JPS5910063B2 - hand tai souchi no seizou houhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of forming a connection electrode for connecting a semiconductor substrate and a wiring pattern on an insulating layer thereof.

In a semiconductor device, electrodes are generally drawn out from regions such as a base and an emitter as shown in FIG.
That is, after finishing the final diffusion process such as emitter diffusion into the semiconductor element, the base region 1, which is, for example, P type, and in this example, N+
SiO is deposited on the entire surface of the emitter region 2 which is a mold.
A window 3a for an emitter electrode is formed in the insulating layer 3 of No. 2 by photo-etching, and a metal such as aluminum is deposited on the entire surface to form a metal layer 4 for leading out the electrode. Next, the metal layer 4 is patterned to form a wiring pattern. The same applies to the base electrode, collector electrode, etc.
By the way, when the metal layer 4 is deposited by a commonly used vapor deposition method, since the peripheral wall of the electrode window 3a portion of the insulating layer 3 is steep, the metal layer 4 is deposited in the shape shown in FIG.
A thin part 4a often occurs near the lower edge of the window,
When patterning the metal layer 4, there is a risk that this portion may be disconnected.

To improve this problem, the electrode window may be tapered to make it mortar-shaped, or a conductor may be initially applied as an insulating layer, and this may be made into an insulator by anodic oxidation, etc., except for the wiring. Several methods have been proposed, such as creating a flat base using The present invention relates to one such proposal, and attempts to prevent wire breakage using a relatively simple method without requiring any special steps. . Generally, when metal particles are introduced into an insulator and their concentration exceeds a predetermined value, the insulator rapidly assumes the properties of the metal and becomes conductive.

The method for forming a connection electrode of the present invention has been made by taking advantage of this phenomenon, and is characterized by the fact that silicon An insulating layer of oxide is formed, a metal is selectively deposited on desired parts of the insulating layer on the element region or the wiring layer, and then heat treatment is performed to form a solid solution of the metal and the insulating layer, The insulating layer is locally conductive and used as a connection electrode between the wiring pattern formed on the surface of the insulating layer and each of the regions or wiring layers. The present invention will be described in detail below with reference to embodiments of the drawings. 3 to 6 are diagrams explaining the method of forming a connection electrode according to the present invention. In these figures, 11 is a silicon semiconductor substrate, 12 is an insulating layer of silicon dioxide (SiO2), and 13 is an aluminum At, gold It is a metal layer of Au, silver Ag, titanium Ti, etc.

First, as shown in FIG. 3, an insulating layer 1 of SiO2 is formed by thermal oxidation or the like on the surface of a silicon semiconductor substrate 11 that has just completed the final diffusion process and is about to be deposited with a metal layer for electrode wiring.
A metal layer 13 is formed by depositing a metal such as aluminum on the entire surface thereof. Next, by photo-etching, the metal layer 13A in the base region, emitter region, etc. of the substrate 11 in the portions corresponding to the electrode contact portions is left, and the other portions of the metal layer 13 are removed, as shown in FIG. In this way, the metal layer 13 corresponding to the electrode contact portion
When heat treatment is performed after A remains, the insulating layer 12 and the metal layer 13A react, and the metal atoms of the metal layer 13A form the insulating layer 1.
2, and a solid solution of metal-SiO2 is formed as shown in FIG. Since this layer has conductivity, it can be used as a connection electrode. Next, as shown in FIG. 6, a metal such as aluminum is deposited over the entire surface of the insulating layer 12 and the connection electrode 14 to form a metal layer 15, and this is patterned to form a predetermined wiring layer. Thereby, the metal layer 15 of the second wiring layer is reliably electrically connected to the electrode contact portion of the semiconductor substrate 11 via the connection electrode 14. Furthermore, since the metal layer 15 has a flat base formed by the layers 12 and 14,
There is no fear of disconnection. The introduction of metal atoms into the insulating layer 12 is carried out by heat treatment three times, and the temperature of this heat treatment is At, Au.
600℃ or higher for Ag, 400℃ or higher for Ti, 550℃ for Ti
This is done by heating at the above temperature for about 30 minutes. The thickness (height) of the metal layer 13 is the same as or slightly thicker than the insulating layer 12, so that these planes are flat 3. Alternatively, the connection electrode 14 may be in a slightly protruding state. In this way, the electrical connection between the metal layer 15 and the connection electrode 14 is ensured. For example, the thickness of the silicon dioxide insulating layer 12 is 0.3 μm, and the metal layer 13 is made of gold (Au) with a thickness of 0.3 μm.
It was formed by vapor deposition to a thickness of 3 μm, and heat treatment was performed at 1050° C. for 20 minutes in nitrogen (N,) gas. As a result, when the gold on the surface was removed and the resistance value of the insulating layer was measured, it was found to be 0.
．． A resistivity of 0.05 Ω-Cm was obtained. As explained in detail above, in the present invention, a metal is selectively deposited on an insulating layer of silicon oxide, and then heat treatment is performed to form a solid solution of the metal and the insulator, thereby making the insulating layer locally conductive. This was used as a connection electrode between the wiring layer and the semiconductor substrate.

As a result, electrodes can be drawn out reliably without causing problems such as disconnection. In addition, although the above explanation has been made regarding the case where electrodes are led out from a region in a semiconductor substrate, the present invention can also be applied to the case where an interlayer connection conductor of a multilayer wiring structure as shown in FIG. 7 is formed. can.

In this case, an insulating layer 17 is deposited on the lower wiring layer 16,
Interlayer connectors 18 are formed by selectively introducing metal into desired locations of the insulating layer 17 using the method described above. After that, insulating layer 1
A metal layer is deposited on 7 and selectively removed to form an upper wiring layer 19 connected to interlayer connector 18 . In this case as well, it is possible to eliminate the difference in level at the connection point between the lower wiring layer and the upper wiring layer, and to perform a connection that does not cause disconnection or the like.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing the structure of the electrode portion of a conventional semiconductor element, FIGS. 3 to 6 are cross-sectional views explaining the method of forming the connection electrode of the present invention, and FIG. 7 is the present invention. FIG. 3 is a sectional view showing another embodiment of the invention. In the figure, 1 and 11 are semiconductor substrates, 2, 12, and 17 are insulating layers, and 14 and 18 are connection electrodes.

Claims (1)

[Claims] 1. Form an insulating layer of silicon oxide to cover an element region formed in a semiconductor substrate or a wiring layer formed on the semiconductor substrate, and select a desired location of the insulating layer on the element region or wiring layer. a wiring pattern in which a metal is deposited on the surface of the insulating layer, a solid solution of the metal and the insulating layer is formed by heat treatment, the insulating layer is made locally conductive, and this is formed on the surface of the insulating layer; A method for manufacturing a semiconductor device, characterized in that the electrode is used as a connection electrode between a region or a wiring layer.