JPS5832434A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent metal wiring from being broken by minimizing surface unevenness through the use of an insulating film of the stacked layer type when covering the entire surface of a substrate after the formation of source and drain regions and providing these regions with openings. CONSTITUTION:Thick field oxide films 112 are formed on the peripheral parts of a P type Si substrate 110. A gate electrode 118 of a polycrystalline Si is formed via a thin gate oxide film 122 at the center surface of the substrate 110 surrounded by the films 112, and on the film 112 a wiring pattern 120 is formed. Then the electrode 118 and the pattern 120 are subjected to heat treatment in an atmosphere of POCl3 to provide them with conductivity, N<+> type source and drain regions 124,126 are formed on the substrate 110, and the entire surface is covered with a stacked layer of an SiO2 film 130 and an SiO2 film 132 with impurities added. Contact holes 134 are formed to the regions 124,126, and by the reactive ion etching the film 132 is left as a film 132b only on the film 130 in the vicinity of the hole 134. The entire surface is then covered with an SiO2 film 136, openings are provided to this film and Al wiring 138 is bonded to each region.

Description

[Detailed description of the invention] The present invention relates to a semiconductor device and a method for manufacturing the same.

Conventionally, in the manufacture of semiconductor devices, substrates have been smoothed to prevent aluminum wiring from breaking. In other words, an insulating film made of meltable silicon oxide is formed on the entire surface of the semiconductor substrate by high-temperature heat treatment with addition of phosphorus or boron before opening the contact hole, then contact F is opened, and then high-temperature heat treatment is performed. Otherwise, the insulating film is melted.

A method of manufacturing, for example, a 1-channel silicon MOg) Tunster will be described with reference to FIGS. First, as shown in FIG. 1(a), a silicon oxide film with a thickness of 1 μm is formed on a P-type silicon substrate 1-, and a region 0S in which sources and drains (a) and r-) are to be formed is formed by photolithography.
IV:! A silicon oxide film 14 with a thickness of 100OX is formed on the exposed nine silicon groups fI7L1- to form a field insulating film 12 by removing the silicon oxide film, and a polycrystalline silicon layer 1 with a thickness of 40001O is formed on the bottom. ．． # is formed by a vapor phase growth method. Thereafter, as shown in FIG. 1(b), a dirt electrode 18 and a 1 m/s-720 layer are formed by photolithography, and the silicon oxide film 14 in the regions where the source and drain are to be formed is removed using the dirt electrode 18 as a mask. r-)
Zero-order phosphorus oxychloride (Pock,
) By performing high temperature heat treatment at 1000 DEG C. for 1 minute in an atmosphere, phosphorus is diffused into the r-) electrode 18 and the wiring Δ turn 20 to lower the resistance. At the same time, phosphorus is also diffused into the exposed silicon substrate 10 to form an N+ type source region 24 and drain region 2C.
As shown in the figure, by high temperature oxidation, the electrode 18, the wiring pattern 20 and the exposed silicon substrate are coated with approximately 1001
A silicon oxide film (doped silicon oxide film) 32 with a thickness of 5,000 mm and doped with phosphorus or phosphorus and boron is formed on the entire surface of the silicon substrate in the shape of the oxide film 2#. After that, a contact hole 34 was formed by photolithography, and a thickness of JSO was formed on the entire surface.
A high-temperature heat treatment is performed at 1000° C. for 5 minutes in an OX 7-doped silicon oxide conversion 1# phosphorus atmosphere to melt the doped silicon oxide film 81 and smooth the unevenness on the substrate surface. Furthermore, the thickness of the contact portion 34 is 50× by photolithography.

AND-fP silicon acid oxide film- is removed.

Next, as shown in Fig.
Form an alkaline layer of μ y#□, set a sialic acid wire j# by photolithography, and form a 1-channel silicone layer (r-)MOg).
? Complete the injista.

In the conventional method, when the smoothing doped silicon oxide @aX is formed by vapor phase growth, the doped silicon oxide film J1! is formed by abnormal growth. ! It is said that the protrusions 40 are generated on the surface (see FIG. 1 (-)), and that the protrusions 401IC) cause the disconnection of the Al2 wiring 31), causing defective photo-etching. A thin and smooth silicon oxide film doped with phosphorus and boron.
When used in a film, during the high-temperature heat treatment in a phosphorous oxychloride atmosphere during smoothing, a certain proportion of microscopic particles are generated in the undoped silicon oxide II x # formed on the top. Through the holes, phosphorus oxychloride and doped silicon oxide film J2 react to form doped silicon oxide IEJ.
A boiling phenomenon may occur, and protrusions 42 may be formed on the surface of the doped silicon oxide film 632 (see No. 1 (-)).

This protrusion 42 also caused the discontinuity in the alignment and was the cause of defective photo engraving. In order to prevent the above-mentioned disadvantages, an and-
It is sufficient to form the doped silicon oxide film J6 thickly.
Since it becomes difficult to smooth the surface of the undoped silicon oxide film 12, the thickness of the undoped silicon oxide film sea is naturally limited, and the generation of micropores cannot be sufficiently prevented.

The present invention was developed in view of the above points, and the thickness of an insulating film that exists on a flat area and can be melted by high-temperature heat treatment is
By reducing the thickness of the insulating film existing on the side surface of the uneven portion or completely removing the thickness, the height difference between the unevenness on the substrate surface can be reduced, or in addition to the same effect, the thickness of the insulating film surface can be reduced. Expressing the area where protrusions occur as the minimum,
This improves the accuracy of the photolithography process, reduces metal wiring breaks and photoetching defects, and supports the life and death conductor device.

The manufacturing method of the semiconductor device described above also includes a step of forming an insulating film that can be melted by high-temperature heat treatment on a semiconductor region having uneven portions, and applying the insulating film to the semiconductor region by reactive ion processing or etching. a step of machining and cindering the insulating film approximately vertically to make the thickness of the insulating film on the flat area thinner than the thickness of the insulating film existing on the side surface of the uneven portion, or completely removing the insulating film, and high-temperature heat treatment. The process consists of a step of melting the insulation layer.

Furthermore, the semiconductor device according to the present invention may include another insulating thin film covering the insulating film.

Embodiments of the present invention will be described in detail below with reference to the drawings. 2-) to 2-)-- are the l-channel series according to the present invention; r-) MOE! ) Manufacturing process diagram of Tunzosta.
As shown in FIG. 2(a), a P-type silicon substrate 11
A silicon oxide film with a thickness of 1 μm is formed on the silicon oxide film 9110 exposed to the 0th order on which a field insulating film 112 is formed by removing the silicon oxide film in the regions where the source, drain and dirt are to be formed by photolithography. Form on top by thickness length method. Then, as shown in FIG. 2(b), the r-) electrode 118 and the wiring/four turns 120 are formed by photolithography, and the source, r-) electrode ixa is used as a mask.
A high temperature heat treatment is performed at 1000° C. for 10 minutes in a zero-order phosphorus oxychloride (Pock) atmosphere to remove the silicon oxide film 114 in the region where the drain is to be formed and form the r-) insulating film 122. Accordingly, phosphorus is diffused into the r-) electrode 118 and the wiring pattern 120 to lower the resistance.

At the same time, phosphorus is also diffused into the exposed silicon substrate 110 to form an N+ type □ source region 124 and drain region 124.
Next, as shown in FIG. 2(C), an oxide film of about 1000X is formed on the electrode 111, the wiring pattern 110, and the exposed silicon substrate 110 by high-temperature oxidation.
1. Next, a 500 mm thick undo silicon oxide film 110 with a thickness of 5 mm for protecting the device is formed. 1. Next, a 5 mm thick silicon oxide film doped with phosphorus or phosphorus and boron is formed on the entire surface of the silicon substrate. (Doped 134 hole opening 0th order 2nd (・) example, t Huff L/
# N (CF4) j OgCCM, water #c (H2) J
# Perform Δ2 350W0 reactive ion etching for 11 minutes in a 1100M atmosphere. In this case, the doped silicon oxide group 112 etching time is 40017 minutes, so P-f) in the ** direction with respect to the substrate. Silicon oxide j1 s !I J h 5zoo The thickness of the silicone film 1sxbo formed on the side surface is approximately 5 mm or more.Although a portion of the silicon substrate 110 is exposed, it is etched by reactive ion processing.

In the process, silicon is processed and processed.

Next, the second (doped silicon oxide film 1 as shown in the figure)
Thickness 500X on the entire surface to cover or protect 31b
An unbuttoned silicon oxide film IJ- is formed. Then the second (-10
A high-temperature heat treatment is performed at 00° C. for 5 minutes to melt the doped silicon oxide metal 111b and smooth the unevenness on the substrate surface. Furthermore, the undoped silicon oxide metal 1111 with a thickness of 56σl of Lecontatato IIJJ4 was removed again by photolithography. In the second step (as shown in the final drawing), an aluminum layer was evaporated to form a 1μ thick layer of aluminum. A p-channel silicon MOS (n-channel silicon p-MOS)
Complete Tsu/Zosta.

The conductor element formed as described above can reduce the area of protrusions on the doped silicon oxide surface that are generated during the process of forming the doped silicon oxide film or the process of melting it by high-temperature heat treatment. Therefore, it is possible to reduce photo-etching failure during disconnection of the aluminum-saving wiring, which may occur in subsequent processes, and improve the reliability of the aluminum-saving wiring.

Furthermore, since the thickness of the semiconductor device can be made thinner than that of conventional semiconductor devices, the height of irregularities on the substrate surface can be reduced, and the accuracy in the photolithography process can be improved.

In addition, in the above example, the do! on a flat area! Although the doped silicon oxide film IJ11 was completely removed by reactive ion etching, the thickness of the doped silicon oxide film existing on the flat area was reduced. It goes without saying that good results can be obtained in terms of improving the accuracy of photolithography even if the thickness of the doped silicon oxide metal present in the uneven parts is made thinner. ) M.O.
JI) I explained about Tunjistar, but P channel MO
8) It can be applied to a tungister or other semiconductor devices such as an MO8 capacitor.

Further, the insulating film that can be melted by high-temperature heat treatment is not limited to the doped silicon oxide film, and other O insulating films may be used, and the wiring is not limited to Aluminum, but may be made of other metals.

As described in detail above, according to the present invention, by forming and melting a thick smoothing insulating film only on the side surfaces of necessary unevenness,
It is possible to provide a highly reliable semiconductor device and a method for manufacturing the same in which cut-off of metal wiring due to protrusions occurring in an insulating film for smoothing metal wiring and the need for photoetching are reduced.

[BRIEF DESCRIPTION OF THE DRAWINGS] The first (Xu to 1(e) is a sectional view showing the manufacturing process of a Thungister (n-channel silicon y+'-) MOS by the conventional smoothing method), the second (→ to 2) The figures are cross-sectional views illustrating the manufacturing process of a grave channel silicon (r-) MOS) tunnel transistor according to the present invention. L → 10.110-silicon substrate, 12.11:t,...field oxide film, 14,114--silicon oxide film, 1
i*11g-・Polycrystalline silicon layer, 1a, 11#-9”
-) electrode, 10.110-wiring/f/-on, xz,
xxx-r-dosilicon film, 24°J J 4-source region, xi, xxi-drain region, 2g, 121-dosilicon film, J#, JJ#-and-l dosilicon oxide film 1.
sx, xxz. 131*, 111b-doped silicon oxide film, 34.
134...Contact, 1g, 11g - Undoped silicon oxide film, M a , 11 # "" Al-saving wiring, 4o, 41 - Projection.

Claims (7)

[Claims] (1) In a semiconductor device having an insulating film that can be melted by high-temperature heat treatment, the thickness of the insulating film O existing on a flat area is greater than the thickness of the insulating film O existing on the side surface of an uneven portion. A semiconductor device characterized in that the insulating film does not exist on a thin or flat region. (2) The semiconductor device according to claim (1), further comprising another insulating thin film covering the insulating film. (3) The semiconductor device according to claim 0) or claim 2, characterized in that the insulating film is made of oxidized silicon or silicon oxidized to which boron and phosphorus are added. . (4) High-temperature heat treatment on semiconductor regions with uneven parts)
Step 1 of forming a fusible 1klsl edge and reactive ion etching, etching the insulating film approximately perpendicularly to the semiconductor region to reduce the thickness of the insulating metal present on the flat region. A semiconductor device characterized in that the step of forming the insulating film on the side surface of the uneven portion to be thinner than the thickness or completely removing it, and the step of melting the insulating film by high temperature heat treatment are performed. Production method. (5) The method for manufacturing a semiconductor device according to claim (4), characterized in that, before melting the insulating film, another insulating thin film is formed to cover the insulating film. (6) The method of manufacturing a semiconductor device according to claim 4 or 5, wherein the insulating film is left on at least the side surfaces of the uneven portion by the reactive ion etching. (7) The insulating film is a phosphorous-doped silicon oxide film or a boron and phosphorus-doped silicon oxide film, A method for manufacturing a semiconductor device according to any one of the above.