JPS6364898B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device, and more particularly to a semiconductor device having an improved structure in a bonding region of a metal electrode.

Requires operation in high frequency bands. In semiconductor devices, it is used to prevent development such as junction breakdown due to sintering of electrode metal into an extremely shallow impurity injection layer, and to prevent reaction between the Pt-Si layer used to form a shot barrier diode and aluminum.
Usually, titanium-aluminum (Ti-Al), titanium-tungsten alloy-aluminum (Ti/W)
-Al), titanium-platinum-gold (Ti-Pt-Au), etc., are used. However, the
Blocking layers such as Ti, Ti/W, etc. generally do not have sufficient adhesion strength with insulating films such as silicon dioxide (SiO ₂ ), so they are formed on the SiO ₂ film in a state where they are drawn out. Metal electrodes with the above multilayer structure When bonding gold (Au) wire, etc. to the bonding area of a layer, the peel strength varies widely and some are extremely weak, resulting in the problem of lowering the quality, manufacturing yield, and reliability of semiconductor devices. It was hot.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor device having a bonding region having a structure in which the adhesive strength between a multilayer electrode and an insulating film is strong, eliminating the above-mentioned conventional drawbacks.

That is, in the present invention, for example, the structure of the bonding region in the electrode layer drawn out from a desired region of the semiconductor substrate onto the insulation on the surface of the semiconductor substrate is strong against the bonding electrode layer between the bonding electrode and the underlying insulating film. It is characterized by the presence of a plasma SiN film with adhesive strength.

Embodiments of the present invention will be described in detail below with reference to the drawings. After forming each region on a semiconductor substrate by a known method, a plasma SiN film is deposited and processed so that the plasma SiN film remains in the bonding region, and then a metal electrode is formed to change the structure of the bonding region. Plasma SiN-Titanium-Aluminum (P.SiN-Ti-Al) Plasma SiN-Titanium
Tungsten alloy - Aluminum (P・SiN -
Ti/W-Al), plasma SiN-titanium-platinum-gold (P/SiN-Ti-Pt-Au) structure.

For example, the following method may be used to form the electrode having the structure of the present invention.

1-1 to 1-3 show a preferred first embodiment of the present invention. First, each region is formed on a semiconductor substrate by a known method, and then a plasma SiN film is deposited on the entire surface with a thickness of approximately 5000 Å. Using the method described above, a plasma SiN film 1-3 is formed by photolithography so that the plasma SiN film remains only in the bonding area (Figure 1-1). After that, a contact hole was made using photolithography technology and Pt was coated on the entire surface, and the semiconductor substrate was heated to 500°C.
Unreacted Pt on the SiO ₂ film and plasma SiN film is removed using aqua regia, etc., and a Pt-Si base contact layer 1-11 is formed in the contact window as shown in Figure 1-2.
An emitter contact layer 1-10 and a shot barrier diode 1-12 are formed (FIG. 1-2).
Thereafter, a metal electrode layer such as a Ti layer, such as a 1000 Å Al layer with a thickness of 1.5 μm is deposited by a method such as sputtering, and then the Ti-Al layer is processed into a desired shape by a method of photolithography to form wiring and By forming the metal electrode layers 1-13 and 1-14, the bonding region is formed by forming an insulating layer (SiO ₂ film) - plasma SiN - titanium - aluminum (SiO ₂ -P.
(SiN-Ti-Al) structure (Fig. 1-3).

Figures 2-1 to 2-6 show a second embodiment of the present invention in which the present invention is applied to two-layer wiring technology.
After forming each region other than the emitter region on a semiconductor substrate by a known method, holes 2-3, 2-4, and 2-5 are formed to become contacts in each region (2-1
figure). Thereafter, a polysilicon film 2-6 is grown to a thickness of approximately 5000 Å over the entire surface by vapor phase growth, an oxide film 2-7 is grown to a thickness of 500 to 600 Å by thermal oxidation, and then a nitride film 2-8 is grown to a thickness of 1100 Å (second -2
figure). Thereafter, a desired portion of the nitride film 2-8 is etched using photolithography technology, and then thermal oxidation is performed to convert the polysilicon film in the portion where the nitride film is not adhered to the surface into an oxide film, forming the desired layer. Pattern 2-9, 2-10, 2-1
1 is formed (Figures 2-3). Thereafter, the desired pattern 2-9 is formed using photolithography technology.
Emitter diffusion is performed by removing only the nitride film and oxide film in the area to form the emitter 2-12. Similarly, the desired pattern 2-10, 2-
P-type and N-type substances are also diffused into the 11th part to lower the resistance, making the base P ⁺ 2-13 and the collector N ⁺ 2-1.
form 4. After that, the oxide film on the polysilicon surface is completely removed, platinum (Pt) is deposited, the substrate is heated to 500°C, and unreacted Pt on the oxide film is removed with aqua regia etc. -9',2-1
0', 2-11' is formed (Figure 2-4). After that, a plasma SiN film 2-15 of approximately 1.0 μm is deposited on the entire surface, and through-holes are made in desired areas using photolithography technology, and then titanium (Ti) is deposited on the entire surface with a thickness of approximately 1000 Å. Furthermore, Ti film 2
2-16 is coated with an Al film 2-17 of approximately 1.0 μm (Figure 2-5). Thereafter, the Ti--Al film is processed into a desired shape using photolithography technology to form the wiring section 2-18 and the metal electrode 2-19, so that the bonding area of the metal electrode section is covered with an insulating layer (SiO ₂ film) - plasma SiN film (P SiN) - titanium (Ti) - aluminum (Al) structure.

In the metal electrode structure according to the present invention formed by the method described above, a plasma SiN film layer exists between the insulating layer (SiO ₂ film) and the metal electrode layer in the bonding region, and the insulating layer ( _SiO2 film)
-Plasma SiN film (P・SiN) -Titanium (Ti)-
It has an aluminum (Al) structure and improves the adhesive strength between the insulating layer (SiO ₂ film) and the titanium layer that constitutes the bottom film of the metal electrode, significantly improving the peel strength of the bonding area. Furthermore, variations in strength are almost eliminated.

In the above embodiment, the blocking layer of the wiring electrode is made of molybdenum (Mo) in addition to titanium.
Titanium/tungsten (Ti/W) may also be used. Further, in the above embodiments, the case where the present invention is applied to a semiconductor integrated circuit has been described, but the present invention can be applied not only to other semiconductor integrated circuits but also to transistors and the like.

As explained above, the semiconductor device having the electrode structure of the present invention has significantly improved bonding strength and almost no variation in strength, so it is extremely effective in improving the manufacturing yield and reliability of semiconductor devices. be.

[Brief explanation of drawings]

FIGS. 1-1 to 1-3 and FIGS. 2-1 to 2-6 are cross-sectional views showing embodiments of a semiconductor device according to the present invention in the order of steps. In the figure, 1-1...silicon substrate, 1
-2...Oxide film, 1-3...Plasma SiN film, 1
-4...Emitsuta area, 1-5...Base area,
1-6...Collector area, 1-7...Emitsuta/
Contact, 1-8...Base contact, 1
-9...Collector contact, 1-10...Emitsuta Pt-Si contact, 1-11...Base
Pt-Si contact, 1-12... shot barrier diode, 1-3... wiring/electrode aluminum, 1-14... wiring, electrode titanium, 2-1...
Silicon substrate, 2-2... Oxide film, 2-3... Emitter contact, 2-4... Base contact, 2-5... Collector contact, 2-6
... Polysilicon film, 2-7 ... Oxide film, 2-8
...Nitride film, 2-9,2-10,2-11...Pattern formed by thermal oxidation, 2-9',2-
10', 2-11'...Wiring area section, 2-12...
Emitsuta area, 2-13...Base P ⁺ area, 2
-13'...Base area, 2-14...Collector
N ⁺ area, 2-14'... Collector area, 2-15
...Plasma SiN film, 2-16...Titanium film, 2
-17...aluminum film, 2-18...wiring part, 2-19...metal electrode part.

Claims (1)

[Claims] 1. In a semiconductor device in which a bonding region is formed in an electrode layer drawn out from a desired region of a semiconductor substrate onto an insulating film provided on the surface of the semiconductor substrate, the bottom layer of the electrode layer in the bonding region is made of Ti. What is claimed is: 1. A semiconductor device comprising: a metal layer having Ti, and a silicon nitride layer existing between the bonding region of the metal layer having Ti and the underlying insulating film.