Semiconductor substrate and preparation method thereof

Abstract

The invention discloses a semiconductor substrate and a preparation method thereof. The semiconductor substrate is formed by bonding a silicon slide glass layer and a device layer, the device layer is located on a first surface of the silicon slide glass layer, and a de-bonding light beam enters from a second surface of the silicon slide glass layer. The semiconductor substrate comprises an anti-reflection layer which is arranged on the second surface of the silicon slide glass layer and is used for eliminating reflected light on the surface of the silicon slide glass layer; the inorganic absorption layer is positioned between the silicon slide glass layer and the device layer and is used for absorbing the de-bonding light beam to be sacrificed; and the inorganic reflection layer is positioned between the inorganic absorption layer and the device layer and is used for reflecting the de-bonding light beam to the inorganic absorption layer, so that the inorganic absorption layer absorbs the de-bonding light beam for the second time. The thermal stability of the semiconductor substrate can be effectively improved, so that the semiconductor substrate is suitable for high-temperature and high-pressure semiconductor processing conditions, meanwhile, the utilization rate of de-bonding light beams can be improved, a device is effectively protected from being damaged by laser irradiation, the de-bonding efficiency is improved, and the cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to a semiconductor substrate and a method for preparing the semiconductor substrate. Background Art

[0002] With the continuous development of integrated circuit technology, electronic products are increasingly moving towards miniaturization, high performance and high reliability. The thickness of the chip has an important impact on the performance of the device. For example, thin chips have many advantages, such as improving heat dissipation efficiency, mechanical and electrical properties, reducing package volume, and reducing weight. When the substrate of the wafer is thinned to 150μm or even thinner, it is easy to break, and the wafer will bend and deform due to stress and cannot be operated. Therefore, it is necessary to temporarily bond with a carrier such as a glass sheet before thinning, and use the temporary carrier as a basis for subsequent process production.

[0003] In the bonded semiconductor substrate, an anti-reflection layer is usually made on the front side of the carrier layer to improve the utilization rate of laser energy. There are usually two layers between the wafer and the carrier. The first layer is a sacrificial layer on the carrier layer, which is used to absorb the laser energy of the debonding beam and be ablated and sacrificed. The second layer is a protective layer between the sacrificial layer and the wafer layer, which is used to protect the wafer from being damaged by the laser.

[0004] However, the problem with the above scheme is that the prior art only considers the energy loss on the front side of the carrier layer, but does not consider the reflection loss on the back side of the carrier layer, so the utilization rate of the laser still needs to be improved. In addition, the sacrificial layer is usually an inorganic material layer, for example, a phenolic resin material containing a light absorber, a glue-like substance such as polyalkyl acrylates, etc. The sacrificial layers made of these inorganic materials have poor thermal stability and are easily decomposed by heat under the high temperature and high pressure conditions of semiconductor processing, thereby causing the wafer to fall off. Moreover, a simple barrier layer does not consider the secondary absorption of laser energy. If you want to improve the debonding efficiency and speed up the sacrificial layer to reach the damage threshold, you need to increase the power of the laser, which will increase the cost of the laser. At the same time, the increase in power will also increase the cost of the optical components in the laser light path.

[0005] In order to solve the above-mentioned problems existing in the prior art, the art is in urgent need of an improved basic semiconductor technology that can effectively improve the thermal stability of the semiconductor substrate, making it suitable for high temperature and high pressure semiconductor processing conditions, while also being able to improve the utilization rate of the debonding beam and effectively protect the device from damage due to laser irradiation, thereby improving the debonding efficiency and reducing costs. Summary of the invention

[0006] A brief summary of one or more aspects is given below to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceived aspects, and is neither intended to identify the key or decisive elements of all aspects nor to define the scope of any or all aspects. Its only purpose is to give some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that will be given later.

[0007] In order to overcome the above-mentioned defects of the prior art, the present invention provides a semiconductor substrate and a method for preparing a semiconductor substrate, which can effectively improve the thermal stability of the semiconductor substrate, making it suitable for high temperature and high pressure semiconductor processing conditions, while also being able to improve the utilization rate of the debonding light beam and effectively protect the device from damage due to laser irradiation, thereby improving the debonding efficiency and reducing costs.

[0008] Specifically, the above-mentioned semiconductor substrate provided according to the first aspect of the present invention is formed by bonding a silicon carrier layer and a device layer, wherein the device layer is located on the first surface of the silicon carrier layer, and the debonding beam is incident from the second surface of the silicon carrier layer, and the semiconductor substrate includes: an anti-reflection layer, located on the second surface of the silicon carrier layer, for eliminating the reflected light on the surface of the silicon carrier layer; an inorganic absorption layer, located between the silicon carrier layer and the device layer, for absorbing the debonding beam and sacrificing it; and an inorganic reflection layer, located between the inorganic absorption layer and the device layer, for reflecting the debonding beam to the inorganic absorption layer, so that the inorganic absorption layer can absorb the debonding beam for the second time.

[0009] Furthermore, in some embodiments of the present invention, the inorganic absorption layer includes a first titanium nitride layer with weak metallic properties.

[0010] Furthermore, in some embodiments of the present invention, the inorganic reflective layer includes a second titanium nitride layer that is a heterostructure with the first titanium nitride layer, wherein the second titanium nitride layer is a titanium nitride layer with strong metallic properties.

[0011] Furthermore, in some embodiments of the present invention, the ratio of titanium atoms to nitrogen atoms in the first titanium nitride layer is 0.6-0.8:1, and the ratio of titanium atoms to nitrogen atoms in the second titanium nitride layer is 0.8-1.2:1.

[0012] Furthermore, in some embodiments of the present invention, the thickness of the first titanium nitride layer is in the range of 30 to 100 nm, and the thickness of the second titanium nitride layer is in the range of 130 to 500 nm.

[0013] Furthermore, in some embodiments of the present invention, the inorganic reflective layer includes a metal reflective layer, wherein the metal reflective layer includes any one of gold and silver.

[0014] Furthermore, in some embodiments of the present invention, the anti-reflection layer includes any one of a silicon nitride film, a silicon oxide film, and a titanium oxide film.

[0015] Furthermore, in some embodiments of the present invention, the semiconductor substrate further includes: a silicon dielectric layer located between the silicon carrier layer and the first titanium nitride layer for growth of the first titanium nitride layer.

[0016] Furthermore, in some embodiments of the present invention, the debonding beam includes an infrared laser, the inorganic absorption layer is an infrared ablation layer, and the inorganic reflection layer is an infrared reflection layer.

[0017] In addition, the method for preparing the above-mentioned semiconductor substrate provided in accordance with the second aspect of the present invention comprises the following steps: obtaining a silicon carrier layer, and preparing an anti-reflection layer on the second surface thereof, for eliminating reflected light on the surface of the silicon carrier layer, wherein a debonding beam is incident from the second surface of the silicon carrier layer; after the preparation of the anti-reflection layer is completed, preparing an inorganic absorption layer on the first surface of the silicon carrier layer, for absorbing the debonding beam and sacrificing it; preparing an inorganic reflection layer on the first surface of the inorganic absorption layer, for reflecting the debonding beam to the inorganic absorption layer, so that the inorganic absorption layer can absorb the debonding beam for a second time; and after the preparation of the inorganic reflection layer is completed, bonding the device layer to the silicon carrier layer on the first surface of the inorganic reflection layer.

[0018] Furthermore, in some embodiments of the present invention, the step of preparing an inorganic reflective layer on the first surface of the inorganic absorption layer includes: preparing a first titanium nitride layer with a thickness of 30 to 100 nm on the first surface of the silicon carrier layer, wherein the ratio of titanium atoms to nitrogen atoms in the first titanium nitride layer is 0.6 to 0.8:1; the step of preparing an inorganic reflective layer on the first surface of the inorganic absorption layer includes: in response to the completion of preparation of the first titanium nitride layer, preparing a second titanium nitride layer with a thickness of 130 to 500 nm on the first surface of the first titanium nitride layer, which is a heterogeneous structure with the first titanium nitride layer, wherein the ratio of titanium atoms to nitrogen atoms in the second titanium nitride layer is 0.8 to 1.2:1. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above features and advantages of the present invention can be better understood after reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings. In the drawings, the components are not necessarily drawn to scale, and components with similar related properties or features may have the same or similar reference numerals.

[0020] Figure 1 A schematic structural diagram of a semiconductor substrate according to some embodiments of the present invention is shown;

[0021] Figure 2 A flow chart showing a method for preparing a semiconductor substrate according to some embodiments of the present invention; and

[0022] Figure 3 Schematic diagrams of reflectivity curves of semiconductor substrates with and without anti-reflection layers provided in accordance with some embodiments of the present invention are respectively shown.

[0023] Reference numerals:

[0024] 100 semiconductor substrate;

[0025] 110 silicon carrier layer;

[0026] 120 device layer;

[0027] 130 anti-reflection layer;

[0028] 140 dielectric layer;

[0029] 151 Inorganic absorption layer;

[0030] 152 Inorganic reflective layer;

[0031] 160 debonding beam; and

[0032] Steps S210 to S240. DETAILED DESCRIPTION

[0033] The following specific embodiments illustrate the implementation of the present invention, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this implementation. On the contrary, the purpose of introducing the invention in conjunction with the implementation is to cover other options or modifications that may be extended based on the claims of the present invention. In order to provide a deep understanding of the present invention, the following description will include many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description.

[0034] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "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 a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In addition, the terms "upper", "lower", "left", "right", "top", "bottom", "horizontal" and "vertical" used in the following description should be understood as the directions shown in the paragraph and the related drawings. Such relative terms are only used for the convenience of description and do not mean that the device described therein must be manufactured or operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0036] It is understood that although the terms "first", "second", "third", etc. may be used herein to describe various components, regions, layers and / or parts, these components, regions, layers and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, regions, layers and / or parts. Therefore, the first component, region, layer and / or part discussed below may be referred to as a second component, region, layer and / or part without departing from some embodiments of the present invention.

[0037] As mentioned above, the problem with the above scheme is that the prior art only considers the energy loss on the front side of the carrier layer, but does not consider the reflection loss on the back side of the carrier layer, so the utilization rate of the laser still needs to be improved. In addition, the sacrificial layer is usually an inorganic material layer, for example, a phenolic resin material containing a light absorber, a glue-like substance such as polyalkyl acrylates, etc. The absorption layer made of these inorganic materials has poor thermal stability and is easily decomposed by heat under the high temperature and high pressure conditions of semiconductor processing, thereby causing the wafer to fall off. Moreover, a simple barrier layer does not consider the secondary absorption of laser energy. If you want to improve the debonding efficiency and speed up the sacrificial layer to reach the damage threshold, you need to increase the power of the laser, which will increase the cost of the laser. At the same time, the increase in power will also increase the cost of the optical components in the laser light path.

[0038] In order to solve the above-mentioned problems existing in the prior art, the present invention provides a semiconductor substrate and a method for preparing a semiconductor substrate, which can effectively improve the thermal stability of the semiconductor substrate, making it suitable for high temperature and high pressure semiconductor processing conditions, while also being able to improve the utilization rate of the debonding beam and effectively protect the device from damage due to laser irradiation, thereby improving the debonding efficiency and reducing costs.

[0039] In some non-limiting embodiments, the semiconductor substrate provided by the first aspect of the present invention may be prepared by the method for preparing the semiconductor substrate provided by the second aspect of the present invention.

[0040] The specific structure of the semiconductor substrate described above will be described below in conjunction with some embodiments of the method for preparing the semiconductor substrate. Those skilled in the art will understand that the embodiments of the method for preparing the semiconductor substrate are only some non-limiting implementations provided by the present invention, which are intended to clearly demonstrate the main concept of the present invention and provide some specific solutions that are convenient for the public to implement, rather than to limit the entire structure or all functions of the semiconductor substrate. Similarly, the semiconductor substrate is also only a non-limiting implementation provided by the present invention, and does not constitute a limitation on the implementation subject of each step in the method for preparing the semiconductor substrate.

[0041] Please see Figure 1 , Figure 1 A schematic structural diagram of a semiconductor substrate provided according to some embodiments of the present invention is shown.

[0042] like Figure 1 As shown, in some embodiments, the semiconductor substrate 100 may be formed by bonding a silicon carrier layer 110 and a device layer 220. The device layer 220 may be located on the first surface of the silicon carrier layer 210, and the debonding beam may be incident from the second surface of the silicon carrier layer 210. In this embodiment, the first surface of the silicon carrier layer 210 may be understood as the front surface of the silicon carrier layer 210, which is a bonding surface for bonding with the device layer 220, and the second surface of the silicon carrier layer 210 may be understood as the back surface of the silicon carrier layer 210, which is an incident surface of the debonding beam 260, so that the debonding beam 260 can penetrate the silicon carrier layer 210 to reach the bonding surfaces of the two to achieve debonding.

[0043] Furthermore, the carrier layer can preferably be a silicon carrier layer 210 made of silicon material. Since high-purity silicon can accurately control the amount of doping elements, the impact of impurities in the raw materials can be reduced, thereby improving the performance and reliability of the final product. Therefore, existing semiconductor devices are mainly designed around silicon devices. However, the commonly used debonding beam of ultraviolet laser can only penetrate the carrier of the glass substrate, and cannot penetrate the silicon carrier layer 210. In this regard, in this embodiment, an infrared laser can be used as a debonding beam. For example, the laser wavelength can be greater than 1200nm, so that the debonding beam can penetrate the silicon carrier layer 210 for debonding.

[0044] In order to better introduce the semiconductor substrate 100 of the present invention, please refer to Figure 2 Common understanding, Figure 2 A flow chart of a method for preparing a semiconductor substrate provided according to some embodiments of the present invention is shown.

[0045] like Figure 2As shown, in some embodiments of the present invention, the method for preparing a semiconductor substrate includes the following steps: First, step S210 may be performed: obtaining a silicon carrier layer, and preparing an anti-reflection layer on the second surface thereof.

[0046] Specifically, combined Figure 1 It is commonly understood that, generally speaking, when an infrared laser with a wavelength greater than 1200 nm is incident on the surface of the silicon carrier layer 110, there will be 46% reflection, and the utilization rate of the laser is significantly reduced. In this regard, in some embodiments, an anti-reflection layer 130 can be prepared on the second surface (i.e., the back surface) of the silicon carrier layer 110 to eliminate the reflected light of the silicon carrier layer 110. In the preparation process of the semiconductor substrate 100, due to the large refractive index of the silicon carrier layer 110, the debonding beam 160 irradiated to the surface of the silicon carrier layer 110 cannot completely penetrate the silicon carrier layer 110 to reach the bonding surface, but a large part of it is reflected. In this regard, in order to minimize the reflection loss of the debonding beam 160, one or more anti-reflection layers 130 can be plated on the back of the silicon carrier layer 110, and the refractive index of the anti-reflection layer 130 can be between the silicon refractive index of the silicon carrier layer 110 and the refractive index of the air. At a certain thickness, the anti-reflection effect can be achieved, thereby eliminating the reflected light on the surface of the silicon carrier layer 110.

[0047] Optionally, the anti-reflection layer 130 may include, but is not limited to, any one of a silicon nitride (SiN) film, a silicon oxide (SiO) film, and a titanium oxide (TiO) film.

[0048] Please continue as Figure 2 As shown, step S120 may be performed: after the anti-reflection layer is prepared, an inorganic absorption layer is prepared on the first surface of the silicon carrier layer to absorb the debonding light beam for sacrifice.

[0049] Specifically, if Figure 1 As shown, in some embodiments of the present invention, the inorganic absorption layer 151 may include a first titanium nitride layer with weak metallic properties. The first titanium nitride layer with weak metallic properties has a high light absorption rate, which is conducive to absorbing the debonding beam, so that it enters the inorganic absorption layer 151 more, so that the inorganic absorption layer 151 can absorb enough laser energy to reach the damage threshold in the subsequent debonding process, thereby ablating and sacrificing to achieve peeling. It can be understood that the first titanium nitride layer is an inorganic absorption layer 151 with low light transmittance but high light absorption rate.

[0050] Since the debonding beam in the present invention uses an infrared laser, the inorganic absorption layer 151 can be an infrared ablation layer ablated by infrared laser irradiation. Compared with the sacrificial layer of organic materials in the prior art, the weakly metallic inorganic first titanium nitride layer has strong thermal stability and can be processed under high temperature and high pressure semiconductor conditions without decomposition and modification.

[0051] In addition, it is worth emphasizing that, since the refractive index of air is about 1 and the refractive index of silicon in the silicon carrier layer 110 is about 3.1, the difference between the two refractive indices is large, so the surface reflection effect is strong in the process of light entering the silicon carrier layer 110 from the air. The refractive index of titanium nitride as the inorganic absorption layer 151 is about 3.3-3.4, which is relatively close to the refractive index of silicon in the silicon carrier layer 110. Therefore, the surface reflection of light entering the inorganic absorption layer 151 from the silicon carrier layer 110 is almost negligible. Therefore, compared with the prior art, the anti-reflection layer 130 is arranged on the front of the silicon carrier layer 110, that is, the position facing the inorganic absorption layer 151, the present invention can achieve a better effect of reducing or eliminating the reflected light on the surface of the silicon carrier layer 110 by arranging the anti-reflection layer 130 on the back of the silicon carrier layer 110, that is, the position facing away from the inorganic absorption layer 151, which can reduce the reflection of the Si surface by about 30%, improve the utilization rate of the laser, and thus improve the processing efficiency.

[0052] Specifically, please refer to Figure 3 , Figure 3 Schematic diagrams of reflectivity curves of semiconductor substrates with and without anti-reflection layers provided in accordance with some embodiments of the present invention are respectively shown.

[0053] like Figure 3 The upper half of the figure shows the reflectivity curve of the debonded infrared laser directly incident on the silicon carrier layer 110 without the anti-reflection layer 130. As shown in point P in the figure, at a wavelength of 2000nm, the reflectivity of the silicon carrier layer 110 is close to 30%. Figure 3 The lower half of the figure shows the reflectivity curve of the silicon carrier layer 110 when the debonding infrared laser is incident from the silicon nitride surface after a 263nm silicon nitride anti-reflection layer 130 is plated on the first surface (i.e., the back surface) of the silicon carrier layer 110. As shown in the Q point in the figure, at a wavelength of 2000nm, the reflectivity of the silicon carrier layer 110 is close to 0%. Therefore, at Figure 3 In the illustrated embodiment, the silicon nitride anti-reflection layer 130 can reduce reflected laser light by 30%.

[0054] Furthermore, in order to improve the firmness of the growth of the first titanium nitride layer on the first surface (i.e., the front surface) of the silicon carrier layer 110, in some preferred embodiments, a silicon dielectric layer can be first prepared on the first surface (i.e., the front surface) of the silicon carrier layer 110 to facilitate the growth of the first titanium nitride layer. Optionally, TEOS can be used as a silicon source in the chemical vapor deposition process to generate a SiO2 film as the silicon dielectric layer.

[0055] Please continue to return Figure 2, then step S130 may be performed: preparing an inorganic reflective layer on the first surface of the inorganic absorption layer to reflect the debonding light beam to the inorganic absorption layer so that the inorganic absorption layer can absorb the debonding light beam for the second time.

[0056] Specifically, if Figure 1 As shown, in some embodiments of the present invention, an inorganic reflective layer 152 can be prepared on the first surface (i.e., the front surface) of the inorganic absorption layer 151. Optionally, the inorganic reflective layer 152 may include a second titanium nitride layer that is a heterostructure with the first titanium nitride layer, wherein the second titanium nitride layer may be a titanium nitride layer with strong metallic properties. Strong metallic properties can enhance the light reflection capability of the inorganic reflective layer 152, which is beneficial for reflecting the infrared laser transmitted through the inorganic absorption layer 151 back into the inorganic absorption layer 151, so that the inorganic absorption layer 151 absorbs the laser energy of the debonding light beam for the second time, and further enhances the utilization rate of the laser energy. Moreover, on the other hand, the inorganic reflective layer 152 has a low light transmittance, and can even be completely opaque, thereby effectively protecting the underlying device layer 120 from laser damage. In this embodiment, by coordinating the reflected laser and secondary absorption between the inorganic reflective layer 152 and the inorganic absorption layer 151 disposed between the silicon carrier layer 110 and the device layer 120, even if the power of the laser is appropriately reduced, the inorganic absorption layer 151 can absorb sufficient laser energy to reach the damage threshold and achieve peeling, thereby improving the debonding efficiency and reducing costs.

[0057] In some embodiments of the present invention, the first titanium nitride layer as the inorganic absorption layer 151 and the second titanium nitride layer as the inorganic reflection layer 152 are mainly made of the same material, titanium nitride, but the ratio of Ti to N is different, which leads to different physical structures, thus forming a titanium nitride layer group with a heterogeneous structure. In this embodiment, two layers of titanium nitride can be prepared separately by adjusting the process parameters for the growth of titanium nitride. The inorganic absorption layer 151 and the inorganic reflection layer 152 can be prepared by one material, which is simple and convenient to operate, and simplifies the process materials and steps.

[0058] Further, in some optional embodiments, the ratio of titanium atoms to nitrogen atoms in the first titanium nitride layer can be 0.6-0.8:1, so that it has weak metallic properties and becomes an inorganic absorption layer 151 with low light transmittance but high light absorption rate. The ratio of titanium atoms to nitrogen atoms in the second titanium nitride layer can be 0.8-1.2:1, so that it has strong metallic properties and becomes an inorganic reflection layer 152 with low light transmittance but high reflectivity. In the inorganic absorption layer 151 and inorganic reflection layer 152 composed of the titanium nitride layer group of this heterostructure provided by the present invention, the second titanium nitride layer can reflect up to 70% of the laser, thereby protecting the device layer 120 while improving the laser energy utilization rate, further improving the completeness of the debonding, and the preparation process is convenient and the operation is simple.

[0059] In addition, the thickness of the first titanium nitride layer as the inorganic absorption layer 151 will also affect the absorption of laser energy. If it is too thin or too thick, the ideal debonding effect cannot be achieved. Preferably, the thickness of the first titanium nitride layer can range from 30 to 100 nm. If the thickness of the first titanium nitride layer is less than 30 nm, it will affect the absorption of laser energy, resulting in insufficient absorbed laser energy to debond the first titanium nitride layer.

[0060] Furthermore, in some embodiments, by adjusting the ratio of titanium atoms and nitrogen atoms in the first titanium nitride layer, the thickness of the first titanium nitride layer can be further reduced. The maximum thickness of the first titanium nitride layer can reach 25 nm. If the thickness of the first titanium nitride layer is less than 25 nm, the laser absorption capacity of the first titanium nitride layer will be seriously affected.

[0061] The thickness of the second titanium nitride layer as the inorganic reflective layer 152 may be in the range of 130 to 500 nm. In some alternative embodiments, the inorganic reflective layer 152 may also be a metal reflective layer. For example, the metal reflective layer may include but is not limited to any one of gold, silver, etc. However, compared with a pure metal reflective layer, the manufacturing process of the titanium nitride reflective layer is simpler and can also save costs.

[0062] In some preferred embodiments, the first titanium nitride layer and the second titanium nitride layer may be deposited simultaneously, that is, the inorganic absorption layer 151 and the inorganic reflection layer 152 are prepared simultaneously, thereby simplifying the process steps and improving the preparation efficiency.

[0063] Please continue to see Figure 2 After that, step S140 may be performed: after the inorganic reflective layer is prepared, the device layer is bonded to the silicon carrier layer on the first surface of the inorganic reflective layer.

[0064] Specifically, if Figure 1 As shown, in some embodiments of the present invention, the device layer 120 can be bonded to the first surface of the inorganic reflective layer 152 in the direction of the first surface of the silicon carrier layer 110 (front direction) to obtain a semiconductor substrate 100, which can be mainly applied to 2.5D and 3D packaging processes. In this embodiment, by performing the above-mentioned multi-layer special coating treatment on the silicon carrier layer 110 in the semiconductor substrate 100, the laser utilization rate of the subsequent debonding beam can be effectively improved, which is convenient for subsequent processing.

[0065] Next, a specific embodiment will be presented to clearly introduce the steps S110 to S130 in the method for preparing the semiconductor substrate and the specific structure of the semiconductor substrate 100 .

[0066] Combination Figure 1 and Figure 2As shown, in one embodiment of the invention, a SiN anti-reflection layer 130 with a thickness of 263 nm is prepared on the incident side of the infrared laser, that is, on the second side (back side) of the silicon carrier layer 110 that first contacts the laser. Optionally, the minimum thickness of the anti-reflection layer 130 can be obtained according to the formula d=λ / 4n, where λ represents the wavelength of the incident laser and n represents the refractive index of the anti-reflection film. Afterwards, on the first side (front side) of the silicon carrier layer 110, TEOS can be used as a silicon source to deposit a thin SiO layer as a silicon dielectric layer 140 to facilitate the subsequent deposition and growth of the first titanium nitride layer, where the thickness of the SiO layer can be 50 nm.

[0067] Subsequently, a first titanium nitride layer with low light transmittance but high light absorption rate can be prepared on the first surface (front side) of the SiO layer as an inorganic absorption layer 151 to absorb the energy of the infrared laser to achieve ablation sacrifice, wherein the ratio of titanium atoms to nitrogen atoms in the first titanium nitride layer can be 0.6-0.8:1, and its thickness can be 100nm. After that, the process parameters of titanium nitride growth can be adjusted to continue growing a layer of titanium nitride layer. The newly obtained second titanium nitride layer is a heterostructure with the first titanium nitride layer, and the second titanium nitride layer is an inorganic reflection layer 152 with low light transmittance but high light reflectivity. The ratio of titanium atoms to nitrogen atoms in the second titanium nitride layer can be 0.8-1.2:1, and its thickness can be 100-200nm. The low light transmittance of the second titanium nitride layer can block the laser and prevent the laser from damaging the device layer 120. At the same time, the high light reflectivity of the second titanium nitride layer can also reflect the laser that is not absorbed by the first titanium nitride layer and return it to the first titanium nitride layer for secondary absorption, further improving the laser utilization rate and ensuring that the first titanium nitride layer can absorb enough laser light and be completely ablated and destroyed.

[0068] Although the above methods are illustrated and described as a series of actions for simplicity of explanation, it should be understood and appreciated that these methods are not limited by the order of the actions, because according to one or more embodiments, some actions may occur in a different order and / or concurrently with other actions from those illustrated and described herein or not illustrated and described herein but understandable to those skilled in the art.

[0069] In summary, the present invention provides a semiconductor substrate and a method for preparing a semiconductor substrate, which can effectively improve the thermal stability of the semiconductor substrate, making it suitable for high temperature and high pressure semiconductor processing conditions. At the same time, it can also improve the utilization rate of the debonding beam and effectively protect the device from damage due to laser irradiation, thereby improving the debonding efficiency and reducing costs.

[0070] The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A semiconductor substrate, formed by bonding a silicon carrier layer and a device layer, wherein: The device layer is located on the first surface of the silicon carrier layer, and the debonding beam is incident from the second surface of the silicon carrier layer, characterized in that the semiconductor substrate comprises: An anti-reflection layer, located on the second surface of the silicon carrier layer, for eliminating reflected light on the surface of the silicon carrier layer; an inorganic absorption layer, located between the silicon carrier layer and the device layer, and used for sacrificially absorbing the debonding beam; and The inorganic reflective layer is located between the inorganic absorption layer and the device layer, and is used for reflecting the debonding light beam to the inorganic absorption layer so that the inorganic absorption layer can absorb the debonding light beam for a second time.

2. The semiconductor substrate according to claim 1, wherein The inorganic absorption layer includes a first titanium nitride layer having a weak metallic property.

3. The semiconductor substrate according to claim 2, wherein: The inorganic reflective layer includes a second titanium nitride layer that is a heterogeneous structure with the first titanium nitride layer, wherein the second titanium nitride layer is a titanium nitride layer with strong metallic properties.

4. The semiconductor substrate according to claim 3, wherein: The ratio of titanium atoms to nitrogen atoms in the first titanium nitride layer is 0.6-0.8:1, and the ratio of titanium atoms to nitrogen atoms in the second titanium nitride layer is 0.8-1.2:

1.

5. The semiconductor substrate according to claim 4, wherein: The thickness of the first titanium nitride layer is in the range of 30 to 100 nm, and the thickness of the second titanium nitride layer is in the range of 130 to 500 nm.

6. The semiconductor substrate according to claim 2, wherein: The inorganic reflective layer includes a metal reflective layer, wherein the metal reflective layer includes any one of gold and silver.

7. The semiconductor substrate according to claim 1, wherein: The anti-reflection layer includes any one of a silicon nitride film, a silicon oxide film, and a titanium oxide film.

8. The semiconductor substrate according to claim 2, wherein: The semiconductor substrate further comprises: The silicon dielectric layer is located between the silicon carrier layer and the first titanium nitride layer to provide growth for the first titanium nitride layer.

9. The semiconductor substrate according to claim 1, wherein: The debonding beam includes an infrared laser, the inorganic absorption layer is an infrared ablation layer, and the inorganic reflection layer is an infrared reflection layer.

10. A method for preparing a semiconductor substrate, characterized in that: The following steps are involved: Obtaining a silicon carrier layer, and preparing an anti-reflection layer on the second surface thereof, for eliminating reflected light on the surface of the silicon carrier layer, wherein the debonding light beam is incident from the second surface of the silicon carrier layer; After the anti-reflection layer is prepared, an inorganic absorption layer is prepared on the first surface of the silicon carrier layer for sacrificially absorbing the debonding light beam; An inorganic reflective layer is prepared on the first surface of the inorganic absorption layer, for reflecting the debonding light beam to the inorganic absorption layer, so that the inorganic absorption layer absorbs the debonding light beam for a second time; and After the inorganic reflective layer is prepared, the device layer is bonded to the silicon carrier layer on the first surface of the inorganic reflective layer.

11. The preparation method according to claim 10, characterized in that: The step of preparing the inorganic reflective layer on the first surface of the inorganic absorption layer comprises: A first titanium nitride layer with a thickness of 30 to 100 nm is prepared on the first surface of the silicon carrier layer, wherein the ratio of titanium atoms to nitrogen atoms in the first titanium nitride layer is 0.6 to 0.8:1; The step of preparing the inorganic reflective layer on the first surface of the inorganic absorption layer comprises: In response to the completion of the preparation of the first titanium nitride layer, a second titanium nitride layer with a thickness of 130 to 500 nm and a heterostructure with the first titanium nitride layer is prepared on the first surface of the first titanium nitride layer, wherein the ratio of titanium atoms to nitrogen atoms in the second titanium nitride layer is 0.8 to 1.2:1.

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