Method of manufacturing a semiconductor device comprising a first field termination zone portion and a second field termination zone portion

Abstract

A method for manufacturing a semiconductor device including a first field termination zone portion and a second field termination zone portion is disclosed. The method includes forming a first field termination zone portion of a first conductivity type on a semiconductor substrate. Forming a drift zone of the first conductivity type on the first field termination zone portion. The average doping concentration of the drift zone is less than 80% of the average doping concentration of the first field termination zone portion. The semiconductor body is processed at a first surface. Thinning is performed by removing material of the semiconductor substrate from a second surface opposite to the first surface. The second field termination zone portion of the first conductivity type is formed by injecting protons at one or more energies into the semiconductor body through the second surface. The deepest range boundary peak of the protons is set in the first field termination zone portion at a vertical distance from the transition portion between the drift zone and the first field termination zone portion in the range from 3 μm to 60 μm. The semiconductor body is annealed by heat treatment.

Description

[0001] Background technology.

[0002] Semiconductor devices, such as insulated gate bipolar transistors (IGBTs) or diodes, are designed to meet requirements, for example, regarding the operating losses of the IGBT, short-circuit robustness, blocking voltage, oscillation behavior during turn-off, cosmic ray robustness or the back-end transistor amplification factor a. pnp There are various requirements for the stability of the device. When certain device characteristics are improved by adjusting specific layout parameters, this may lead to negative effects on other device characteristics. Therefore, semiconductor device design may require a compromise between the requirements for different device characteristics.

[0003] It would therefore be desirable to improve methods of manufacturing insulated gate bipolar transistor semiconductors including field stop zones that allow for an improved compromise between device characteristics. Summary of the invention

[0004] The present disclosure relates to a method for manufacturing a semiconductor device in a semiconductor body, including forming a first field termination zone portion of a first conductivity type on a semiconductor substrate. Forming a drift zone of the first conductivity type on the first field termination zone portion. The average doping concentration of the drift zone is set to be less than 80% of the average doping concentration of the first field termination zone portion. Processing the semiconductor body at a first surface of the semiconductor body. Thinning the semiconductor body by removing material of the semiconductor substrate from a second surface of the semiconductor body opposite to the first surface. Forming a second field termination zone portion of the first conductivity type by injecting protons at one or more energies into the semiconductor body through the second surface. The deepest range boundary peak of the protons is set in the first field termination zone portion at a vertical distance from the transition between the drift zone and the first field termination zone portion in the range from 3 μm to 60 μm. Annealing the semiconductor body by heat treatment.

[0005] The present disclosure relates to another method of manufacturing a semiconductor device in a semiconductor body, including forming a drift zone of a first conductivity type on a semiconductor substrate. The semiconductor body is processed at a first surface of the semiconductor body. The semiconductor body is thinned by removing material of the semiconductor substrate from a second surface of the semiconductor body opposite to the first surface. A first field termination zone portion of the first conductivity type is formed between the second surface and the drift zone by implanting protons into the semiconductor body through the second surface and setting a vertical distance between a range boundary peak of the protons and the second surface in a range from 5 μm to 70 μm. The average doping concentration of the first field termination zone portion is set to be greater than 120% of the average doping concentration of the drift zone. A second field termination zone portion of the first conductivity type is formed by implanting protons at one or more energies into the semiconductor body through the second surface. The deepest range boundary peak of the protons is set in the first field termination zone portion at a vertical distance from a transition between the drift zone and the first field termination zone portion in a range from 3 μm to 60 μm. The semiconductor body is annealed by a thermal treatment.

[0006] In one or more embodiments, the second field termination zone may also be formed by introducing a dopant of the first conductivity type into the semiconductor body through the second surface, wherein the dopant is a deep dopant.

[0007] Those skilled in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings are included to provide a further understanding of the present invention, and the accompanying drawings are incorporated in and constitute a part of this description. The accompanying drawings illustrate embodiments and together with the description are used to explain the principles of the present invention. As other embodiments of the present invention and the intended advantages become better understood by reference to the following detailed description, they will be easily appreciated.

[0009] Figure 1 is a flowchart illustrating an example of manufacturing a semiconductor device.

[0010] Figure 2 is a flowchart illustrating another example of manufacturing a semiconductor device.

[0011] Figure 3A is a schematic cross-sectional view of a semiconductor body for illustrating a process of manufacturing a semiconductor device by forming a first field stop zone portion on a semiconductor substrate.

[0012] Figure 3BAfter forming the drift zone on the first field end zone portion Figure 3A Schematic cross-sectional view of a semiconductor body depicted in .

[0013] Figure 3C After processing the semiconductor body at the first surface of the semiconductor body Figure 3B Schematic cross-sectional view of a semiconductor body depicted in .

[0014] Figure 3D After thinning of the semiconductor body at a second surface opposite to the first surface Figure 3C Schematic cross-sectional view of a semiconductor body depicted in .

[0015] Figure 3E After forming the second field stop zone portion by proton implantation or by doping with deep dopants and annealing Figure 3D Schematic cross-sectional view of a semiconductor body depicted in .

[0016] Figure 4A is a schematic cross-sectional view of a semiconductor body for illustrating a process of manufacturing a semiconductor device by forming a drift zone.

[0017] Figure 4B After processing the semiconductor body at the first surface of the semiconductor body Figure 4A Schematic cross-sectional view of a semiconductor body depicted in .

[0018] Figure 4C After thinning of the semiconductor body at a second surface opposite to the first surface Figure 4B Schematic cross-sectional view of a semiconductor body depicted in .

[0019] Figure 4D After forming a first field termination zone portion between the second surface and the drift zone Figure 4C Schematic cross-sectional view of a semiconductor body depicted in .

[0020] Figure 4E After forming the second field stop zone portion by proton implantation or by doping with deep dopants and annealing Figure 4D Schematic cross-sectional view of a semiconductor body depicted in .

[0021] Figure 5 is a schematic cross-sectional view of a semiconductor body for illustrating an example of a semiconductor device including a first field stop zone portion and a second field stop zone portion.

[0022] Figure 6is a schematic line diagram illustrating a doping concentration profile along a vertical direction through a first field stop zone portion and a second field stop zone portion. DETAILED DESCRIPTION

[0023] In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which specific embodiments in which the present disclosure can be practiced are shown by way of illustration. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. For example, features illustrated or described for one embodiment may be used in other embodiments or in combination with other embodiments to derive further embodiments. It is intended that the present disclosure includes such modifications and variations. Examples are described using specific language, which should not be interpreted as limiting the scope of the appended claims. The drawings are not to scale and are for illustrative purposes only. For clarity, if not otherwise stated, the same elements have been indicated by corresponding reference numerals in different drawings.

[0024] The terms "having", "comprising", "including" and "comprising" are open ended and these terms indicate the presence of stated structures, elements or features but do not exclude the presence of additional elements or features. The quantifiers "a", "an" and the pronoun "the" are intended to include the plural as well as the singular, unless the context clearly indicates otherwise.

[0025] The term "electrically connected" describes a constant low-ohmic connection between electrically connected elements, such as direct contact between the elements involved or a low-ohmic connection via metal and / or highly doped semiconductors. The term "electrically coupled" includes the possibility that one or more intermediate elements adapted for signal transmission may be present between the electrically coupled elements (e.g. elements temporarily providing a low-ohmic connection in a first state and a high-ohmic electrical decoupling in a second state).

[0026] The figures illustrate the relative doping concentrations by indicating a “+” or “-” next to the doping type “n” or “p”. - ” indicates a lower doping concentration than the doping concentration of the “n”-doped region, while “n + An “n”-doped region has a higher doping concentration than an “n”-doped region. Doped regions of the same relative doping concentration do not necessarily have the same absolute doping concentration. For example, two different “n”-doped regions may have the same or different absolute doping concentrations.

[0027] The term "horizontal" as used in this specification intends to describe an orientation substantially parallel to a first or main surface of a semiconductor substrate or body. This may be, for example, the surface of a wafer or a die.

[0028] The term “vertical” as used in this specification intends to describe an orientation that is arranged substantially perpendicular to the first surface (ie parallel to the normal direction of the first surface of the semiconductor substrate or body).

[0029] In this specification, the second surface of a semiconductor substrate or semiconductor body is considered to be formed by the lower surface or backside surface of the semiconductor substrate, while the first surface is considered to be formed by the upper surface, front surface or main surface of the semiconductor substrate. The terms "above" and "below" as used in this specification therefore describe the relative position of one structural feature to another structural feature.

[0030] In this specification, n-doping is referred to as the first conductivity type and p-doping is referred to as the second conductivity type. Alternatively, semiconductor devices may be formed with the opposite doping relationship, so that the first conductivity type may be p-doped and the second conductivity type may be n-doped.

[0031] Figure 1 is a schematic flow chart for illustrating a method 1000 of manufacturing a semiconductor device, for example a power semiconductor device, such as a power insulated gate bipolar transistor (power IGBT) or a power diode, in a semiconductor body.

[0032] It will be appreciated that, although method 1000 is illustrated and described below as a series of actions or events, it is not intended to explain the illustrated order of such actions or events in a limiting sense. For example, in addition to those illustrated and / or described herein, some actions may occur in different orders and / or simultaneously with other actions or events. In addition, all illustrated actions may not be required to implement one or more aspects of the disclosed embodiments herein. In addition, one or more of the actions depicted herein may be performed in one or more separated actions and / or stages.

[0033] Reference Figure 1 , processing feature S100 includes forming a first field termination zone portion of a first conductivity type on a semiconductor substrate. In one or more embodiments, the semiconductor body is a silicon semiconductor body (e.g., a silicon semiconductor substrate (such as a silicon (Si) semiconductor wafer)). The semiconductor wafer can be a wafer of any size (e.g., a Czochralski (CZ) wafer (such as a standard CZ and magnetic CZ (MCZ) wafer or an 8-inch (200mm), 12-inch (300mm) or 18-inch (450mm) float zone (FZ) wafer)). Before forming the first field termination zone portion, the semiconductor body may include no semiconductor layer, one or even multiple semiconductor layers on top of the semiconductor substrate. Substrate materials other than silicon (e.g., silicon carbide (SiC), gallium arsenide (GaAs), gallium nitride (GaN) or other A III BV Compound semiconductors, germanium (Ge) or silicon germanium (SiGe)) may be used alternatively as substrate materials. In one or more embodiments, for example, a highly doped semiconductor layer configured to act as a back-side emitter layer may be formed on top of a semiconductor substrate. The first field termination zone portion may be formed by an epitaxial layer growth process, for example, vapor phase epitaxy, liquid phase epitaxy (LPE), molecular beam epitaxy (MBE) or chemical vapor deposition (CVD) may be used to increase the thickness of the semiconductor body. In one or more embodiments, in-situ doping during the layer growth process may be used to completely, predominantly or partially set a target doping profile in the first field termination zone portion. The doping concentration profile set by in-situ doping may be constant or nearly constant, or may be slightly reduced with increasing growth thickness. One or more optional doping processes (e.g., diffusion and / or ion implantation processes) may be subsequently performed to set or change the doping profile in the first field termination zone portion.

[0034] Reference Figure 1 , processing feature S110 includes forming a drift zone of the first conductivity type on the first field stop zone portion, wherein the average doping concentration of the drift zone is set to be less than 80% of the average doping concentration of the first field stop zone portion. The average doping concentration of the drift zone can be determined by averaging the doping concentration along the vertical extension of the drift zone (e.g., along the vertical extension of the IGBT drift zone between the body region and the first field stop zone portion or along the vertical extension of the diode drift zone between the anode region and the first field stop zone portion). The average doping concentration of the first field stop zone portion can be determined by averaging the doping concentration along the vertical extension of the first field stop zone portion (e.g., along the vertical extension of the first field stop zone portion between the end of the drift zone (at which the increase in doping concentration occurs at the transition to the first field stop zone portion) and the further increase in doping concentration at the transition between the first field stop zone portion and the second field stop zone portion or the emitter or drain region). In one or more embodiments, the vertical extension of the drift zone may be in the range of 20 μm to 700 μm, and the average doping concentration of the drift zone may be in the range of 5×10 12 cm -3 to 2x10 14 cm -3 In the range of 1x10 13 cm -3 to 1x10 14 cm -3range, is configured to achieve a drift zone of a vertical power IGBT or a vertical power diode as follows: the vertical power IGBT or the vertical power diode has a rated maximum load current of more than 1A and a rated load terminal for a load terminal breakdown voltage of greater than 300V, or greater than 400V, or greater than 600V, or greater than 650V, or greater than 900V, or greater than 1000V, or greater than 1200V, or greater than 1600V, or greater than 1700V, or greater than 3300V, or greater than 4500V (for example, 6500V)).

[0035] Reference Figure 1 , processing feature S120 includes processing the semiconductor body at the first surface of the semiconductor body. Processing the semiconductor body at the first surface may include processing for forming doped semiconductor regions, such as masked doping processing or unmasked doping processing, such as ion implantation and / or diffusion processing for forming a body region, a source region, a highly doped body contact region, a channel implant region, an anode region or a cathode region of a diode, an edge termination structure (such as a lateral doping variation (VLD) region or a junction termination extension (JTE) region, a guard ring, a channel termination) of a transistor (such as an IGBT). Processing the semiconductor body at the first surface may further include processing for forming an insulating region, such as a thermal oxidation process, a thermal nitridation process, a dielectric layer deposition process (such as chemical vapor deposition (CVD), low pressure chemical vapor deposition (LPCVD), plasma enhanced chemical vapor deposition (PEPCVD), atmospheric pressure chemical vapor deposition (APCVD), sub-atmospheric pressure chemical vapor deposition (SACVD), and high density plasma chemical vapor deposition (HDP CVD)). Exemplary insulating regions are gate insulating layers (e.g. thermal oxides or nitrides or high-k and low-k dielectrics), field insulating layers (e.g. field oxide layers), insulating spacers (e.g. deposited oxides such as tetraethylorthosilicate glass (TEOS), borophosphosilicate glass (BPSG), borosilicate glass (BSG), phosphosilicate glass (PSG)), device insulating layers (e.g. local oxidation of silicon (LOCOS) or trench insulation). Processing the semiconductor body at the first surface may further include processes for forming conductive regions, such as physical vapor deposition of materials such as metals and metal compounds. The semiconductor body may be deposited at the first surface by a process such as a PVD, a chemical vapor deposition (CVD) of a material such as doped polysilicon or tungsten, and an electrochemical deposition (ECD) of a material such as copper. Exemplary conductive regions are gate electrodes, conductive paths at the wiring level, bonding pads, vias, and contacts. Processing the semiconductor body at the first surface may further include a process for removing material from the first surface, such as an etching process or an abrasive process such as grinding or polishing, and chemical mechanical polishing (CMP). Exemplary structures resulting from the removal of material are trenches, such as gate trenches or field trenches or trench isolations, contact holes.

[0036] Reference Figure 1 , processing feature S130 includes thinning the semiconductor body by removing material of the semiconductor substrate from a second surface of the semiconductor body opposite to the first surface. In one or more embodiments, the semiconductor body is mechanically supported by a carrier attached to the first surface. The material of the semiconductor substrate can be removed by chemical treatment (e.g., by etching (such as dry etching or wet etching)), mechanical treatment (e.g., abrasive processing (such as grinding or polishing)) and chemical mechanical treatment (such as chemical mechanical polishing (CMP)). In one or more embodiments, a combination of more than one treatment for removing the material of the semiconductor substrate can be used, for example, the first treatment has a greater material removal rate than the second treatment after the first treatment. For example, this can allow fine adjustment of the target wafer thickness. The treatment for removing the material of the semiconductor substrate from the second surface can also include a so-called TAIKO treatment. The TAIKO treatment is a wafer thinning process in which the outer support ring along the edge of the wafer is not thinned during the thinning process. The outer support ring can provide improved thin wafer handling during subsequent processing. For example, wafers thinned using the TAIKO process can typically maintain their rigidity without being attached to an additional carrier.

[0037] Reference Figure 1 , processing feature S140 includes forming a second field termination zone portion of the first conductivity type by implanting protons at one or more energies into the semiconductor body through the second surface. The deepest range boundary peak of the protons is set in the first field termination zone portion at a vertical distance from the transition between the drift zone and the first field termination zone portion in the range from 3μm to 60μm. One or more proton implants can be coordinated to set a combination of characteristics of the second field termination zone portion (e.g., doping concentration gradient, vertical extension, doping concentration). In one or more embodiments, the doping concentration of the second field termination zone portion is set high enough in the IGBT to enable effective charge compensation of the electron current flow to the rear emitter caused by cosmic ray absorption. The minimum doping concentration of the second field termination zone portion in an IGBT with an n-type drift zone can be set to be greater than 2x10 15 cm -3 Donor, or greater than 1x10 16 cm -3 donor, or even greater than 5x10 16 cm -3Donor. In one or more embodiments, the decreasing doping concentration gradient on the doping concentration in the second field termination zone portion may be arranged in an appropriate manner to enlarge the space charge region during disturbances due to cosmic ray absorption so that the electric field peak in the rear side portion close to the rear side emitter is kept low or kept at a minimum. In one or more embodiments, the vertical extension of a portion of the second field termination zone portion that electrically compensates for the high electron density caused by cosmic ray absorption (e.g., a portion of the second field termination zone portion between the peak concentration of the second field termination zone portion and the first field termination zone portion) may be greater than 1 μm or even greater than 3 μm.

[0038] Reference Figure 1 , in some embodiments, processing feature S140', which can replace processing feature S140, includes forming a second field termination zone portion of the first conductivity type by introducing a dopant of the first conductivity type into the semiconductor body through the second surface, wherein the dopant is a deep dopant. For example, the deep dopant can be introduced by ion implantation or diffusion. Unlike shallow dopants (such as boron (B) or phosphorus (P) in silicon), deep dopants require energy greater than thermal energy to ionize, so that only a small portion of the deep dopant present in the semiconductor body contributes to free carriers. For example, at room temperature (e.g., 25°C), the deep dopant can be three or five times greater than the thermal energy away from either band edge. For example, the deep dopant can be selenium.

[0039] Reference Figure 1 , processing feature S150 includes annealing the semiconductor body by heat treatment. This can enable activation of hydrogen-related donors or deep dopants. In one or more embodiments, the annealing temperature can be set in the range of 300°C to 500°C, or in the range of 350°C to 450°C, or in the range of 360°C to 440°C, or even in the range of 380°C to 420°C. In one or more embodiments, annealing can be performed in a period between 10 minutes and 10 hours, or in a period between 20 minutes and 5 hours, or in a period between 30 minutes and 2 hours. During the annealing process, a complex formation of hydrogen-related donors due to protons and crystal defects occurs, such as vacancies introduced by proton irradiation.

[0040] In one or more embodiments, thinning the semiconductor body is terminated at a vertical distance from the transition between the drift zone and the first field stop zone portion in the range from 5 μm to 70 μm. For example, at the transition between the drift zone and the first field stop zone portion, the doping concentration increases from a lower level in the drift zone to a higher level in the first field stop zone portion.

[0041] In one or more embodiments, the first field stop zone portion and the drift zone are formed by an epitaxial layer formation process, for example by chemical vapor deposition (CVD).

[0042] Figure 2 is a schematic flow chart for illustrating a method 2000 of manufacturing a semiconductor device in a semiconductor body.

[0043] It will be appreciated that, although method 2000 is illustrated and described below as a series of actions or events, the illustrated order of such actions or events should not be interpreted in a limiting sense. For example, in addition to those illustrated and / or described herein, some actions may occur in different orders and / or occur simultaneously with other actions or events. In addition, all illustrated actions may not be required to realize one or more aspects of the disclosed embodiments herein. In addition, one or more of the actions depicted herein may be performed in one or more separated actions and / or stages.

[0044] Reference Figure 2 , processing feature S200 includes forming a drift zone of a first conductivity type on a semiconductor substrate. Figure 1 The details provided in the processing feature S110 of the method 1000 illustrated in FIG. 1 to form the drift zone apply accordingly.

[0045] Reference Figure 2 , processing feature S210 includes processing the semiconductor body at the first surface of the semiconductor body. Figure 1 The details provided in the processing feature S120 of the method 1000 illustrated in FIG. 1 to form the drift zone apply accordingly.

[0046] Reference Figure 2 , processing feature S220 includes thinning the semiconductor body by removing material of the semiconductor substrate from a second surface of the semiconductor body opposite to the first surface. The details provided with reference to forming the drift zone by processing feature S130 of the method 1000 illustrated in FIG. 1 apply accordingly.

[0047] Reference Figure 2, processing feature S230 includes forming a first field termination zone portion of a first conductivity type between the second surface and the drift zone by: implanting protons into the semiconductor body through the second surface, and setting a vertical distance between a range boundary peak of the protons and the second surface in a range from 8μm to 70μm. Processing feature S230 further includes setting an average doping concentration of the first field termination zone portion that is greater than 120% of the average doping concentration of the drift zone. The typical profile shape of the donor profile for hydrogen is closely related to the initial damage profile of the radiation-induced lattice defects. The profile therefore typically exhibits an extended penetration range with an approximately constant concentration, followed by a well-defined peak (i.e., a range boundary peak near the range boundary of the protons).

[0048] Reference Figure 2 , processing feature S240 includes forming a second field stop zone portion of the first conductivity type by implanting protons at different energies into the semiconductor body through the second surface. The deepest range boundary peak of the protons is disposed in the first field stop zone portion at a vertical distance from a transition between the drift zone and the first field stop zone portion in the range from 3 μm to 60 μm. Referring to Figure 1 The details provided for forming the second field termination zone portion in processing feature S140 of the method 1000 illustrated in FIG. 1 apply accordingly.

[0049] Reference Figure 2 In some embodiments, a processing feature S240' that can replace the processing feature S240 includes forming a second field termination zone portion of the first conductivity type by introducing a dopant of the first conductivity type into the semiconductor body through the second surface, wherein the dopant is a deep dopant. Figure 1 The details provided for forming the second field termination zone portion in the processing feature S140 ′ of the method 1000 illustrated in FIG. 1 apply accordingly.

[0050] Reference Figure 2 , processing feature S250 anneals the semiconductor body by heat treatment. Figure 1 The details provided for forming the second field termination zone portion in processing feature S150 of the method 1000 illustrated in FIG. 1 apply accordingly.

[0051] exist Figure 1 In the embodiment of the method 1000 illustrated in FIG. 1 , the first field stop zone portion is doped by in-situ doping and optionally further doping processes such as diffusion and / or ion implantation and activation. Figure 2 In the embodiment of the method 2000 illustrated in FIG. 2 , the first field stop zone portion is formed by proton implantation and annealing.

[0052] Reference Figure 1and Figure 2 In one or more embodiments, the first field stop zone portion and the second field stop zone portion may be formed in one and the same ion implantation apparatus (eg, in one and the same ion implanter).

[0053] Reference Figure 1 and Figure 2 In one or more embodiments, for example, a ratio of the ion implantation energy of protons of the first field termination zone portion to the ion implantation energy of protons associated with the deepest range boundary peak of the second field termination zone portion is set in a range from 2 to 50 or from 5 to 20. This can enable relaxation of the electric field strength and reduce oscillatory behavior during a turn-off operation.

[0054] Reference Figure 1 and Figure 2 In one or more embodiments, the vertical extension of the second field stop zone portion is arranged in the range from 1 μm to 15 μm. The vertical extension of the first field stop zone portion may refer to the extension between the end of the drift zone, at which the increase in doping concentration occurs at the transition to the first field stop zone portion, and the further increase in doping concentration at the transition between the first field stop zone portion and the second field stop zone portion.

[0055] Reference Figure 1 and Figure 2 In one or more embodiments, protons for the second field termination zone portion are implanted based on three to ten different ion implantation energies ranging from 200 keV to 700 keV. This can allow for reduced fluctuations in the doping profile in the transition region to the first field termination zone portion, resulting in a more gradual decrease in the doping profile from the second field termination zone portion to the first field termination zone portion.

[0056] Reference Figure 1 and Figure 2 In one or more embodiments, the ratio of the minimum ion implantation energy to the maximum ion implantation energy among the three to ten different ion implantation energies used to form the second field termination zone portion is set in the range from 50% to 90%. This can be beneficial in reducing the fluctuation of the doping profile in the transition region to the first field termination zone portion.

[0057] Reference Figure 1 and Figure 2 In one or more embodiments, as the ion implantation energy increases among three to ten different ion implantation energies, the ratio of the ion implantation dose of the proton implantation is set to be smaller. This can allow a more gradual decrease in the doping profile from the second field termination zone portion to the first field termination zone portion.

[0058] Reference Figure 1 and Figure 2 In one or more embodiments, the ion implantation dose associated with one of the three to ten different ion implantation energies is set to be between 3% and 70% of the ion implantation dose associated with another of the three to ten different implantation energies that is the next greater ion implantation energy for the one of the three to ten different ion implantation energies. This may allow for a more gradual decrease in the doping profile from the second field stop zone portion to the first field stop zone portion.

[0059] Reference Figure 1 and Figure 2 In one or more embodiments, the annealing temperature of the heat treatment is set in the range from 360°C to 440°C, and the duration of the heat treatment is set in the range from 30 minutes to 2 hours.

[0060] Methods 1000 and 2000 may allow for improved smoothing of a doping profile segment in a transition region between a second field termination zone portion and a first field termination zone portion. The thermal budget of the annealing process may be set as a function of proton implantation parameters for the second field termination zone portion, for example, as a function of quantity, energy and dose for improving the smoothness of the doping profile of the first field termination zone portion in a transition region between the second field termination zone portion and the first field termination zone portion.

[0061] Reference Figure 1 and Figure 2 In one or more embodiments, the implantation dose of protons introduced into the second field termination zone portion is set at from 1 x 10 13 cm -2 Up to 2 x 10 15 cm -2 This may allow the space charge region to be enlarged during disturbances due to cosmic ray absorption so that the electric field peak in the rear side portion close to the rear side emitter of the IGBT is kept low or at a minimum.

[0062] Reference Figure 1 and Figure 2 In one or more embodiments, the doping concentration of the drift zone is set at 5 x 10 12 cm -3 to 5 x 10 14 cm -3 This can allow the preparation of high voltage power devices that are configured to block reverse voltages of hundreds or thousands of volts.

[0063] Reference Figure 1 and Figure 2 In one or more embodiments, the gradient or average gradient of the dopant concentration profile in the second field termination zone portion is set to be less than 1×10 21 cm -4 This may be beneficial with regard to improving the turn-off softness behavior.

[0064] Reference Figure 1 and Figure 2 In one or more embodiments, q1 is equal to the integral of the ionized dopant charge along the vertical extension of the first field termination zone portion, and q2 is equal to the integral of the ionized dopant charge along the vertical extension of the second field termination zone portion, and the doping concentration profiles of the first field termination zone portion and the second field termination zone portion are adjusted to be set at a ratio of q2 to q1 in the range from 1 to 8. In one or more embodiments, q1 is set to be less than the breakdown charge of the semiconductor body. The charge q1 can be set to be less than 80% of the breakdown charge of the semiconductor body, or less than 60% of the breakdown charge of the semiconductor body, or even less than 40% of the breakdown charge of the semiconductor body. In one or more embodiments, for example, for the purpose of improving cosmic ray robustness, the sum of q1 and q2 can be set to be greater than the breakdown charge of the semiconductor body.

[0065] By combining the first field stop zone and the second field stop zone, a desired voltage blocking capability and turn-off softness can be achieved. Furthermore, forming the first field stop zone portion and the second field stop zone portion further allows for an adjustment of the isolation of the voltage blocking behavior (which is based among other things on the characteristics of the drift zone and the first field stop zone portion) and the backside emitter efficiency (which is based among other things on the doping profile in the second field stop zone portion). Thus, thickness variations caused by the process technology for the thinning of the semiconductor body can still result in acceptable variations in the short-circuit robustness.

[0066] In one or more embodiments, the semiconductor device is a diode, and processing the semiconductor body at the first surface includes forming a p-doped anode region in the semiconductor body at the first surface. A first load terminal contact (eg, an anode terminal contact) may be electrically coupled to the semiconductor body at the first surface.

[0067] In one or more embodiments, the semiconductor device is a transistor, and processing the semiconductor body at the first surface includes forming a source region and a gate electrode structure at the first surface.

[0068] In one or more embodiments, the doping concentration profile of the second field termination zone portion includes a plurality of peaks, and the doping concentration profile is configured to decrease from a maximum value to an adjacent minimum value along a vertical direction toward the second surface by less than 50% of the concentration value at the maximum value. For example, as the distance between adjacent doping peaks decreases, the overlap of the doping profiles of adjacent doping peaks increases, thereby resulting in a more uniform increase in the doping concentration of the field termination zone toward the second surface.

[0069] In one or more embodiments, method 1000 or method 2000 further includes introducing a dopant of the first conductivity type into the semiconductor body through the second surface, wherein the dopant is a deep dopant. In one or more embodiments, for example, the dopant is introduced by ion implantation and activated by laser annealing. This can allow for improved temperature characteristics of turn-off softness or high temperature leakage current behavior. In one or more embodiments, the dopant is a selenium dopant.

[0070] FIG. 3A to FIG. 3E is a cross-sectional view of a semiconductor body used to illustrate an example of a processing feature.

[0071] Figure 3A The cross-sectional view of FIG. 1 illustrates an example of processing features for forming a first field termination zone portion 106 of a first conductivity type on a semiconductor substrate 104. Figure 1 The further details provided for the processing feature S100 illustrated in FIG. 1 apply accordingly.

[0072] Figure 3B The cross-sectional view of FIG. 1 illustrates an example of processing features for forming a drift zone 108 of a first conductivity type on a first field termination zone portion, wherein the average doping concentration of the drift zone 108 is set to be less than 80% of the average doping concentration of the first field termination zone portion 106. Figure 1 The further details provided for the processing feature S100 illustrated in FIG. 1 apply accordingly. Figure 3B Two exemplary doping profiles in the drift zone 108 and in the first field termination zone portion 106 are illustrated in the right part of , for example a first profile (solid line) with a constant doping concentration c1 in the drift zone 108 and a constant doping concentration c2 in the first field termination zone portion 106 or a second profile (dashed line) with a doping concentration which increases slightly in the first field termination zone portion 106 towards the semiconductor substrate 104 and also increases in a portion of the drift zone 106 close to the first surface 102.

[0073] Figure 3CThe cross-sectional view of illustrates an example of processing a semiconductor body at a first surface 102, resulting in a processed portion 110, which may include a portion of the semiconductor body 100 adjacent to the first surface 102 and a wiring region on the semiconductor body 100 at the first surface 102. Figure 1 The further details provided for the processing feature S120 illustrated in FIG. 1 apply accordingly.

[0074] Figure 3D The cross-sectional view of FIG. 1 illustrates an example of thinning a semiconductor body by removing material of the semiconductor substrate from a second surface 112 of the semiconductor body 100 opposite to the first surface 102. The material removal may be performed using mechanical material removal (e.g., lapping and polishing), chemical etching, plasma etching, or laser ablation. Figure 1 Further details provided in the process feature S130 illustrated in FIG. 1 apply accordingly. In one or more embodiments, the semiconductor substrate 104 is completely removed. In some other embodiments, a portion 104' of the semiconductor substrate 104 may remain after thinning.

[0075] Figure 3E The cross-sectional view of the diagram is shown by combining the i An example of protons being implanted into the semiconductor body 100 through the second surface 112 to form a second field stop zone portion 114 of the first conductivity type. The deepest range boundary peak of the protons is arranged in the first field stop zone portion 106 at a vertical distance da from the transition between the drift zone 108 and the first field stop zone portion 106 in the range from 3 μm to 60 μm. Instead of proton implantation, the second field stop zone portion 114 can be prepared by deep dopants, such as selenium, by introducing deep dopants (by ion implantation and / or diffusion). Figure 3E , the semiconductor body 100 is further annealed by heat treatment, thereby activating the relevant hydrogen donors or deep dopants, such as in Figure 3E Therefore, the lower portion of the first field termination zone portion 106 becomes the second field termination zone portion 114. For example, regarding the charges q1, q2 associated with the first field termination zone portion 106 and the second field termination zone portion 114, or the injected 2 i The dose Φ i , energy Ei, number n or gradient α of the doping concentration profile in the second field termination zone portion 114, referred to herein Figure 1 The further details provided for the processing features S140, S150 illustrated in FIG. 1 apply accordingly.

[0076] FIG. 4A to FIG. 4Eis a cross-sectional view of a semiconductor body used to illustrate an example of a processing feature.

[0077] Figure 4A The cross-sectional view of FIG. 1 illustrates an example of processing features for forming a drift zone 208 of a first conductivity type on a semiconductor substrate 204. Figure 2 The further details provided for the processing feature S200 illustrated in FIG. 1 apply accordingly.

[0078] Figure 4B The cross-sectional view of FIG. 1 illustrates an example of processing features of the semiconductor body 200 at the first surface 202, resulting in a processed portion 210, which may include a portion of the semiconductor body 200 adjacent to the first surface 202 and a wiring region on the semiconductor body 200 at the first surface 202. Figure 2 The further details provided for the processing feature S210 illustrated in FIG. 1 apply accordingly.

[0079] Figure 4C The cross-sectional view of FIG. 1 illustrates an example of thinning a semiconductor body by removing material of the semiconductor substrate from a second surface of the semiconductor body 200 opposite to the first surface 202. The material removal may be performed using mechanical material removal (e.g., lapping and polishing), chemical etching, plasma etching, or laser ablation. Figure 2 Further details provided in the process feature S220 illustrated in FIG. 2 apply accordingly. In one or more embodiments, the semiconductor substrate 204 is completely removed. In some other embodiments, a portion 204' of the semiconductor substrate 204 may remain after thinning.

[0080] Figure 4D The cross-sectional view of illustrative embodiment shows an example of forming a first field termination zone portion 206 of a first conductivity type between the second surface 212 and the drift zone by implanting protons into the semiconductor body 200 through the second surface 212 and setting a vertical distance db between a range boundary peak value Eb of the protons and the second surface 212 in a range from 5 μm to 70 μm. In addition, the average doping concentration of the first field termination zone portion 206 is set to be greater than 120% of the average doping concentration of the drift zone. Figure 2 Further details provided for the processing feature S230 illustrated in FIG. 1 apply accordingly. Figure 4D In the right part of FIG. 2 , exemplary doping profiles in the drift zone 208 and in the first field stop zone portion 206 are illustrated, for example, a constant doping concentration c1 in the drift zone 208 and an almost constant doping concentration with an average doping concentration c2 in the first field stop zone portion 206. Thus, the lower part of the drift zone 208 becomes the first field stop zone portion 206.

[0081] Figure 4E The cross-sectional view of the diagram is shown by combining the i An example of protons being implanted into the semiconductor body 200 through the second surface 212 to form a second field termination zone portion 214 of the first conductivity type. The deepest range boundary peak Ea1 of the protons is arranged in the first field termination zone portion 206 at a vertical distance da from the transition between the drift zone 208 and the first field termination zone portion 206 in the range from 3 μm to 60 μm. Instead of proton implantation, the second field termination zone portion 114 can be prepared by deep dopants, such as selenium, by introducing deep dopants (by ion implantation and / or diffusion). Figure 4E , the semiconductor body 200 is further annealed by heat treatment, thereby activating the relevant hydrogen donors, such as in Figure 4E as shown in the figure on the right side of the diagram.

[0082] For example, with respect to the charges q1, q2 or the injected I associated with the first field termination zone portion 206 and the second field termination zone portion 214. 2 i The dose Φ i , energy Ei, quantity or gradient α of the doping concentration profile in the second field termination zone portion 214, referred to herein Figure 2 The further details provided for the processing features S240, S250 illustrated in FIG. 1 apply accordingly.

[0083] In one or more embodiments, the proton implant(s) used to prepare the first field stop zone portion 206 and the second field stop zone portion 214 may be annealed in a common annealing process, for example, Figure 2 The processing feature S250 illustrated in FIG. 2 can be used to activate dopants in the first field termination zone portion 206 and the second field termination zone portion 214. In addition, for example, Figure 2 One or more optional annealing processes are performed between process features S240 and S250. In one or more embodiments, for example, one or more proton implants for preparing first field termination zone portion 206 may be performed after or between some of the proton implants used to prepare second field termination zone portion 214.

[0084] Figure 5 is a schematic cross-sectional view illustrating an example of a semiconductor device that may be prepared by, for example, including processing features of method 1000 and method 2000 described above.

[0085] In the left circled portion of the processed portion 110, 210, the first load contact L1 (eg, anode electrode contact) of the power diode is electrically connected to the p+ The doped anode region 325 may be formed, for example, when performing processing feature S120 or S210. + Doped anode region 325 .

[0086] In the right circled portion of the processed portion 110 , 210 , the first load contact L1 (eg, source electrode contact) of the insulated gate bipolar transistor is electrically connected to the p-doped body region 326 and the n-doped body region 326 . + doped source region 327. Further, a control electrode contact C (eg, a gate electrode contact) is electrically connected to a gate electrode 328. A gate dielectric 329 is arranged between the gate electrode 328 and the drift zone 108, 208. For example, the first load contact L1, the p-doped body region 326, the n-doped body region 327, and the n-doped source region 327 may be formed when performing process feature S120 or S210. + Doped source region 327 , gate electrode 328 , and gate dielectric 329 .

[0087] In the left circled portion at the bottom of the semiconductor body 100 , 200 , the second load contact L2 (eg, cathode electrode contact) is electrically connected to n + The doped cathode region 330 may be formed, for example, by a doping process after thinning the semiconductor body 100, 200 or by layer deposition and doping before performing the processing features S100 and S200. + For example, the n-doped cathode region 330 may also be formed partially or completely in the portion 104′, 204′ of the semiconductor substrate 104, 204 that may remain after thinning. + Doped cathode region 330 .

[0088] In the right circled portion at the bottom of the semiconductor body 100 , 200 , the second load contact L2 (eg, the back side emitter electrode contact) is electrically connected to p + The doped backside emitter region 331 may be formed, for example, by a doping process after thinning the semiconductor body 100, 200 or by layer deposition and doping before performing the processing features S100 and S200. + For example, the p-doped backside emitter region 331 may also be formed partially or completely in the portion 104 ′, 204 ′ of the semiconductor substrate 104 , 204 that may remain after thinning. + Doped backside emitter region 331 .

[0089] Figure 61 is a schematic line diagram illustrating an example of a profile of a doping concentration c along a vertical direction into a depth of a semiconductor device that can be manufactured by the method 1000 or the method 2000 described above. A device including a doping concentration as depicted by a first curve c1 can be manufactured by performing a processing feature of the method 1000 including three proton implants for manufacturing the second field stop zone portion 114. A device including a doping concentration as depicted by a second curve c2 can be manufactured by performing a processing feature of the method 2000 including five proton implants for manufacturing the second field stop zone portion 214.

[0090] In one or more embodiments, q1 is equal to the integral of the ionized dopant charge along the vertical extension of the first field termination zone portion 106, 206, and q2 is equal to the integral of the ionized dopant charge along the vertical extension of the second field termination zone portion 114, 214, and the doping concentration profiles of the first field termination zone portion 106, 206 and the second field termination zone portion 114, 214 are adjusted to set a ratio of q2 to q1 in the range from 1 to 8. In one or more embodiments, q1 is set to be less than the breakdown charge of the semiconductor body, thereby enabling an effective field termination function of the first field termination zone portion and the second field termination zone portion. In one or more embodiments, q1 is set to be less than 80% of the breakdown charge of the semiconductor body 100, 200.

[0091] In one or more embodiments, the maximum gradient αa, αb of the doping concentration profile c1, c2 between the absolute maximum value of the doping concentration in the second field stop zone portion 114, 214 and the transition between the first field stop zone portion and the second field stop zone portion is less than 10 21 Dopant atoms / cm -4 or less than 10 20 Dopant atoms / cm -4 . This may allow for improved softness.

[0092] In one or more embodiments, the number of doping concentration peaks in the second field termination zone portion 114 , 214 is set in the range from three to ten.

[0093] In one or more embodiments, the vertical extension e2 of the second field termination zone portion 114 , 214 is arranged in the range from 1 μm to 15 μm.

[0094] In one or more embodiments, the doping concentration profile of the second field termination zone portion includes a plurality of peaks, and the doping concentration profile is arranged to decrease from a maximum value (e.g. Figure 6 The peak Ea2 shown in the figure) to the adjacent minimum value (for example Figure 6 The minimum value Ma2) shown in the figure is reduced by less than 50% of the concentration value at the maximum or peak.

[0095] In one or more embodiments, for example, a doping concentration ratio of a peak in the second field termination zone portion 114, 214 to an adjacent peak positioned closer to the second surface 112, 212 (e.g., a doping concentration ratio between peak Ea2 and peak Ea3) is in the range of 50% to 95%, or in the range of 70% to 95%, or in the range of 90% to 95%.

[0096] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that various replacements and / or equivalent implementations may replace the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptation or variation of the specific embodiments discussed herein. Therefore, it is intended that the present invention is limited only by the claims and their equivalents.

Claims

1. A method of manufacturing a semiconductor device in a semiconductor body, the method comprising: forming a first field stop zone portion of a first conductivity type on a semiconductor substrate; forming a drift zone of the first conductivity type on the first field stop zone portion, wherein an average doping concentration of the drift zone is set to be less than 80% of an average doping concentration of the first field stop zone portion; processing the semiconductor body at a first surface of the semiconductor body; thinning the semiconductor body by removing material of the semiconductor substrate from a second surface of the semiconductor body opposite the first surface; forming a second field stop zone portion of the first conductivity type by implanting protons at one or more energies into the semiconductor body through the second surface, wherein a deepest range boundary peak of the protons is arranged in the first field stop zone portion at a vertical distance from a transition between the drift zone and the first field stop zone portion in the range from 3 μm to 60 μm; and annealing the semiconductor body by heat treatment, The protons in the second field termination zone are implanted with at least three different ion implantation energies.

2. The method of claim 1, wherein: The thinning of the semiconductor body is terminated at a vertical distance from a transition between the drift zone and the first field stop zone portion in the range from 5 μm to 70 μm.

3. The method of claim 1, wherein: The first field stop zone portion and the drift zone are formed by an epitaxial layer formation process.

4. A method of manufacturing a semiconductor device in a semiconductor body, the method comprising: forming a drift zone of a first conductivity type on a semiconductor substrate; processing the semiconductor body at a first surface of the semiconductor body; thinning the semiconductor body by removing material of the semiconductor substrate from a second surface of the semiconductor body opposite the first surface; forming a first field stop zone portion of the first conductivity type between the second surface and the drift zone by implanting protons into the semiconductor body through the second surface and setting a vertical distance between a range boundary peak of the protons and the second surface in the range from 5 μm to 70 μm, and further setting an average doping concentration of the first field stop zone portion greater than 120% of an average doping concentration of the drift zone; forming a second field stop zone portion of the first conductivity type by implanting protons at one or more energies into the semiconductor body through the second surface, wherein a deepest range boundary peak of the protons is arranged in the first field stop zone portion at a vertical distance from a transition between the drift zone and the first field stop zone portion in the range from 3 μm to 60 μm; and annealing the semiconductor body by heat treatment, Wherein q1 is equal to the integral of the ionized dopant charge along the vertical extension of the first field termination zone portion, and q2 is equal to the integral of the ionized dopant charge along the vertical extension of the second field termination zone portion, and wherein the doping concentration profiles of the first field termination zone portion and the second field termination zone portion are adjusted to set a ratio of q2 to q1 in the range from 1 to 8.

5. The method of claim 4, wherein: A ratio of the ion implantation energy of protons of the first field termination zone portion to the ion implantation energy of protons associated with the deepest range boundary peak of the second field termination zone portion is set in a range from 2 to 50.

6. The method of claim 4, wherein: The vertical extension of the second field termination zone portion is arranged in the range from 1 μm to 15 μm.

7. The method of claim 4, wherein: Protons are implanted into the second field stop zone portion at three to ten different ion implantation energies ranging from 200 keV to 700 keV.

8. The method of claim 7, wherein: A ratio of the smallest ion implantation energy to the largest ion implantation energy among the three to ten different ion implantation energies is set in a range from 50% to 90%.

9. The method of claim 7, wherein: As the ion implantation energy among the three to ten different ion implantation energies increases, the ion implantation dose of the proton implantation is set smaller.

10. The method of claim 7, wherein: An ion implantation dose associated with one of the three to ten different ion implantation energies is set between 3% and 70% of an ion implantation dose associated with another of the three to ten different ion implantation energies that is the next larger ion implantation energy for the one of the three to ten different ion implantation energies.

11. The method of claim 4, wherein: The annealing temperature of the heat treatment is set in the range from 360° C. to 440° C., and the duration of the heat treatment is set in the range from 30 minutes to 2 hours.

12. The method of claim 4, wherein: The proton implantation dose of the second field termination zone portion is set at 1 x 10 13 cm -2 to 5x 10 15 cm -2 in the range.

13. The method of claim 4, wherein: The doping concentration of the drift zone is set at 5x 10 12 cm -3 to 5x 10 14 cm -3 in the range.

14. The method of claim 4, wherein: The gradient of the dopant concentration profile of the second field termination zone portion is set to be less than 1×10 21 cm -4 .

15. The method of claim 4, wherein: q1 is set to be smaller than the breakdown charge of the semiconductor body.

16. The method of claim 4, wherein: q1 is set to be less than 60% of the breakdown charge of the semiconductor body.

17. The method of claim 4, wherein: The semiconductor device is a diode, and wherein processing the semiconductor body at the first surface comprises forming a p-doped anode region in the semiconductor body at the first surface.

18. The method of claim 4, wherein: The semiconductor device is a transistor, and wherein processing the semiconductor body at the first surface comprises forming a source region and a gate electrode structure at the first surface.

19. The method of claim 4, wherein: The doping concentration profile of the second field termination zone portion comprises a plurality of peaks, and wherein the doping concentration profile is arranged to decrease from a maximum value to an adjacent minimum value along a vertical direction toward the second surface by less than 50% of a concentration value at the maximum value.

20. The method of claim 4, further comprising introducing a dopant of the first conductivity type into the semiconductor body through the second surface, wherein: The dopant is a deep dopant.

21. A method of manufacturing a semiconductor device in a semiconductor body, the method comprising: forming a first field stop zone portion of a first conductivity type on a semiconductor substrate; forming a drift zone of the first conductivity type on the first field stop zone portion, wherein an average doping concentration of the drift zone is set to be less than 80% of an average doping concentration of the first field stop zone portion; processing the semiconductor body at a first surface of the semiconductor body; thinning the semiconductor body by removing material of the semiconductor substrate from a second surface of the semiconductor body opposite the first surface; forming a second field stop zone portion of the first conductivity type by introducing a dopant of the first conductivity type into the semiconductor body through the second surface, wherein the dopant is a deep dopant; and annealing the semiconductor body by heat treatment, The second field termination zone portion is formed by introducing dopants of the first conductivity type into the semiconductor body via the second surface after thinning the semiconductor body.

22. The method of claim 21, wherein the dopant is a selenium dopant.

23. A method of manufacturing a semiconductor device in a semiconductor body, the method comprising: forming a drift zone of a first conductivity type on a semiconductor substrate; processing the semiconductor body at a first surface of the semiconductor body; thinning the semiconductor body by removing material of the semiconductor substrate from a second surface of the semiconductor body opposite the first surface; forming a first field stop zone portion of the first conductivity type between the second surface and the drift zone by implanting protons into the semiconductor body through the second surface and setting a vertical distance between a range boundary peak of the protons and the second surface in the range from 5 μm to 70 μm, and further setting an average doping concentration of the first field stop zone portion greater than 120% of an average doping concentration of the drift zone; forming a second field stop zone portion of the first conductivity type by introducing a dopant of the first conductivity type into the semiconductor body through the second surface, wherein the dopant is a deep dopant; and annealing the semiconductor body by heat treatment, Wherein after annealing, the doping concentration profile of the second field termination zone portion comprises a plurality of local maxima, wherein the doping concentration decreases on either side of the respective local maximum.

24. The method of claim 23, wherein: The dopant is a selenium dopant.

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