Formation method of trap-rich layer and ion implantation layout structure of trap-rich layer
By using inclined ion implantation and photoresist layer mask technology in the preparation of RF devices, a trap-rich layer is formed, which solves the lattice damage caused by high energy injection and improves device reliability and yield.
Patent Information
- Application Number
- CN202510294516.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-12
- Publication Date
- 2025-07-11
AI Technical Summary
During the preparation of RF devices, high-energy, high-dose rare gas ion implantation causes serious damage to the crystal lattice on the surface of the silicon in the active region, affecting the reliability and yield of the device, and it is difficult to completely repair the annealing.
Using the tilt ion implantation technology, the combined ion implantation window pattern of island or trench patterns is defined on the photoresist layer, and the patterned photoresist layer is used as a mask to incline ion implant the substrate to form a trap-rich layer to reduce lattice damage, and the lattice is repaired through subsequent thermal annealing process.
Effectively reduce lattice damage on the surface of the active region of RF devices, improve device reliability and yield, and ensure that the annealing process is easier to repair lattice defects.
Smart Images
Figure CN120299990A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor manufacturing technology, and particularly relates to a method for forming a trap-rich layer and an ion implantation layout structure of the trap-rich layer. Background Art
[0002] For radio frequency devices, such as radio frequency switches, low noise amplifiers, etc., electrical isolation from the substrate is particularly emphasized. Commonly, SOI (Silicon on Insulator) technology or Triple well technology is used for isolation. In addition, in the industry, a highly resistive trap-rich layer on a bulk silicon substrate is also used for electrical isolation.
[0003] During the preparation process of radio frequency devices, a polysilicon trap-rich layer containing Ar ions or O ions and the like is formed at the bottom of the radio frequency device through ion implantation and annealing processes of high-dose rare gas ions such as Ar or oxygen ions. This trap-rich layer can effectively isolate the radio frequency device from the substrate at its bottom, and can reduce parasitic losses and harmonics from the substrate.
[0004] However, if high-energy and high-dose rare gas ions such as Ar are directly implanted, the lattice damage on the silicon surface of the active region will be relatively serious, becoming polycrystalline or even amorphous, and it is difficult to completely repair through annealing, which affects reliability and yield. In addition, due to excessive annealing, it is easy to cause the repair of the originally expected polysilicon trap-rich layer, losing its original function. Summary of the Invention
[0005] The present application provides a method for forming a trap-rich layer and an ion implantation layout structure of the trap-rich layer, which can solve the problem that the lattice on the silicon surface of the active region is severely damaged due to the ion implantation process during the formation of the trap-rich layer, resulting in the reduction of the reliability and yield of radio frequency devices.
[0006] On the one hand, an embodiment of the present application provides a method for forming a trap-rich layer of a radio frequency device, including: Providing a substrate; Coating a photoresist layer on the surface of the substrate; Defining an ion implantation window pattern on the photoresist layer through an ion implantation layout structure for forming a trap-rich layer, so as to obtain a patterned photoresist layer, wherein the ion implantation window pattern is one or more combinations of an island pattern, a trench pattern, etc.; Using the patterned photoresist layer as a mask, performing inclined ion implantation on the substrate to obtain a trap-rich layer in the substrate; Removing the patterned photoresist layer.
[0007] Optionally, in the method for forming a trap-rich layer of the radio frequency device, the ion implantation window pattern is an island pattern arranged in an array.
[0008] Optionally, in the method for forming the rich trap layer of the radio frequency device, the ion implantation window pattern is a groove pattern arranged at intervals.
[0009] Optionally, in the method for forming the rich trap layer of the radio frequency device, the ion implantation window pattern is a combined pattern of a plurality of groove patterns arranged longitudinally and a plurality of groove patterns arranged transversely.
[0010] Optionally, in the method for forming the rich trap layer of the radio frequency device, the ion implantation window pattern is a combined pattern of an island pattern arranged in an array and a groove pattern arranged at intervals.
[0011] Optionally, in the method for forming the rich trap layer of the radio frequency device, in the ion implantation layout structure, the area of the ion implantation window pattern is 50% - 80% of the area of the ion implantation region.
[0012] Optionally, in the method for forming the rich trap layer of the radio frequency device, using the patterned photoresist layer as a mask, when performing inclined ion implantation on the substrate to obtain a rich trap layer in the substrate, the implantation inclination angle is 0° - 60°, the ion implantation energy is 50 KeV - 10 MeV, and the ion implantation dose is 1E13 / cm 2 ~5E15 / cm 2 。
[0013] Optionally, in the method for forming the rich trap layer of the radio frequency device, after removing the patterned photoresist layer, the method for forming the rich trap layer of the radio frequency device further includes: performing a thermal annealing process on the substrate after forming the rich trap layer.
[0014] On the other hand, an embodiment of the present application further provides an ion implantation layout structure for a rich trap layer, including: a dark field pattern and an ion implantation window pattern located inside the dark field pattern, wherein the ion implantation window pattern is one or a combination of an island pattern and a groove pattern.
[0015] Optionally, in the ion implantation layout structure of the rich trap layer, in the ion implantation layout structure, the area of the ion implantation window pattern is 50% - 80% of the area of the ion implantation region.
[0016] The technical solution of the present application has at least the following advantages: In the method for forming a rich trap layer provided by the present application, an ion implantation layout structure for forming a rich trap layer is used to define an ion implantation window pattern on a photoresist layer. Among them, the ion implantation window pattern is one or a combination of an island pattern and a trench pattern. Further, in the present application, by using the photoresist layer (patterned photoresist layer) with the ion implantation window pattern formed as a mask, the substrate is subjected to inclined ion implantation to form a rich trap layer, which can greatly reduce the lattice damage on the surface of the active region in the RF device area. At the same time, a certain number of undamaged single-crystalline silicon islands are retained on the surface of the active region, which can provide attachment points for lattice repair, making lattice repair easier in the subsequent thermal annealing process, reducing the defects retained by the active region devices on the surface of the rich trap layer, and improving the reliability and yield of the devices. Brief Description of the Drawings
[0017] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0018] Figure 1 is a flowchart of the method for forming a rich trap layer of the RF device according to an embodiment of the present invention; Figure 2 is a schematic diagram of a semiconductor structure after forming a photoresist layer according to an embodiment of the present invention; Figure 3(a) is a schematic diagram of the first ion implantation layout structure of the rich trap layer according to an embodiment of the present invention; Figure 3(b) is a schematic diagram of the second ion implantation layout structure of the rich trap layer according to an embodiment of the present invention; Figure 3(c) is a schematic diagram of the third ion implantation layout structure of the rich trap layer according to an embodiment of the present invention; Figure 4 is a schematic diagram of defining an ion implantation window pattern on the photoresist layer by using the ion implantation layout structure shown in Figure 3(b) according to an embodiment of the present invention; Figure 5 is a schematic diagram of the ion implantation process for the substrate using the patterned photoresist layer as a mask according to an embodiment of the present invention; Figure 6 is a schematic diagram of the semiconductor structure after removing the patterned photoresist layer according to an embodiment of the present invention; Among them, the reference numerals are explained as follows: 11 - dark field pattern, 12 - ion implantation area, 13 - island pattern, 14 - trench pattern; 20 - Substrate, 21 - Shallow trench isolation structure, 22 - Trap-rich layer, 30 - Photoresist layer. Detailed implementation manners
[0019] The technical solutions in the present application will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the scope of protection of the present application.
[0020] In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.
[0021] In the description of the present application, it should be noted that unless otherwise clearly defined and limited, the terms "mounted", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can also be the communication inside two elements. It can be a wireless connection or a wired connection. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.
[0022] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.
[0023] The embodiment of the present application provides a method for forming a trap-rich layer of a radio frequency device. Refer to Figure 1 , Figure 1 which is a flowchart of the method for forming a trap-rich layer of a radio frequency device in the embodiment of the present invention. The method for forming a trap-rich layer of the radio frequency device includes: First, perform step S1: Refer to Figure 2 , and provide a substrate 20.
[0024] In this embodiment, the substrate 20 is a high-resistance substrate of a conventional radio frequency device.
[0025] In this embodiment, before forming the trap-rich layer 22, the preparation process of the shallow trench isolation structure 21 has been completed in the substrate 20.
[0026] In other embodiments, after forming the rich trap layer 22 and after performing a thermal annealing process on the substrate 20 after forming the rich trap layer 22, the process of preparing the shallow trench isolation structure 21 may be carried out.
[0027] Then, step S2 is performed: Continuing to refer to Figure 2 , a photoresist layer 30 is coated on the surface of the substrate 20.
[0028] Next, step S3 is performed: Referring to FIGS. 3(a), 3(b), 3(c) and Figure 4 , through the ion implantation layout structure for forming the rich trap layer, an ion implantation window pattern is defined on the photoresist layer to obtain a patterned photoresist layer 30, wherein the ion implantation window pattern is one or a combination of an island pattern 13 and a trench pattern 14.
[0029] Preferably, the ion implantation layout structure of the rich trap layer includes: a dark field pattern 11 and an ion implantation window pattern, wherein the ion implantation window pattern is one or a combination of an island pattern 13 and a strip-shaped trench pattern 14.
[0030] Referring to FIG. 3(a), the ion implantation window pattern may be an island pattern 13 arranged in an array.
[0031] Referring to FIG. 3(b), the ion implantation window pattern may be trench patterns 14 arranged at intervals.
[0032] Referring to FIG. 3(c), the ion implantation window pattern may be a combined pattern of a plurality of trench patterns 14 arranged longitudinally and a plurality of trench patterns 14 arranged transversely.
[0033] Furthermore, the ion implantation window pattern may also be a combined pattern of an island pattern 13 arranged in an array and trench patterns 14 arranged at intervals (not shown).
[0034] It should be noted that the above four graphic structures are only 4 schematic diagrams of the ion implantation layout structure of the rich trap layer, and the ion implantation layout structure of the rich trap layer provided in the present application is not limited to the above four graphic structures.
[0035] Preferably, in the ion implantation layout structure, the area of the ion implantation window pattern is 50% - 80% of the area of the ion implantation region 12, so as to ensure the subsequent ion implantation process. Through inclined ion implantation, a rich trap layer can be formed in the bottom substrate vertically downward through the ion implantation window of the present application. Among them, the ion implantation region is the overlapping region in space of the covering region where the rich trap layer is formed in the subsequent substrate.
[0036] Taking the ion implantation layout structure of the rich trap layer shown in Fig. 3(b) of the present application as an example, the ion implantation layout structure of the rich trap layer is formed on a customized photomask (reticle), and then using this photomask, through photolithography processes such as exposure and development, an ion implantation window pattern is defined on the photoresist layer 30 to obtain a patterned photoresist layer 30, that is, the ion implantation layout pattern of the rich trap layer on the photomask (reticle) is transferred to the photoresist layer 30.
[0037] Further, step S4 is performed: Referring to Figure 5 , using the patterned photoresist layer 30 as a mask, inclined ion implantation is performed on the substrate 20 to obtain a rich trap layer 22 in the substrate 20.
[0038] Among them, the implanted ions are ions related to inert gases such as argon ions, or the implanted ions are oxygen ions.
[0039] Preferably, when using the patterned photoresist layer 30 as a mask to perform inclined ion implantation on the substrate 20 to obtain the rich trap layer 22 in the substrate 20, the implantation inclination angle is 0° to 60°, the ion implantation energy is 50 keV to 10 MeV, and the ion implantation dose is 1E13 / cm 2 ~5E15 / cm 2 .
[0040] Through inclined ion implantation, the present application can further ensure that a rich trap layer 22 meeting the area requirements is formed in the bottom substrate 20 vertically downward in the ion implantation region 12 through the ion implantation window of the present application.
[0041] Among them, the rich trap layer 22 is a buried ion implantation region. The depth of the rich trap layer 22 in the substrate 20 is determined by the specific ion implantation energy and the specific ion implantation dose.
[0042] It should be noted that since the photoresist layer of the present application does not completely expose the ion implantation region 12, the ion implantation process of the present application only causes slight lattice damage to the surface of the active region exposed at the bottom of the ion implantation window pattern (the trench pattern 14 in this embodiment), avoiding the situation where the lattice of the active region silicon surface of the entire ion implantation region 12 is severely damaged and becomes polycrystalline or even amorphous in the traditional process of preparing the rich trap layer.
[0043] In the present application, by using a photoresist layer (patterned photoresist layer) with an ion implantation window pattern as a mask to perform inclined ion implantation on a substrate to form a trap-rich layer, the lattice damage on the surface of the active region in the RF device area can be greatly reduced. At the same time, a certain number of undamaged single-crystalline silicon islands are retained on the surface of the active region, which can provide attachment points for lattice repair, making lattice repair easier in the subsequent thermal annealing process, reducing the defects retained by the active region devices on the surface of the trap-rich layer, and improving the reliability and yield of the devices.
[0044] Finally, step S5 is executed: Refer to Figure 6 , and the patterned photoresist layer 30 is removed through an ashing process.
[0045] Furthermore, after removing the patterned photoresist layer 30, the method for forming the trap-rich layer of the RF device may further include: performing a thermal annealing process on the substrate 20 after forming the trap-rich layer 22. In the present application, the damaged lattice on the surface of the active region of the substrate can be effectively repaired through the thermal annealing process.
[0046] It should be noted that the present application does not make any limitations on the preparation process after the thermal annealing process, and it can be a conventional preparation process for RF devices.
[0047] Based on the same inventive concept, the embodiments of the present application also provide an ion implantation layout structure of a trap-rich layer. Referring to FIGS. 3(a), 3(b), and 3(c), the ion implantation layout structure of the trap-rich layer includes: a dark field pattern 11 and an ion implantation window pattern located inside the dark field pattern 11, where the ion implantation window pattern is one or a combination of an island pattern 13 and a strip-shaped trench pattern 14.
[0048] Preferably, in the ion implantation layout structure, the area of the ion implantation window pattern is 50% - 80% of the area of the ion implantation region 12.
[0049] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present application.
Claims
1. A method for forming a rich trap layer of a radio frequency device, characterized in that Comprising: Providing a substrate; Coating a photoresist layer on the surface of the substrate; Defining an ion implantation window pattern on the photoresist layer through an ion implantation layout structure for forming a trap-rich layer, so as to obtain a patterned photoresist layer, wherein the ion implantation window pattern is one or more combinations of an island pattern, a trench pattern; Using the patterned photoresist layer as a mask to perform inclined ion implantation on the substrate, so as to obtain a trap-rich layer in the substrate; Removing the patterned photoresist layer.
2. The method for forming a rich trap layer of a radio frequency device according to claim 1, wherein The ion implantation window pattern is an island pattern arranged in an array.
3. The method for forming a rich trap layer of a radio frequency device according to claim 1, wherein The ion implantation window pattern is a trench pattern arranged at intervals.
4. The method for forming a rich trap layer of a radio frequency device according to claim 1, wherein The ion implantation window pattern is a combined pattern of a plurality of trench patterns arranged longitudinally and a plurality of trench patterns arranged transversely.
5. The method for forming a rich trap layer of a radio frequency device according to claim 1, wherein The ion implantation window pattern is a combined pattern of an island pattern arranged in an array and a trench pattern arranged at intervals.
6. The method for forming a rich trap layer of a radio frequency device according to claim 1, wherein In the ion implantation layout structure, the area of the ion implantation window pattern is 50% - 80% of the area of the ion implantation region.
7. The method for forming a rich trap layer of the radio frequency device according to claim 1, characterized in that, During the process of performing inclined ion implantation on the substrate using the patterned photoresist layer as a mask to obtain a trap-rich layer in the substrate, the inclined angle of implantation is 0° to 60°, the ion implantation energy is 50 keV to 10 MeV, and the ion implantation dose is 1E13 / cm 2 ~5E15 / cm 2 .
8. The method for forming a rich trap layer of a radio frequency device according to claim 1, wherein After removing the patterned photoresist layer, the method for forming a trap-rich layer of the radio frequency device further includes: performing a thermal annealing process on the substrate after forming the trap-rich layer.
9. An ion implantation layout structure with a rich trap layer, characterized in that, Comprising: A dark field pattern and an ion implantation window pattern located inside the dark field pattern, wherein the ion implantation window pattern is one or more combinations of an island pattern, a trench pattern.