阅读说明：本技术 一种透明半导体材料双面对准标记的制备方法 (Preparation method of transparent semiconductor material double-sided alignment mark ) 是由 田亮 李玲 葛欢 朱辰 姜春艳 吴昊 吴军民 潘艳 于 2019-11-06 设计创作，主要内容包括：本发明公开了一种透明半导体材料双面对准标记的制备方法,该制备方法包括如下步骤：根据用户输入的标记工艺参数在透明半导体材料样品正面确定激光入射位置；根据激光入射位置,在透明半导体材料样品内部形成激光标记；根据激光标记,在透明半导体材料样品的背面形成对准标记。本发明实施例提供的透明半导体材料双面对准标记的制备方法,通过在透明半导体材料内部形成激光标记,并根据激光标记在样品背面形成对准标记,因此,该制备方法无需在样品表面形成刻蚀标记,最大限度的保证了样品正面的完整性,不会导致样品中器件结构的破坏,避免了样品表面损伤对样品中器件分布的影响,提高了样品的性能和可靠性。(The invention discloses a preparation method of a transparent semiconductor material double-sided alignment mark, which comprises the following steps: determining a laser incidence position on the front surface of the transparent semiconductor material sample according to marking process parameters input by a user; forming a laser mark inside the transparent semiconductor material sample according to the laser incidence position; an alignment mark is formed on the back surface of the transparent semiconductor material sample according to the laser marking. According to the preparation method of the transparent semiconductor material double-sided alignment mark provided by the embodiment of the invention, the laser mark is formed in the transparent semiconductor material, and the alignment mark is formed on the back of the sample according to the laser mark, so that the preparation method does not need to form an etching mark on the surface of the sample, the integrity of the front of the sample is ensured to the maximum extent, the structure of a device in the sample cannot be damaged, the influence of the surface damage of the sample on the distribution of the device in the sample is avoided, and the performance and the reliability of the sample are improved.)

1. A preparation method of a transparent semiconductor material double-sided alignment mark is characterized by comprising the following steps:

determining a laser incidence position on the front surface of the transparent semiconductor material sample according to marking process parameters input by a user;

forming a laser mark inside the transparent semiconductor material sample according to the laser incidence position;

and forming an alignment mark on the back surface of the transparent semiconductor material sample according to the laser mark.

2. The method for preparing the double-sided alignment mark of the transparent semiconductor material as claimed in claim 1, wherein the distance between the laser mark and the front side of the transparent semiconductor material sample is 2/3-4/5 of the total thickness of the transparent semiconductor material sample.

3. The method for preparing the double-sided alignment mark of the transparent semiconductor material as claimed in claim 1, wherein the laser beam is a dual beam or a triple beam.

4. The method for preparing the double-sided alignment mark of the transparent semiconductor material according to claim 3, wherein the laser beam is an ultraviolet, deep ultraviolet, infrared or deep infrared laser beam.

5. The method for preparing the double-sided alignment mark of the transparent semiconductor material according to claim 1, wherein forming the alignment mark on the back side of the transparent semiconductor material sample according to the laser mark comprises:

coating photoresist on the back of the transparent semiconductor material sample;

and according to the laser mark, carrying out exposure, development and hardening on the photoresist, and forming an alignment mark on the back surface of the transparent semiconductor material sample.

6. The method for preparing the double-sided alignment mark of the transparent semiconductor material according to claim 1, further comprising:

and detecting the overlay error between the laser mark and the alignment mark, and removing the transparent semiconductor material sample with the overlay error precision lower than 1 um.

7. The method for preparing the double-sided alignment mark of the transparent semiconductor material according to claim 1, wherein the width of the laser mark is 1um to 10 um.

8. The method for preparing the double-sided alignment mark of the transparent semiconductor material according to claim 1, wherein the transparent semiconductor material sample comprises: at least one of silicon carbide, gallium nitride, gallium oxide, diamond material.

Technical Field

The invention relates to the technical field of semiconductor power device preparation, in particular to a preparation method of a transparent semiconductor material double-sided alignment mark.

Background

In recent years, the third generation of transparent semiconductor material, wide bandgap transparent semiconductor material, has become a new type of power for the development of the electronic industry today. The wide-bandgap transparent semiconductor material has the characteristics of high thermal conductivity, high electronic saturation velocity, high breakdown voltage, low dielectric constant and the like, so that the wide application range is ensured theoretically, and the wide-bandgap transparent semiconductor material can be used for power electronic devices such as SiC and GaN.

In the process of preparing the electronic power device, the characteristic size of the large-scale integrated circuit is directly determined by the photoetching process, and the photoetching process is a key process for manufacturing the large-scale integrated circuit. Specifically, the photolithography process transfers a pattern on a mask to a photoresist coated on a surface of a silicon wafer by an exposure method, and then transfers the pattern to the silicon wafer by a developing, etching, or the like process.

Double-sided alignment mark lithography is a process technology developed for silicon and other semiconductor substrates. The double-sided alignment mark lithography needs to make lithography patterns on both sides of a substrate and realize mapping alignment exposure, if the patterns are not axially symmetrical, two mask plates with the patterns in a mirror image relationship need to be designed in advance, and each mask plate is used for exposing one surface of the substrate. However, when the double-sided alignment mark lithography is performed on the semiconductor substrate, the surface of the substrate material is easily damaged, which affects the distribution of devices on the wafer.

Disclosure of Invention

In view of this, embodiments of the present invention provide a method for preparing a double-sided alignment mark of a transparent semiconductor material, so as to solve the problem in the prior art that when a double-sided alignment mark is used for photolithography, the surface of a substrate material is easily damaged, and the distribution of devices on a wafer is affected.

The technical scheme provided by the embodiment of the invention is as follows:

the embodiment of the invention provides a preparation method of a double-sided alignment mark of a transparent semiconductor material, which comprises the following steps: determining a laser incidence position on the front surface of the transparent semiconductor material sample according to marking process parameters input by a user; forming a laser mark inside the transparent semiconductor material sample according to the laser incidence position; and forming an alignment mark on the back surface of the transparent semiconductor material sample according to the laser mark.

Optionally, the laser mark is at a distance from the front side of the transparent semiconductor material sample of 2/3 to 4/5 of the total thickness of the transparent semiconductor material sample.

Optionally, the beam of the laser is a two-way beam or a three-way beam.

Optionally, the beam of the laser is an ultraviolet, deep ultraviolet, infrared or deep infrared laser beam.

Optionally, forming an alignment mark on the back surface of the transparent semiconductor material sample according to the laser mark, including: coating photoresist on the back of the transparent semiconductor material sample; and according to the laser mark, carrying out exposure, development and hardening on the photoresist, and forming an alignment mark on the back surface of the transparent semiconductor material sample.

Optionally, the method for preparing the double-sided alignment mark of the transparent semiconductor material further includes: and detecting the overlay error between the laser mark and the alignment mark, and removing the transparent semiconductor material sample with the overlay error precision lower than 1 um.

Optionally, the width of the laser mark is 1um-10 um.

Optionally, the transparent semiconductor material sample comprises: at least one of silicon carbide, gallium nitride, gallium oxide, diamond material.

The technical scheme of the invention has the following advantages:

according to the preparation method of the transparent semiconductor material double-sided alignment mark provided by the embodiment of the invention, the laser mark is formed in the transparent semiconductor material, and the alignment mark is formed on the back surface of the sample according to the laser mark, so that compared with the double-sided alignment mark photoetching process in the prior art, the preparation method does not need to form an etching mark on the surface of the sample, the integrity of the front surface of the sample is ensured to the maximum extent, the damage of a device structure in the sample is avoided, the influence of the damage of the surface of the sample on the device distribution in the sample is avoided, and the performance and the reliability of the sample are improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a flow chart of a method for fabricating a double-sided alignment mark of a transparent semiconductor material according to an embodiment of the present invention;

FIG. 2 is a flow chart of a method for fabricating a double-sided alignment mark of a transparent semiconductor material according to another embodiment of the present invention;

FIG. 3 is a flow chart of a method for fabricating a double-sided alignment mark of a transparent semiconductor material according to another embodiment of the present invention;

FIG. 4 is a flow chart of a method for fabricating a double-sided alignment mark of a transparent semiconductor material according to another embodiment of the present invention;

fig. 5A to 5E are schematic structural diagrams obtained by a method for manufacturing a double-sided alignment mark of a transparent semiconductor material according to an embodiment of the invention.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; the two elements may be directly connected or indirectly connected through an intermediate medium, or may be communicated with each other inside the two elements, or may be wirelessly connected or wired connected. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The embodiment of the invention provides a preparation method of a double-sided alignment mark of a transparent semiconductor material, which comprises the following steps:

step S101: determining a laser incidence position on the front surface of the transparent semiconductor material sample according to marking process parameters input by a user; specifically, the transparent semiconductor material sample may be a silicon wafer, or may also be a transparent material such as silicon carbide, gallium nitride, gallium oxide, diamond, and the like. When the transparent semiconductor material is a silicon wafer, the determined laser incidence position can be used for scribing a channel position at the edge of the front surface of the silicon wafer, so that the performance of a device in a sample is not influenced.

Step S102: forming a laser mark inside the transparent semiconductor material sample according to the laser incidence position; in particular, the laser mark may be disposed near the back of the sample, so that the position of the laser mark may be more conveniently determined when the alignment mark is formed on the back of the sample. For example, the laser mark may be located a distance from the front side of the transparent semiconductor material sample of 2/3 to 4/5 of the total thickness of the transparent semiconductor material sample.

Step S103: an alignment mark is formed on the back surface of the transparent semiconductor material sample according to the laser marking. Specifically, back side alignment marks may be formed at corresponding positions on the back side of the transparent semiconductor material sample by a photolithography process according to the positions of the laser marks.

Alternatively, the laser mark forming process may be implemented by using a laser marking machine, and specifically, the laser mark forming process may be implemented by using the following steps:

step S201: fixing a transparent semiconductor material sample on an objective table of a laser marking machine; specifically, a transparent semiconductor material sample was placed on a stage with the front side up, and the sample was fixed by vacuum-pumping.

Step S202: adjusting the laser beam focal length, the laser beam energy and the objective table position of the laser marking machine according to the laser incidence position; specifically, the adjustment of the position of the stage can be performed under the control of a stepping motor built in the stage, and the stepping precision of the stepping motor can be smaller than 1 um.

Step S203: and focusing the laser beam emitted by the laser marking machine inside the transparent semiconductor material sample to form a preset mark inside the transparent semiconductor material sample. Alternatively, the width of the laser mark may be 1um to 10um, the number of the preset marks may be set according to the size of the transparent semiconductor material sample, for example, 10 preset marks may be formed inside the transparent semiconductor material sample.

According to the preparation method of the transparent semiconductor material double-sided alignment mark provided by the embodiment of the invention, the laser mark is formed in the transparent semiconductor material, and the alignment mark is formed on the back surface of the sample according to the laser mark. Therefore, compared with the double-sided alignment mark photoetching process in the prior art, the preparation method does not need to form an etching mark on the surface of the sample, ensures the integrity of the front side of the sample to the maximum extent, does not cause the damage of the device structure in the sample, avoids the influence of the damage of the surface of the sample on the device distribution in the sample, and improves the performance and the reliability of the sample.

As an alternative implementation manner of the embodiment of the present invention, the laser beam is a two-way beam or a three-way beam. Specifically, the two or three beams may be focused at the same position inside the sample, thereby forming a laser mark; meanwhile, the two-path light beam or the three-path light beam is focused inside the transparent semiconductor material sample to form a permanent mark, so that the preparation of the alignment mark on the back surface of the subsequent sample is facilitated. Alternatively, the beam of laser light may be an ultraviolet, deep ultraviolet, infrared or deep infrared laser beam.

As an alternative implementation manner of the embodiment of the present invention, the step S103 forms an alignment mark on the back surface of the transparent semiconductor material sample according to the laser mark, and includes the following steps:

step S301: coating photoresist on the back of the transparent semiconductor material sample; specifically, before coating the photoresist, the sample may be subjected to HMDS precleaning, and then the sample is placed in a spin coater for photoresist coating, where the photoresist may be of AZ703 type, the rotation speed of the spin coater during coating may be 4000 rpm, the thickness of the photoresist formed by coating is 1.5um, and after coating, the formed photoresist may be baked, specifically at 110 degrees for 60 seconds.

Step S302: and according to the laser mark, carrying out exposure, development and hardening on the photoresist to form an alignment mark on the back surface of the transparent semiconductor material sample. Specifically, after baking is completed, the photoresist may be subjected to ultraviolet exposure for 15 seconds, depending on the position of the laser mark. And then, the exposed sample is placed into a developing machine for development, 2.38% of tetramethyl ammonium hydroxide can be used as a developing solution during development, and the development time can be 60 seconds. After the development is finished, the sample is subjected to a film hardening treatment, and then an alignment mark can be formed on the back surface of the transparent semiconductor material sample.

As an optional implementation manner of the embodiment of the present invention, the method for preparing the double-sided alignment mark of the transparent semiconductor material further includes: and detecting the overlay error between the laser mark and the alignment mark, and removing the transparent semiconductor material sample with the overlay error precision lower than 1 um. Specifically, when performing overlay error detection, an electronic scanning microscope may be used for overlay accuracy measurement, and an optical microscope may also be used for measurement, which is not limited in the present invention.

As an optional implementation manner of the embodiment of the present invention, the method for preparing the double-sided alignment mark of the transparent semiconductor material may include the following steps:

step S401: determining a laser incidence position 1 on the front surface of a transparent semiconductor material sample 2 according to marking process parameters input by a user; the specific process structure is shown in fig. 5A.

Step S402: forming a laser mark 3 inside a transparent semiconductor material sample 2 according to the laser incident position 1; the structure after step S402 is shown in fig. 5B.

Step S403: the transparent semiconductor material sample 2 is inverted, the back surface of the transparent semiconductor material sample 2 is coated with the photoresist 4, and the structure after step S403 is shown in fig. 5C.

Step S404: the photoresist 4 is exposed, developed and hardened according to the laser mark 3, and an alignment mark 5 is formed on the back surface of the transparent semiconductor material sample 2, and the structure after step S404 is shown in fig. 5D.

Step S405: and detecting an alignment error between the laser mark 3 and the alignment mark 5, and removing the transparent semiconductor material sample with the alignment error precision lower than 1um, wherein the specific process structure is shown in fig. 5E.

Optionally, the transparent semiconductor material prepared by the method for preparing the transparent semiconductor material double-sided alignment mark provided by the embodiment of the invention can be used for preparing high-power devices such as a Schottky Barrier Diode (SBD), a metal oxide field effect transistor (MOSFET), a metal semiconductor field effect transistor (MESFET), an Insulated Gate Bipolar Transistor (IGBT), a High Electron Mobility Transistor (HEMT), a Light Emitting Diode (LED) and the like. The thickness of the prepared high-power device can be 80um to 700 um.

According to the preparation method of the transparent semiconductor material double-sided alignment mark provided by the embodiment of the invention, the mark preparation can be carried out in a very small range of a sample by adopting the laser etching mark, the integrity of the front side of the sample is ensured to the maximum extent, the damage of a device structure in the sample is avoided, the influence of the surface damage of the sample on the device distribution in the sample is avoided, and the performance and the reliability of the sample are improved.

Although the present invention has been described in detail with respect to the exemplary embodiments and the advantages thereof, those skilled in the art will appreciate that various changes, substitutions and alterations can be made to the embodiments without departing from the spirit and scope of the invention as defined by the appended claims. For other examples, one of ordinary skill in the art will readily appreciate that the order of the process steps may be varied while maintaining the scope of the present invention.

Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.