JPH03270225A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To avoid the positional slips between mutual openings by a method wherein shallow openings are formed in all regions to form the openings using the first laminated body, next the second laminated body is formed so as to repeat the excavating process of the regions to form the deep openings. CONSTITUTION:Shallow openings are formed in all regions to form the openings using the first laminated body 10 comprising the first flattened layer 8 formed on the first layers 7 and the first resist layer 9. Next, the second laminated body 16 comprising the second flattened layer 14 and the second resist layer 15 is formed so as to repeat the excavating process of the shallow openings in the regions to form the deep openings one by one using the second laminated body 16 and the first laminated body 10. Through these procedures, the positional slips between mutual openings can be avoided.

Description

[Detailed Description of the Invention] (Summary) Regarding an etching method for forming a plurality of apertures with different depths without positional deviation between the apertures, each of the etching method forms a plurality of apertures with different depths in regions of different film thicknesses of a layer with an uneven film thickness. The purpose of the present invention is to provide an etching method that prevents misalignment between openings with different depths when forming openings with different depths. Form a first laminate with a resist layer of 1, form shallow openings in all Ti areas where openings are to be formed using the first laminate, and then apply a second planarization layer. and second
forming a second laminate with a resist layer, and using the second laminate and the first laminate to sequentially excavate the shallow opening in the region where the deep opening is to be formed; The configuration is such that openings with different depths are formed by repeating the process of sequentially forming deep openings.

[Industrial application field]

The present invention relates to an etching method for forming a plurality of openings having different depths without causing positional deviation between the openings.

(Prior art) As semiconductor devices become more highly integrated and miniaturized, their manufacturing methods have become more complex. It may be necessary to etch the openings to different depths.

For example, as shown in FIG. 8, a first conductor 1! is formed on an insulating film 2 formed on a semiconductor layer 1! There is a first layer 7 in which a film 3, a second conductive film 4, and a third conductive WA5 are laminated with each other with an interlayer insulating film 6 interposed therebetween.
Glabellar insulation with different thicknesses formed on the conductor 1] 1] 4 and the third conductor WIS! ! The steps according to the prior art for forming openings with different depths in the holes 16 will be described below.

As shown in FIG. 9, a first resist layer 9 is formed and patterned to form a first conductive film 1#3 and a second conductive film 4.
and the opening 1] in the opening formation region on the third conductive film 5, respectively. 12 and 13, and the opening 1]. The interlayer insulation II6 is etched using the resist layer 9 with the resist layers 12 and 13 formed thereon as a mask, and the etching is performed to a depth that reaches the third conductive layer M5.

The first resist layer 9 is removed, a second resist layer 15 is formed as shown in FIG. The second resist layer 15 is removed from above, and etching is performed using the second resist layer 15 in which the opening is formed as a mask to form the opening 1 and the opening 12 to a depth that reaches the second conductive film 4. To dig deeper.

Hereinafter, the same process is repeated, and the first] rf! As shown in FIG. 12, an opening 1 reaching the first conductor II3 is formed, and as shown in FIG.
] WX1B is formed and patterned to form a fourth conductive film 18 that connects the first conductive to the film 3, the second conductive m1]1!4, and the third conductive film 5.

[Problem to be solved by the invention]

To form multiple apertures of different depths, a photolithographic process must be performed using a number of masks corresponding to the types of apertures of different depths, in which case the alignment between the masks is required, but if the alignment accuracy of one mask is ±0.3 n,
For example, when forming two types of openings with different depths,
A maximum displacement of 0.6n may occur between the two apertures.

An object of the present invention is to eliminate this drawback, and when forming apertures with different depths in regions of different film thicknesses of a layer with an uneven film thickness, positional deviations occur between the apertures with different depths. It is an object of the present invention to provide an etching method that prevents the occurrence of.

[Means to solve the problem]

The above purpose is to apply a first planarization layer (8) on the first layer (7).
) and a first resist layer (9).
and apply the above-mentioned first
A shallow opening is formed using the laminate (10), and then a second planarization layer (14) and a second resist layer (15) are formed.
forming a second laminate (16) with the first laminate (16), and using the second laminate (16) and the first laminate (10) to sequentially form a deep opening; This is coupled by a semiconductor device manufacturing method including a process of forming openings with different depths, the era of which is repeating the process of digging an opening and sequentially forming deep openings. Note that the first resist layer (9) and the second resist layer (15) may be multilayer resist layers, and the first layer (7) may be a patterned conductive film (3). (4) (5) and interlayer insulation film! It may also be a laminate with I(6).

[Effect]

In the method for forming openings with different depths according to the present invention,
A first planarization layer 8 and a first resist layer 9 on the first layer 7
A first stacked body 10 is formed with a first stacked body 10, and openings are formed in the first stacked body 10 in areas corresponding to all the open-shaped Ti regions having different depths, and this first stacked body 10 is used as a mask. First, the first layer 7 is excavated to the depth of the shallowest opening, and then the second layer 7 is excavated in the area where a deeper opening is to be formed.
A second laminate 16 is formed of the planarization layer 14 and the second resist layer 16, and the second laminate 16 and the first laminate 10 are formed.
As a mask, all the openings with different depths are formed by sequentially repeating the process of digging the shallow openings to the depth of the deep opening, so the positions between the openings with different depths are This is determined by the position of the first opening formed in the first stacked body IO, and no positional deviation occurs between the openings.

〔Example〕

Hereinafter, a method for forming a plurality of openings having different depths according to an embodiment of the present invention will be described with reference to the drawings.

Referring to FIG. 2, a first conductive layer 1 is formed on an insulating film 2 formed on a semiconductor layer 1.
] 13, a second conductive film 4, and a third AT film 5 are laminated with a glabella insulating film 6 made of silicon dioxide interposed therebetween. A case where openings with different depths are formed in interlayer insulating films 6 of different thicknesses formed on the second conductive film 4 and the third conductive film 5 will be described as an example.

See Figure 3 Novolac resin, such as NPR-820 manufactured by Nagase Sangyo.
A first stacked body 10 of a first flattening layer 8 made of silicon and a first resist layer 9 containing silicon is formed, and the first resist layer 9 is patterned using a photolithography method. An opening 1] is formed on the conductor 1] of the second conductor 1.
An opening 12 is formed on the third conductive film 4 , and an opening 13 is formed on the third conductive film 5 .

Refer to FIG. 4. Using the patterned first resist layer 9 as a mask, the first flattening layer 8 is etched by oxygen plasma etching, and then the interlayer insulating film 6 is etched using carbon tetrafluoride or the like. Plasma etching and opening 1]. 12 and 13 are excavated to a depth that reaches the third conductive film 5, respectively.

Refer to FIG. 1 A second laminate 16 of a second flattening layer 14 and a second resist layer 15 is formed, patterned using a photolithography method, and formed on the first conductive layer 1]3. opening 1 formed on the second conductive film and opening 12 formed on the second conductive film.
The opening 17 is formed by removing the area covering the area. The alignment accuracy between this opening 17 and the opening 1 on the first conductive film and the opening 12 on the second conductive film may be loose.

Referring to FIG. 5, the second planarization layer 14 exposed in the opening 17 is removed by oxygen plasma etching, and then the first planarization layer 14 is etched away.
The interlayer insulating film 6 is plasma etched using carbon tetrafluoride using the laminate IO as a mask, and the opening 1 and the opening 2 are dug to a depth that reaches the second conductive film.

Referring to FIG. 6, the same steps are repeated to dig the opening 1 to a depth that reaches the first conductive film 3.

Refer to FIG. 7. All planarization layers and resist layers are removed by oxygen plasma etching to form a fourth conductor tl1]8, which is patterned to form a first conductor 1]3 and a second conductor. Conductivity 1]
Fourth conductor 1]i1 connected to E4 and third conductor 9M5
form 8.

Note that instead of the first resist layer 9 and the second resist layer 15 containing silicon, an intermediate layer made of a silicone resin such as OCD manufactured by Tokyo Ohka Co., Ltd. and a novolac resin such as NPR-2505Σ manufactured by Nagase Sangyo Co., Ltd. are used. A laminate with a resist layer may also be used.

It goes without saying that by further repeating the above steps, three or more types of openings with different depths can be formed.

〔Effect of the invention〕

As explained above, in the method for manufacturing a semiconductor device according to the present invention, a first laminate of a first planarization layer and a first resist layer is formed on a first layer, and a laminate of ``W41'' is formed. Form shallow openings in all areas using the body as a mask to form openings of different depths, and then drill this shallow opening to form a second opening in any area except the area where you want to form an even deeper opening. A second laminate of a flattening layer and a second resist layer is formed, and using the previously patterned first laminate and second laminate as a mask, the depth of the next deep opening is determined. All the openings with different depths are formed by sequentially repeating the step of excavating the shallow openings described above, so the positions between the openings with different depths are the same as in all the areas where openings with different depths are formed. Since the depth is determined by the position of the shallow aperture initially formed in the depth, no misalignment occurs between apertures of different depths.

[Brief explanation of drawings]

1 to 7 are process diagrams illustrating a method of forming openings with different depths according to an embodiment of the present invention. 8 to 12 are process diagrams for forming openings with different depths according to the prior art. 1 ・ ・ ・ 2 ・ ・ ・ 3 ・ ・ 4 ・ ・ 5 ・ ・ 6 ・ ・ 7 ・ ・ ・ 8 ・ ・ ・ 9 ・ ・ ・ 10 ・ ・ 1]. 12゜14・ ・ ・ 15・ ・ ・ Semiconductor layer, insulating film, first H/A! film, second conductive film, third conductive film, glabellar insulating film, first layer, first planarization layer, first resist layer, first laminate, 13... opening, second planarization layer, second resist layer, 16... second stacked body, 17... opening, 18... fourth conductive film.

Claims (1)

[Claims] [1] A first flattening layer (8) on the first layer (7) and a first flattening layer (8) on the first layer (7).
forming a first laminate (10) with a resist layer (9) of the first laminate (10);
0) to form a shallow opening and a second planarization layer (1
4) and the second resist layer (15).
6), and by using the second laminate (16) and the first laminate (10) to excavate the shallow openings in the region where deep openings are to be formed successively. 1. A method of manufacturing a semiconductor device, comprising a step of forming openings with different depths, the step of forming openings being repeated. [2] The method of manufacturing a semiconductor device according to claim 1, wherein the first resist layer (9) and the second resist layer (15) are multilayer resist layers. [3] Claims 1 and 2, wherein the first layer (7) is a laminate of patterned conductive films (3), (4), and (5) and an interlayer insulating film (6). A method of manufacturing the semiconductor device described above.