JPH04298040A - Manufacture of integrated circuit - Google Patents

Abstract

PURPOSE:To solve the problem that the failure ratio due to the discontinuity of wiring in an integrated circuit increases with increasing time for heating. CONSTITUTION:In the prior art, an aluminum wiring layer and an inner insulating layer of SiO2 are formed in sequence on a first main surface of a silicon substrate. After a heat treatment in an atmosphere containing hydrogen and nitrogen, a gold layer is formed on the other main surface opposite the first surface of the substrate, and then the substrate is heat-treated in a nitrogen atmosphere. To reduce the failure ratio due to discontinuity, a new method is provided in which an aluminum wiring layer, an insulating layer of SiO2, and a gold layer are formed, and heat treatments are performed first in a nitrogen atmosphere, then in an atmosphere containing nitrogen and hydrogen.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention provides a method in which a wiring layer made of Al is formed on a first main surface of a semiconductor substrate made of Si, and
An interlayer insulating film made of SiO2 is formed on the first main surface of the semiconductor substrate and extends to cover the wiring layer, and a second interlayer insulating film that is opposite to the first main surface of the semiconductor substrate is formed. The present invention relates to a method for manufacturing a semiconductor integrated circuit device having a configuration in which a conductor layer made of Au is attached on the main surface of the semiconductor integrated circuit device.

0002

2. Description of the Related Art Conventionally, a wiring layer made of Al is formed on a first main surface of a semiconductor substrate made of Si, and a wiring layer is formed on the first main surface of the semiconductor substrate to cover the wiring layer. A semiconductor having a structure in which an interlayer insulating film made of SiO2 is formed, and a conductor layer made of Au is further attached on a second main surface facing the first main surface of the semiconductor substrate. Integrated circuit devices have been widely proposed for a variety of reasons. Conventionally, in manufacturing such a semiconductor integrated circuit device, a first step of forming a wiring layer on the first main surface of the semiconductor substrate is performed, and after the first step, the semiconductor substrate is A second step of forming an interlayer insulating film made of SiO2 extending to cover the wiring layer is performed on the first main surface, and after the second step, a mixed gas of hydrogen and nitrogen is applied. A third step is performed in which heat treatment is performed in an atmosphere.
After the step, a fourth step of forming the conductor layer on the second main surface of the semiconductor substrate is performed, and after the fourth step,
A method has been proposed that includes a fifth step of heat treatment in a nitrogen gas atmosphere.

According to such a conventional manufacturing method of a semiconductor integrated circuit device, in the third step, undesirable impurity elements such as Br, which are inevitably contained in the wiring layer formed in the first step, are removed. Since hydrogen can be substituted for hydrogen, the final wiring layer can be obtained with a low disconnection rate.

Furthermore, in the fifth step, the conductor layer formed in the fourth step can be formed into a eutectic alloy with the second main surface of the semiconductor substrate, so that the conductor layer is formed on the second main surface side of the semiconductor substrate. It can be obtained as being well connected with.

[0005]

[Problems to be Solved by the Invention] However, in the case of the above-mentioned conventional method for manufacturing a semiconductor integrated circuit device, the wire breakage rate with respect to the heating time of the wiring layer in the obtained semiconductor integrated circuit device increases rapidly with time. It had drawbacks.

Accordingly, the present invention aims to propose a novel method for manufacturing a semiconductor integrated circuit device that can effectively avoid the above-mentioned drawbacks.

[0007]

Means for Solving the Problems A method for manufacturing a semiconductor integrated circuit device according to the present invention includes forming a wiring layer made of Al on a first main surface of a semiconductor substrate made of Si, SiO2 extending over the above wiring layer on the surface
manufacturing a semiconductor integrated circuit device having a structure in which an interlayer insulating film made of is formed, and a conductor layer made of Au is attached on a second main surface opposite to the first main surface of the semiconductor substrate. (i) taking a first step of forming the wiring layer on the first main surface of the semiconductor substrate; (ii)
) After the first step, a second step is performed to form an interlayer insulating film made of SiO2 extending over the wiring layer on the first main surface of the semiconductor substrate, (iii)
After the second step, a third step of forming the conductor layer on the second main surface of the semiconductor substrate is performed, and (iv) after the third step, heat treatment in a nitrogen gas atmosphere is performed. A fourth step is followed by heat treatment in an atmosphere of a mixed gas of nitrogen and hydrogen.

[0008]

[Operations and Effects] According to the method for manufacturing a semiconductor integrated circuit device according to the present invention, the heat treatment in a nitrogen gas atmosphere in the fourth step corresponds to the fifth step in the conventional method for manufacturing a semiconductor integrated circuit device. As a result, the conductor layer formed in the third step can be formed into a eutectic alloy with the semiconductor substrate on the surface of the semiconductor substrate. It can be obtained as being well connected to the substrate.

However, in the method for manufacturing a semiconductor integrated circuit device according to the present invention, after the conductor layer is formed in the third step, heat treatment in an atmosphere of a mixed gas of nitrogen and hydrogen is also performed in the fourth step. Therefore, by the heat treatment, the conductor layer can be further formed into a eutectic alloy on the surface of the semiconductor substrate. It can be coupled to a semiconductor substrate.

Furthermore, according to the method for manufacturing a semiconductor integrated circuit device according to the present invention, the heat treatment in the atmosphere of a mixed gas of nitrogen and hydrogen in the fourth step is the third step in the conventional method for manufacturing a semiconductor integrated circuit device. As it is compatible with the manufacturing process, it is possible to replace undesirable impurity elements such as Br, which are inevitable to be included in the wiring layer, with hydrogen, as in the case of the conventional manufacturing method of semiconductor integrated circuit devices. The resulting wiring layer can be obtained with a low disconnection rate similar to the conventional manufacturing method of a semiconductor integrated circuit device.

However, in the method of manufacturing a semiconductor integrated circuit device according to the present invention, the heat treatment in an atmosphere of a mixed gas of nitrogen and hydrogen in the fourth step is performed on the second main surface of the semiconductor substrate in the third step. Since the process is carried out with a conductor layer formed on top, it is inevitable that Br will be included in the wiring layer.
Undesirable impurity elements such as
A lower wire breakage rate can be obtained than in the conventional manufacturing method of a semiconductor integrated circuit device. In addition, in the method for manufacturing a semiconductor integrated circuit device according to the present invention, as described above, the heat treatment in the atmosphere of a mixed gas of nitrogen and hydrogen in the fourth step is carried out in the second step of the semiconductor substrate in the third step. Since the process is carried out with the conductor layer formed on the main surface, the stress applied to the wiring layer can be greatly alleviated by the interlayer insulating film formed in the second step, so that the final result can be reduced. The wiring layer can be obtained with a lower disconnection rate than in the conventional manufacturing method of a semiconductor integrated circuit device.

0012

[Embodiment] Next, an embodiment of the method for manufacturing a semiconductor integrated circuit device according to the present invention will be described.

An embodiment of the method for manufacturing a semiconductor integrated circuit device according to the present invention is as follows:

As mentioned in the section [Means for solving the problem], S
A wiring layer made of Al is formed on a first main surface of a semiconductor substrate made of i, and an interlayer insulating film made of SiO2 is formed on the first main surface of the semiconductor substrate and extends to cover the wiring layer. (i
) taking a first step of forming the wiring layer on the first main surface of the semiconductor substrate; (ii) after the first step;
A second step of forming an interlayer insulating film made of SiO2 extending to cover the wiring layer is performed on the first main surface of the semiconductor substrate, and (iii) after the second step, the A third step of forming the conductor layer on the second main surface of the semiconductor substrate is performed, and (iv) after the third step, heat treatment is performed in a nitrogen gas atmosphere, followed by nitrogen and hydrogen treatment. A fourth step is a heat treatment in a mixed gas atmosphere.

[0014] In the first step, the wiring layer made of Al is formed by sputtering a layer made of Al on the semiconductor substrate without heating it, and then the layer made of Al is formed by sputtering. It was formed by performing an etching process using a mask.

Furthermore, the interlayer insulating film made of SiO2 in the second step was formed by a low-temperature deposition method.

Furthermore, in the third step, a conductor layer made of Au was formed to a thickness of 0.3 μm by vapor deposition without heating the semiconductor substrate.

[0017] Furthermore, heat treatment in a nitrogen gas atmosphere in the fourth step is carried out at a temperature in the temperature range of 390 to 430°C, particularly at a temperature of 400°C, for 15 minutes, and a mixed gas of nitrogen and hydrogen is Heat treatment in an atmosphere of 39
Temperatures in the temperature range from 0°C to 430°C, inter alia 4
The test was carried out at a temperature of 00°C for 30 minutes.

Note that after the fourth step, the semiconductor substrate is
Cooling was performed at a rate of °C/sec.

According to the embodiment of the method for manufacturing a semiconductor integrated circuit device according to the present invention described above, the estimated wire breakage rate with respect to the heating time shown in FIGS. As is clear from the measurement results shown,
A semiconductor integrated circuit device can be manufactured with a wire breakage rate in wiring layers that is significantly lower than that in conventional semiconductor integrated circuit device manufacturing methods.

Note that FIG. 1 shows a width of 0.8 μm and a width of 0.5 μm.
For a wiring layer having a thickness of μm and a length of 7 mm,
The case is shown in which heating is performed at a temperature of 400° C. in a nitrogen gas atmosphere.

Note that FIG. 2 shows a width of 1.0 μm and a width of 0.5 μm.
For a wiring layer having a thickness of μm and a length of 7 mm,
The case is shown when heated in air at a temperature of 400°C.

[Brief explanation of the drawing]

FIG. 1 shows the measurement results of the cumulative disconnection rate of a wiring layer with respect to the heating time in a nitrogen gas atmosphere, which is used to explain the effects of the method for manufacturing a semiconductor integrated circuit device according to the present invention. It is a figure shown in comparison with the case of.

FIG. 2 shows the measurement results of the cumulative disconnection rate of the wiring layer with respect to the heating time in air in the case of the conventional semiconductor integrated circuit device manufacturing method, which is used to explain the effects of the semiconductor integrated circuit device manufacturing method according to the present invention. FIG.

Claims (1)

[Claims] 1. A wiring layer made of Al is formed on a first main surface of a semiconductor substrate made of Si, and a wiring layer made of Al is formed on a first main surface of a semiconductor substrate made of Si.
SiO2 extending over the main surface of the wiring layer and covering the wiring layer.
manufacturing a semiconductor integrated circuit device having a structure in which an interlayer insulating film made of is formed, and a conductor layer made of Au is attached on a second main surface opposite to the first main surface of the semiconductor substrate. To do this, a first step of forming the wiring layer on the first main surface of the semiconductor substrate is performed, and after the first step, the wiring layer is formed on the first main surface of the semiconductor substrate. A second step is performed to form an interlayer insulating film made of SiO2 extending to cover the layer, and after the second step, a second step is performed to form the conductive layer on the second main surface of the semiconductor substrate. 3
After the third step, a fourth step is performed in which heat treatment is performed in a nitrogen gas atmosphere, followed by heat treatment in a mixed gas atmosphere of nitrogen and hydrogen. A method for manufacturing a semiconductor integrated circuit device.