TWI813392B - Semiconductor device and method of manufacturing the same - Google Patents

Abstract

A semiconductor device includes an insulating base layer, a semiconductor layer, an insulating layer, an isolation trench and a gettering site. The semiconductor layer and the insulating layer are disposed on the insulating base layer in sequence, and the isolation trench is disposed in the semiconductor layer and passes through the insulating layer. The isolation trench includes a first cross-section, a second cross-section and a third cross-section from top to bottom. The first cross-section is higher than the bottom surface of the insulating layer, and the second cross-section and the third cross-section are lower than the bottom surface of the insulating layer. The gettering site is disposed in the semiconductor layer and in contact with the isolation trench, and the vertex of the gettering site is lower than the second cross-section.

Description

Semiconductor device and manufacturing method thereof

This case relates to a semiconductor device, in particular to a semiconductor device with a suction site and a manufacturing method thereof.

Semiconductor devices in integrated circuits, such as transistors, are usually manufactured on a semiconductor substrate, and the manufacturing process of the semiconductor device usually includes multiple semiconductor processes such as doping, thin film deposition, and epitaxial growth. The semiconductor substrate will inevitably include impurity atoms, and during the above-mentioned semiconductor manufacturing process, impurity atoms may be further produced in the semiconductor substrate. Such impurity atoms are conductive copper, iron, gold, etc. atom. When impurity atoms exist in the semiconductor substrate, it not only increases the leakage current of the semiconductor device, such as junction leakage current, but also reduces the breakdown voltage of the semiconductor device, thus degrading the electrical performance of the semiconductor device.

In order to eliminate impurity atoms in the semiconductor substrate, a gettering site is generally provided in the semiconductor substrate to capture the impurity atoms in the semiconductor substrate. However, the gettering portion is generally fabricated in a bulk semiconductor rather than in a semiconductor-on-insulator (SOI) substrate. Therefore, for a semiconductor device fabricated on a semiconductor-clad insulating layer substrate, it is still necessary to further improve the gettering portion of the semiconductor device and its fabrication method.

In view of this, it is necessary to provide an improved semiconductor device to overcome the shortcomings of the conventional semiconductor device.

A semiconductor device includes an insulating base layer, a semiconductor layer, an insulating layer, an isolation trench and a suction site. The semiconductor layer is disposed on the insulating base layer, and the insulating layer is disposed on the semiconductor layer. The isolation trench is disposed in the semiconductor layer and penetrates the insulating layer. The isolation trench includes a first cross section, a second cross section and a third cross section from top to bottom. The first cross section is higher than the bottom surface of the insulating layer, and the second cross section and the third cross section are lower than the bottom surface of the insulating layer. The gettering sites are disposed in the semiconductor layer and respectively contact the isolation trenches. The apex of the getter sites is lower than the second cross section.

A method for manufacturing a semiconductor device includes the following steps. A substrate is provided, on which an insulating base layer and a semiconductor layer are sequentially arranged. An insulating layer is formed on the semiconductor layer, wherein the insulating layer includes a bottom surface. Forming an isolation trench in the semiconductor layer and the insulating layer to expose the insulating base layer. The steps of forming the isolation trench include: etching the insulating layer to form an upper through hole in the insulating layer; and after etching the insulating layer, etching the semiconductor layer to A lower through hole is formed in the semiconductor layer, the lower part of the lower through hole includes a tapered portion, and during the process of etching the semiconductor layer, an etching inhibition layer is formed simultaneously, and the etching inhibition layer covers the inner side wall of the upper through hole. After the isolation trench is formed, the insulating layer is used as an ion implantation mask to form a suction site, where the suction site contacts the isolation trench, and the apex of the suction site is lower than the bottom surface of the insulation layer. Form insulating material in the isolation trench.

According to embodiments of the present disclosure, since the apex of the gettering site is lower than the bottom surface of the insulating layer, the gettering site can be further away from the upper part of the semiconductor layer, thereby preventing the lattice defects in the gettering site from negatively affecting the electric field distribution in the upper part of the semiconductor layer. , or to prevent the impurity atoms in the gettering part from being attracted by the electric field and diffusing outward to the upper part of the semiconductor layer, thereby improving the electrical performance of the semiconductor device.

In addition, since each isolation trench includes a first section, a second section, and a third section from top to bottom, section, when the width of the first section and the third section is smaller than the width of the second section, in the process of forming the suction part, it can be more conducive to allow the suction part to be formed only at the lower periphery of the isolation trench without being Formed on the upper perimeter of the isolation trench.

1: Chip structure

20: Semiconductor component area

22:Quarantine Zone

30: Semiconductor component area

40: Semiconductor component area

100:Semiconductor device

101: Base

103:Insulating base layer

105: Semiconductor layer

105c: vertex

107:Oxide cushion

109:Nitride pad

111:Cushion

113:Sag area

117:Insulation layer

117c: Bottom corner

119: Bottom surface

121:Etching mask

123:Open your mouth

125:Upper ditch

127: Upper through hole

131:Transient ditch

132:Inside wall

133:Expansion Department

134:Inside wall

135:Lower ditch

136:Inside wall

137:Tapering part

141: Etch inhibition layer

143:Inside wall

147:Lower through hole

151:Isolation ditch

153: Suction site

155: vertex

161:Insulating materials

163:Filling material

171:Well area

173: Source doped region

175:Heavily doped region

181: Drift area

183: Drain doped region

185:Insulation structure

191: Gate structure

193:Dielectric layer

195:Field board

197:Etch mask

200:Deep Trench Isolation Structure

400: Section

402: Section

404: Section

406: Section

408: Section

410: Section

412: Section

A:wafer area

B: Cutting area

P1: first section

P2: Second section

P3: The third section

Wp1:width

Wp2:Width

Wp3:Width

Wt1:width

In order to make the following easier to understand, the drawings and their detailed text descriptions may be referred to simultaneously when reading this disclosure. Through the specific embodiments in this article and with reference to the corresponding drawings, the specific embodiments of the present disclosure are explained in detail, and the working principles of the specific embodiments of the present disclosure are explained. In addition, features in the drawings may not be drawn to actual scale for the sake of clarity, and therefore the dimensions of some features in some drawings may be intentionally exaggerated or reduced.

Figure 1 is a schematic top view of a chip structure according to an embodiment of the present disclosure.

Figure 2 is a schematic cross-sectional view along the tangent line A-A' of Figure 1 according to an embodiment of the present disclosure.

FIG. 3 is an enlarged schematic diagram of a partial area of the semiconductor device in FIG. 1 .

4 to 10 are schematic cross-sectional views of different process stages of manufacturing a semiconductor device according to an embodiment of the present disclosure.

The present disclosure provides several different embodiments that can be used to implement different features of the disclosure. To simplify explanation, examples of specific components and arrangements are also described in this disclosure. These examples are provided for illustrative purposes only and are not intended to be limiting in any way. For example, the following description of "the first feature is formed on or above the second feature" may mean "the first feature is in direct contact with the second feature" or "the first feature is in direct contact with the second feature". "There are other features between the features", so that the first feature and the second feature are not in direct contact. Additionally, various embodiments in the present disclosure may use repeated references Symbols and/or textual annotations. These repeated reference symbols and notations are used to make the description more concise and clear, but are not used to indicate the correlation between different embodiments and/or configurations.

In addition, for the space-related descriptive words mentioned in this disclosure, such as: "under", "low", "lower", "above", "above", "upper", "top" ", "bottom" and similar words are used to describe the relative relationship between one element or feature and another (or multiple) elements or features in the drawings for the convenience of description. In addition to the orientations shown in the drawings, these spatially related terms are also used to describe possible orientations of the semiconductor device during use and operation. As the semiconductor device is oriented differently (rotated 90 degrees or other orientations), the spatially related description used to describe its orientation should be interpreted in a similar manner.

Although this disclosure uses terms such as first, second, third, etc. to describe various elements, components, regions, layers, and/or sections, it should be understood that these elements, components, regions, layers, and/or blocks should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, and/or block from another element, component, region, layer, and/or block, and do not themselves imply or represent the element. There is no previous serial number, nor does it represent the order of arrangement of one component with another component, or the order of the manufacturing method. Therefore, a first element, component, region, layer, or block discussed below may also be termed a second element, component, region, layer, or block without departing from the scope of the specific embodiments of the disclosure. Of.

The terms "about" or "substantially" used in this disclosure generally mean within 20%, preferably within 10%, and more preferably within 5% of a given value or range, or Within 3%, or within 2%, or within 1%, or within 0.5%. It should be noted that the quantities provided in the specification are approximate quantities, that is, even without specifically stating "approximately" or "substantially", the meaning of "approximately" or "substantially" may still be implied.

Although the invention of the present disclosure is described below through specific embodiments, the inventive principles of the present disclosure can also be applied to other embodiments. In addition, in order not to obscure the spirit of the present invention, Certain details have been omitted which are within the scope of the knowledge of a person of ordinary skill in the art.

Figure 1 is a schematic top view of a chip structure according to an embodiment of the present disclosure. As shown in FIG. 1 , the wafer structure 1 can be disposed in the wafer area A of the wafer, and the wafer area A can be surrounded by the dicing lane area B. In subsequent processes, cutting can be performed along the scribe lane area B to separate adjacent wafer areas A from each other. Wafer area A may include an integrated circuit, and the integrated circuit includes a plurality of semiconductor element areas, such as semiconductor element areas 20, 30, and 40 respectively used to accommodate power transistors, logic operation elements, or memory elements, but not Limited to this. For the semiconductor device 100 in the wafer area A, it includes a semiconductor element area 20 and an isolation area 22 . The isolation region 22 includes, for example, a deep trench isolation structure, which can surround the semiconductor device region 20 to electrically insulate the semiconductor device region 20 from other semiconductor device regions 30 and 40 or from the semiconductor device region A in the chip region A. other areas.

Figure 2 is a schematic cross-sectional view along the tangent line A-A' of Figure 1 according to an embodiment of the present disclosure. As shown in FIG. 2 , the semiconductor device 100 at least includes a substrate 101 , an insulating base layer 103 , a semiconductor layer 105 , at least two insulating layers 117 , at least two isolation trenches 151 , and at least two gettering sites 153 . The substrate 101 may be a semiconductor substrate, an insulating substrate, or other suitable handle substrate. According to an embodiment of the present disclosure, the substrate 101 can be removed, so that the bottom surface of the insulating base layer 103 is exposed. The insulating base layer 103, such as a buried insulating layer, is disposed on the substrate 101, and its composition includes, for example, silicon oxide or other silicon-containing oxides, or other suitable insulating materials. By providing the insulating base layer 103 , leakage current can be prevented from flowing from the substrate 101 to the layer disposed above the insulating base layer 103 . The semiconductor layer 105 is disposed on the insulating base layer 103, and its composition includes, for example, a silicon semiconductor, such as single crystal silicon, or a compound semiconductor, such as gallium nitride or silicon carbide. An insulating layer 117 , such as a shallow trench isolation structure, is disposed on the semiconductor layer 105 , and the insulating layer 117 includes a bottom surface buried in the semiconductor layer 105 . The isolation trench 151 is disposed in the semiconductor layer 105 and penetrates some of the insulating layers 117 . The isolation trench 151 can be filled with insulating material, so that the isolation trench 151 and the penetrating insulating layer 117 can be used as part of the deep trench isolation structure 200 composition. By providing the insulating base layer 103 and the deep trench isolation structure 200, the semiconductor device region 20 can be electrically insulated from external regions.

The gettering site 153 is disposed in the semiconductor layer 105 and contacts the isolation trench 151 . The suction sites 153 will be located between the isolation trenches 151 and separated from each other laterally (for example, in the X direction). The gettering site 153 is, for example, a doping region, such as an arsenic doping region or other suitable doping region, which can be used to capture impurity atoms in the semiconductor layer 105, such as conductive atoms such as copper, iron, and gold, to avoid Impurity atoms negatively affect the electrical performance of the semiconductor device 100 . According to an embodiment of the present disclosure, the gettering portion 153 itself is conductive, and the gettering portion 153 is formed through ion implantation, so it has more lattice defects than the adjacent semiconductor layer 105 . In addition, since the gettering site 153 is used to capture impurity atoms in the semiconductor layer 105, when the impurity atoms are trapped in the gettering site 153, the gettering site 153 will have a high concentration of impurity atoms. According to an embodiment of the present disclosure, by arranging the suction part 153 only at the lower periphery of the isolation trench 151 but not at the upper periphery of the isolation trench 151 , the suction part 153 can be positioned in the vertical direction (for example, the Z direction). ) are separated from each doped region located on the upper part of the semiconductor layer 105, such as source doped region, drain doped region, well region, base region, drift region and other doped regions. In this way, current can be prevented from flowing through the gettering site 153 , or lattice defects in the gettering site 153 can be prevented from negatively affecting the electric field distribution in each doped region, or impurity atoms can be prevented from being trapped in the gettering site 153 The doped regions are attracted by the electric field and diffuse outward, thereby improving the electrical performance of the semiconductor device.

According to an embodiment of the present disclosure, in addition to the above-mentioned components, the semiconductor device 100 may also include other components, such as doping regions, insulation structures, and electrode structures. As still shown in FIG. 2 , the semiconductor device 100 includes a well region 171 having a first conductivity type (for example, p-type), which is disposed on the upper part of the semiconductor layer 105 and located on one side of the semiconductor element region 20 . The source doped region 173 and the heavily doped region 175 have the second conductivity type (eg n-type) and the first conductivity type respectively, and are disposed in the well region 171 . The base doped region 177 has the first conductivity type and is disposed in the well region 171 and is disposed close to the source doped region 173 and the heavily doped region 175 . The drift region 181 has the second conductivity type and is disposed on the upper part of the semiconductor layer 105 and on the other side of the semiconductor element region 20 one side. The drain doped region 183 has the second conductivity type and is disposed in the drift region 181 . The insulation structure 185 is disposed in the drift region 181 to increase the current transfer path in the drift region 181 . The gate structure 191 is disposed on the semiconductor layer 105 and spans the junction between the well region 171 and the drift region 181 . The upper part of the partial well region 171 is immediately adjacent to and overlaps the bottom surface of the gate structure 191 and serves as a channel region of the semiconductor device 100 . The dielectric layer 193 and the field plate 195 are sequentially disposed on the drift region 181 and partially overlap the gate structure 191 . When operating the semiconductor device 100, the electric field distribution in the drift region 181 can be controlled by applying a bias voltage to the field plate 195.

FIG. 3 is an enlarged schematic diagram of a partial area of the semiconductor device in FIG. 1 . As shown in FIG. 3 , the deep trench isolation structure 200 is disposed on the insulating base layer 103 and includes an isolation trench 151 . The isolation trench 151 includes an upper trench 125 and a lower trench 135 . The upper trench 125 will be disposed in the upper through hole 127 , where the upper through hole 127 is a hole penetrating the insulating layer 117 . The lower trench 135 will overlap the lower through hole 147 , where the lower through hole 147 is a hole that penetrates the semiconductor layer 105 , and the lower through hole 147 will expose the top surface of the insulating base layer 103 .

The etching inhibitor layer (inhibitor) 141 will cover the inner side wall of the upper through hole 127, so that the inner side wall 143 of the etching inhibitor layer 141 overlaps the inner side wall 132 of the upper trench 125. The etch inhibition layer 141 is composed of, for example, a polymer (eg, fluorine-containing polymer) or an oxide (eg, silicon-containing oxide), which may be a solid product formed during the plasma etching process performed to form the isolation trench 151 . According to an embodiment of the present disclosure, the etching inhibition layer 141 is not limited to covering only the inner side wall of the upper through hole 127 , but may further cover part of the inner side wall of the lower through hole 147 , so that part of the inner side wall of the etching inhibition layer 141 can further overlap. On part of the inner wall of the lower trench 135. According to an embodiment of the present disclosure, the etching inhibition layer 141 has an inclined surface, and the width of the opening defined by it gradually increases from top to bottom. However, according to other embodiments, the cross-sectional profile of the etching inhibition layer 141 in the vertical direction (such as the Z direction) may also include vertical surfaces or curved surfaces, and the narrowest point of its opening width is not limited to its top, but may be at Its middle or bottom end.

Regarding the isolation trench 151, the isolation trench 151 may include multiple trench sections, such as from top to The lower part includes a first section P1, a second section P2, and a third section P3. The first cross section P1 is higher than the bottom surface 119 of the insulating layer 117 and is defined between two opposite etching inhibition layers 141 and has a width Wp1. The second cross section P2 is lower than the bottom surface 119 of the insulating layer 117 and is located in the lower trench 135 of the isolation trench 151 , for example, in the outer expansion portion 133 of the lower trench 135 , and has a width Wp2. The third cross section P3 is lower than the bottom surface 119 of the insulating layer 117 and is located in the lower trench 135 of the isolation trench 151 , for example, in the tapered portion 137 of the lower trench 135 , and has a width Wp3. The relationship between widths Wp1, Wp2, and Wp3 satisfies the following equations (1) and (2): Wp1<Wp2 (1)

Wp3<Wp2 (2)

In addition, the upper through hole 127 in the insulating layer 117 may have a width Wt1, and the width relationship between the upper through hole 127 and the third section P3 of the isolation trench 151 satisfies the following formula (3): Wt1>Wp3 (3)

For the expanded portion 133 of the lower trench 135, its local inner wall 134 will expand outward, so that its local width will be wider than the width Wt1 of the upper through hole 127, and the expanded portion 133 will be in the vertical direction (for example, The cross-sectional profile in the Z direction may include inclined or curved surfaces. In addition, as for the top end of the expanded portion 133, the top end will be adjacent to the bottom corner 117c of the insulating layer 117 and the top corner 105c of the semiconductor layer 105, and since the inner side wall 134 of the expanded portion 133 will expand outward, so that The bottom corner 117c of the insulating layer 117 and the top corner 105c of the semiconductor layer 105 are laterally (eg, X-direction) separated from each other.

Regarding the tapered portion 137 of the lower trench 135, the tapered portion 137 will be located below the expanded portion 133, but is not limited to being immediately adjacent to the expanded portion 133, and the inner wall 136 of the tapered portion 137 will taper from top to bottom, and Has an inclined or curved surface.

According to an embodiment of the present disclosure, the width of any cross-section in the expanded portion 133 is greater than the width Wt1 of the upper through-hole 127 , and the width of some cross-sections in the tapered portion 137 is smaller than the width Wt1 of the upper through-hole 127 . In addition, in addition to the outer expansion part 133 and the tapered part 137, the lower trench 135 may also include other Sections, such as vertical sections or curved sections.

The suction site 153 will contact a partial area of the isolation trench, be disposed along the inner side wall 136 of the tapered portion 137 of the lower trench 135 , and directly contact the insulating base layer 103 . The apex 155 of the suction part 153 will be lower than the second cross-section P2, so the suction part 153 will be vertically (eg, Z-direction) separated from the outer expansion part 133 of the lower trench 135.

Insulating materials can be disposed in the isolation trenches 151 of the deep trench isolation structure 200 to increase the electrical isolation capability of the deep trench isolation structure 200 . According to an embodiment of the disclosure, the isolation trench 151 may include an insulating material 161 and a filling material 163. The insulating material 161 may cover the inner side walls 132, 134, and 136 of the isolation trench 151, and the filling material 163 may fill the isolation trench. 151 in. The composition of the filling material 163 may be an insulating material or a conductive material, depending on actual requirements. According to an embodiment of the present disclosure, there may be no compliant insulating material 161 in the isolation trench 151, so that the filling material 163 will directly contact the inner side walls 132, 134, 136 of the isolation trench 151. In this case, the composition of the filling material 163 may be insulating. Material.

According to an embodiment of the present disclosure, in order to protect the surface of the semiconductor layer 105, an additional pad layer 111 may be provided between the semiconductor layer 105 and the insulating layer 117, such as an oxide pad layer 107 and a nitride pad layer 109, but is not limited thereto. .

In order to enable those with ordinary knowledge in the art to implement the semiconductor device of the present disclosure, the manufacturing method of the semiconductor device of the present disclosure is further described below.

FIG. 4 is a schematic cross-sectional view of a process stage of manufacturing a semiconductor device according to an embodiment of the present disclosure. As shown in cross-section 400 in FIG. 4 , a substrate 101 is provided, on which an insulating base layer 103 and a semiconductor layer 105 are sequentially disposed. The insulating base layer 103 may be a bonding layer, so the semiconductor layer 105 may be bonded to the substrate 101 by bonding. A pad layer 111 is provided on the surface of the semiconductor layer 105, including, for example, an oxide pad layer 107 and a nitride pad layer 109. When the composition of the semiconductor layer 105 is single crystal silicon, the composition of the oxide pad layer 107 may include silicon oxide, and the composition of the nitride pad layer 109 may include silicon nitride. An opening can be formed in the pad layer 111, and the pad layer 111 is used as an etching mask to form at least two recessed areas on the surface of the semiconductor layer 105. 113, and the bottom surface of the recessed area 113 will be vertically separated from the insulating base layer 103. After that, the insulating layer 117 is deposited so that the insulating layer 117 covers the pad layer 111 and fills the recessed area 113 . In order to allow the recessed area 113 to be filled with the insulating layer 117, a high density plasma chemical vapor deposition (HDPCVD) or other suitable plasma enhanced chemical vapor deposition (plasma) process may be performed. enhanced chemical vapor deposition (PECVD) to form the insulating layer 117. At this process stage, the insulating layer 117 filled in the recessed area 113 will have a bottom surface 119 that is separated from the insulating base layer 103 in a vertical direction (eg, Z direction).

In subsequent processes, at least one isolation trench may be further formed in the insulating layer 117 and the semiconductor layer 105 to expose the insulating base layer 103 . The process of forming the isolation trench is shown in Figures 5 to 7.

FIG. 5 is a schematic cross-sectional view of a process stage of manufacturing a semiconductor device according to an embodiment of the present disclosure. As shown in cross-section 402 in FIG. 5 , an etching mask 121 , such as a photoresist, is formed, and the etching mask 121 has an opening 123 therein. Next, the insulating layer 117 exposing the opening 123 is etched to form an upper through hole 127 in the insulating layer 117 . The bottom surface of the upper through hole 127 includes a width Wt1, and the width Wt1 is smaller than the width of the bottom surface of the recessed area 113. At this process stage, the upper through hole 127 will overlap the upper trench 125, and in subsequent processes, the upper trench 125 will form the upper part of the isolation trench.

FIG. 6 is a schematic cross-sectional view of a process stage of manufacturing a semiconductor device according to an embodiment of the present disclosure. After the insulating layer 117 is etched to form the upper through hole 127 , as shown in cross-section 404 in FIG. 6 , the semiconductor layer 105 is etched using the insulating layer 117 as an etching mask, such as by performing a plasma etching process or other suitable etching. process to form the transient trench 131 in the semiconductor layer 105 . During the process of etching the conductor layer 105, the etching inhibition layer 141 will be formed at the same time, and the etching inhibition layer 141 will cover the inner side wall of the upper through hole 127. In addition, the thickness of the etching inhibition layer 141 is not fixed, but will continue to change, for example, gradually become thicker as the etching of the semiconductor layer 105 proceeds. According to an embodiment of the present disclosure, a deep reactive ion etching (DRIE) process is used to form the transient trench 131 by etching. due to deep reaction Solid products produced by the ion etching process, such as fluorine-containing polymers or other polymers, or silicon-containing oxides or other oxides, will be deposited on the inner sidewalls of the upper through holes 127, causing the two opposite etching inhibition layers 141 to The first cross section P1 of the upper trench 125 defines a width Wp1, and the width Wp1 is smaller than the width Wt1 of the upper through hole 127. According to the embodiment of the present disclosure, at this process stage, the etching inhibition layer 141 has an inclined surface, and the width of the opening defined by it gradually increases from top to bottom. However, according to other embodiments, the cross-sectional profile of the etching inhibition layer 141 in the vertical direction (such as the Z direction) may also include vertical surfaces or curved surfaces, and the narrowest point of its opening width is not limited to its top, but may be in the middle end or bottom.

For the transient trench 131, it includes an expanded portion 133. The width Wp2 of the expanded portion 133 at the second cross-section P2 is wider than the width Wt1 of the upper through hole 127, and is also wider than the width Wp1 of the first cross-section P1 of the upper trench 125. Still wide.

FIG. 7 is a schematic cross-sectional view of a process stage of manufacturing a semiconductor device according to an embodiment of the present disclosure. As shown in cross-section 406 of FIG. 7 , the semiconductor layer 105 is continued to be etched, for example, deep reactive ion etching (DRIE) or other suitable etching processes are continued to form a lower through hole 147 in the semiconductor layer 105 ( or called lower trench 135), and exposes the insulating base layer 103. The lower through hole 147 includes an expanded portion 133 and a tapered portion 137 , and the tapered portion 137 is located below the expanded portion 133 . The inner wall 136 of the tapered portion 137 tapers from top to bottom and has an inclined surface or a curved surface. The bottom surface of the tapered portion 137 includes a width Wp3, and the width Wp3 is smaller than the width Wp2 of the outer expansion portion 133. The upper trench 125 and the lower trench 135 may form part of the isolation trench 151, and the isolation trench 151 includes the inner sidewall 132, the inner sidewall 134, and the inner sidewall 136 from top to bottom, and the inner sidewall 143 of the etching inhibition layer 141 overlaps The inner side wall 132 of the upper trench 125 .

FIG. 8 is a schematic cross-sectional view of a process stage of manufacturing a semiconductor device according to an embodiment of the present disclosure. After the isolation trench 151 is formed, an ion implantation process is performed using the insulating layer 117 as an ion implantation mask, or using the etching inhibition layer 141 as an ion implantation mask at the same time, as shown in section 408 in FIG. 8 . A suction site 153 is formed that contacts the isolation trench 151 . Since the first section P1 and the second section of the isolation trench 151 The relationship between the widths Wp1, Wp2, and Wp3 between the cross-section P2 and the third cross-section P3 satisfies the above equations (1) and (2). Therefore, when the ion implantation process is performed, the suction part 153 will only be formed in the tapered The apex 155 of the suction portion 153 is lower than the bottom surface 119 of the insulating layer 117 .

FIG. 9 is a schematic cross-sectional view of a process stage of manufacturing a semiconductor device according to an embodiment of the present disclosure. After the suction part 153 is formed, as shown in the cross-section 410 in FIG. 9 , the insulating material 161 and the filling material 163 are sequentially formed in the isolation trench 151 , wherein the insulating material 161 can cover the inner side wall 132 of the isolation trench 151 . , 134, 136, and the filling material 163 can be filled into the isolation trench 151. The composition of the filling material 163 may be an insulating material or a conductive material, depending on actual requirements.

FIG. 10 is a schematic cross-sectional view of a process stage of manufacturing a semiconductor device according to an embodiment of the present disclosure. As shown in cross-section 412 in FIG. 10 , an etching process is performed to remove the filling material 163 , the insulating material 161 and the insulating layer 117 that are not covered by the etching mask 197 until the pad layer 111 is exposed and is formed in the isolation area 22 Deep Trench Isolation Structure 200. In subsequent processes, a suitable semiconductor process may be performed, for example, a doped region, an insulating structure, an electrode structure or a field plate may be further formed in the semiconductor element region 20 to form a semiconductor device similar to that shown in FIG. 2 according to the present disclosure. In one embodiment, the base 101 may be further removed to expose the bottom surface of the insulating base layer 103, but is not limited thereto.

According to the above embodiment, since the suction site 153 in the semiconductor device 100 is only disposed at the lower periphery of the isolation trench 151 but not at the upper periphery of the isolation trench 151 , the suction site 153 can be positioned in the vertical direction (eg, Z direction) separated from each doped region or each component located on the upper part of the semiconductor layer 105. In this way, current can be prevented from flowing through the gettering site 153 , or lattice defects in the gettering site 153 can be prevented from negatively affecting the electric field distribution in each doped region, or impurity atoms can be prevented from being trapped in the gettering site 153 The electric field attracts and diffuses outward into each doped region, thereby improving the electrical performance of the semiconductor device 100 . In addition, since each isolation trench 151 includes a first cross-section P1, a second cross-section P2, and a third cross-section P3 from top to bottom, when the widths Wp1 and Wp3 of the first cross-section P1 and the third cross-section P3 are smaller than the width of the second cross-section P2 At Wp2, during the process of performing the ion implantation process to form the gettering part 153, it is more conducive to form the gettering part 153 only at the lower periphery of the isolation trench 151, and not at the upper periphery of the isolation trench 151. .

The above are only preferred embodiments of the present invention, and all equivalent changes and modifications made in accordance with the patentable scope of the present invention shall fall within the scope of the present invention.

101: Base

103:Insulating base layer

105: Semiconductor layer

105c: vertex

107:Oxide cushion

109:Nitride pad

111:Cushion

117:Insulation layer

117c: Bottom corner

119: Bottom surface

125:Upper ditch

127: Upper through hole

132:Inside wall

133:Expansion Department

134:Inside wall

135:Lower ditch

136:Inside wall

137:Tapering part

141: Etch inhibition layer

143:Inside wall

147:Lower through hole

151:Isolation trench

153: Suction site

155: vertex

161:Insulating materials

163:Filling material

200:Deep Trench Isolation Structure

P1: first section

P2: Second section

P3: The third section

Wp1:Width

Wp2:Width

Wp3:Width

Wt1:width

Claims (20)

A semiconductor device includes: an insulating base layer; a semiconductor layer disposed on the insulating base layer; at least two insulating layers disposed on the semiconductor layer, and each insulating layer includes a bottom surface; at least two isolation trenches, each The isolation trench is disposed in the semiconductor layer and penetrates each of the insulating layers, wherein each isolation trench includes a first cross-section, a second cross-section, and a third cross-section from top to bottom, and the first cross-section is higher than each The bottom surface, the second cross-section and the third cross-section of the insulating layer are lower than the bottom surface of each of the insulating layers; and at least two gettering sites are provided in the semiconductor layer and respectively contact the isolation trenches, wherein each A vertex of the suction part is lower than the second cross section. The semiconductor device of claim 1, wherein each of the insulating layers includes a bottom corner laterally separated from a top corner of the semiconductor layer. The semiconductor device of claim 1, wherein each isolation trench penetrates the semiconductor layer to expose the insulating base layer. The semiconductor device as claimed in claim 1, wherein each of the gettering sites is provided along an inner side wall of a lower portion of each of the isolation trenches. The semiconductor device of claim 1, wherein the gettering sites between the isolation trenches are laterally separated from each other. The semiconductor device according to claim 1, wherein the width relationship between the first cross-section, the second cross-section and the third cross-section satisfies the following equations (1) and (2): Wp1<Wp2 (1) Wp3<Wp2 (2) Wherein, Wp1 is the width of the first cross section, Wp2 is the width of the second cross section, and Wp3 is the width of the third cross section. The semiconductor device according to claim 1, further comprising: at least two upper through holes, respectively disposed in the insulating layers; and an etching inhibition layer covering the inner sidewalls of each of the upper through holes. The semiconductor device according to claim 7, wherein the width relationship between each upper through hole and the third section of each isolation trench satisfies the following formula (3): Wt1>Wp3 (3) where Wt1 is each The width of the upper through hole. The semiconductor device of claim 7, wherein the etching inhibition layer is composed of a polymer or a silicon-containing oxide. The semiconductor device of claim 7, wherein the inner sidewall of the etching inhibition layer overlaps the inner sidewall of the upper portion of each isolation trench. The semiconductor device of claim 7, wherein the etching inhibition layer includes an inclined surface. The semiconductor device according to claim 7, further comprising at least two lower through holes disposed in the semiconductor layer, wherein the etching inhibition layer further covers the inner sidewalls of each of the lower through holes. The semiconductor device of claim 1, wherein the surface of the semiconductor layer includes at least two recessed areas, and the insulating layers are respectively filled in the recessed areas. The semiconductor device of claim 1 further includes an active device region disposed between the isolation trenches, and the active device region includes a doping region vertically separated from the gettering sites. A method of manufacturing a semiconductor device, including: providing a substrate on which an insulating base layer and a semiconductor layer are sequentially provided; forming an insulating layer on the semiconductor layer, wherein the insulating layer includes a bottom surface; forming at least one isolation trench Forming the at least one isolation trench in the semiconductor layer and the insulating layer to expose the insulating base layer includes: etching the insulating layer to form an upper through hole in the insulating layer; and after etching the insulating layer, The semiconductor layer is etched to form a lower through hole in the semiconductor layer. The lower part of the lower through hole includes a tapered portion, and during the process of etching the semiconductor layer, an etching inhibition layer is formed simultaneously. The etching inhibition layer Cover the inner wall of the upper through hole; after forming the at least one isolation trench, use the insulating layer as an ion implantation mask to form a suction site, wherein the suction site contacts the at least one isolation trench, and the suction site A vertex of the removal part is lower than the bottom surface of the insulating layer; and an insulating material is formed in the at least one isolation trench. The method of manufacturing a semiconductor device according to claim 15, wherein the at least one isolation trench includes a first cross-section, a second cross-section, and a third cross-section from top to bottom, and the first cross-section is higher than each of the insulating layers. The bottom surface of the insulation layer, the second cross-section and the third cross-section are lower than the bottom surface of each insulation layer, and the width relationship between the first cross-section, the second cross-section and the third cross-section satisfies the following formula (1) and formula (2): Wp1<Wp2 (1) Wp3<Wp2 (2) Wherein, Wp1 is the width of the first cross section, Wp2 is the width of the second cross section, and Wp3 is the width of the third cross section. The method of manufacturing a semiconductor device according to claim 15, wherein the etching inhibition layer is composed of a polymer or a silicon-containing oxide. The method of manufacturing a semiconductor device as claimed in claim 15, wherein during etching of the semiconductor layer, the etching inhibition layer gradually becomes thicker. The method of manufacturing a semiconductor device as claimed in claim 15, wherein the process of forming the gettering region further includes using the etching inhibition layer as an ion implantation mask. The manufacturing method of a semiconductor device as claimed in claim 15, wherein the suction site is in direct contact with the insulating base layer.

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