Silicon substrate structure
By designing a trench structure formed in a specific lattice direction on the silicon substrate, the poor epitaxial uniformity and cracks caused by warping of the silicon substrate in heterogeneous epitaxial technology are solved, and a more stable and uniform epitaxial process is achieved.
Patent Information
- Application Number
- CN202311393486.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-09-11
- Filing Date
- 2023-10-25
- Publication Date
- 2025-03-18
AI Technical Summary
In the prior art, heterogeneous epitaxial technology causes silicon substrate warping at high temperatures, affecting the uniformity of the epitaxial process, and may lead to the emergence of cracks.
A silicon substrate structure is designed that includes a plurality of grooves formed in a specific lattice direction to relieve stress caused by substrate warping and provide space for strain relief when temperature changes.
Through the design of the trench structure, the occurrence of cracks during the epitaxial process is reduced, the epitaxial uniformity is improved, and the production yield of the epitaxial film is improved.
Smart Images
Figure CN119653843A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a silicon substrate structure, in particular to a silicon substrate structure with a plurality of grooves formed along a specific lattice direction for eliminating stress during epitaxy. Background Art
[0002] Epitaxy technology plays a key role in semiconductor manufacturing and optoelectronics. It can be mainly divided into two materials: silicon carbide and gallium nitride. The silicon crystal base structure is manufactured through the epitaxial growth of the gallium nitride layer, which is an indispensable basic material for building semiconductor components. Due to production cost considerations, the mainstream of gallium nitride substrates at this stage is still silicon-based gallium nitride technology that grows gallium nitride epitaxy on a silicon substrate, which is a heterogeneous epitaxy technology in the semiconductor industry. Therefore, when the epitaxy grows, the gallium nitride layer will become longer and thicker due to high-temperature expansion, and the silicon substrate will also expand as the temperature rises. The deformation under the silicon substrate will also increase with the thickness of the gallium nitride epitaxial layer, and the tensile strain of the substrate will gradually increase. When the thickness of the gallium nitride film exceeds a certain threshold value, the compressive stress below will shift to other directions, and the squeezing effect on the lower lattice will be more obvious. In addition, as the temperature of epitaxial growth increases, the thermal expansion effect of the gallium nitride layer will become more significant, resulting in an increase in tensile stress, further increasing the amplitude of the central warping of the silicon substrate, and seriously affecting the uniformity of the epitaxy process.
[0003] However, due to the lattice mismatch of the two different materials and the large difference in thermal expansion coefficient, strain is easily accumulated in the heterogeneous materials, causing deformation when the temperature rises during epitaxial growth and uneven stress release when the temperature drops, affecting the quality of epitaxial film formation or causing cracks. The current epitaxial technology used to improve heterogeneous materials includes using pattern design on the front of the epitaxial substrate, designing corresponding grooves on the front of the substrate and filling them with stress compensation materials, and using a buffer layer structure to absorb stress. A more effective epitaxial material is needed to improve the warping of the substrate at high temperatures, and to make the heating range uniform and the stress release averagely after cooling.
[0004] In view of this, the present invention proposes a silicon substrate structure to solve the problems of poor uniformity during epitaxial growth and easy cracking during extension in the prior art. Summary of the invention
[0005] The object of the present invention is to provide a silicon substrate structure, aiming to provide a substrate structure that can enable stable epitaxial growth. The present invention designs grooves at the bottom of the substrate structure, and the grooves are formed according to three specific lattice directions. When the temperature rises, the deformation of the silicon lattice below is spatially compressible, which in turn enables the epitaxial layer above the substrate to grow stably. The groove space can compensate for the deformation caused by the warping of the substrate and relieve the stress gradually accumulated due to the deformation. On the other hand, when the temperature drops, the silicon lattice compressed under the high temperature state will gradually aggregate together, and the cooled gallium nitride layer will also provide compressive strain to the silicon substrate, and the substrate has a groove design that can reduce the deformation amount and release the strain evenly. Therefore, the use of the silicon substrate structure of the present invention can reduce the occurrence of cracks during the epitaxial process, improve uniformity, and further improve the production yield of epitaxial films.
[0006] To achieve the above-mentioned purpose, the present invention discloses a silicon substrate structure, comprising a substrate, a first groove, a second groove and a third groove. The substrate comprises a first surface and a second surface, the first surface is formed on one side of the silicon (111) lattice plane, and the second surface is formed on the other side opposite to the silicon (111) lattice plane; the first groove is arranged on the second surface of the substrate along a first direction; the second groove is arranged on the second surface of the substrate along a second direction; the third groove is arranged on the second surface of the substrate along a third direction; wherein the first direction is defined as the direction from the silicon (111) lattice plane to the silicon (1-1-1) lattice plane, the second direction is defined as the direction from the silicon (-11-1) lattice plane to the silicon (1-11) lattice plane, and the third direction is defined as the axial direction of the silicon [1-10] crystal direction.
[0007] In one embodiment, the first direction forms a first angle with a fourth direction of the silicon (111) lattice plane, and the second direction forms a second angle with the fourth direction of the silicon (111) lattice plane, wherein the fourth direction is perpendicular to the third direction, and the first angle is substantially equal to the second angle.
[0008] In one embodiment, the first angle and the second angle are 35.26±3 degrees.
[0009] In one embodiment, the first groove has a plurality of first groove bodies parallel to the first direction and arranged side by side, the second groove has a plurality of second groove bodies parallel to the second direction and arranged side by side, and the third groove has a plurality of third groove bodies parallel to the third direction and arranged side by side.
[0010] In one embodiment, any one of the first groove bodies, any one of the second groove bodies, or any one of the third groove bodies are arranged continuously or in sections.
[0011] In one embodiment, the first trench body has a first width, the second trench body has a second width, and the third trench body has a third width. The first width, the second width, and the third width may be equal.
[0012] In one embodiment, the first width, the second width, and the third width are respectively between 10 micrometers and 5 millimeters.
[0013] In one embodiment, the substrate and the first groove body define a first height, the substrate and the second groove body define a second height, and the substrate and the third groove body define a third height. The first height, the second height, and the third height may be equal.
[0014] In one embodiment, the first height, the second height and the third height are respectively between 500 micrometers and 2000 micrometers.
[0015] In one embodiment, the substrate has an outer periphery and a cutting edge, and the outer periphery is connected to the cutting edge to define the substrate as a non-circular substrate.
[0016] After referring to the accompanying drawings and the embodiments described below, a person skilled in the art will be able to understand other objects, technical means and embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 is a schematic diagram of a silicon substrate structure and a gallium nitride layer combination according to an embodiment of the present invention;
[0018] Figure 2 A top view of a silicon substrate structure according to an embodiment of the present invention;
[0019] Figure 3 is a schematic diagram of a silicon substrate structure according to an embodiment of the present invention;
[0020] Figure 4 is a schematic diagram of a silicon substrate structure according to another embodiment of the present invention;
[0021] Figure 5 is a schematic diagram of a silicon substrate structure according to another embodiment of the present invention;
[0022] Figure 6 is a schematic diagram of a silicon substrate structure according to another embodiment of the present invention; and
[0023] Figure 7 It is a side view of the silicon substrate structure of the present invention.
[0024] Description of Reference Numerals
[0025] 1000 Silicon substrate structure
[0026] 2000 GaN layer
[0027] 1 substrate
[0028] 11 First Surface
[0029] 12 Second Surface
[0030] 13 Peripheral part
[0031] 14 Trimming
[0032] 2 First groove
[0033] 21 first groove body
[0034] 3 Second groove
[0035] 31 Second groove body
[0036] 4 Third groove
[0037] 41 Third groove body
[0038] D1 First direction
[0039] D2 Second direction
[0040] D3 third direction
[0041] D4 Fourth direction
[0042] θ1 First angle
[0043] θ2 Second angle
[0044] W1 First Width
[0045] W2 Second width
[0046] W3 Third Width
[0047] H1 First Height
[0048] H2 Second Height
[0049] H3 The third height. DETAILED DESCRIPTION
[0050] The present invention will be explained below by way of examples, and the examples of the present invention are not intended to limit the present invention to any specific environment, application or special method as described in the examples. Therefore, the description of the examples is only for the purpose of explaining the present invention, and is not intended to limit the present invention. It should be noted that in the following examples and drawings, elements that are not directly related to the present invention have been omitted and are not shown, and the dimensional relationship between the elements in the drawings is only for easy understanding, and is not intended to limit the actual proportion.
[0051] Please also read Figure 1 and Figure 2 . Figure 1 FIG. 1 is a schematic structural diagram of a silicon substrate structure 1000 and a gallium nitride layer 2000 according to an embodiment of the present invention. Figure 2 The top view of a silicon substrate structure 1000 according to an embodiment of the present invention is shown. A gallium nitride layer 2000 is disposed on the silicon substrate structure 1000 to allow epitaxial growth based on the silicon substrate structure 1000 of the present invention. The silicon substrate structure 1000 includes a substrate 1, a first trench 2, a second trench 3, and a third trench 4, wherein the first trench 2, the second trench 3, and the third trench 4 are formed on the same surface of the substrate 1.
[0052] In detail, the substrate 1 is a silicon substrate oriented along the (111) crystal, and the substrate 1 includes a first surface 11, a second surface 12, a peripheral portion 13 and a cutting edge portion 14. The first surface 11 is formed on one side of the silicon (111) lattice plane. In other words, the first surface 11 is on the surface of the silicon (111) lattice plane of the substrate 1. The second surface 12 is formed on the other side of the silicon (111) lattice plane. In other words, the second surface 12 is below the surface of the silicon (111) lattice plane of the substrate 1. The peripheral portion 13 and the cutting edge portion 14 are both outer edge regions of the substrate 1, wherein the peripheral portion 13 is connected to the cutting edge portion 14 to define the substrate 1 as a non-circular substrate. It should be noted that the cutting edge portion 14 in this embodiment is located at the lower edge of the substrate 1 as an example, and its cutting edge position can be adjusted according to actual needs and is not limited here.
[0053] Further describing the first groove 2, the second groove 3 and the third groove 4, the first groove 2 is arranged on the second surface 12 of the substrate 1 along a first direction D1, and the first groove 2 has a plurality of first groove bodies 21 parallel to the first direction D1 and arranged side by side. The second groove 3 is arranged on the second surface 12 of the substrate 1 along a second direction D2, and the second groove 3 has a plurality of second groove bodies 31 parallel to the second direction D2 and arranged side by side. The third groove 4 is arranged on the second surface 12 of the substrate 1 along a third direction D3, and the third groove 4 has a plurality of third groove bodies 41 parallel to the third direction D3 and arranged side by side. The first groove 2, the second groove 3 and the third groove 4 are arranged in the same lattice direction. Among them, the first direction D1 is defined as the direction from the silicon (111) lattice plane to the silicon (1-1-1) lattice plane, the second direction D2 is defined as the direction from the silicon (-11-1) lattice plane to the silicon (1-11) lattice plane, and the third direction D3 is defined as the axial direction of the silicon [1-10] crystal direction. At the same time, there is a direction on the substrate 1 that is perpendicular to the third direction D3 and is defined as a fourth direction D4 on the silicon (111) lattice plane.
[0054] As described above, the first direction D1 and the fourth direction D4 form a first angle θ1, the second direction D2 and the fourth direction D4 form a second angle θ2, and the first angle θ1 is substantially equal to the second angle θ2. In this embodiment, the angles of the first angle θ1 and the second angle θ2 are 35.26±3 degrees. In other words, the angle between the first groove body 21 and the second groove body 31 is the sum of the first angle θ1 and the second angle θ2.
[0055] Next, the first groove body 21, the second groove body 31 and the third groove body 41 are described. Figure 7 As shown, the first groove body 21 has a first width W1, the second groove body 31 has a second width W2, and the third groove body 41 has a third width W3. In detail, the first groove body 21, the second groove body 31 and the third groove body 41 can be groove bodies of equal width, and the first width W1 is equal to the second width W2 and equal to the third width W3. On the other hand, the first groove body 21, the second groove body 31 and the third groove body 41 can also be groove bodies of unequal widths, so at least two of the first width W1, the second width W2 and the third width W3 are unequal. In this embodiment, the first width W1, the second width W2 and the third width W3 can be respectively between 10 micrometers (μm) and 5 millimeters (mm).
[0056] As shown above, the first surface 11 of the substrate 1 and the first groove body 21 define a first height H1, the first surface 11 of the substrate 1 and the second groove body 31 define a second height H2, and the first surface 11 of the substrate 1 and the third groove body 41 define a third height H3. In detail, the first groove body 21, the second groove body 31 and the third groove body 41 can be groove bodies of equal height, and the first height H1 is equal to the second width H2 and equal to the third width H3. On the other hand, the first groove body 21, the second groove body 31 and the third groove body 41 can also be groove bodies of unequal heights, so at least two of the first height H1, the second height H2 and the third height H3 are unequal. In this embodiment, the first height H1, the second height H2 and the third height H3 are respectively between 500 micrometers (μm) and 2000 micrometers (μm). In other words, the first height H1, the second height H2 and the third height H3 are the distances reserved between the deepest parts of the first groove body 21, the second groove body 31 and the third groove body 41 and the first surface 11 of the substrate 1. The width distance of each groove body and the height distance between each groove body and the surface of the substrate 1 provide stress release for the substrate 1 due to temperature changes during epitaxy.
[0057] See next Figures 3 to 6To illustrate multiple embodiments of the silicon substrate structure 1000 of the present invention. Figure 3 As shown, the first groove bodies 21 formed on the second surface 12 of the substrate 1 are parallel to each other along the first direction D1, the second groove bodies 31 formed on the second surface 12 of the substrate 1 are parallel to each other along the second direction D2, and the third groove bodies 41 formed on the second surface 12 of the substrate 1 are parallel to each other along the third direction D3, wherein the first groove body 21, the second groove body 31 or the third groove body 41 is a continuous groove body and extends to the outer peripheral portion 13 and the trimming portion 14 of the substrate 1, and the first groove body 21, the second groove body 31 and the third groove body 41 present an interconnected triangular pattern. In another embodiment of the present invention, similarly, the first groove body 21, the second groove body 31 and the third groove body 41 are respectively arranged on the substrate 1 along the first direction D1, the second direction D2 and the third direction D3, wherein the first groove body 21, the second groove body 31 or the third groove body 41 is a discontinuous and segmented groove body, and is only arranged on the periphery of the second surface 12 of the substrate 1, and the central area of the substrate 1 does not form the groove body, such as Figure 4 Furthermore, in another embodiment of the present invention, the first groove body 21, the second groove body 31 or the third groove body 41 is also a discontinuous and segmented groove body, and the first groove body 21, the second groove body 31 and the third groove body 41 are respectively uniformly arranged on the substrate 1 along the first direction D1, the second direction D2 and the third direction D3, so that the first groove body 21, the second groove body 31 and the third groove body 41 present a triangular pattern that is not connected to each other, as shown in FIG. Figure 5 Alternatively, in another embodiment of the present invention, the first groove body 21, the second groove body 31 or the third groove body 41 is also a discontinuous groove body and presents a segmented groove body, and the segmented first groove body 21, the second groove body 31 and the third groove body 41 are connected to each other to form a closed triangular pattern, and the triangular patterns of different sizes can overlap each other, such as Figure 6 It should be noted that the first trench body 21, the second trench body 31 and the third trench body 41 of the silicon substrate structure 1000 of the present invention are mainly designed and formed according to the corresponding lattice directions. The first trench body 21 is based on the first direction D1, the second trench body 31 is based on the second direction D2, and the third trench body 41 is based on the third direction D3. The trench bodies formed in these three specific directions all have the function of alleviating or eliminating the stress generated at the bottom of the substrate due to high temperature warping, and Figures 3 to 6 The embodiment is taken as an example, and the position and number of the groove bodies formed can be adjusted according to actual needs and are not limited here.
[0058] In this embodiment, the user can form the first groove body 21, the second groove body 31 and the third groove body 41 by etching, laser cutting and scraping, and the manufacturing method is not limited here. In addition, the first groove body 21, the second groove body 31 and the third groove body 41 can be distributed according to the local stress ratio of the substrate 1 to distribute the groove body density on the substrate 1. For example, the distribution of the groove body can form a comprehensive or local pattern on the second surface 12 of the substrate 1. The pattern can also be overlapped or crossed with different sizes, and the groove body can also be adjusted in size to be used alternately.
[0059] In summary, the silicon substrate structure of the present invention comprises a combination of a substrate, a first groove, a second groove and a third groove, wherein the grooves are formed along respective corresponding lattice directions, and through the design of a plurality of first groove bodies in the first groove, a plurality of second groove bodies in the second groove, and a plurality of third groove bodies in the third groove, and the combination of the width of the groove body and the remaining thickness of the substrate after deducting the groove depth, the silicon substrate structure has a compression space for strain release. Thus, the occurrence of epitaxial cracks can be reduced, and the uniformity of epitaxial and the production yield can be improved.
[0060] The above embodiments are only used to illustrate the implementation methods of the present invention and to explain the technical features of the present invention, and are not used to limit the protection scope of the present invention. Any changes or equivalent arrangements that can be easily completed by those skilled in the art belong to the scope claimed by the present invention, and the scope of protection of the present invention shall be subject to the attached claims.
Claims
1. A silicon substrate structure, comprising: A substrate comprising a first surface and a second surface, wherein the first surface is formed on one side of a silicon (111) crystal lattice plane, and the second surface is formed on the other side opposite to the silicon (111) crystal lattice plane; A first groove is disposed on the second surface of the substrate along a first direction; a second groove disposed on the second surface of the substrate along a second direction; and a third groove disposed on the second surface of the substrate along a third direction; Among them, the first direction is defined as the direction from the silicon (111) lattice plane to the silicon (1-1-1) lattice plane, the second direction is defined as the direction from the silicon (-11-1) lattice plane to the silicon (1-11) lattice plane, and the third direction is defined as the axial direction of the silicon [1-10] crystal direction.
2. The silicon substrate structure according to claim 1, wherein: The first direction forms a first angle with a fourth direction of the silicon (111) lattice plane, and the second direction forms a second angle with the fourth direction of the silicon (111) lattice plane, wherein the fourth direction is perpendicular to the third direction, and the first angle is substantially equal to the second angle.
3. The silicon substrate structure according to claim 2, wherein: The first angle and the second angle are 35.26±3 degrees.
4. The silicon substrate structure according to claim 1, wherein: The first groove has a plurality of first groove bodies parallel to the first direction and arranged side by side, the second groove has a plurality of second groove bodies parallel to the second direction and arranged side by side, and the third groove has a plurality of third groove bodies parallel to the third direction and arranged side by side.
5. The silicon substrate structure according to claim 4, wherein: Any one of the first groove bodies, any one of the second groove bodies or any one of the third groove bodies are arranged continuously or in sections.
6. The silicon substrate structure according to claim 4, wherein: The first trench body has a first width, the second trench body has a second width, and the third trench body has a third width. The first width, the second width, and the third width may be equal.
7. The silicon substrate structure according to claim 6, wherein: The first width, the second width and the third width are respectively between 10 micrometers and 5 millimeters.
8. The silicon substrate structure according to claim 4, wherein: The substrate and the first groove body define a first height, the substrate and the second groove body define a second height, and the substrate and the third groove body define a third height. The first height, the second height and the third height may be equal.
9. The silicon substrate structure according to claim 8, wherein: The first height, the second height and the third height are respectively between 500 micrometers and 2000 micrometers.
10. The silicon substrate structure according to claim 1, wherein: The substrate has an outer periphery and a cutting edge, wherein the outer periphery is connected to the cutting edge to define the substrate as a non-circular substrate.