JP3163591B2 - Wiring structure formation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring structure having a structure in which an insulating film forming a groove is formed on a substrate, and a wiring layer is formed so as to fill the groove in the insulating film. To a method of forming

[0002]

2. Description of the Related Art Hitherto, a wiring structure forming method described below with reference to FIGS. 7 to 9 has been proposed.

That is, a substrate 1 made of, for example, a semiconductor is prepared in advance (FIG. 7A).

Then, an insulating film 2 made of polyimide, silicon oxide, silicon nitride or the like is formed on the substrate 1 (FIG. 7B).

Next, a mask layer 3 made of, for example, a photoresist and having a window 3a having a plane pattern corresponding to a wiring layer to be formed as shown in FIG. Is formed by a photolithography method (FIG. 7C). In this case, the wiring layer to be formed, that is, the window 3 a of the mask layer 3 has a width W ₁ represented by W ₁ ≧ 2d, where d is the thickness of the insulating film 2.

[0006] Next, by etching of the mask of the mask layer 3 to the insulating film 2, the insulating film 2, the planar pattern corresponds to the window 3a of the mask layer 3 - having emissions, therefore, W ₁ mentioned above the grooves 2a having a width W ₁ represented by ≧ 2d, formed to a depth reaching the substrate 1 (Fig. 7D).

Next, the mask layer 3 is removed from the insulating film 2 (FIG. 7E).

Next, on the substrate 1, the region extending to the groove 2 a of the insulating film 2 on the upper surface of the substrate 1, the inner side surface of the groove 2 a of the insulating film 2, and the upper surface of the insulating film 2 are continuously extended. 2 thickness d
The conductor layer 4 having a sufficiently small thickness t ₁ compared to, by sputtering, formed as a part of is used as a subsequent plating electrode layer and a wiring layer (Fig. 8
F). In this case, since the conductor layer 4 is formed to have a thickness t ₁ that is sufficiently smaller than the thickness d of the insulating film 2, the region facing the groove 2 a of the insulating film 2 on the upper surface of the substrate 1, the insulating film 2 grooves 2a
Along the plane defined by the inner surface of the
While maintaining the _1, it has been extended.

Next, another conductive layer 5 made of, for example, gold is formed on the conductive layer 4 by a plating method using the conductive layer 4 as an electrode layer for plating, and is represented by (dt- ₁ ). Is formed to have a thickness t ₂ substantially equal to the thickness of the wiring layer main body, so that t = (t ₂ + t) by the conductor layers 4 and 5.
₁ ) Therefore, a conductor layer laminate 6 having a thickness t substantially equal to the thickness d of the insulating film 2 is formed (FIG. 8G). In this case, has a width W ₁ of the groove 2a of the insulating film 2 is represented by W ₁ ≧ 2d, formed approximately the same thickness t ₂ and thickness represented the conductor layer 5 at (d-t ₁₎ Therefore, the conductor layer 5 is made of the insulating film 2
Although the upper surface and the surface of the position corresponding to the angle portion of the inner surface of the groove 2a of rounded, along the upper surface of the conductor layer 4, and extend keeping the thickness t _2, therefore, conductor The layer stack 6 has a rounded surface at a position corresponding to a corner formed between the upper surface of the insulating film 2 and the inner surface of the groove 2a, but has a region facing the groove 2a of the insulating film 2 on the upper surface of the substrate 1. Along the inner surface of the groove 2a of the insulating film 2 and the continuous surface formed by the upper surface of the insulating film 2,
The length is extended while maintaining the thickness t (= t ₂ + t ₁ ). Therefore, in the region facing the groove 2 a of the insulating film 2, the width on the substrate 1 side is substantially equal to (W ₁ -2t). It has a width W _2, to form a groove 6a having a width slightly wider W ₂ 'than the width W ₂ at the side opposite to the substrate 1 side.

Next, a relatively thick mask layer 7 made of, for example, a photoresist and having a plane pattern completely filling only the groove 6a is formed on the conductor layer laminate 6 (FIG. 1). 8H).

Next, a mask layer 7 for the conductor laminate 6 is formed.
Milling is performed on the insulating film 2 until the substrate 1 is reached, so that the wiring layer extending from the conductor layer stack 6 to fill the groove 2a in the insulating film 2 is filled. 8 and thus the groove 2 on the substrate 1
Then, a wiring structure 9 having a configuration in which the insulating film 2 forming a is formed, and the wiring layer 8 is formed so as to fill the groove 2a of the insulating film 2 is formed (FIG. 8I). In this case, the thickness of the mask layer 7 is reduced, and
Remains on top.

Next, the mask layer 7 is removed from above the wiring layer 8 (FIG. 8J).

The above is the method of forming a wiring structure that has been conventionally proposed.

According to the conventional wiring structure forming method shown in FIGS. 7 to 9, the insulating film 2 forming the groove 2a is formed on the substrate 1, and the insulating film 2 is buried in the groove 2a of the insulating film 2. Wiring structure 9 having a configuration in which wiring layer 8 is formed as described above,
It can be easily formed, and in this case, the wiring layer 8 constituting the wiring structure 9 can be formed to have substantially the same upper surface height as the insulating film 2.

For this reason, on the wiring structure 9 just formed,
When forming a multilayer wiring structure by extending another wiring layer through another insulating film, forming another insulating film extending and forming the other wiring layer as having a flat upper surface. Therefore, another wiring layer can be formed with less risk of interruption.

[0016]

In the case of the conventional wiring structure forming method described above with reference to FIGS. 7 to 9, the wiring layer 8 of the wiring structure 9 is formed.
From the conductor layer stack 6 by ion milling using the mask layer 7 as a mask that completely fills only the grooves 6a of the conductor layer stack 6, with the thickness d of the insulating film 2 being twice or more. of can be formed as having a width W _1, in this case, the groove 6a of the conductive layer stack 6, the substrate 1 side as described above the (W ₁ -2t) and approximately equal width W ₂ And has a width W ₂ ′ slightly larger than the width W ₂ on the side opposite to the substrate 1 side, and is therefore formed to expand upward, so that the wiring layer 8 Projection 1
0, so that the wiring layer 8 may not be formed as having a flat upper surface having the same height as the upper surface of the insulating film 2 over the entire area, Therefore, in the above description, it has been described that another wiring layer can be formed on the wiring structure 9 with another insulating film interposed therebetween with less risk of interruption, but in fact, the other wiring layer is interrupted. There was a drawback that it might be formed.

Thus, the present invention is free of the above-mentioned disadvantages,
It is intended to propose a new wiring structure forming method.

[0018]

According to the present invention, there is provided a method for forming a wiring structure, comprising the steps of (i) forming an insulating film on a substrate;
(Ii) a first groove row having a configuration in which a large number of grooves having a width of not more than twice the thickness thereof are arranged in the insulating film at intervals of not more than twice the thickness of the insulating film; And (iii) a plurality of first conductors having a configuration in which a plurality of first conductors are arranged on the substrate so as to fill the respective grooves constituting the first groove row. (Iv) removing the insulating film from the substrate in the region where the first conductor row is formed, thereby forming the first conductor row on the substrate. Forming a second groove row having a configuration in which a plurality of second grooves each having an outer surface of each of the plurality of first conductors of one conductor row as an inner surface are arranged; On the substrate, the plurality of second conductors are respectively arranged in the plurality of second grooves constituting the second groove row. A second conductor columns having a configuration that is arranged with great buried formed, thus, a step of forming a wiring layer according to the first and second conductor columns.

[0019]

According to the wiring structure forming method of the present invention,
As in the case of the conventional wiring structure forming method described above with reference to FIGS. 7 to 9, an insulating film forming a groove is formed on a substrate, and a wiring layer is formed so as to fill the groove in the insulating film. Can easily be formed, and in this case, the wiring layer forming the wiring structure is formed as having approximately the same top surface height as the insulating film. be able to.

For this reason, as in the case of the conventional wiring structure forming method described above with reference to FIGS. 7 to 9, another wiring layer is formed by extension through another insulating film on the wiring structure just formed. In the case of forming a multi-layer wiring structure, another insulating film extending from another wiring layer can be formed as having a flat upper surface, so that another wiring layer is formed with less risk of interruption. be able to.

However, in the case of the wiring structure forming method according to the present invention, the wiring layer is easily formed as having a flat upper surface having the same height as the upper surface of the insulating film over the entire region including the side portions in the width direction. Therefore, another wiring layer can be formed on the wiring structure via another insulating film with almost no risk of interruption.

[0022]

Embodiment 1 Next, a first embodiment of a method for forming a wiring structure according to the present invention will be described with reference to FIGS.

In FIGS. 1 to 5, parts corresponding to those in FIGS. 7 to 9 are denoted by the same reference numerals. 13

The method for forming a wiring structure according to the present invention shown in FIGS. 1 to 5 takes the following sequential steps and performs the same steps as the conventional wiring structure forming method described above with reference to FIGS. A wiring structure having a structure in which an insulating film having a groove formed thereon is formed and a wiring layer is formed so as to fill the groove in the insulating film.

That is, the same substrate 1 is prepared in advance as in the case of the conventional wiring structure forming method described above with reference to FIGS. 7 to 9 (FIG. 1A).

Then, the same insulating film 2 is formed on the substrate 1 as in the case of the conventional wiring structure forming method described above with reference to FIGS. 7 to 9 (FIG. 1B).

Next, a region having a planar pattern made of, for example, a photoresist and corresponding to a wiring layer to be formed, as shown in FIG. 4A, FIG. 4B or FIG. in the thickness of the insulating film 2 multiple window 13b having a width H ₁ represented by H ₁ ≦ 2d when the d is, are sequentially arranged at a distance S ₁ represented by S ₁ ≦ 2d Layer 13 having a window row 13c having a suitable configuration is formed by photolithography (FIG. 1).
C). Each window 13b of the window row 13c of the mask layer 13
4A, it is extended only in the length direction of the wiring layer to be formed in the case of FIG. 4A, and is extended in both the length direction and the width direction of the wiring layer to be formed in the case of FIG. 4B. ,
In the case shown in FIG. 4C, the wiring layer is formed so as to be interrupted and extended in the length direction and the width direction of the wiring layer to be formed.

Next, by etching of the mask of the mask layer 13 to the insulating film 2, the insulating film 2, groove array 2c that correspond to the window column 13c of the mask layer 13, therefore, H ₁ ≦ 2d described above groove 2 having a width H ₁ represented in
Numerous b is a groove array 2c having a configuration that is sequentially arranged at a distance S ₁ represented by S ₁ ≦ 2d described above, to a depth reaching the substrate 1 (Fig. 1D).

Next, on the substrate 1, each groove 2b of the groove array 2c of the insulating film 2 on the upper surface of the substrate 1 and the window array 13c of the mask layer 13 are formed.
Of each of the grooves 2 in the groove row 2c of the insulating film 2 facing the respective windows 13b
b of the inner surface and the inner surface of each window 13b of the window columns 13c of the mask layer 13, and continuously extend to the upper surface of the mask layer 13, and conductors having a sufficiently small thickness t ₁ compared to the thickness d of the insulating film 2 The layer 4 is formed by sputtering, as in the case of the conventional wiring structure forming method described above with reference to FIGS. 7 to 9, so as to be used as an electrode layer for plating and to be a part of the wiring layer ( (FIG. 1E). In this case, since the conductor layer 4 is formed to have a thickness t ₁ that is sufficiently smaller than the thickness d of the insulating film 2, each groove 2 b of the groove row 2 c of the insulating film 2 on the upper surface of the substrate 1 is formed. A region facing each window 13b of the window array 13c of the mask layer 13, an inner surface of each groove 2b of the groove array 2c of the insulating film 2, an inner surface of each window 13b of the window array 13c of the mask layer 13, and an upper surface of the mask layer 13 Along the plane defined by, while maintaining the thickness t ₁ .

Next, another conductor layer 5 is formed on the conductor layer 4.
By a plating method using the conductor layer 4 as a plating electrode layer, a thickness t ₂ represented by t ₂ ≧ (H ₁ −2t ₁ ) / _2.
Then, the conductor layer is formed so as to become the wiring layer main body, so that the conductor layer laminate 6 including the conductor layers 4 and 5 is formed (FIG. 2F). In this case, each groove 2 of the groove row 2c of the insulating film 2
b has a width H ₁ represented by H ₁ ≦ 2d, and the conductor layer 5 is formed to have a thickness t ₂ represented by t ₂ ≧ (H ₁ −2t ₁ ) / 2. 5 cooperate with the conductor layer 4 and each groove 2b of the groove array 2c of the insulating film 2 and the window array 13 of the mask layer 13.
c is formed as completely filling each window 13b,
Therefore, the conductor layer laminate 6 extends on the upper surface of the mask layer 13 while maintaining the thickness (t ₁ + t ₂ ).
The grooves 2b of the groove row 2c and the windows 13b of the window row 13c of the mask layer 13 are continuously and completely filled.

Next, the conductor layer laminate 6 and the mask layer 13
Milling of the substrate 1 on the insulating film 2
From the conductor layer stack 6 to a large number of conductors 11 in each groove 2b of the groove row 2c of the insulation film 2 until the height position corresponding to the height of the upper surface of the insulation film 2 is reached.
The conductor row 11 having a configuration in which “a” is arranged so as to fill each of the plurality of grooves 2b of the groove row 2c of the insulating film 2 is formed (FIG. 2G).

Next, FIG. 5A or FIG.
Alternatively, as shown in FIG. 5C, a diagram of the conventional wiring structure forming method described above with reference to FIGS. 7 to 9, which is made of, for example, a photoresist and exposes a region where the conductor row 11 is formed, to the outside. The width W ₁ is the same as that formed in the step shown in FIG. 7C.
Of the mask layer 3 having the window 3a having
H).

Next, the insulating film 2 is removed in a region facing the window 3a of the mask layer 3 by an etching process that allows dry etching using the mask layer 3 as a mask. 2, FIG.
Grooves 2a having a width W ₁ of the same as formed in the step shown in FIG. 7D of the conventional wiring structure forming method described above in FIG. 9 is formed and, on the substrate 1, in the region facing the groove 2a Then, a configuration is obtained in which a groove row 12 having a configuration in which a large number of grooves 12b having an outer surface of a large number of conductors 11a as an inner surface is arranged (FIG. 2I). Table In this case, the grooves 12b of the groove array 12 has a spacing S ₁ and equal to the width H ₂ represented by S ₁ ≦ 2d described above, also, a number of grooves 12b are H ₁ ≦ 2d described above are successively arranged while maintaining a width H ₁ equal spacing S ₂ being.

[0034] Next, the mask layer 3 is removed from the insulating film 2.
(FIG. 2J).

Next, a groove row 1 on the upper surface of the substrate 1 is formed on the substrate 1.
Area facing each groove 12b of 2c, each groove 12b of groove row 12c
Of the insulating film 2 and the upper surface of the insulating film 2
Of the 'conductor layer 4 having a' thin enough thickness t ₁ compared to the thickness d, as in the case of forming the conductor layer 4 in the step shown in FIG. 1E, by sputtering, subsequent plating electrode layer And used as a part of the wiring layer,
(FIG. 3K). In this case, since the conductor layer 4 ′ is formed to have a sufficiently small thickness t ₁ ′ as compared with the thickness d of the insulating film 2, a region facing each groove 12 b of the groove row 12 c of the substrate 1, inner surfaces of the groove 12b of the groove array 12c, and along the surface by the upper surface of the insulating film 2, while maintaining the thickness t ₁ ', is extended.

Next, another conductive layer 5 'is formed on the conductive layer 4' in the same manner as the case where the conductive layer 5 is formed in the step shown in FIG. According to the plating method used as the layer, the thickness t ₂ ′ represented by t ₂ ′ ≧ (H ₂ −2t ₁ ′) / 2,
Thus, a conductor layer laminate 6 'is formed by the conductor layers 4' and 5 '(FIG. 3L). In this case, the groove row 12
c each groove 12b has a width H ₂ represented by H ₂ ≦ 2d,
Since forming 'a t _2' conductor layer 5 _{≧ (H 2 -2t 1 ')} / 2 the thickness t ₂ represented by', conductor layer 5 'is conductor layer 4' cooperating with Therefore, the conductor layer laminate 6 ′ is formed so as to completely fill each groove 12 b of the groove row 12 c, so that the thickness (t ₁ ′ + t ₂ ′) is maintained on the upper surface of the insulating film 2. Although it is extended, it is formed as completely filling each groove 12b of the groove row 12c.

Next, ion milling of the conductor layer laminate 6 ′ is performed on the insulating film 2 to reach the substrate 1,
By performing the process until reaching the height position with respect to the upper surface height of the insulating film 2 in each groove 12b of 2c, a large number of conductors 11a 'are removed from the large number of grooves 12b of the groove row 12c from the conductor layer laminate 6'. To form a conductor row 11 'having a configuration arranged so as to be buried in each of the conductor rows 11'
And 11 'are formed (FIG. 3M).

The above is the first embodiment of the wiring structure forming method according to the present invention.

According to the wiring structure forming method of the present invention shown in FIGS. 1 to 5, the groove 2a is formed on the substrate 1 in the same manner as in the conventional wiring structure forming method described above with reference to FIGS. A wiring structure 9 having a structure in which the insulating film 2 is formed and the wiring layer 8 is formed so as to fill the groove 2a of the insulating film 2 can be easily formed. In this case, the wiring layer 8 forming the wiring structure 9 is
It can be formed as having the same upper surface height as.

For this reason, as in the case of the conventional wiring structure forming method described above with reference to FIGS.
On top, another wiring layer is extended through another insulating film,
In the case of forming a multilayer wiring structure, another insulating film extending from another wiring layer can be formed as having a flat upper surface, and therefore, the other wiring layer can be formed with less risk of interruption. Can be.

However, in the case of the wiring structure forming method according to the present invention shown in FIGS. 1 to 5, the wiring layer 8 has the same height as the upper surface of the insulating film 2 over the entire region including the width direction side portions. It can be easily formed as having a flat upper surface, so that another wiring layer can be formed on the wiring structure 9 via another insulating film with almost no risk of interruption.

[0042]

Embodiment 2 Next, a second embodiment of the method for forming a wiring structure according to the present invention will be described with reference to FIG.

In FIG. 6, parts corresponding to those in FIGS. 1 to 5 are denoted by the same reference numerals.

The second embodiment of the wiring structure forming method according to the present invention is the same as the first embodiment of the wiring structure forming method according to the present invention described above with reference to FIGS. A similar wiring structure is formed as it is formed.

1A to 1D in the first embodiment of the wiring structure forming method according to the present invention described above with reference to FIGS.
6A, an insulating film 2 is formed on the substrate 1 similar to that obtained in FIG. 10, and the insulating film 2 has a width H as shown in FIG. 6A. ₁ (≦ 2
A groove row 2c having a configuration in which a large number of grooves 2b having d) are arranged with an interval S ₁ (≦ 2d) is obtained by an etching process using the mask layer 13.

Next, as shown in FIG. 6B, the mask layer 13 is removed from the insulating film 2.

Next, as shown in FIG. 6C, the insulating film of the substrate 1 is formed according to the steps described above with reference to FIG. 1E in the first embodiment of the wiring structure forming method according to the present invention described above with reference to FIGS. Area facing each groove 2b of the second groove row 2c, each groove 2 of the groove row 2c
b, and continuously extends on the upper surface of the insulating film 2.
A conductor layer 4 similar to that described above with reference to FIG. 1E is formed.

Next, as shown in FIG. 6D, a conductive layer 5 similar to that described with reference to FIG. 2F is formed on the conductive layer 5 in accordance with the process described above with reference to FIG. 2F.

Next, as shown in FIG. 6E, according to the steps described above with reference to FIG. 2G in the first embodiment of the wiring structure forming method according to the present invention described above with reference to FIGS. From 6, a conductor row 11 similar to that described above with reference to FIG. 2G is formed by ion milling.

Hereinafter, in the first embodiment of the wiring structure forming method according to the present invention described above with reference to FIGS. 1 to 5, steps similar to those described above with reference to FIGS. In 3M, a similar wiring structure 9 similar to that described above and similarly forming the wiring layer 8 is formed.

The above is the second embodiment of the wiring structure forming method according to the present invention.

According to the second embodiment of the wiring structure forming method according to the present invention, the conductor layer laminate 6 is formed by the first method of the wiring structure forming method according to the present invention described above with reference to FIGS. In the case of the embodiment, instead of forming the mask layer 13 without removing it,
Except that the mask layer 13 is formed without being removed,
Since the wiring structure forming method according to the first embodiment of the present invention described above with reference to FIGS.
It is apparent that the same excellent operational effects as those of the first embodiment of the wiring structure forming method according to the present invention described above with reference to FIGS.

In the above description, the wiring structure forming method according to the present invention has been described only with reference to the two embodiments, and various modifications and changes may be made without departing from the spirit of the present invention. .

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing sequential steps in a first embodiment of a method for forming a wiring structure according to the present invention.

FIG. 2 is a schematic cross-sectional view showing a first embodiment of a wiring structure forming method according to the present invention, which is a sequential step following the sequential step shown in FIG.

FIG. 3 is a schematic cross-sectional view showing a first embodiment of the wiring structure forming method according to the present invention, which is a sequential step following the sequential step shown in FIG. 2;

FIG. 4 is an example of a schematic plan view of a mask layer formed in the step of FIG. 1C in the first example of the wiring structure forming method according to the present invention.

FIG. 5 is an example of a schematic plan view of a mask layer formed in the step of FIG. 1H in the first example of the wiring structure forming method according to the present invention.

FIG. 6 is a schematic sectional view showing sequential steps in a second embodiment of the wiring structure forming method according to the present invention.

FIG. 7 is a schematic cross-sectional view showing sequential steps in a conventional wiring structure forming method.

FIG. 8 is a schematic cross-sectional view showing a conventional wiring structure forming method in a sequential step following the sequential step shown in FIG. 7;

FIG. 9 is a schematic plan view of a mask layer formed in the step of FIG. 7C in a conventional wiring structure forming method.

[Explanation of symbols]

Reference Signs List 1 substrate 2 insulating film 2a groove 2b formed in insulating film 2 many grooves forming groove line 2c 2c groove line formed in insulating film 2 3 mask layer 3a window of mask layer 3 4, 4 ' Conductor layer 5, 5 'Conductor layer 6, 6' Conductor layer laminate 7 Mask layer 8 Wiring layer 9 Wiring structure 11, 11 'Conductor row 11a, 11a' Many conductors forming the conductor row Conductor 13 mask layer 13b many windows 13c constituting window row 13c window row of mask layer 13

Claims (1)

(57) [Claims] A step of forming an insulating film on a substrate, wherein a plurality of grooves having a width of not more than twice the thickness of the insulating film have an interval of not more than twice the thickness of the insulating film. Forming a first groove row having a configuration that is arranged while being held; and, on the substrate, a plurality of first conductors are respectively formed in the plurality of grooves forming the first groove row. Forming a first conductor row having a configuration that is buried and arranged, and removing the insulating film from the substrate in a region where the first conductor row is formed, A second groove row having a configuration in which a large number of second grooves each having an outside surface of each of the large number of first conductors of the first conductor row as an inner surface is formed on the substrate. A plurality of second conductors on the substrate, wherein the plurality of second conductors constitute the second groove row. Forming a second conductor columns having a configuration that is arranged with great filled in the grooves, respectively,
Forming a wiring layer using the first and second conductor rows.