TWI525806B - Semiconductor structure and manufacturing method of the same - Google Patents

Description

Semiconductor structure and method of manufacturing same

The present disclosure relates to a semiconductor structure and a method of fabricating the same, and more particularly to a semiconductor structure having a stable strip-like stacked structure and a method of fabricating the same.

In recent years, the structure of semiconductor elements has been constantly changing, and the memory storage capacity of the elements has also been increasing. Memory devices are used in many products, such as MP3 players, digital cameras, computer files, and the like. As applications increase, so does the demand for memory devices toward smaller sizes and larger memory capacities. In response to this demand, it is required to manufacture a memory device having a high component density and a small size.

Therefore, designers are all committed to developing a three-dimensional memory device that not only has many stacked planes but also achieves higher memory storage capacity, has a smaller size, and has good characteristics and stability.

The disclosure relates to a semiconductor structure and a method of fabricating the same. In an embodiment, the strip of stretch material of the semiconductor structure is formed on the strip stack structure, so that the compressive stress of the strip stack structure can be appropriately compensated by the tensile stress of the strip of stretch material, so that the strip stack structure can be reduced. In the case of bending, the stability and reliability of the semiconductor structure are improved.

In accordance with an embodiment of the present disclosure, a semiconductor structure is proposed. The semiconductor structure includes a substrate, a strip-like stacked structure, and a tensile material strip. The strip-like stacked structure is formed vertically on the substrate, and the strip-shaped stacked structure has compressive stress. The strip-shaped stacked structure includes a plurality of conductive strips and a plurality of insulating strips, and the conductive strips and the insulating strips are interlaced. The strip of stretch material is formed on the strip stack structure, and the strip of stretch material has tensile stress.

In accordance with another embodiment of the present disclosure, a method of fabricating a semiconductor structure is presented. The method of fabricating a semiconductor structure includes the following steps. Providing a substrate; vertically forming a strip-like stacked structure on the substrate, the strip-shaped stacked structure has compressive stress; and forming a strip of stretchable material on the strip-shaped stacked structure, the strip of the stretchable material having tensile stress. The strip-shaped stacked structure includes a plurality of conductive strips and a plurality of insulating strips, and the conductive strips and the insulating strips are alternately arranged.

In order to better understand the above and other aspects of the present invention, the preferred embodiments are described below, and in conjunction with the drawings, the detailed description is as follows:

100‧‧‧Semiconductor structure

110‧‧‧Substrate

120‧‧‧ strip stack structure

120a‧‧‧Surface

120s, 130s‧‧‧ side

120t, 130t‧‧‧ thickness

121‧‧‧ Conductive strip

121a‧‧‧ Conductive layer

123‧‧‧Insulation strip

123a‧‧‧Insulation

130‧‧‧Extension strips

130a‧‧‧Stretchable material layer

140‧‧‧ bottom oxide layer

140a‧‧‧Bottom oxidized material layer

150‧‧‧ cover oxide layer

160‧‧‧Dielectric components

170‧‧‧Flexible wire

170a‧‧‧layer of conductive material

A‧‧‧ area

D1, D2‧‧‧ direction

L1, L2‧‧‧ length

PR1, PR2‧‧‧ patterned photoresist

T‧‧‧ tensile stress

W1, W2‧‧‧ width

1 is a perspective view of a semiconductor structure of an embodiment of the present disclosure. Figure.

2 to 8 are schematic views showing a method of fabricating a semiconductor structure in accordance with an embodiment of the present invention.

9A and 9B are schematic views respectively showing a scanning electron micrograph (SEM) of a semiconductor structure according to an embodiment of the present disclosure and a comparative example.

In the embodiments disclosed herein, a semiconductor structure and a method of fabricating the same are presented. In an embodiment, the strip of stretch material of the semiconductor structure is formed on the strip stack structure, so that the compressive stress of the strip stack structure can be appropriately compensated by the tensile stress of the strip of stretch material, so that the strip stack structure can be reduced. In the case of bending, the stability and reliability of the semiconductor structure are improved. However, the examples are for illustrative purposes only and are not intended to limit the scope of the invention. In addition, the drawings in the embodiments are omitted in order to clearly show the technical features of the present invention.

Please refer to FIG. 1 , which is a perspective view of a semiconductor structure 100 in accordance with an embodiment of the present disclosure. The semiconductor structure 100 includes a substrate 110, a strip-like stacked structure 120, and a strip of extensible material 130. As shown in FIG. 1, the strip-like stacked structure 120 is vertically formed on the substrate 110, and the strip-shaped stacked structure 120 has compressive stress. The strip-shaped stacked structure 120 includes a plurality of conductive strips 121 and a plurality of insulating strips 123. The conductive strips 121 and the insulating strips 123 are interlaced. A strip of extensible material 130 is formed on the strip stack structure 120, and the strip of extensible material 130 has tensile stress. According to an embodiment of the present disclosure, the strip of extensible material 130 is formed on the strip stack structure 120, such that The compressive stress of the strip-shaped stacked structure 120 can be appropriately compensated by the tensile stress of the strip of tensile material 130, and the degree of bending of the strip-shaped stacked structure 120 toward the width direction can be reduced, thereby improving the structure of the strip-shaped stacked structure 120. The stability reduces the probability of improper contact of the strip stack structure 120 with adjacent components and improves the reliability of the semiconductor structure 100 as an component.

As shown in FIG. 1 (please refer to FIG. 5 at the same time), in an embodiment, the strip-shaped stacked structure 120 has an aspect ratio of about 5 to 200; in another embodiment, the aspect ratio of the strip-shaped stacked structure 120 It is about 15~50. For example, when the width W1 of the strip-shaped stacked structure 120 is, for example, 40 nm, the length L1 of the strip-shaped stacked structure 120 is, for example, 800 to 1200 nm. In the embodiment, the conductive strip 121 comprises polysilicon, and the insulating strip 123 comprises yttrium oxide, both of which have compressive stress.

In some embodiments, the strip stack structure 120 may include, for example, about 8 to 12 pairs of conductive strips 121 and insulating strips 123, each of the strips 131 and each of the strips having a thickness of about 300 angstroms (Å). In this embodiment, as shown in FIG. 1, the strip-shaped stacked structure 120 includes eight conductive strips 121 and eight insulating strips 123 which are staggered, and the strip-shaped stacked structure 120 has a thickness of 120t of about 4800 angstroms. However, the number and thickness of the conductive strips 121 and the insulating strips 123 can be appropriately selected according to practical applications, and are not limited to the foregoing amounts and thicknesses.

In some embodiments, the strip stack structure 120 may further include a bottom oxide layer 140 and a cap oxide layer 150. The bottom oxide layer 140 is located between the lowermost conductive strip 121 and the substrate 110, and the cap oxide layer 150 is located under the strip of extensible material 130. In the present embodiment, the bottom oxide layer 140 and the cap oxide layer 150 are made of, for example, hafnium oxide. In the embodiment, the thickness of the bottom oxide layer 140 is about 500 to 2500 angstroms (Å), according to the number of the conductive strips 121 and the insulating strips 123 in the strip-shaped stacked structure 120. It will be different. In one embodiment, the thickness of the bottom oxide layer 140 is, for example, about 1000 angstroms. In the embodiment, the thickness of the cap oxide layer 150 is about 300-2000 angstroms, which varies according to the number of the conductive strips 121 and the insulating strips 123 in the strip-shaped stacked structure 120. In one embodiment, the thickness of the cap oxide layer 150 is, for example, about 1000 angstroms. However, the material and thickness of the bottom oxide layer 140 and the cap oxide layer 150 may be appropriately selected according to practical applications, and are not limited to the above materials and thicknesses.

In an embodiment, as shown in FIG. 1, a strip of extensible material 130 is formed on the top surface 120a of the strip stack 120. In some embodiments, the strip of extensible material 130 comprises a dielectric material, for example comprising a tantalum nitride layer or a tantalum carbide layer. In one embodiment, the thickness of the strip of extensible material 130 is, for example, 100 to 1000 angstroms; in another embodiment, the thickness of the strip of extensible material 130 is, for example, 200 to 500 angstroms (Å); conductive according to the strip-shaped stacked structure 120 The number of strips 121 and the strips 123 may vary.

In some embodiments, the ratio of the thickness 130t of the strip of extensible material 130 to the thickness 120t of the strip stack 120 is about 1:5 to 1:100. In other words, as the thickness of the strip-like stack 120 is greater, the thickness of the strip of extensible material 130 also needs to be increased to provide sufficient stress compensation. For example, in one embodiment, when the strip of extensible material 130 has a thickness of about 500 angstroms (Å), the strip-shaped stacked structure 120 includes eight pairs of conductive strips 121 and insulating strips 123 having a thickness of about 4,800 angstroms. The oxide layer 140 has a thickness of about 500 angstroms and the cap oxide layer 150 has a thickness of about 500 angstroms. The ratio of the thickness of the strip of stretchable material 130 to the thickness of the strip stack 120 is about 500/(4800+500+). 500) = 1:11. In another embodiment, when the strip of extensible material 130 has a thickness of about 200 angstroms (Å), the strip-shaped stacked structure 120 includes 12 pairs of conductive strips 121 and insulating strips 123 having a thickness of about 7,200 angstroms. The thickness of the bottom oxide layer 140 is about 1000 angstroms, and the thickness of the cap oxide layer 150 is about 800 angstroms. The ratio of the thickness of the strip of the stretch material strip 130 to the thickness of the strip stack structure 120 is about: 200/(7200+1000). +800) = 1:45.

In one embodiment, as shown in FIG. 1 (please refer to FIG. 5 at the same time), the length L2 of the strip of stretch material 130 is substantially the same as the length L1 of the strip stack 120, and both sides of the strip of stretch material 130 The sides 130s are substantially aligned with the two sides 120s of the strip stack 120. In the present embodiment, as shown in FIG. 1, the strip of extensible material 130 covers the top surface 120a of the strip-shaped stacked structure 120, and the pattern of the strip of extensible material 130 is substantially the same as the pattern of the strip-like stacked structure 120.

As shown in FIG. 1, the semiconductor structure 100 further includes a dielectric member 160 and a conductive line 170. The dielectric element 160 is formed on the strip stack structure 120, and the conductive line 170 is formed on the dielectric element 160. The dielectric element 160 may be an ONO structure, an ONONO structure, or a material layer composed of a tunneling material/trapping material/blocking material, and is applied to a NAND storage material. . The extending direction D1 of the conductive line 170 is perpendicular to the extending direction D2 of the strip-shaped stacked structure 120. In one embodiment, the semiconductor structure 100 is, for example, a 3D vertical gate memory device, and the conductive lines 170 are used as word lines, and the strip stacked structure 120 is used as bit lines. In another embodiment, the semiconductor structure 100 is, for example, a three-dimensional memory device having ultra-thin U-shaped channels, the conductive lines 170 can be used as bit lines, and the strip-shaped stacked structure 120 can be used as words. Yuan line.

2 to 8 are schematic views showing a method of fabricating a semiconductor structure in accordance with an embodiment of the present invention.

Please refer to Figures 2~5 to provide a substrate 110 which is vertically formed into a strip pile. The stacked structure 120 is on the substrate 110, and a strip of extensible material 130 is formed on the strip-like stacked structure 120. In the embodiment, the method of manufacturing the strip-shaped stacked structure 120 and the strip of stretchable material 130 includes, for example, the following steps.

As shown in FIG. 2, a plurality of conductive layers 121a and a plurality of insulating layers 123a are formed on the substrate 110, and the conductive layer 121a and the insulating layer 123a are alternately arranged. In the embodiment, as shown in FIG. 2, the bottom oxide material layer 140a may be selectively formed on the substrate 110 before the conductive layer 121a and the insulating layer 123a are formed; and after the conductive layer 121a and the insulating layer 123a are formed, A cap oxide material layer 150a is selectively formed over the conductive layer 121a and the insulating layer 123a.

Next, as shown in Fig. 3, a stretchable material layer 130a is formed over the conductive layer 121a and the insulating layer 123a. In the present embodiment, the stretchable material layer 130a is, for example, a tantalum nitride layer. In an embodiment, the layer of extensible material 130a can be any layer of dielectric material having tensile stress, such as a layer of tantalum carbide. In some embodiments, the layer of extensible material 130a is formed, for example, by low temperature chemical vapor deposition or physical vapor deposition. In one embodiment, when the stretchable material layer 130a is formed by physical vapor deposition, the tensile stress of the stretchable material layer 130a can be adjusted by adjusting the parameters in the deposition process, for example, the ratio of the gas source. In the embodiment, the thickness of the stretchable material layer 130a is, for example, 100 to 1000 angstroms.

Next, as shown in FIG. 4, the patterned photoresist PR1 is formed on the conductive layer 121a and the insulating layer 123a, and the patterned photoresist PR1 has a predetermined pattern of the conductive strip 121 and the insulating strip 123. That is, the patterned photoresist PR1 has a predetermined pattern of the strip-like stacked structure 120.

Next, as shown in FIG. 5, the stretchable material layer 130a is patterned to form a strip of extensible material 130, and the patterned conductive layer 121a and the insulating layer 123a. The conductive strip 121 and the insulating strip 123 are formed. In the embodiment, for example, according to the patterned photoresist PR1 (the predetermined pattern of the conductive strip 121 and the insulating strip 123), the conductive layer 121a and the insulating layer 123a are etched to form the conductive strip 121 and the insulating strip 123, and the extensible material layer 130a is etched. To form a strip of extensible material 130.

In one embodiment, the strip stack structure 120 and the strip of extensible material 130 are formed, for example, in the same process. In the present embodiment, as shown in FIGS. 2 to 5, the patterned stretchable material layer 130a and the patterned conductive layer 121a and the insulating layer 123a are simultaneously performed, for example.

Referring to FIG. 6, a dielectric member 160 is formed on the strip stack structure 120. In an embodiment, the dielectric component 160 can include at least a tunneling material, a capture material, and a barrier material. For example, the dielectric component 160 can have a multilayer structure, such as an ONO composite layer or an ONONO composite layer or a BE-SONOS composite layer, or an ONO structure including, for example, a stack of yttrium oxide and tantalum nitride.

Referring to FIGS. 7-8, a conductive line 170 is formed on the dielectric member 160. In the embodiment, the method of manufacturing the conductive line 170 includes, for example, the following steps.

As shown in FIG. 7, a conductive material layer 170a is formed on the dielectric member 160.

Next, as shown in FIG. 8, the conductive material layer 170a is patterned to form the conductive lines 170, and the extending direction D1 of the conductive lines 170 is perpendicular to the extending direction D2 of the strip-shaped stacked structure 120. In an embodiment, the conductive material layer 170a is etched, for example, according to the patterned photoresist PR2 to form the conductive lines 170. In this embodiment, the strip of extensible material 130 is, for example, a tantalum nitride layer. Thus, the strip of extensible material 130 can not only provide stress relaxation, but also has the effect of a hard mask layer in the etching process of the conductive material layer 170a. .

In another embodiment, an insulating layer (not shown) may be formed on the dielectric member 160, then at least one trench is formed in the insulating layer, and a conductive material is filled into the trench to form the conductive line 170. In the present embodiment, the strip of extensible material 130 is, for example, a tantalum nitride layer. In the planarization process of the insulating layer before forming the conductive line 170, the strip of extensible material 130 also has the effect of a hard mask layer. Thus far, the semiconductor structure 100 shown in FIG. 8 is formed.

In order to make the above description of the present invention more apparent, the following specific embodiments are described in detail below. The following is a series of schematic diagrams of semiconductor structures of the examples and comparative examples. However, the following examples are for illustrative purposes and are not to be construed as limiting the implementation of the disclosure.

9A and 9B are schematic views respectively showing a scanning electron micrograph of a semiconductor structure according to an embodiment of the present disclosure and a comparative example, wherein the strip-shaped stacked structure 120 in the semiconductor structure of the embodiment includes a plurality of pairs of conductive The strip 121 and the insulating strip 123 have a strip of extensible material 130; the semiconductor structure of the comparative example has only a strip-like stacked structure 120 and does not have a strip of extensible material. The conductive strip 121 in the embodiment and the comparative example is a polycrystalline silicon having a compressive stress of -200 MPa, and the insulating strip 123 is a cerium oxide having a compressive stress of -300 MPa, and the strip of the stretching material 130 in the embodiment has, for example, 1000 MPa. The tensile stress of the tantalum nitride. .

As shown in FIGS. 9A and 9B, the tensile material strip 130 of the semiconductor structure of the embodiment has a tensile stress T stretched outward in the longitudinal direction of the strip-shaped stacked structure 120, which can effectively relieve the overall stress, and thus the strip The stacked structure 120 does not bend or deform. In contrast, the semiconductor structure of the comparative example does not have a strip of extensible material, and therefore the compressive stress of the strip-shaped stacked structure 120 cannot be compensated. As shown in the area A and the cartoon figure in FIG. 9B, the strip-shaped stacked structure 120 is bent. The shape of the shape, particularly toward the width direction, even causes improper contact between the adjacent strip-like stack structures 120.

Accordingly, according to an embodiment of the present disclosure, in the semiconductor structure, the strip of stretch material is formed on the strip stack structure, so that the compressive stress of the strip stack structure can be appropriately compensated by the tensile stress of the strip of stretch material, which can be substantially Reducing the case where the strip-shaped stacked structure is bent toward the width direction, so that the strip-shaped stacked structure has a good and linear shape of the bit line (or word line), thereby improving the structural stability of the semiconductor structure, and Improve the reliability of semiconductor structures as components.

In conclusion, the present invention has been disclosed in the above preferred embodiments, and is not intended to limit the present invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

100‧‧‧Semiconductor structure

110‧‧‧Substrate

120‧‧‧ strip stack structure

120a‧‧‧Surface

120t, 130t‧‧‧ thickness

121‧‧‧ Conductive strip

123‧‧‧Insulation strip

130‧‧‧Extension strips

140‧‧‧ bottom oxide layer

150‧‧‧ cover oxide layer

160‧‧‧Dielectric components

170‧‧‧Flexible wire

D1, D2‧‧‧ direction

Claims (8)

A semiconductor structure comprising: a substrate; a strip-like stacked structure vertically formed on the substrate, the strip-shaped stacked structure having compressive stress, the strip-shaped stacked structure comprising: a plurality of conductive strips; and a plurality of insulating layers Strips, the conductive strips are interlaced with the insulating strips; and a tensile material strip formed on the strip stack structure, the strip of tensile material having tensile stress And wherein the length of the strip of stretch material is substantially the same as the length of the strip stack. The semiconductor structure of claim 1, wherein the strip-shaped stacked structure has an aspect ratio of about 5 to 200. The semiconductor structure of claim 1, wherein the two sides of the strip of stretch material are substantially aligned with the sides of the strip stack. The semiconductor structure of claim 1, further comprising: a dielectric element formed on the strip-shaped stacked structure; and a conductive line formed on the dielectric element, the extending direction of the conductive line A direction perpendicular to the extending direction of the strip-shaped stacked structure; wherein the strip of stretchable material comprises a tantalum nitride layer or a tantalum carbide layer, and a ratio of a thickness of the strip of the stretchable material to a thickness of the strip-shaped stacked structure is about 1:5~1:100, the strip of the stretchable material has a thickness of 100~1000 angstroms (Å), and the conductive strips comprise polycrystalline germanium, and the insulating strips comprise yttrium oxide. A method for fabricating a semiconductor structure, comprising: providing a substrate; vertically forming a strip-shaped stacked structure on the substrate, the strip-shaped stacked structure having compressive stress, the strip-shaped stacked structure comprising: a plurality of conductive strips; and a plurality of insulating strips The conductive strips are staggered with the insulating strips; and a strip of stretchable material is formed on the strip-shaped stacked structure, the strip of stretchable material has tensile stress, wherein the strip-shaped stacked structure and the strip of stretchable material It is formed in the same process. The manufacturing method of the semiconductor structure of claim 5, wherein the forming the conductive strips and forming the insulating strips comprises: forming a plurality of conductive layers and a plurality of insulating layers, the conductive layers and the conductive layers The insulating layers are staggered; and the conductive layers and the insulating layers are patterned to form the conductive strips and the insulating strips. The method of fabricating a semiconductor structure according to claim 6, wherein the step of forming the strip of extensible material comprises: forming a layer of a stretchable material over the conductive layer and the insulating layers; The layer of extensible material is patterned to form the strip of extensible material according to the conductive strips and a predetermined pattern of one of the insulating strips. The manufacturing method of the semiconductor structure of claim 7, further comprising: forming a dielectric element on the strip-shaped stacked structure; and forming a conductive line on the dielectric element, the extending direction of the conductive line And extending perpendicular to the extending direction of the strip-shaped stacked structure; wherein the strip of stretchable material is formed by physical vapor deposition, and the ratio of the thickness of the strip of the stretchable material to the thickness of the strip-shaped stacked structure is about 1: 5~1:100, the thickness of the stretch strip is 100~1000 angstroms (Å), patterning the stretchable material layer and patterning the conductive layers and the insulating layers simultaneously.