JPS63132446A - Manufacture of semiconductor - Google Patents

Abstract

PURPOSE:To improve a patterning precision by a method wherein, after a groove is dug on a semiconductor substrate, oxide masks for the surface other than the grooved region and a selective oxide film to be used for isolation on the sidewall surface of the groove are simultaneously patterned. CONSTITUTION:An oxide mask 2 is formed on the whole surface of a semiconductor substrate 1 and thereafter, an Si oxide film 5 is formed and this is subjected to deep groove etching. Then, after an Si nitride film 2 is formed on the whole surface, an Si oxide film 7 is formed on the whole surface and this is etched. Subsequently, the oxide mask 2 is removed to perform an entire surface etching, the whole surface of the Si oxide film 3 is etched and the oxide mask 2 only on the bottom surface of a groove is removed. Subsequently, the Si nitride film 2 is patterned simultaneously with the removal via a photoengraving process, wherein a multilayer resist is used, and an isolation of the surface other the grooved region on the substrate and an isolation oxide film on the sidewall surface of the groove are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a three-dimensional semiconductor device having a grooved region in a semiconductor substrate, and particularly to a method for manufacturing a #I film corresponding to the number of elements thereof.

(Prior art) '!t! Figures 9 to 16 show the surface of a conventional t-conductor substrate other than the grooved area in a three-dimensional semiconductor device having a grooved area on the semiconductor substrate, and the groove. FIG. 3 is a fragmentary cross-sectional view of a main part showing a process sequence of an example of a method for forming an inter-element isolation oxide film on a side wall surface and a bottom surface of the semiconductor device.

(Components) In Fig. 9, 1 is a conductive substrate made of crystalline silicon, 2 is an oxide mask such as silicon nitride 11!2, 3 is a silicon oxide film of silicon nitride film 2, etc. 'F of etc.
4 in FIG. 10 of the next process is an inter-element isolation oxide film such as a silicon oxide film, and then the 1st! 5 in Fig. 15 is an etching mask material such as a silicon oxide film used in trench etching of the silicon substrate l;
13] 6 in the first step is an etching mask material such as a resist used when patterning the oxide mask material 2, and 7 in the next step in FIG. 14 is a conductor.
This is an etching mask material such as a silicon oxide film used for patterning the oxidation mask material 2 when separating and oxidizing the bottom surface of a groove dug in the trench.

(Conventional manufacturing method) Next, a conventional manufacturing method will be explained.

FIG. 8 is a cross-sectional view of the main part in the final second step according to the present invention, which will be described later.
The object is to form an inter-element isolation oxide film 4 on the surface of the conductor J^ board 1 other than the grooved area, and on the sidewalls and bottom surfaces of the groove.

First, as shown in FIG. 9, after applying a layer of oxide mask material 2 to the entire surface of the semiconductor substrate 1'', the isolation regions other than the grooved regions on the semiconductor substrate 1 are formed by photolithography. FIG. 10 shows the state in which the oxidation mask 2 is patterned through the process and separated and oxidized as shown in 4. Next, an etching material 5 to be used in trench etching of the semiconductor substrate 1 is formed, and after patterning through a photolithography process, the state of the trench trench etching is shown in Figure 11. After thermally oxidizing the single-crystal silicon, a silicon nitride film, which becomes the oxidation mask 2, is formed on the entire human face.
Next, the silicon multilayer resist that becomes the oxidation mask 2 was used, but it was patterned through a true plate making process. Indicates the condition. That is, here, the oxidation mask 2 is removed only in the region where the sidewalls of the grooves dug in the surface of the conductor substrate 1 are to be separated.

Next, the resist 6 is removed, and silicon oxide 11Q 7 is etched on the entire surface, as shown in Figure 14. This silicon oxide 11Q 7 is then etched by anisotropic etching such as reactive ion etching. is shown in FIG. 15, and the silicon oxide film 7 only on the side wall surface of the trench is viewed from the -F plane direction II.
s! Because J'J is thick, it is not etched and remains as a frame. Subsequently, FIG. 16 shows the state after the entire surface etching of the oxide mask 2 and the entire surface etching of the silicon oxide 1tQ7, in which only the oxide mask 2 at the bottom of the groove is removed. That is, the surface of the semiconductor substrate 1 other than the grooved region is masked by a silicon oxide film 5 which is a mask material for trench etching, and the side wall surface of the trench is masked by a frame of a silicon oxide film 7 formed by anisotropic etching. Only the oxide mask 2 at the bottom of the groove is removed. In the steps up to this point, the oxide mask on the sidewalls of the trench was patterned, and then the oxide mask 2 on the bottom of the trench was removed. Next, the separated and oxidized state is shown in Figure 8.
The interlayer process is completed.

To summarize the above steps in a cylindrical manner, first, an oxide film 4 is formed on the surface of the semiconductor substrate 1 other than the grooved area, and then, after digging a groove, the entire surface is covered with an oxide mask 2. The process sequence can be summarized as follows: covering, patterning the oxide mask on the sidewalls of the trench, then removing the oxide mask 2 on the bottom of the trench, and finally oxidizing the region separating the sidewalls of the trench from the bottom at the same time. can.

(Problem to be Solved by the Invention) However, in the conventional manufacturing method as described in 1- below, isolation oxidation of the surface of the semiconductor substrate IF other than the grooved region and separation of the sidewall surface of the groove are required. Since 1l11 oxidation and oxidation are performed in separate steps, respective patterning masks are required, and self-alignment of both is difficult. In addition, a margin for mask alignment must be taken in terms of pattern layout, and furthermore, mask misalignment is likely to occur during the trenching process, and the S oxide film region and the trench f region on the surface other than the trenching region. If rr occurs, diagonal etching of the semiconductor substrate 1 will occur and the silicon oxide film 7 shown in FIG.
There were problems such as the possibility that the oxidized mask 2 on the side wall surface of the trench could be removed without leaving a frame (f).

This invention was made in order to solve the problems of the conventional manufacturing method as described in L.The present invention was made in order to solve the problems of the conventional manufacturing method as described in L. Poor patterning of the oxide mask during isolation oxidation on the sidewall surface of the TM due to self-alignment of the oxidized region and overlap between the isolation oxide film region on the surface other than the grooved region on the semiconductor substrate and the grooved region. The purpose of the present invention is to provide a method for manufacturing a conductor that can prevent this.

[Means for solving problems]

For this reason, in the conductor manufacturing method according to the present invention, after trenches are dug in the semiconductor JJi The oxide film and both oxide masks are patterned simultaneously using a single patterning mask.By adopting the method, we aim to achieve goal 11.

[Effect]

By the above manufacturing method, "V conductor 1. Since the oxidation mask on the surface other than the grooved area of the (plate) and the full (lu11 wall surface) is patterned at the same time, it is no longer necessary to take a margin for mask alignment on the pattern layout, which reduces the size of the i-conductor device. Miniaturization becomes easier.

In addition, since the isolation oxide 11Q is formed on the substrate surface after trenching the semiconductor substrate, diagonal etching of the substrate due to the separation region between the trenching region and the substrate surface will not occur, and the substrate will not be completely etched. This prevents defective patterning of the oxidation mask on the sidewall surface.

Furthermore, by patterning the oxidation mask for the isolation oxidation of the surface other than the grooved area of the ゛r-body substrate substrate and the isolation oxidation of the sidewall surface of γlη using a single patterning mask, the manufacturing process is simpler than the conventional method. be shortened.

(Example) The present invention will now be explained based on examples.

1 to 8 show an embodiment of the t-conductor manufacturing method using the present invention in a two-culm sequence. Explanatory diagram of the method Exactly the same phase as the components shown in Figures 9 to 16''!l
belongs to.

(Manufacturing method) Next, the manufacturing method according to the present invention will be explained. As in the conventional example, the final goal is to form an oxidized film on the surface of the semiconductor substrate between elements f, as shown in No. 81A. First, as shown in FIG. 1, on the entire surface of the semiconductor substrate 1,
After forming the oxide mask 2, a silicon oxide film 195 used as an etching mask material for groove etching is formed, and then a silicon oxide film 5 is patterned through a photolithography process, and the semiconductor substrate 1 is grooved. Figure 2 shows the etched state. The steps up to this point are the semiconductor substrate 18
In addition to forming the grooved area on the top, an oxide mask 2 covers the surface other than the grooved area, and the silicon oxide layer 5, which is the etching mask material for the grooved etching, is covered. be.

Next, the quasi-crystalline silicon of the semiconductor substrate 1 is thermally oxidized to form a silicon nitride film 2 on the entire surface, and then a silicon oxide film 7 is further formed on the entire surface as shown in FIG.
Figure 4 shows a state in which this silicon oxide ttQ7 is etched using anisotropic etching such as reactive ion etching.The silicon oxide film on only the side wall surface of the trench is thick from the top surface direction, so the etching is difficult. It remains as a frame without being removed. FIG. 5 shows the state in which the oxide mask 2 is removed and the entire surface is etched, and the silicon oxide film 3 is etched over the entire surface.
only are removed.

In other words, the surface of the (i-conductor) 1ζ plate l other than the grooved area is covered with a silicon oxide film 5, which is a mask material for groove etching, and the sidewalls of the groove are covered with a silicon oxide film formed by anisotropic etching. Masked by the frame of the membrane 7, only the oxide mask 2 at the bottom of the groove is removed. This process is
As described above, this is completely the same as the conventional example described in +iif. Next, the oxidized state is shown in FIG. 6, where the isolation oxide film at the bottom of the trench was not formed.

Next, the surface area other than the grooved area of ゛conductor substrate i, 1 +11! Figure 7 shows the state in which silicon nitride +142, which serves as an oxidation mask for oxidation and isolation oxidation of the sidewalls of the trench, is simultaneously patterned through a photolithography process using a multilayer resist. 1
The resist 6 of No. 1 has not yet been removed. Next, this resist 6 is removed, and the separated and oxidized state is removed.
It is a diagram. With this, the isolation other than the grooved area of the base plate and the isolation oxide film on the side wall surfaces have been formed, and all the isolation plates are completed.

In the description of the embodiment described in "-", the method for manufacturing the element isolation oxide film shown in FIG. Selective oxidation on the side wall! Of course, this method can also be applied to the Jf method for producing general f-element separation using IQ.

(Effects of the Invention) As explained in 1-1 below, according to the manufacturing method of the present invention, after a semiconductor substrate is fully excavated, the surface other than the grooved area and the side wall surface of the groove are separated. By simultaneously patterning the oxidation mask of the selective oxide film used, the number of plate-making steps and separation oxidation steps is reduced compared to the conventional manufacturing method, and the patterning grain size is improved, making it possible to miniaturize and miniaturize the T-conductor device. can contribute to

[Brief explanation of the drawing]

1 to 8 are fragmentary cross-sectional views of essential parts showing an external process sequence of a semiconductor manufacturing method according to an embodiment of the present invention. FIGS. 9 to 16 are sectional views showing each process sequence of an example of the conventional manufacturing method. ... Oxidation mask 3 ... Oxidation mask underlay 4 ... Minute m oxidation +19 5.6.7 ... Etching mask (Masuo Rijin Oiwa @ * Machine General) "W & Law~↑ Comparison procedure amendment (voluntary) 1. Indication of the case Patent application No. 61-258980 2
, Title of invention: y, Conductor manufacturing method 3, Person making the amendment (Contact number 03 (213) 342 + Patent Department) (,'1・
', 7 ゝ\--' Formula % Formula %) 5. Subject of amendment (1) Scope of Claims and Detailed Description of the Invention in Specification-F. (2) Drawings 4 and 14. 6. Contents of amendment (1) The scope of claims is amended as shown in the attached sheet. (2) “Silicon oxidation [7(
7) J wor silicone 111i3.5.7 (7) J
Correct it. (3) In the third line of page 6 of the specification, "self-alignment of both" is corrected to "self-alignment of both." (4) "Self-alignment" on page 6, line 16 of the specification is corrected to "self-alignment." (5) ``Remove oxide mask 2 and perform etching on the entire surface'' on page 9, lines 18 to 19 of Akira IBM.
"Full-face etching," he corrected. (6) “Silicon Oxide JIQ” on page 9, line 19 of the specification
"3" is corrected to "silicon oxide film 3,5.7". (7) "Kowade," on page 10, line 18 of specification δ is corrected to "Here, J." (8) "Separation other than trenching area" on page 10, line 19 of specification I corrected it to "Other than the fully dug area I!! Oxidation I model". (9) "Because the isolation oxide film was not formed" on page 10, line 20 of Specification-F, r minute Il! This means that the oxide film was formed at the same time.'' (10) “All” in page 10, line 20 of the specification is replaced with “
Correct all 1's with this. (11) In the fourth line of page 11 of the specification, ``This invention covers not only the structure shown in FIG. (12) "Applicable to the manufacturing method" on page 11, line 6 of the specification applies to the r manufacturing method, and correction 1-1. (13) On page 11, lines 13 to 14 of the specification, ``The number of photolithography steps and separation oxidation steps will be reduced'' will be corrected to ``R, the number of photolithography steps will be reduced,'' and J. (14) Figures 4 and 14 of the drawings will be corrected as shown in the attached sheet. 7. IJ record of attached documents (1) One document stating the scope of claims after amendment (2) Drawings after amendment Figures 4 and 14 One copy of claims (1) Groove in semiconductor substrate In a three-dimensional semiconductor device having a trenched region, the amount of elements on the surface of the conductor substrate other than the trenched region and the side wall surface of the trench is I! ! A semiconductor manufacturing method characterized in that one oxide layer is formed using one patterning mask. (2) A method of manufacturing a semiconductor according to claim 1, characterized in that a selective oxide film is used on the surface of the semiconductor substrate other than the grooved region and between the elements on the sidewall surface of the groove. (3) The scope of the claim characterized in that the t 1'1 of the planes of the holes Δ, Ω, and LL dug in the semiconductor substrate are patterned using a multilayer resist. The semiconductor manufacturing method according to item 1 or 2. Figure 4

Claims (3)

[Claims] (1) In a three-dimensional semiconductor device having a grooved region on a semiconductor substrate, a patterning mask is used to form an inter-element isolation oxide film on the surface of the semiconductor substrate other than the trenched region and on the sidewalls of the trench. A semiconductor manufacturing method characterized by forming a semiconductor. (2) A method of manufacturing a semiconductor according to claim 1, characterized in that a selective oxide film is used for isolation between elements on a surface other than the grooved region on the semiconductor substrate and on sidewall surfaces of the groove. (3) A semiconductor manufacturing method according to claim 1 or 2, characterized in that a mask of a selective oxide film on a side wall surface of a trench dug in the semiconductor substrate is patterned using a multilayer resist. .