CN104124149B - Method of forming semiconductor device - Google Patents

Abstract

The invention provides a method for forming a semiconductor device, which comprises the following steps: providing a substrate, wherein the substrate comprises a dielectric layer; forming a hard mask layer on the dielectric layer; forming a strip-shaped opening in the hard mask layer; more than two columnar structures distributed along the length direction of the strip-shaped opening are formed on the strip-shaped opening; forming a side wall on the hard mask layer on the side surface of the columnar structure, wherein the double thickness of the side wall along the length direction of the same strip-shaped opening is smaller than the distance between two adjacent columnar structures on the same strip-shaped opening; removing the columnar structure; and forming a through hole or a groove in the dielectric layer by taking the side wall and the hard mask layer as masks. According to the forming method of the semiconductor device, through holes or grooves are formed in the positions occupied by the columnar structures on the same strip-shaped opening and the positions between the two adjacent side walls, so that one through hole or groove is additionally formed between the two adjacent columnar structures on the same strip-shaped opening, and a densely arranged through hole or groove array is formed.

Description

Method of forming semiconductor device

technical field

The invention relates to the field of semiconductor technology, in particular to a method for forming a semiconductor device.

Background technique

In the semiconductor manufacturing industry, it is usually necessary to use photolithography technology, which uses the principle of optical-chemical reactions and chemical and physical etching methods to transfer circuit graphics to the surface of a single crystal or a dielectric layer to form effective graphic windows or functional graphics. .

The resolution of the traditional lithography process has reached the theoretical value. In order to overcome the limitation of the theoretical resolution of the traditional lithography process, improve the integration density of semiconductor devices and form structures with nanoscale dimensions, high-resolution lithography processes have been developed and Use, for example, litho-etch-litho-etch (LELE) and litho-etch-etch (LLE) lithography techniques. However, when using these technologies to make vias, trenches, metal plugs or metal interconnections, the formed vias, trenches, metal plugs or metal interconnections are usually The desired dense alignment could not be achieved.

Therefore, a new method for forming a semiconductor device is needed to solve the problems existing in the prior art.

Contents of the invention

The problem to be solved by the present invention is to provide a method for forming a semiconductor device to increase the arrangement density of via holes, trenches, metal plugs or metal interconnection lines.

In order to solve the above problems, the present invention provides a method for forming a semiconductor device, comprising:

providing a substrate comprising a dielectric layer thereon;

forming a hard mask layer on the dielectric layer;

forming one or more stripe openings in the hard mask layer through the thickness of the hard mask layer;

Forming more than two columnar structures distributed along the length direction of the strip-shaped openings on the strip-shaped openings, the upper surface of the columnar structures is higher than the upper surface of the hard mask layer;

A side wall on the hard mask layer is formed on the side of the columnar structure, and the thickness of the side wall along the length direction of the same strip-shaped opening is twice smaller than that of two adjacent strip-shaped openings. the distance between the columnar structures;

removing the columnar structures;

Using the sidewall and the hard mask layer as a mask, a via hole or a groove is formed in the dielectric layer.

Optionally, the method further includes: forming a metal layer in the through hole or the trench, and the upper surface of the metal layer is flush with the upper surface of the dielectric layer.

Optionally, the hard mask layer is a metal hard mask layer, and before forming the metal hard mask layer on the dielectric layer, the method further includes: forming an etching stop layer on the dielectric layer.

Optionally, the material of the metal hard mask layer includes titanium nitride or copper nitride, with a thickness of The material of the etching stop layer includes one or more combinations of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide and silicon carbonitride.

Optionally, the material of the sidewall includes at least one or any combination of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, silicon carbonitride, titanium nitride and copper nitride.

Optionally, the material of the columnar structure includes photoresist material, silicon-containing bottom anti-reflection layer material, amorphous carbon material and silicon nitride material in any combination of one or more, and the height is 5nm-100nm.

Optionally, the strip openings have a width of 5 nm to 200 nm.

Optionally, there are more than two strip-shaped openings, and the distance between two adjacent strip-shaped openings is less than or equal to twice the thickness of the side wall.

Optionally, the cross-sectional shape of the columnar structure is a circle, an ellipse, a rectangle or a rhombus.

The present invention also provides another method for forming a semiconductor device, including:

provide the substrate;

forming one or more first strip structures on the substrate;

forming a first sidewall on the substrate on the side of the first strip structure;

removing said first strip-like structure;

forming a sacrificial layer covering the first sidewall and the substrate;

One or more second strip structures are formed on the sacrificial layer, the length direction of the second strip structures and the length direction of the first sidewall form an angle greater than or equal to 45° and less than or equal to 90° Angle;

forming a second side wall on the sacrificial layer on the side of the second strip structure;

The sacrificial layer and the first sidewall are etched using the second sidewall as a mask, and the sacrificial layer is removed to form a plurality of pillars arranged in a matrix.

Optionally, the material of the first strip structure includes one or any combination of photoresist material, silicon-containing bottom anti-reflection layer material, amorphous carbon material and silicon nitride material.

Optionally, the material for making the first sidewall includes copper nitride, and after forming the plurality of pillars, annealing the plurality of pillars in a hydrogen atmosphere is further included, so that the copper nitride is reduced to copper.

Optionally, an ultra-low-k dielectric material is formed between the pillars.

Optionally, the material for making the first sidewall or the second sidewall includes at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, silicon carbonitride, titanium nitride and copper nitride Any combination of one or more.

Compared with the prior art, the technical solution of the present invention has the following advantages:

In a method for forming a semiconductor device provided by the present invention, one or more strip-shaped openings penetrating through the thickness of the hard mask layer are first formed in the hard mask layer on the dielectric layer, and then the strip-shaped openings are Form more than two columnar structures distributed along the length direction of the strip-shaped opening, and then form sidewalls on the hard mask layer on the side of the columnar structures, so that the columnar structures occupy the same strip-shaped opening. A through hole or groove is formed at the position and between two adjacent side walls, so that an additional through hole or groove is formed between two adjacent columnar structures on the same strip-shaped opening, thereby forming a dense The array of through holes or grooves is arranged, and the distance between adjacent through holes or grooves can be smaller than the limit value of traditional photolithography process.

In another method for forming a semiconductor device provided by the present invention, a first sidewall is formed on a substrate, a sacrificial layer is formed to cover the first sidewall and the substrate, and a first sidewall is formed on the sacrificial layer. the second side wall, and then use the second side wall as a mask to etch the first side wall, and then form a plurality of columns arranged in a matrix at the position corresponding to the second side wall in the first side wall, because the first side wall The distance between the walls can be smaller than the limit value of the traditional photolithography process, and the distance between the second side walls can be smaller than the limit value of the traditional photolithography process. Therefore, in the column array formed, the distance between adjacent columns can be smaller than that of the traditional photolithography process. The limit value of the engraving process, and the column array is regularly arranged and the density is high.

Description of drawings

1 to 13 are schematic diagrams of a method for forming a semiconductor device provided by Embodiment 1 of the present invention;

14 to 23 are schematic diagrams of a method for forming a semiconductor device according to Embodiment 2 of the present invention.

detailed description

As mentioned in the background art, when using plate-engraving-plate-engraving or plate-plate-lithography and other photolithography techniques to make vias, trenches, metal plugs or metal interconnections , two mask plates are needed, and the formed vias, trenches, metal plugs or metal interconnections usually cannot achieve the required dense arrangement, and it is difficult to form matrix-distributed vias, trenches, and metal plugs plugs or metal interconnects.

To this end, the present invention provides a method for forming a semiconductor device. First, one or more strip-shaped openings are formed in the hard mask layer on the dielectric layer through the thickness of the hard mask layer, and then the strip-shaped openings are Form more than two columnar structures distributed along the length direction of the strip-shaped opening, and then form sidewalls on the hard mask layer on the side of the columnar structures, so that the columnar structures occupy the same strip-shaped opening. A through hole or groove is formed at the position between two adjacent side walls in the same strip structure, so that an additional through hole or groove is formed between two adjacent column structures on the same strip opening. Grooves, thereby forming a densely arranged through-hole or trench array. Since an opening is formed between two adjacent sidewalls in the same strip structure, the final formed gap between two adjacent through-holes or trenches The distance can be smaller than the limit value of conventional photolithography process.

In another method for forming a semiconductor device provided by the present invention, firstly a first strip structure is formed on the substrate, then a first spacer is formed on the side of the first strip structure, and a sacrificial layer is formed to cover the first strip structure. sidewalls and the substrate, forming second sidewalls on the sacrificial layer, and then etching the first sidewalls using the second sidewalls as a mask to form a plurality of pillars arranged in a matrix, due to the first The distance between the sidewalls can be smaller than the limit value of the traditional photolithography process, and the distance between the second sidewalls can also be smaller than the limit value of the traditional photolithography process. Therefore, in the column array formed by using their overlapping positions, the adjacent The distance between the pillars can be smaller than the limit value of the traditional photolithography process, and the metal plugs distributed in matrix can be formed.

In order to make the above objects, features and advantages of the present invention more comprehensible, specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

Embodiment 1 of the present invention provides a method for forming a semiconductor device. This embodiment will be described below with reference to FIGS. 1 to 13 .

Referring to FIG. 1 , a substrate (not shown) is provided, and a dielectric layer 100 is included on the substrate.

The present invention does not limit the substrate. Specifically, the material of the substrate may be silicon or silicon germanium with a single crystal structure or an amorphous structure, or silicon-on-insulator (SOI) or germanium-on-insulator (GOI). And may include other materials, such as compounds such as doped gallium arsenide. This embodiment takes a silicon substrate with a single crystal structure as an example.

The dielectric layer 100 formed on the substrate may be an interlayer dielectric layer or a top dielectric layer. The material of the dielectric layer 100 may be a silicon oxide material, or a low-k or ultra-low-k material. Please continue to refer to FIG. 1 , a hard mask layer 120 is formed on the dielectric layer 100 .

In this embodiment, the hard mask layer 120 is a metal hard mask layer, and its material may be titanium nitride or copper nitride. Using a metal hard mask as the hard mask layer 120, there will be a higher selectivity when etching the dielectric layer 100, that is, the dielectric layer 100 can be fully etched while the metal hard mask layer is not etched. . In order to achieve a better mask effect, in this embodiment, the thickness of the hard mask layer 120 can be set as On the one hand, the hard mask layer 120 in the thickness range can ensure that it can play the role of a mask during etching, and on the other hand, it is not too thick, so that it can be removed by planarization as soon as possible later.

In this embodiment, since the hard mask layer 120 is a metal hard mask layer, it is easy to etch the dielectric layer 100 when the strip openings 121 are subsequently formed. Therefore, in this embodiment, before forming the hard mask layer 120 on the dielectric layer 100 , an etch stop layer 110 may be formed on the dielectric layer 100 , as shown in FIG. 1 . In this way, when etching the hard mask layer 120 , the etching stop layer 110 can be used as an etching end point, thereby protecting the dielectric layer 100 . The material of the etch stop layer 110 may be one or any combination of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide and silicon carbonitride. The thickness range of the etching stop layer 110 can be

Please refer to FIG. 1 and FIG. 2 in combination, one or more strip openings 121 are formed in the hard mask layer 120 through the thickness of the hard mask layer 120 .

FIG. 2 is a schematic top view of the structure shown in FIG. 1 , and FIG. 1 is a cross-sectional view taken along the direction A-A in FIG. 2 . It can be seen from FIG. 2 that in this embodiment, three parallel strip openings 121 are provided. The width W1 of the strip openings 121 can be 5 nm to 200 nm, and the length L1 of the strip openings 121 is at least twice the pitch ( Pitch, refers to the distance between two units on a chip or wafer, in this embodiment, the distance between two strip openings 121 is a pitch), so that at least two For the columnar structures 131 (please refer to FIG. 5 ), in this embodiment, the length L1 of the strip-shaped openings 121 is more than three times the pitch, so as to form three columnar structures 131 subsequently (refer to step 4). It should be noted that, in other embodiments of the present invention, there may be one, two or more than four strip openings 121 . When there are multiple strip openings 121 , they are not limited to be parallel to each other, but can each form a certain angle, such as 30°, 45° or 60°.

Please refer to FIG. 5 and FIG. 6 in combination, three columnar structures 131 distributed along the lengthwise direction of the strip-shaped openings 121 are formed on each strip-shaped opening 121 , and the upper surfaces of the columnar structures 131 are higher than the upper surface of the hard mask layer 120 .

Please refer to FIG. 3 , FIG. 4 , FIG. 5 and FIG. 6 for the formation process of the columnar structure 131 . As shown in FIG. 3 , a mask material layer 130 is first formed on the hard mask layer 120 and the etch stop layer 110 , and then a plurality of photoresist patterns 141 are formed on the mask material layer 130 . In this embodiment, the photoresist pattern 141 is located right above the strip openings 121 , as shown in FIG. 3 .

Fig. 3 is a cross-sectional view taken along the direction A-A in Fig. 4 . FIG. 4 is a top view of the structure shown in FIG. 3 . It can be seen from FIG. 4 that patterned photoresist patterns 141 are distributed on the mask material layer 130 in a matrix. In this embodiment, the width W2 of the photoresist pattern 141 is greater than or equal to the width W1 of the strip opening 121 , and the length L2 of the photoresist pattern 141 is smaller than the length L1 of the strip opening 121 . It can be seen from FIG. 4 that the length L2 of the photoresist pattern 141 is much smaller than the length L1 of the strip opening 121 , so that at least three photoresist patterns 141 can be disposed on one strip opening 121 . After the patterned photoresist pattern 141 in FIG. 4 is formed, the mask material layer 130 is etched using the photoresist pattern 141 as a mask to form a columnar structure 131 , as shown in FIG. 5 . Fig. 5 is a sectional view cut along the A-A direction in Fig. 4, and Fig. 6 is a top view of the structure shown in Fig. 5, as can be seen from Fig. 6, each columnar structure 131 is evenly distributed in each strip opening 121, this The uniform distribution method can make the formed structure more regular.

In this embodiment, the obtained columnar structure 131 has two sections with a wide top and a narrow bottom, wherein the lower section just fills the strip-shaped opening 121 . This is because the mask material layer 130 has already filled the strip-shaped opening 121, so the width of the lower section of the columnar structure 131 (not marked) is equal to the width W1 of the strip-shaped opening 121, and the columnar structure 131 is transferred by the photoresist pattern 141. Therefore, the length L3 and the width W3 of the upper section of the columnar structure 131 are equal to the length L2 and the width W2 of the photoresist pattern 141 respectively. In other embodiments of the present invention, the columnar structure 131 can also be made to have the same width up and down (it can be realized by setting the photoresist pattern 141 directly above the strip-shaped opening 121, and the photoresist pattern 141 is equal to the width of the strip-shaped opening 121. accomplish). The height of the columnar structure 131 can be 5nm˜100nm, such as: 5nm, 50nm or 100nm, and its height is greater than that of the hard mask layer 120 .

In this embodiment, the mask material layer 130 may be a bottom anti-reflection layer material, such as an amorphous carbon material, or a silicon-containing bottom anti-reflection layer material, or a silicon nitride material, or one of them random combination.

It should be noted that, in other embodiments of the present invention, the mask material layer 130 may be directly made of a photoresist material. The exposure and development technology directly forms the mask material layer 130 into the columnar structure 131 .

In this embodiment, the cross-section of the columnar structure 131 is elliptical, but in other embodiments of the present invention, the cross-section of the columnar structure 131 can also be circular, rectangular or diamond-shaped, etc., and these cross-sections are regular-shaped columns. The structure 131 facilitates the growth of the subsequent sidewall 150 (please refer to FIG. 7 ), but the present invention does not limit the cross-sectional shape of the columnar structure 131 .

Please refer to FIG. 7 and FIG. 8 in combination. The sidewall 150 is formed on the side of the columnar structure 131 shown in FIG. 5 and FIG. 6 , and the sidewall 150 is located on the hard mask layer 120 at the same time. FIG. 7 is a cross-sectional view taken along the direction A-A in FIG. 8 , and FIG. 8 is a top view of the structure shown in FIG. 7 .

Please refer to FIG. 7 , the sidewall 150 is formed on the side of the columnar structure 131 and is located on the upper surface of the hard mask layer 120. The sidewall 150 can be formed by atomic layer deposition (ALD). The material of the sidewall 150 includes silicon oxide, At least one or any combination of silicon nitride, silicon oxynitride, silicon carbide, silicon carbonitride, titanium nitride and copper nitride. The thickness of the sidewall 150 may be 2 nm˜100 nm.

In this embodiment, the thickness of the side wall 150 is T, the distance between two adjacent columnar structures 131 on the same strip opening 121 is marked as S, and the distance between two adjacent side walls 150 on the same strip opening 121 is The distance is marked as ΔH, then there is S=2T+ΔH. In this embodiment, an opening is subsequently formed at the position occupied by the columnar structure 131, and a through hole or groove is further formed, and an opening can be formed at the position between two adjacent side walls 150 on the same strip opening 121, so that The added openings also further form through holes or grooves, so that the distance between two adjacent through holes or grooves on the same strip opening 121 is smaller than the pitch, so small as to be only the thickness T of the sidewall 150, thus The produced through holes or grooves are densely packed in the length direction of the strip openings 121 , and thus densely packed through holes or grooves can be formed.

In this embodiment, it is preferable to set ΔH equal to the length L3 of the columnar structure 131 (please refer to FIG. 8 ), so that whether it is a through hole or a groove formed at the corresponding position of the columnar structure 131 or the same strip opening 121 The through holes or grooves formed at corresponding positions between two adjacent upper sidewalls 150 are all equal in size.

In this embodiment, there are three strip-shaped openings 121 , and there are also three columnar structures 131 on each strip-shaped opening 121 . However, in other embodiments of the present invention, the number of strip-shaped openings 121 and the number of columnar structures 131 contained on each strip-shaped opening 121 can be other values, for example, two strip-shaped openings are set, each Four columnar structures are arranged on the strip-shaped openings, and for example, five strip-shaped openings are provided, and five columnar structures are arranged on each strip-shaped opening. The number of shaped openings and columnar structures.

In this embodiment, the distance between two adjacent strip-shaped openings 121 is less than or equal to twice the thickness (2T) of the side wall 150, that is, the distance between two adjacent strip-shaped openings 121 is relatively close, and the same lateral direction The three columnar structures 131 above are on the same straight line (for example, the three columnar structures 131 are located in the direction A-A in FIG. 8 ), so the side walls 150 are connected to each other along the width direction of the strip opening 121 . However, in other embodiments of the present invention, the side walls 150 may not be connected together, for example, when there is only one strip-shaped opening 121, or the distance between the columnar structures 131 between different strip-shaped openings 121 is greater than that of the two sides of the side wall 150. double thickness (2T). In fact, whether the side walls 150 between different strip-shaped openings 121 are connected to each other or not does not affect the formation of gaps between adjacent side walls 150 of the same strip-shaped opening 121 in this embodiment, thus does not affect the technical solution of this embodiment. Therefore, in this embodiment, the connection problem of the side walls 150 between different strip-shaped openings 121 may not be considered. However, in this embodiment, the three columnar structures 131 in the same transverse direction are arranged on the same straight line. This arrangement can not only make the subsequently formed opening array more regular, but also allow the distance between different strip openings 121 to be adjusted. The smaller the size, the higher the density of the subsequently formed opening array.

It should be noted that, in this embodiment, the side wall 150 is slightly thicker at the left and right tips and thinner at the upper and lower parts, as shown in FIG. 8 . This is because the cross-section of the columnar structure 131 of the deposited sidewall 150 is elliptical, so when the sidewall 150 is deposited and formed, the material of the sidewall 150 grows along the cross-sectional shape of the columnar structure 131, and the finally obtained sidewall 150 The cross section of the columnar structure 131 presents a flat structure similar to the cross section of the columnar structure 131.

Please refer to FIG. 7 , FIG. 8 and FIG. 9 in conjunction to remove the columnar structure 131 .

7 and 8 show that side walls 150 are formed on the side of the columnar structure 131 , after which the columnar structure 131 is removed, as shown in FIG. 9 . When the columnar structure 131 is directly formed by photoresist or organic bottom anti-reflection layer, the columnar structure 131 can be removed by ashing process, and when the columnar structure 131 is made of silicon nitride, it can be removed by phosphoric acid solution.

After the columnar structure 131 is removed, an opening 122 is formed at the position of the original columnar structure 131, and an opening 123 is formed at the position of the strip-shaped opening 121 between two adjacent side walls 150 on the same strip-shaped opening 121, as shown in FIG. 9 . In this way, originally only three photoresist patterns 141 and three columnar structures 131 were formed on one strip opening 121, but finally five openings (respectively three openings 122 and three columnar structures 131) were formed on one strip opening 121. two openings 123).

Referring to FIGS. 9 to 13 , using the sidewall 150 and the hard mask layer 120 as a mask, the via hole 101 is etched in the dielectric layer 100 . In this embodiment, after the above-mentioned three openings 122 and two openings 123 are formed on one strip-shaped opening 121, the spacer 150 and the hard mask layer 120 are used as masks to etch the medium below the opening 122 and the opening 123. layer 100 , forming a via hole 101 on the dielectric layer 100 . It should be noted that, in the structure shown in FIG. 9 , the central part is an interconnection structure area, and the periphery is a non-interconnection structure area. In this embodiment, corresponding via holes or grooves are made in the interconnection structure area. Therefore, before etching with the sidewall 150 as a mask, a mask layer (not shown) may be provided to shield the surrounding non-interconnection structure region, and then etch, and then remove the mask layer.

Please refer to FIG. 10, which is a schematic cross-sectional view of the structure shown in FIG. 9 cut along the B-B line. From FIG. 10, three openings 122 and two openings 123 distributed on the same strip opening 121 can be seen more clearly , there are only side walls 150 between the openings, and the distance between the openings is small, so their dense density is high.

Please refer to FIG. 11. FIG. 11 is a schematic cross-sectional view of the structure shown in FIG. 9 cut along the C-C line. From FIG. 11, it can be seen that the opening 123 is formed between adjacent side walls 150 on the same strip opening 121, Due to the increased formation of openings 123, the density of the openings is increased, the space utilization rate is improved, and a large number of openings can be made in a small area, and these openings are used to form through holes or grooves in the follow-up, so that the openings can be formed in a small area. A large number of through-holes or grooves are produced inside.

Please refer to FIG. 12. FIG. 12 is a schematic cross-sectional view of the structure shown in FIG. 9 cut along the D-D line. It can be seen from FIG. 12 that the position originally occupied by the columnar structure 131 forms an opening 122 after the columnar structure 131 is removed. , the opening 122 is used for further forming through holes or trenches.

During the process of etching the through hole 101 using the sidewall 150 and the hard mask layer 120 as a mask, the sidewall 150 is etched away simultaneously. When the hard mask layer 120 is a metal hard mask layer, the etch stop layer 110 is further included between the dielectric layer 100 and the hard mask layer 120 , therefore, the etch stop layer 110 is also etched during the above process.

In this embodiment, the density of the through holes 101 formed in the dielectric layer 100 is high, because, except for the position of the strip opening 121 (refer to FIG. 9 ) previously occupied by the columnar structure 131 (that is, the position of the opening 122 in FIG. 9 ) In addition to the formation of the through hole, the through hole 101 is also formed at the position between two adjacent side walls 150 on the same strip opening 121 originally. In Fig. 13, three rows of through holes 101 are formed (the direction of the row refers to the B-B direction shown in Fig. 9 or the direction parallel to the B-B direction), and each row includes five through holes 101. Among the five through holes 101, The second and fourth through holes 101 counted from top to bottom in each row in FIG. 13 are formed by etching the corresponding opening 122 in the original FIG. Forming five through holes 101 increases the density of the through holes 101 .

Through the above-mentioned steps, in this embodiment, an array of through holes 101 with an adjacent spacing smaller than the limit value of the traditional photolithography process is formed on the same strip opening 121 , and the formed array of through holes 101 is regularly arranged and highly dense.

It should be noted that, in this embodiment, the through holes 101 are formed in the dielectric layer 100 , and in other embodiments of the present invention, trenches may also be formed in the dielectric layer 100 .

After the above steps are completed, this embodiment can also continue to form a metal layer (not shown) in the through hole 101, and remove the part of the metal layer higher than the upper surface of the dielectric layer 100 and the hard mask layer 120 through a planarization process. and the etch stop layer 110 , so that the upper surface of the metal layer is flush with the upper surface of the dielectric layer 100 .

In this embodiment, through the above steps, three columnar structures 131 are firstly formed in the three strip-shaped openings 121, and then nine openings 123 are formed at the positions of the nine columnar structures 131. These nine openings 123 correspond to form nine through holes or grooves. However, in this embodiment, by forming a side wall 150 on the side of the columnar structure 131, and by controlling the thickness of the side wall 150, an opening 122 is formed between two adjacent side walls 150 on the same strip opening 121, so that a The strip-shaped openings 121 form a total of five openings (three openings 122 and two openings 123 respectively), a total of fifteen openings are formed in the three strip-shaped openings 121, and finally fifteen through holes 101 are formed, so that the strip The density of the through holes 101 formed on the shaped openings 121 is increased by (15-9)/9=66.7%.

In other embodiments of the present invention, assuming that there are N strip-shaped openings 121, M columnar structures 131 are correspondingly formed on each strip-shaped opening 121. In this way, if only M×N columnar structures 131 are formed openings, only M×N openings can be formed, and finally only M×N through holes or trenches can be formed, but through the method for forming a semiconductor device provided by the present invention, two adjacent openings can be formed An additional opening is formed between the columnar structures 131, so that (2M-1)×N openings can be formed in total, and finally (2M-1)×N through holes or trenches can be formed, that is, (M- 1)×N openings, so the density of the formed via holes or trenches is increased by (M-1)/M%. When M is 100, the density of formed via holes or trenches increases by 99%, and the larger M is, the more the density increases.

Embodiment 2 of the present invention provides another method for forming a semiconductor device. The method for forming a semiconductor device provided in this embodiment will be described below with reference to FIGS. 14 to 23 .

In this embodiment, for the convenience of description, a three-dimensional coordinate axis is defined. The three-dimensional coordinate axis includes three axes of X, Y and Z, and they are perpendicular to each other. Referring to the coordinate arrows at the lower left corner of the figure, for example, FIG. 14 is a schematic X-Z sectional view, and FIG. 15 is a schematic X-Y sectional view.

Referring to FIG. 14 , a substrate 200 is provided.

The material of the substrate 200 may be silicon or silicon germanium with a single crystal or amorphous structure, silicon-on-insulator (SOI) or germanium-on-insulator (GOI), and may include other materials, such as doped gallium arsenide, etc. compounds, the substrate 200 is not limited in this embodiment.

Please refer to FIG. 14 and FIG. 15 in combination, a first strip structure 211 is formed on the substrate 200 .

In this embodiment, the material of the first strip structure 211 may be one or more of a photoresist material, a bottom anti-reflection layer material (such as amorphous carbon), a silicon-containing bottom anti-reflection layer material, and a silicon nitride material. any combination of . The formation process of the first strip structure 211 can adopt techniques well known to those skilled in the art, and will not be repeated here.

FIG. 15 is a schematic top view of the structure shown in FIG. 14 . In this embodiment, three first strip structures 211 parallel to each other are provided, as shown in FIG. 15 . In other embodiments of the present invention, the number of the first strip structures 211 may also be one, two or more than four, and the present invention does not limit the number of the first strip structures 211 . In this embodiment, the width of the first strip structure 211 may be 2nm˜200nm, and the first strip structure 211 in this width range can subsequently form a required pillar array.

Please refer to FIG. 16 , the first sidewall 221 on the substrate 200 is formed on the side of the first strip structure 211 shown in FIG. 14 and FIG. 15 .

In this embodiment, atomic layer deposition (ALD) can be used to form the first side wall 221. Specifically, the first side wall is deposited on the upper surface and side surfaces of the first strip structure 211 and the upper surface of the substrate 200 by using the atomic layer deposition method. A wall material layer (not shown), and then the first side wall 221 is formed through the existing side wall forming process. The material of the first sidewall 221 is copper nitride. In this embodiment, the width of the first sidewall 221 may be 2 nm˜200 nm. In this embodiment, copper nitride is used to make the first side wall 221 . After the pillars are finally formed, annealing is performed on the pillars in a hydrogen atmosphere, so that the copper nitride is reduced to copper to form the copper pillars.

Please continue to refer to FIG. 17 , the first strip structure 211 in FIG. 16 is removed.

In this embodiment, after the first sidewall 221 is formed, the first strip structure 211 is removed, and the first sidewall 221 is retained, as shown in FIG. 17 . Different methods can be used to remove the first strip structure 211 of different materials. For example, when the first strip structure 211 is formed by photoresist or organic bottom anti-reflection layer, the first strip structure 211 can be removed by ashing process. structure 211, and when the first strip structure 211 is made of silicon nitride, phosphoric acid solution can be used to remove it.

Please refer to FIG. 18 and FIG. 19 in combination, a sacrificial layer 230 is formed to cover the first sidewall 221 and the substrate 200 .

In this embodiment, after removing the first strip structure 211, a sacrificial layer 230 is formed to cover the first sidewall 221. The formation of the sacrificial layer 230 can form a flat layer structure above the first sidewall 221, so as to continue to form other layers. It can be seen in the X-Z section shown in FIG. 18 that the sacrificial layer 230 is filled between the first side walls 221 and is higher than the first side wall 221 by a certain height. In the Y-Z section shown in FIG. 19 , the same It can be seen that the sacrificial layer 230 forms a flat layer structure above the first sidewall 221 .

Please refer to FIG. 18 and FIG. 19 , the second strip structure 241 is formed on the sacrificial layer 230 , wherein the length direction of the second strip structure 241 forms an included angle of 90° with the length direction of the first sidewall 221 .

It should be noted that, in other embodiments of the present invention, the lengthwise direction of the second strip structure 241 and the lengthwise direction of the first side wall 221 may also form any other included angle greater than or equal to 45° and less than 90°, for example 45°, 60° or 75° etc. When the length direction of the second strip structure 241 and the length direction of the first side wall 221 form an included angle range greater than or equal to 45° and less than 90°, the first side wall 221 is followed by the second side wall 251 (please refer to this Embodiment Subsequent steps) in the overlapped portion, the cross section of the overlapped portion will be in a shape with a relatively large ratio of area to perimeter. For example, in this embodiment, the cross section of the overlapped portion is rectangular. It is generally desired that the cross-section of the column 222 to be fabricated also has a relatively large area-to-peripheral ratio, thus providing a guarantee for forming the column 222 of the desired shape within the range of the included angle.

In this embodiment, referring to FIG. 18 and FIG. 19 , it can be known that there are three second strip structures 241 , which are elongated and distributed above the sacrificial layer 230 . In other embodiments of the present invention, the number of second strip structures 241 may also be one, two or more than four, and the present invention does not limit the number of second strip structures 241 . At the same time, the width of the second strip structure 241 can be 2nm-200nm, the second strip structure 241 in this width range matches the width range of the above-mentioned first strip structure 211, and the first strip structure can be further set The width of 211 is equal to the width of the second strip structure 241 , so that the post 222 formed subsequently (refer to the subsequent steps in this specification) has a square cross section.

Please refer to FIG. 20 to FIG. 22 in combination, the second sidewall 251 on the sacrificial layer 230 is formed on the side of the second strip structure 241 shown in FIG. 18 and FIG. 19 .

In this embodiment, a second sidewall material layer (not shown) is formed on the sacrificial layer 230 , and the second sidewall material layer is formed on the top and side of the second strip structure 241 and the upper surface of the sacrificial layer 230 . In this embodiment, atomic layer deposition (ALD) can be used to form the second sidewall material layer, and the material can be silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, silicon carbonitride, and titanium nitride. Any combination of at least one or more, but it is necessary to ensure that the material of the second side wall material layer is different from the material of the sacrificial layer 230 and the first side wall 221, and it is best to choose the same material as the sacrificial layer 230 and the first side wall 221 material has a higher etch selectivity than the material.

After forming the second sidewall material layer, the sidewall etching process is continued to form the second sidewall material layer to form the second sidewall 251 , as shown in FIG. 22 . In this embodiment, the thickness of the second side wall 251 may also be 2 nm˜200 nm.

Please refer to FIG. 22, the second side wall 251 is located on the upper surface of the sacrificial layer 230, and, according to the above description, the length direction of the first side wall 221 and the length direction of the second side wall 251 are perpendicular to each other, although the first side wall 221 and the second side wall 251 are separated by a sacrificial layer 230, but there is a corresponding position between the two side walls (that is, a position where the upper and lower sides overlap). The projection of the corresponding position of the first side wall 221 on the sacrificial layer 230 is the same as that of the second The projections of corresponding positions of the two sidewalls 251 on the sacrificial layer 230 coincide.

Please refer to FIG. 22 and FIG. 23 in combination, using the second sidewall 251 as a mask, etch the sacrificial layer 230 and the first sidewall 221 , and remove the sacrificial layer 230 to form a plurality of pillars 222 arranged in a matrix.

In this embodiment, the sacrificial layer 230 and the second sidewall 251 may be etched by plasma of halogen elements. During etching, only the portion of the first sidewall 221 at the above corresponding position is retained, and after the etching is completed, the first sidewall 221 is etched to form a column 222 . The pillars 222 formed are pillars 222 of copper nitride material. Next, the post 222 can be annealed in a hydrogen atmosphere to reduce the copper nitride to copper to form the copper post 222. Specifically, annealing can be performed at a temperature of 100°C to 400°C to form Copper column 222.

In this embodiment, copper nitride is used to make the first side wall 221. Copper nitride is a metal compound, which can be formed by atomic layer deposition, so it can be used to form the first side wall 221 with a small thickness. Therefore, it is ensured that the pillars 222 arranged densely will be formed later, and the copper nitride is easily reduced to copper, and the pillars 222 are easily reduced to metal plugs later, so it is particularly suitable for the technical solution of the present invention.

After the above steps, this embodiment forms a dense array of uprights 222, the uprights 222 are on the first side wall 221, and the uprights 222 are formed at the corresponding positions of the above-mentioned first side walls 221, and the corresponding positions It is determined by the vertical overlap between the first sidewall 221 and the second sidewall 251. Since the distances between the first sidewall 221 and the second sidewall 251 can be smaller than the limit value of the photolithography process, this implementation In the column array 222 formed in the example, the distance between adjacent columns 222 may be smaller than the limit value of the traditional photolithography process, and the formed column 222 array is regular and dense.

Although not shown in the figure, after the above steps are completed, this embodiment can continue to form a low-k or ultra-low-k dielectric material between the formed pillars 222 (in this case, the pillars 222 can be reduced copper pillars). Prior to this, the sacrificial layer 230 remaining in the above process must be removed first, and the remaining sacrificial layer 230 and the second sidewall 251 can be removed by oxygen (O-) plasma, and then physical vapor deposition (PVD ), chemical vapor deposition (CVD) or atomic layer deposition (ALD) to form a low-k or ultra-low-k dielectric material on the substrate 200 between the pillars 222 . After the low-k or ultra-low-k dielectric material is formed, the post 222 is converted into a metal plug.

The forming methods of the two semiconductor devices provided by the present invention respectively adopt strip-shaped openings and strip-shaped structures, and at the same time cooperate with the sidewall forming process and the method of etching the sidewalls as a mask to form a matrix arrangement. Holes, grooves or metal plugs, the formed through holes, grooves or metal plugs are arranged regularly and densely.

Although the present invention is disclosed above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, so the protection scope of the present invention should be based on the scope defined in the claims.

Claims (9)

1. the forming method of a semiconductor device, it is characterised in that including:

Substrate is provided, described substrate comprises dielectric layer；

Described dielectric layer is formed hard mask layer；

Described hard mask layer is formed and runs through one or more strip of described hard mask layer thickness and open Mouthful；

The two or more post along described strip Opening length directional spreding is formed in each described strip opening Shape structure, the upper surface of described column structure is higher than the upper surface of described hard mask layer；

Being formed in the side of described column structure and be positioned at the side wall on described hard mask layer, described side wall is along same Double thickness on strip Opening length direction described in is less than adjacent two institutes on same described strip opening State the distance between column structure；

Remove described column structure；

With described side wall and described hard mask layer as mask, described dielectric layer forms through hole or groove.

2. forming method as claimed in claim 1, it is characterised in that also include: at described through hole or ditch Groove is formed the upper surface flush of metal level, the upper surface of described metal level and described dielectric layer.

3. forming method as claimed in claim 1, it is characterised in that described hard mask layer is metal hard mask Layer, before forming described metal hard mask layer, also includes: at described dielectric layer on described dielectric layer Upper formation etching stop layer.

4. forming method as claimed in claim 3, it is characterised in that the material bag of described metal hard mask layer Including titanium nitride or copper nitride, thickness isThe material of described etching stop layer includes oxygen One or more combination in any of SiClx, silicon nitride, silicon oxynitride, carborundum and carbonitride of silicium.

5. forming method as claimed in claim 3, it is characterised in that the material of described side wall include silicon oxide, One in silicon nitride, silicon oxynitride, carborundum, carbonitride of silicium, titanium nitride and copper nitride or many The combination in any planted.

6. forming method as claimed in claim 1, it is characterised in that the material of described column structure includes light Photoresist material, siliceous bottom anti-reflective layer material, amorphous carbon material and the one of silicon nitride material or The combination in any that person is multiple, height is 5nm～100nm.

7. forming method as claimed in claim 1, it is characterised in that the width of described strip opening is 5nm～200nm.

8. forming method as claimed in claim 1, it is characterised in that described strip opening is two or more, The adjacent distance between two described strip openings is less than or equal to the twice of described side wall thicknesses.

9. forming method as claimed in claim 1, it is characterised in that the shape of cross section of described column structure For circular, oval, rectangle or rhombus.