JPH0212872A - Semiconductor device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a contact hole structure for a semiconductor device.

[Background Art] In recent years, semiconductor devices have become increasingly finer and more highly integrated. The same is true for contact holes, whose dimensions are becoming finer down to the submicron region. Here, Figure 2C
A conventional contact hole and contact between a wiring layer and a silicon substrate will be described using (L') and (b). In Fig. 2 (α>, <b>, 201 is a P-type silicon substrate, 2
02&iNu impurity layer, 206 is a silicon oxide film for element isolation, 204 is a silicon oxide film, 205 is a contact hole, and 206 is an aluminum wiring. An N-type impurity layer 202 formed on a silicon substrate 201 and an aluminum wiring 206 are ohmically connected through a contact hole 205 formed in a silicon oxide film 2.4. Conventionally, the contact hole 205 is square or circular, and the width of the aluminum wiring is larger than the diameter of the contact hole, as shown in FIG. 2 (α), 1.6).

[Problems to be Solved by the Invention] However, in the prior art described above, when contact holes are miniaturized to the submicron region, light is diffracted in the photolithography process when forming contact holes, resulting in circular or square shapes. When passing through the contact hole mask, the intensity of the light is weakened, so the resist is not completely exposed and the contact hole cannot be opened.

In addition, in the conventional technology described above, when the contact hole is miniaturized to a submicron region, it becomes difficult for sputtered aluminum to enter the contact hole in the aluminum sputtering process for forming an aluminum electrode after the contact hole is formed. The aluminum film inside becomes thinner. As a result, there have been problems in that the aluminum wiring and the silicon substrate are not connected, or that if current continues to flow between the aluminum wiring and the silicon substrate, the thin aluminum film in the contact hole is disconnected.

In addition, in the conventional technology described above, the aluminum wiring width is made larger than the contact hole diameter, and it is necessary to increase the aluminum wiring width by taking into account the alignment margin between the contact hole mask and the aluminum electrode mask, and the aluminum wiring spacing must be increased. Another problem was that it was difficult to miniaturize.

The present invention is intended to solve these problems.The purpose of the present invention is to make it possible to open a contact hole even if the contact hole is miniaturized, to increase the thickness of the aluminum film inside the contact hole, and to increase the thickness of the aluminum film in the contact hole. An object of the present invention is to provide a semiconductor device in which the spacing can be further miniaturized.

[Means for Solving the Problems] A semiconductor device of the present invention includes: an active region provided on a semiconductor substrate; an oxide film provided on the semiconductor substrate; a wiring layer provided on the oxide film; In a semiconductor device having a contact hole provided in the oxide film that connects the semiconductor substrate and the wiring layer, the contact hole is elongated and the wiring layer crosses in a short side direction of the elongated contact hole, and The wiring layer may cover the active region within the contact hole.

[Example] An example of the present invention will be described in detail with reference to FIG. 1st
Figure (α) is a plan view showing one embodiment of the present invention, Figure 1Cb
) is a sectional view showing one embodiment of the present invention. In FIG. 1, 101 is a P-type silicon substrate, 102 is an N-type impurity layer, 103 is a silicon oxide film for element isolation, 104 is a silicon oxide film, 105 is a contact hole, and 106 is an aluminum wiring.

Next, a manufacturing method of this embodiment shown in FIG. 1 will be described.

First, a P-type silicon substrate 101 was heated to 100% in an oxidizing atmosphere.
Approximately 1,000
An oxide film of X is formed, and then a silicon nitride film of about 500' is formed by CIVD.

Next, unnecessary portions of the silicon nitride film are removed by photolithography, followed by oxidation at 1000° C. in an oxidizing atmosphere to form a silicon oxide film with a thickness of approximately 1 μm on the portions where the silicon nitride film was removed. Next, the silicon nitride film is removed to form an oxide film 103 for element isolation. Next, an N-type impurity, here phosphorus, is ion-implanted at an implantation energy of 80 Ke'V and a dose of 4 x 10'' cm-2, and then
An N-type impurity layer 102 is formed by performing 00'0(7)7.

Next, approximately 7,000 silicon oxide films are formed by CVD, and unnecessary portions of the silicon oxide films are removed by photolithography to form elongated contact holes 105. Next, aluminum is formed to a thickness of approximately 1 μm by sputtering, and unnecessary portions of the aluminum are removed by photolithography to form aluminum wiring 106 into elongated contact holes 10.
It is formed so as to cross the short side direction of 5.

In a conventional contact hole as shown in Figure 2, if the size of the hole is 0.6 μm in length and 0.6 μm in width, lens NA =
Although it is impossible to form a contact hole even if a 0.45 reduction projection exposure apparatus is used, the size of the contact hole in this embodiment as shown in FIG. ．．
If it is 0 μm, the resist can be opened by using a reduction projection exposure apparatus with a lens N A =0.45.

In addition, when using a conventional contact hole as shown in Fig. 2, whose size is 0.8 μm in length and 8 μm in width, and the thickness of the silicon oxide film 204 is 700X, it is difficult for aluminum atoms to enter the contact hole. Therefore, the thickness of the aluminum film inside the contact hole is less than 10% of the thickness of the aluminum film on the flat part.On the other hand, in this embodiment shown in Fig. 1, the size of the contact hole is 1. When aluminum is sputtered with a width of 5.0 μm and a silicon oxide film 104 thickness of 7000 μm, aluminum atoms from the long side of the contact hole easily enter the contact hole, and the aluminum film in the center of the contact hole is The thickness is 40 to 50% of the aluminum film thickness of the flat part, and if the aluminum wiring is passed through the center of the contact hole, there will be no disconnection or poor contact.

In addition, the size of the bottom of the conventional contact hole as shown in Figure 2 is 6μm in length and 0.8μ in width.

If the thickness of the silicon oxide film 204 is 700X and the taper angle of the contact hole is 70°, the size of the upper part of the contact hole is 1.3μ" vertically * 1.3μ horizontally.
m. Here, if the overlapping precision of the mask for the contact hole 205 and the aluminum wiring 206 is 0.3 μm, the minimum dimension of the aluminum wiring width in FIG. 2 is 1.9 μm.
It becomes μm. On the other hand, in this embodiment shown in FIG. 1, the size of the bottom of the contact hole is 0.8 μm in length and 5.0 μm in width.
, the thickness of the silicon oxide film 104 is 7oooK, the width of the N-type impurity layer 102 is 0.8/J77L, and the N-type impurity layer 10
Assuming that the overlay accuracy of the mask of 2 and the aluminum wiring 106 is 0.3 μm, the aluminum arrangement ii in FIG. 1!
The minimum dimension of 1lli is 1.4 μm, and the aluminum wiring width can be reduced by 0.5 μm compared to the conventional example shown in FIG.

In this example, the LOOO3 method was used for element isolation.
As shown in FIG. Although only two aluminum wires crossed the contact hole, six or more aluminum wires may cross the contact hole as shown in Figure 4.Also, a long and narrow contact hole may be bent in the middle as shown in Figure 5. Furthermore, although aluminum is used for the wiring layer in this embodiment, other materials such as polycrystalline silicon, high melting point metals such as molybdenum, titanium, and tungsten, and metals such as copper, iron, silver, and platinum may also be used. However, a wiring layer having a laminated structure in which these materials are stacked may also be used.

[Effects of the Invention] As described above, according to the present invention, if the contact hole is elongated and two or more wiring layers cross in the short side direction of the elongated contact hole, the contact hole and the wiring layer can be miniaturized. It becomes possible to miniaturize semiconductor devices,
It plays a major role in achieving high integration. Also, since the aluminum wiring inside the contact hole has better coverage,
The resistance of the connection between the silicon substrate and the aluminum wiring can be reduced, the operation of the semiconductor device can be made faster, and the reliability of the semiconductor device can be increased because it is resistant to electromigration. These advantages have the effect of providing high-speed, high-quality semiconductor devices.

[Brief explanation of the drawing]

FIGS. 1(α) and 1(b) are a main plan view and a main sectional view showing an embodiment of the semiconductor device of the present invention. FIG. 2(α), Cb) is a main plan view and main sectional view of a semiconductor device according to a conventional example. 3(α), t(b), FIG. 4, and FIG. 5 are plan views and cross-sectional views showing other embodiments of the present invention.
,301,401,501 ・・・・・・・・・・・・
・P-type silicon substrate 102.202, 302, 402, 502...
...... N-type impurity layer 103, 203, 303... Element isolation oxide film 104, 204, 304... Silicon oxide film 1
05.205,305,405,505...
...Contact hole 106, 206, 306, 406, 506...
・・・・・・More than aluminum wiring

Claims (1)

[Claims] an active region provided on a semiconductor substrate, an oxide film provided on the semiconductor substrate, a wiring layer provided on the oxide film, and a layer provided on the oxide film connecting the semiconductor substrate and the wiring layer. In the semiconductor device, the contact hole is elongated, the wiring layer traverses the short side direction of the elongated contact hole, and the wiring layer covers the active region within the contact hole. A semiconductor device characterized by: