阅读说明：本技术 一种异质衬底上的薄膜结构及其制备方法 (Thin film structure on heterogeneous substrate and preparation method thereof ) 是由 欧欣 陈阳 黄凯 赵晓蒙 鄢有泉 李忠旭 于 2020-07-23 设计创作，主要内容包括：本发明涉及薄膜材料技术领域,特别涉及一种异质衬底上的薄膜结构及其制备方法,包括：提供键合体,键合体包括异质衬底层和键合于异质衬底层上的薄膜材料基板层,薄膜材料基板层中具有缺陷层；获取预设剥离应力,所述预设剥离应力为在第一退火温度时所述薄膜材料基板层中所述缺陷层处的第一最大热应力；在第一退火温度条件下,对键合体进行退火处理,使薄膜材料基板层以预设剥离应力沿缺陷层开始剥离；在剥离过程中,通过调整退火温度控制薄膜材料基板层以预设剥离应力沿缺陷层剥离,至得到异质衬底上的薄膜结构。本发明能够有效降低热应力差异对薄膜剥离厚度的影响,提高异质衬底上薄膜结构的厚度均一性。(The invention relates to the technical field of thin film materials, in particular to a thin film structure on a heterogeneous substrate and a preparation method thereof, wherein the thin film structure comprises the following steps: providing a bonding body, wherein the bonding body comprises a heterogeneous substrate layer and a thin film material substrate layer bonded on the heterogeneous substrate layer, and the thin film material substrate layer is provided with a defect layer; obtaining a preset stripping stress, wherein the preset stripping stress is a first maximum thermal stress at the position of the defect layer in the thin film material substrate layer at a first annealing temperature; annealing the bonding body at a first annealing temperature, so that the thin film material substrate layer begins to be stripped along the defect layer at a preset stripping stress; and in the stripping process, controlling the thin film material substrate layer to strip along the defect layer by adjusting the annealing temperature to preset stripping stress, so as to obtain the thin film structure on the foreign substrate. The method can effectively reduce the influence of the thermal stress difference on the peeling thickness of the film and improve the thickness uniformity of the film structure on the foreign substrate.)

1. A method for fabricating a thin film structure on a foreign substrate, the method comprising:

providing a bonding body, wherein the bonding body comprises a heterogeneous substrate layer and a thin film material substrate layer bonded on the heterogeneous substrate layer, and the thin film material substrate layer is provided with a defect layer;

obtaining a preset stripping stress, wherein the preset stripping stress is a first maximum thermal stress at the position of the defect layer in the thin film material substrate layer at a first annealing temperature;

annealing the bonding body at the first annealing temperature condition to enable the thin film material substrate layer to start to be stripped along the defect layer at the preset stripping stress;

and in the stripping process, controlling the thin film material substrate layer to strip along the defect layer by adjusting the annealing temperature according to the preset stripping stress, so as to obtain the thin film structure on the foreign substrate.

2. The method of claim 1, wherein said obtaining a first maximum thermal stress at the defect layer of the thin-film material substrate layer at a first annealing temperature comprises:

obtaining a first modeling result of the bonding body;

performing finite element analysis according to the first modeling result and thermodynamic parameters of the thin film material substrate layer and the heterogeneous substrate layer to obtain a first thermal stress distribution of the thin film material substrate layer at a first annealing temperature;

determining a first maximum thermal stress of the thin-film material substrate layer at the defect layer from the first thermal stress profile.

3. The method for manufacturing a thin film structure according to claim 2, wherein the controlling the thin film material substrate layer to be peeled along the defect layer at the preset peeling stress by adjusting the annealing temperature until obtaining the thin film structure on the heterogeneous substrate layer comprises:

monitoring a morphological change of the thin-film material substrate layer during the stripping process;

updating the first modeling result according to the form change to obtain a second modeling result;

performing finite element analysis according to the second modeling result and thermodynamic parameters of the thin film material substrate layer and the heterogeneous substrate layer to obtain a second thermal stress distribution of the thin film material substrate layer in the current state under the first annealing temperature condition;

determining a second maximum thermal stress of the thin film material substrate layer in the current form at the defect layer according to the second thermal stress distribution;

performing finite element analysis according to the second modeling result and a second maximum thermal stress to obtain a second annealing temperature when the second maximum thermal stress is equal to the preset stripping stress;

adjusting the annealing temperature to the second annealing temperature to enable the thin film material substrate layer in the current form to be stripped continuously with the preset stripping stress;

and repeating the steps until the stripping process is finished to obtain the film structure on the foreign substrate.

4. The method of claim 3, wherein monitoring the morphology of the thin film material substrate layer during the peeling process comprises:

monitoring Newton ring state change of the thin film material substrate layer in a stripping process by using optical equipment;

and obtaining the form change of the thin film material substrate layer in the stripping process according to the Newton ring state change.

5. The method for preparing according to any one of claims 1 to 4, further comprising:

counting a temperature curve of the annealing temperature along with the time change in the stripping process;

and annealing the bonding body corresponding to the first modeling result according to the temperature curve of at least one time of statistics to obtain the thin film structure on the heterogeneous substrate.

6. The method of producing as claimed in any one of claims 1 to 4, wherein the bonding body comprises a bonding body produced by:

providing a heterogeneous substrate and a thin film material substrate;

performing ion implantation on the thin film material substrate to form a defect layer;

bonding the heterogeneous substrate and the thin film material substrate with the defect layer to obtain the bonded body; and the surface of the thin film material substrate, which is close to the defect layer, is a bonding surface.

7. The method according to claim 6, wherein the ions implanted by the ion implantation include one or more of hydrogen ions and rare gas ions.

8. The method of claim 6, wherein the energy of the implanted ions is in the range of 20kev to 2000kev and the dose of the implanted ions is in the range of 1e15 to 1e17 during the ion implantation.

9. The method of claim 1, wherein the thin film structure has a thickness of 10nm to 2000 nm.

10. The method of manufacturing according to claim 1, wherein the foreign substrate layer is a silicon substrate layer, a glass substrate layer, a silicon carbide substrate layer, a sapphire substrate layer, or a silicon substrate layer having an oxide layer.

11. The method according to claim 1, wherein the thin film material substrate layer is LiNbO₃Substrate layer or LiTaO₃A substrate layer.

12. The method of claim 1, wherein the first annealing temperature is 100 ℃ to 300 ℃.

13. A thin film structure on a foreign substrate, characterized by being produced by the production method as claimed in any one of claims 1 to 12.

Technical Field

The invention relates to the technical field of thin film materials, in particular to a thin film structure on a heterogeneous substrate and a preparation method thereof.

Background

The Smart Cut method (Smart-Cut) is one of the main methods for fabricating functional material thin films, such as fabricating silicon thin film (SOI) wafers or piezoelectric material thin film (POI) wafers on heterogeneous substrates. In the preparation process, a defect layer needs to be formed in the functional material substrate, and annealing is carried out to peel off the functional material substrate so as to obtain the functional material thin film layer. However, in the annealing process, due to the difference of the linear expansion coefficients, the bonding body formed by the heterogeneous substrate and the functional material substrate is bent, so that the difference of the thermal stress in the functional material substrate is caused, and the uniformity of the peeling thickness of the thin film is further influenced, such as the thickness distribution diagram of the lithium tantalate thin film structure on the silicon substrate prepared by peeling in the prior art shown in fig. 1.

Therefore, there is a need to provide an improved method for preparing a thin film structure on a foreign substrate to solve the above-mentioned problems in the prior art.

Disclosure of Invention

In view of the above problems in the prior art, the present disclosure provides a thin film structure on a foreign substrate and a method for manufacturing the same, and the specific technical solution is as follows:

in one aspect, the present disclosure provides a method for preparing a thin film structure on a foreign substrate, the method comprising:

providing a bonding body, wherein the bonding body comprises a heterogeneous substrate layer and a thin film material substrate layer bonded on the heterogeneous substrate layer, and the thin film material substrate layer is provided with a defect layer;

obtaining a preset stripping stress, wherein the preset stripping stress is a first maximum thermal stress at the position of the defect layer in the thin film material substrate layer at a first annealing temperature;

annealing the bonding body at the first annealing temperature condition to enable the thin film material substrate layer to start to be stripped along the defect layer at the preset stripping stress;

and in the stripping process, controlling the thin film material substrate layer to strip along the defect layer by adjusting the annealing temperature according to the preset stripping stress, so as to obtain the thin film structure on the foreign substrate.

In another aspect, the present disclosure provides a thin film structure on a foreign substrate, which is prepared by the above preparation method.

Due to the technical scheme, the thin film structure on the heterogeneous substrate and the preparation method thereof provided by the invention have the following beneficial effects:

according to the method, the annealing temperature of the bonding body is adjusted, the stripping condition of the thin film material substrate is regulated and controlled, so that the stripping process is controlled to be completed under the same stress condition, the influence of thermal stress difference on the stripping thickness of the thin film is effectively reduced, and the thickness uniformity of the thin film structure on the heterogeneous substrate is improved.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings used in the description of the embodiment or the prior art will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

FIG. 1: the thickness distribution diagram of the lithium tantalate thin film structure on the silicon substrate prepared by stripping in the prior art is provided by the embodiment of the disclosure;

FIG. 2: the flow chart of the method for preparing the thin film structure on the foreign substrate provided by the embodiment of the disclosure;

FIG. 3: the bonding body provided by the embodiment of the disclosure has a first thermal stress distribution simulation diagram under a first annealing temperature condition;

FIG. 4: the embodiment of the disclosure provides a simulation diagram of changes of Newton's ring states in a preparation process of a thin film structure on a foreign substrate.

The piezoelectric material wafer substrate layer comprises 1-a piezoelectric material wafer substrate layer before stripping, 2-a piezoelectric material wafer substrate layer at the early stripping stage, 3-a piezoelectric material wafer substrate layer at the middle stripping stage, 4-a piezoelectric material wafer film structure, A-a piezoelectric material wafer substrate layer without stripping and B-Newton rings.

Detailed Description

The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are only a part of the embodiments of the present disclosure, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification. All numerical values, whether explicitly indicated or not, are herein defined as modified by the term "about". The term "about" generally refers to a range of values that one of ordinary skill in the art would consider equivalent to the recited value to produce substantially the same property, function, result, etc. A numerical range indicated by a low value and a high value is defined to include all numbers subsumed within the numerical range and all subranges subsumed within the numerical range.

It should be noted that the terms "first," "second," and the like in the description and claims of the present disclosure and in the above-described drawings are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions.

A method for fabricating a thin film structure on a foreign substrate according to an embodiment of the present disclosure is described below, please refer to fig. 2, and fig. 2 is a schematic flow chart of the fabrication method. The present specification provides method steps as described in the examples or flowcharts, but may include more or fewer steps based on routine or non-inventive labor. The order of steps recited in the embodiments is merely one manner of performing the steps in a multitude of orders and does not represent the only order of execution. In the actual implementation of the preparation method, the method according to the embodiment or the drawings may be executed in sequence or in parallel. The method comprises the following steps:

s100: providing a bonding body, wherein the bonding body comprises a heterogeneous substrate layer and a thin film material substrate layer bonded on the heterogeneous substrate layer, and the thin film material substrate layer is provided with a defect layer;

wherein the heterogeneous substrate layer and the thin film material substrate layer are made of different materials.

In practical application, the depth of the defect layer directly affects the thickness of the thin film structure, and the smaller the distance between the defect layer and the bonding surface is, the smaller the thickness of the prepared thin film structure is.

In some embodiments, the hetero-substrate layer may be an insulator in its entirety or on its surface.

S200: obtaining a preset stripping stress, wherein the preset stripping stress is a first maximum thermal stress at the position of the defect layer in the thin film material substrate layer at a first annealing temperature;

the thickness of the defect layer is small relative to the thickness of the thin film material substrate, and therefore, the position of the defect layer is not strictly limited to the position of the defect layer, and may be near the defect layer or close to the position of the defect layer.

In practical applications, the first annealing temperature may be determined experimentally or may be determined by simulation calculation. Different ion implantation doses and expected stripping times can be set to different first annealing temperatures, and when the bonding body is annealed under the first annealing temperature condition, the thin film material substrate can start to strip along the defect layer.

Further, the first annealing temperature may be optimized such that at the first annealing temperature, the first maximum thermal stress corresponds to a location as close as possible to the defect layer.

In some embodiments, the location at which the first maximum thermal stress is generated is at an edge of the thin-film material substrate layer and is proximate to the location of the defect layer.

In one embodiment, the thin film material substrate is a circular plate, and the position corresponding to the first maximum thermal stress is a circle region of the side surface of the thin film material substrate, which is close to the defect layer.

In another embodiment, the thin film material substrate is a square plate, and the positions corresponding to the first maximum thermal stress are respectively located in regions, close to the defect layer, of four side edges of the thin film material substrate.

S300: annealing the bonding body at the first annealing temperature condition to enable the thin film material substrate layer to start to be stripped along the defect layer at the preset stripping stress;

in practical application, the defects in the defect layer can evolve and gather during annealing to form a porous layer, and the depth of the evolving and gathering can be influenced by thermal stress. Specifically, the larger the thermal stress is, the deeper the evolution and aggregation depth is, the deeper the porous layer is formed, and the larger the thickness of the thin film structure obtained after stripping is; the smaller the thermal stress is, the shallower the depth of evolution and aggregation is, the shallower the depth of the porous layer is formed, and the smaller the thickness of the thin film structure obtained after peeling is.

Further, due to the difference of the linear expansion coefficients, the bonding body can be bent at the annealing temperature, so that the difference of thermal stress is caused, the depth of evolution and aggregation of the defect layer is greatly influenced, and the uniformity of the thickness of the stripped film structure is influenced. In some cases, the thickness difference of the thin film structure can reach 10nm to 50nm, which is very unfavorable for the treatment of the subsequent process.

S400: and in the stripping process, controlling the thin film material substrate layer to strip along the defect layer by adjusting the annealing temperature according to the preset stripping stress, so as to obtain the thin film structure on the foreign substrate.

In practical application, in the stripping process, the stress at the position where the thin film material substrate layer is stripped is controlled to be approximately equal to the preset stripping stress.

Therefore, the stripping condition of the thin film material substrate layer is regulated and controlled by adjusting the annealing temperature of the bonding body so as to control the stripping process to be completed under the same stress condition, the influence of thermal stress difference on the stripping thickness of the thin film is effectively reduced, and the thickness uniformity of the thin film structure on the heterogeneous substrate is improved.

Based on some or all of the foregoing embodiments, in this disclosure, the step S200 may include:

s210: obtaining a first modeling result of the bonding body;

in practical application, the bonding body can be directly modeled according to the size of the bonding body, the thickness of the heterogeneous substrate layer and the thickness of the thin film material substrate layer, and a first modeling result is obtained; the sizes and the thicknesses of the heterogeneous substrate and the thin film material substrate can also be respectively obtained, modeling is carried out on the heterogeneous substrate and the thin film material substrate, and then a first modeling result of the bonding body is obtained through simulation.

S220: performing finite element analysis according to the first modeling result and thermodynamic parameters of the thin film material substrate layer and the heterogeneous substrate layer to obtain a first thermal stress distribution of the thin film material substrate layer at a first annealing temperature;