to light to complete the patterning. Thereafter, an A/layer 24 as a conductor layer material is formed by vapor deposition over the entire surface as shown in the figure (see Q).

Then, when the remaining photoresist film 23 is removed, the conductor layer on the photoresist film 23 is also removed integrally by a so-called lift-off method, and the conductor layers 14 and 7 are connected by the remaining conductor layer 24 like the hole shown in the figure. Then, new wiring and circuits are constructed. In this example, the gate 2 and the input terminal A are connected by the input signal line 22, that is, the A1 layer 24. Note that normally, after the change, the PSG film etc. A final passivation film is formed, but illustration thereof is omitted.

Therefore, according to this modification method, the conductor layer is cut with a laser beam and the photoresist film is patterned, so there is no need to create a photomask pattern with a different pattern (partial modification of wiring can be done extremely easily). Can be done.

〔effect〕

+11 At least some of the signal lines of a semiconductor device formed with multiple conductor wiring layers are configured as the top layer of the conductor wiring layers. Therefore, when changing the function of the device, it is necessary to cut a part of the top layer wiring or create a new one. (You only need to change it, and you can easily perform t'L.)

(2) When changing the wiring in the last conductive layer, a laser is used to cut the conductive layer, and a laser is also used to pattern the photoresist film and new wiring, so the photomask is remade when changing the wiring. is not necessary, and the functions of the device can be changed extremely easily.

(3) Since the function of a device can be partially changed without the need for a photomask, it is effective in manufacturing a small number of semiconductor devices, especially custom IOs and LSIs.

(4) Since wiring can be changed by partial laser irradiation and lift-off methods, change time can be shortened and design changes can be made quickly.

Although the invention has been specifically explained above based on the embodiments of the invention made by the present inventor, it goes without saying that the present invention is not limited to the above embodiments, and can be modified in various ways without departing from the gist thereof. Nor. For example, the wiring layer is 3
It is not necessary to have a multilayer structure, and it may be only one layer. Delivery #! Instead of the lift-off method for new installation, a mask vapor deposition method or a direct patterning method using a laser may be used.

[Application field]

The above explanation has mainly focused on the case where the invention made by the present inventor is applied to the functional change of logic ICs, which is the field of application that formed the background of the invention. The present invention can be applied to semiconductor devices of moderate quality, such as log 10. Furthermore, it can be used not only as a method for changing circuit functions, but also as a method for correcting incorrect wiring patterns in various types of 10.

Furthermore, the present invention is applicable not only to semiconductor devices, but also to wiring formed on insulating wiring substrates such as ceramic or glass epoxy, or wiring substrates made of silicon, as a method for changing the function or modifying the wiring pattern. Is possible.

[Brief explanation of drawings]

Fig. 1 is a sectional view of the embodiment of the present invention, Fig. 2 is a plan view, Fig. 3) and [F]) are circuit diagrams before and after the functional change, respectively.
FIG. 4 is a sectional view showing the method of the present invention in the order of steps.

Claims (1)

[Claims] 1. In a semiconductor device in which circuit elements are formed on the main surface of a semiconductor wafer and a plurality of conductor wiring layers are formed on the upper surface thereof, the number of signal lines connected to the circuit elements (
A semiconductor device characterized in that a portion of each of the conductor wiring layers is formed as the uppermost layer of the conductive wiring layer. 2. The semiconductor device according to claim 1, wherein the wiring portion formed in the uppermost layer has a structure in which middle and lower layer wirings are connected in a bridge shape. 3. Selectively cut some of the signal lines of the circuit elements formed on the top layer of the semiconductor wafer, while forming new patterns of conductor layers on other parts to make connections between other parts, and create wiring. A method for changing the function of a semiconductor device, the method comprising changing a pattern. 4. The newly formed wiring is formed by a lift-off method in which a photoresist is selectively exposed and patterned, a conductive layer is formed on the entire surface, and then the photoresist is removed. How to change the functionality of the device.