Manufacturing method of semiconductor device
By forming an annular solid joint at low air pressure and maintaining the semiconductor substrate by using the air pressure differential adsorption force, the problems of bonding difficulties and high-temperature treatment in the prior art are solved, and efficient and low-cost semiconductor substrate processing is achieved.
Patent Information
- Application Number
- CN202380085253.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-12-14
- Filing Date
- 2023-12-05
- Publication Date
- 2025-07-22
AI Technical Summary
In the prior art, when using hydrogen ion implantation to form a semiconductor substrate, it is necessary to use a support to maintain the semiconductor substrate, which makes it difficult to bond and costly during high-temperature treatment, and it is difficult to effectively remove the support, affecting subsequent processing.
By forming an annular solid joint in a low air pressure atmosphere, the semiconductor substrate and the second substrate are firmly bonded, and the semiconductor substrate is maintained by the adsorption force generated by the air pressure difference, avoiding the entire area bonding and simplifying the processing process.
The stable maintenance of the semiconductor substrate under high temperature treatment is achieved, the processing flow is simplified, the cost is reduced, and the defects caused by stress is reduced, and the manufacturing efficiency of semiconductor devices is improved.
Smart Images
Figure CN120359595A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a manufacturing technology of semiconductor devices. Background Art
[0002] As a manufacturing technology of semiconductor devices, there is a technology having a process of forming a semiconductor substrate with a required thickness (for example, a thickness of 150 μm or less) by grinding (polishing) a semiconductor wafer (for example, a wafer having a thickness of about 300 μm).
[0003] In recent years, as semiconductor materials that can operate semiconductors normally even at a high temperature of up to 300°C, wide bandgap (WBG) materials such as GaAs, SiC, GaN, AlN, BN, and diamond have attracted much attention. WBG materials are also semiconductor materials that can achieve high switching speeds. From this point of view, they are expected as materials for semiconductor devices for high-speed communication. In addition, WBG materials are also semiconductor materials that are resistant to high electric fields. From this point of view, they are also expected as materials for semiconductor devices for high voltage. Thus, WBG materials have advantages as materials for semiconductor devices in various aspects.
[0004] On the other hand, WBG materials are expensive materials. Nevertheless, in the case of forming a semiconductor substrate of a WBG material by grinding a semiconductor wafer, the portion removed by grinding in the semiconductor wafer becomes wasted, resulting in a significant increase in manufacturing cost.
[0005] Then, in order to prevent such waste, the following technology has been proposed: a split layer is formed in the semiconductor wafer by injecting hydrogen ions from the surface of the semiconductor wafer, and the semiconductor wafer is split at the split layer, thereby forming a semiconductor substrate (for example, refer to Patent Document 1). According to such a technology, a thin semiconductor substrate can be manufactured without wasting the semiconductor material constituting the semiconductor wafer.
[0006] Prior Art Documents
[0007] Patent Documents
[0008] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2007-250576 Summary of the Invention
[0009] Technical Problem to be Solved by the Invention
[0010] In the above-described technique of forming a semiconductor substrate by implanting hydrogen ions, when dividing a semiconductor wafer at a dividing layer, it is necessary to hold the portion that becomes the semiconductor substrate with a support body (such as a glass substrate). On the other hand, the semiconductor substrate separated from the semiconductor wafer is exposed to a high-temperature atmosphere in a state of being held by the support body in a process of forming a circuit on the semiconductor substrate. Therefore, in order to hold the semiconductor substrate with the support body, it is necessary to previously bond the semiconductor wafer and the support body, but it is difficult to select an adhesive as a bonding means.
[0011] Thus, in the prior art, as a bonding means between the semiconductor wafer and the support body, the following method (direct bonding method) is used: after performing CMP (Chemical Mechanical Polishing) on both bonding surfaces of the two, the bonding surfaces are directly bonded to each other, and thus the bonding surfaces are bonded to each other in the entire region by an interatomic force or an intermolecular force.
[0012] However, in the bonding using CMP, (1) there is a problem that the cost required for the CMP process becomes high, and (2) since the semiconductor wafer and the support body are firmly bonded, when it is desired to remove the support body from the semiconductor substrate separated from the semiconductor wafer, there is a problem that a process of shaving off the support body by grinding or the like is required.
[0013] Thus, an object of the present invention is to facilitate the processing of a semiconductor substrate after the formation of the semiconductor substrate in a manufacturing technique of a semiconductor device having a process of forming a semiconductor substrate using a dividing layer.
[0014] Technical means for solving technical problems
[0015] The manufacturing method of the semiconductor device of the present invention includes a dividing layer forming step, a fixing portion forming step, and a dividing step. In the dividing layer forming step, a dividing layer is formed at a position of a predetermined depth from the surface of a first substrate mainly composed of a semiconductor, and the dividing layer is used to enable a semiconductor substrate having a thickness of the predetermined depth to be separated from the first substrate. After the dividing layer forming step, in the fixing portion forming step, a fixing portion for fixing the portion that becomes the semiconductor substrate in the first substrate to a second substrate is formed in a ring shape in an atmosphere of a pressure lower than a predetermined pressure, and thus the inside of the ring is sealed. After the fixing portion forming step, in the dividing step, the first substrate is divided at the dividing layer in the atmosphere of the predetermined pressure.
[0016] According to the above manufacturing method, in the step of forming the fixed connection part, by forming a ring-shaped fixed connection part in an atmosphere with a pressure lower than a specified pressure (e.g., atmospheric pressure), in an atmosphere with a specified pressure (the atmosphere used in the dividing step), a pressure difference can be generated between the pressure inside the ring (internal pressure) and the pressure outside the ring (external pressure) of the fixed connection part. As a result, an adsorption force caused by the pressure difference can be generated between the first substrate and the second substrate. Thus, in an atmosphere with a specified pressure, the first substrate and the second substrate can be firmly joined by using the joining force of the fixed connection part and the adsorption force generated by the pressure difference between the internal pressure and the external pressure. Therefore, even if the first substrate and the second substrate are not joined over the entire area of the joining surface as in the prior art (i.e., even if joining using CMP is not performed), sufficient joining force to hold the semiconductor substrate separated from the first substrate in the dividing step on the second substrate can be obtained.
[0017] Effect of the Invention
[0018] According to the present invention, in a manufacturing technique of a semiconductor device having a process of forming a semiconductor substrate using a dividing layer, the processing of the semiconductor substrate after its formation becomes easy. Description of the Drawings
[0019] Figure 1 It is a conceptual diagram showing the manufacturing method of the embodiment in the order of processing.
[0020] Figure 2 It is shown in the order of processing Figure 1 of the subsequent processing.
[0021] Figure 3 It is a top view (plan view) showing the shape of the fixed connection part formed in the embodiment.
[0022] Figure 4 It is a conceptual diagram showing a part of the manufacturing method of the first modification example in the order of processing.
[0023] Figure 5 (A) of [] is a conceptual diagram showing the dividing layer formation step performed by the manufacturing method of the second modification example, Figure 5 and (B) of [] is a conceptual diagram showing a comparative example.
[0024] Figure 6 It is a conceptual diagram showing a part of the manufacturing method of the fourth modification example in the order of processing.
[0025] Figure 7 It is a top view showing the shape of the fixed connection part formed in the fourth modification example.
[0026] Figure 8 (A) of [] and Figure 8 (B) of [] are showing regardingFigure 6 and Figure 7 Conceptual diagram and top view of another modification example of the manufacturing method of
[0027] Figure 9 is a top view showing a first example of the shape of the fixed connection portion Q formed in the fifth modification example.
[0028] Figure 10 of (A) and Figure 10 of (B) are top views respectively showing a second example and a third example of the shape of the fixed connection portion Q formed in the fifth modification example.
[0029] Figure 11 of (A) is a conceptual diagram showing the fixed connection portion forming step and the cutting step performed by the manufacturing method of the sixth modification example, Figure 11 of (B) is a top view showing the shape of the fixed connection portion formed in the sixth modification example.
[0030] Figure 12 is a conceptual diagram showing the cutting step and the peeling step performed by the manufacturing method of the eighth modification example. Detailed implementation mode
[0031] Hereinafter, the manufacturing method of the semiconductor device of the present invention will be specifically described for its implementation mode and modification examples. In addition, the manufacturing method described below can be implemented using various known devices.
[0032] [1] Implementation mode
[0033] Figure 1 and Figure 2 are conceptual diagrams showing the manufacturing method of the implementation mode in the order of processing. In this manufacturing method, a dividing layer forming step S1, a fixed connection portion forming step S2, a dividing step S3, a device forming step S4, a cutting step S5, a peeling step S6, and a singulation step S7 are sequentially performed. Hereinafter, each step will be specifically described.
[0034] <Dividing layer forming step S1>
[0035] In the dividing layer forming step S1 (refer to Figure 1)In this case, a dividing layer 111 is formed at a position of a prescribed depth Dt from the surface 11a of a first substrate 11 mainly composed of a semiconductor. Here, the first substrate 11 is not particularly limited. For example, it is a single crystal semiconductor wafer, and as its main component (semiconductor), wide bandgap (WBG) materials such as GaAs, SiC, GaN, AlN, BN, and diamond can be used. In addition, the dividing layer 111 is a layer for enabling a semiconductor substrate K having a thickness Td corresponding to the prescribed depth Dt to be separated from the first substrate 11, and can be formed by implanting hydrogen ions from the surface 11a of the first substrate 11. According to the method of implanting hydrogen ions, the dividing layer 111 can be formed at a position about 10 μm deep from the surface 11a or at a shallower position than that, and as a result, a thin semiconductor substrate K having a thickness Td can be obtained.
[0036] Here, when forming the dividing layer 111, instead of the method of implanting hydrogen ions, a method of irradiating a laser with a position at a prescribed depth Dt from the surface 11a as a focal point can be used. According to this method, the position of the focal point can be changed in the depth direction, and thus the dividing layer 111 can be formed at a required depth position. Therefore, according to the method of irradiating a laser, the dividing layer 111 can be formed at a position deeper than the method of implanting hydrogen ions (for example, at a depth position about 50 to 150 μm from the surface 11a), and as a result, a larger semiconductor substrate K having a thickness Td can be obtained.
[0037] The first substrate 11 is divided at the dividing layer 111 in a subsequent dividing step S3, and as a result, a semiconductor substrate K having a thickness Td corresponding to the prescribed depth Dt is separated from the first substrate 11. Here, when dividing the first substrate 11, it is necessary to hold the portion that becomes the semiconductor substrate K with a support. Then, in the subsequent bonding portion forming step S2, a second substrate 12 serving as a support is bonded to the surface 11a of the first substrate 11.
[0038] <Bonding Portion Forming Step S2>
[0039] The second substrate 12 is not particularly limited. For example, it is a polycrystalline semiconductor wafer, and as its main component (semiconductor), wide bandgap (WBG) materials such as GaAs, SiC, GaN, AlN, BN, and diamond can be used. In addition, as the second substrate 12, a substrate formed of other materials (Si, sapphire, quartz, etc.) not limited to semiconductors can be used instead of the semiconductor wafer.
[0040] In the bonding portion forming step S2, a bonding portion Q for bonding the portion of the first substrate 11 that becomes the semiconductor substrate K to the second substrate 12 is formed in a ring shape in an atmosphere at a pressure lower than a specified pressure Pt, thereby sealing the inside of the ring. Here, the specified pressure Pt is the pressure of the atmosphere used in the dividing step S3 described later, and is not particularly limited, for example, it is the atmospheric pressure.
[0041] Specifically, in the bonding portion forming step S2 (refer to Figure 1 ), the metal layer forming step S21 and the laser irradiation step S22 are sequentially performed.
[0042] In the metal layer forming step S21, a metal layer 13 is formed on the entire surface 11a of the first substrate 11. The metal layer 13 is formed with a thickness of 1 μm or less using a film forming method such as vapor deposition, but is not particularly limited. In addition, metals such as Cu, Al, Cr, Ti, Ta, and Au can be used as the main component of the metal layer 13.
[0043] Then, in the laser irradiation step S22, the first substrate 11 and the second substrate 12 are opposed to each other in such a state that the metal layer 13 is interposed therebetween. Then, in this state, by irradiating the portion of the metal layer 13 where the bonding portion Q is to be formed (in this embodiment, the portion on the peripheral edge portion 112 of the first substrate 11. Details will be described later, (refer to Figure 3 )) with laser light, that portion is heated. At this time, the first substrate 11 and the second substrate 12 may also be clamped by a quartz plate or the like to improve the adhesion between them and the portion of the metal layer 13 where the bonding portion Q is to be formed.
[0044] By irradiating the metal layer 13 with laser light in this way, at the laser irradiation site (the portion where the bonding portion Q is to be formed), the metal layer 13 can be melted together with the first substrate 11 and the second substrate 12, or the metal that is the main component of the metal layer 13 can be diffused into the first substrate 11 and the second substrate 12. As a result, at each interface between the first substrate 11 and the second substrate 12 and the metal layer 13, a compound (such as metal silicide) or alloy (such as metal-Si alloy) of the main components (such as semiconductor) of the first substrate 11 and the second substrate 12 and the metal is formed, thereby enabling the formation of the bonding portion Q that firmly bonds the first substrate 11 (the portion that becomes the semiconductor substrate K) to the second substrate 12.
[0045] Such a bonding portion Q is continuously and annularly formed in an atmosphere at a pressure lower than the specified pressure Pt, whereby the inside of the ring is sealed in a state at a pressure lower than the specified pressure Pt.
[0046] Figure 3 is a top view showing the shape of the bonding portion Q formed in this embodiment. As Figure 3As shown, in the present embodiment, on the peripheral portion 112 of the first substrate 11 (specifically, the peripheral portion of the part of the first substrate 11 that becomes the semiconductor substrate K. Also refer to Figure 1 ), a fixing portion Q is formed over the entire circumference of the peripheral portion 112. In the example of Figure 3 , the first substrate 11 is in the shape of a disc, and the fixing portion Q is formed in a circular ring shape along the peripheral portion 112.
[0047] In addition, the shape of the fixing portion Q is not limited to a circular ring shape, and can be appropriately changed to a ring shape of other shapes (polygons, etc.) according to the peripheral shape of the first substrate 11. Further, when the fixing portion Q is formed on the peripheral portion 112 of the first substrate 11 as in the present embodiment, in the metal layer forming step S21, it is not limited to the case where the metal layer 13 is formed on the entire surface 11a of the first substrate 11. Instead, the metal layer 13 can be formed only in the region on the peripheral portion 112 of the surface 11a, or the metal layer 13 can be formed only in the portion where the fixing portion Q is to be formed on the surface 11a. Furthermore, in the metal layer forming step S21, instead of forming the metal layer 13 on the surface 11a of the first substrate 11, the metal layer 13 can be formed on the surface 12a of the second substrate 12. In this case, in the metal layer forming step S21, it is not limited to the case where the metal layer 13 is formed on the entire surface 12a of the second substrate 12. Instead, the metal layer 13 can be formed only in the region on the surface 12a that faces the peripheral portion 112, or the metal layer 13 can be formed only in the portion where the fixing portion Q is to be formed on the surface 12a.
[0048] According to such a fixing portion forming step S2, by forming the annular fixing portion Q in an atmosphere at a pressure lower than a specified pressure Pt (e.g., atmospheric pressure), in an atmosphere at the specified pressure Pt (the atmosphere used in the subsequent dividing step S3), a pressure difference can be generated between the pressure (internal pressure) inside the ring of the fixing portion Q and the pressure (external pressure) outside the ring. As a result, an adsorption force caused by the pressure difference can be generated between the first substrate 11 and the second substrate 12. Therefore, in an atmosphere at the specified pressure Pt, using the bonding force based on the fixing portion Q and the adsorption force caused by the pressure difference between the internal pressure and the external pressure, the first substrate 11 and the second substrate 12 can be firmly bonded. Thus, even if the first substrate 11 and the second substrate 12 are not bonded over the entire area of the bonding surface as in the prior art (i.e., even if bonding using CMP is not performed), sufficient bonding force for holding the semiconductor substrate K separated from the first substrate 11 on the second substrate 12 in the subsequent dividing step S3 can be obtained.
[0049] Thus, in the case where the fixing portion Q is formed in a ring shape along the peripheral portion 112 as in the present embodiment, the peripheral portion 112 in the semiconductor substrate K can be held on the second substrate 12 by the bonding force based on the fixing portion Q, and the portion inside the fixing portion Q in the semiconductor substrate K (the portion provided with a plurality of device regions Rd) can be held on the second substrate 12 by the adsorption force caused by the pressure difference. As a result, the semiconductor substrate K can be held on the second substrate 12 with sufficient bonding force.
[0050] <Dividing step S3>
[0051] In the dividing step S3 (refer to Figure 1 ), the atmospheric pressure of the atmosphere is adjusted to a specified pressure Pt (for example, atmospheric pressure). Thus, the portion of the first substrate 11 that becomes the semiconductor substrate K is held on the second substrate 12 with sufficient bonding force (the bonding force based on the fixing portion Q and the adsorption force generated by the pressure difference between the internal pressure and the external pressure). Then, in the dividing step S3, in the atmosphere of the specified pressure Pt, the first substrate 11 is divided at the dividing layer 111.
[0052] Thus, the semiconductor substrate K having the dividing layer 111 and having a thickness Td corresponding to the depth (specified depth Dt) is separated from the first substrate 11 while being held on the second substrate 12. Then, the following-described device forming step S4 is performed on the semiconductor substrate K. On the other hand, the remaining portion 11R (the remaining portion after division) of the first substrate 11 other than the semiconductor substrate K is reused for manufacturing a new semiconductor substrate K and semiconductor devices.
[0053] <Device forming step S4>
[0054] In the device forming step S4 (refer to Figure 2 ), at least a part (hereinafter, referred to as "element Gd") of the elements included in the semiconductor devices is manufactured in each of the plurality of device regions Rd provided in the semiconductor substrate K (also refer to Figure 3 ). In the device forming step S4, elements Gd such as MOSFETs and Schottky diodes can be formed in each device region Rd, but there is no particular limitation. In addition, before forming the element Gd on the semiconductor substrate K, the surface Ka of the semiconductor substrate K (the surface that appears due to the division of the dividing layer 111) may be ground to adjust the smoothness (surface roughness) of the surface Ka to the smoothness required for manufacturing the element Gd on the semiconductor substrate K.
[0055] Such a device forming step S4 is mostly performed at a high temperature exceeding 1000°C. Here, consider the case where the coefficient of thermal expansion of the semiconductor substrate K is different from that of the second substrate 12. In this case, if the semiconductor substrate K and the second substrate 12 are bonded over the entire area of the bonding surface as in the prior art (i.e., bonding using CMP is performed), then due to such bonding over the entire area of the bonding surface, when the device forming step S4 is performed at a high temperature, the substrate with the larger coefficient of thermal expansion among the semiconductor substrate K and the second substrate 12 stretches the other substrate and expands it beyond the coefficient of thermal expansion. Conversely, the other substrate hinders the expansion of one substrate. Therefore, stress is generated in the semiconductor substrate K and the second substrate 12, and this stress may cause defects such as deformation to appear in the semiconductor substrate K and the second substrate 12. In addition, the stress generated in the semiconductor substrate K may also be the cause of defects in elements Gd such as MOSFETs and Schottky diodes formed on the semiconductor substrate K.
[0056] On the other hand, in the present embodiment, the semiconductor substrate K and the second substrate 12 are not bonded to each other inside the fixed portion Q. Therefore, in the case where the device forming step S4 is performed at a high temperature, inside the fixed portion Q, the substrate with the larger coefficient of thermal expansion among the semiconductor substrate K and the second substrate 12 can bend independently of the other substrate. As a result, both of these substrates can expand by an amount corresponding to their own coefficient of thermal expansion. Therefore, stress is not easily generated in the semiconductor substrate K and the second substrate 12, and thus, defects are not easily generated in elements Gd such as MOSFETs and Schottky diodes formed on the semiconductor substrate K.
[0057] <Cutting step S5>
[0058] In the cutting step S5 (refer to Figure 2 ), the semiconductor substrate K and the second substrate 12 are held on the holding sheet 14 in a posture where the semiconductor substrate K faces the holding sheet 14. In this state, the second substrate 12 and the semiconductor substrate K are cut annularly along the fixed portion Q inside the annular fixed portion Q. Specifically, the cutting is performed in such a way that the cutting line becomes a cutting line surrounding all the device regions Rd provided on the semiconductor substrate K. The cutting method at this time can use a blade cutting method, a plasma etching method, a laser ablation method, etc.
[0059] In this embodiment, the semiconductor substrate K and the second substrate 12 are not bonded to each other inside the bonding portion Q. Therefore, by cutting inside the annular bonding portion Q, the portions of the semiconductor substrate K and the second substrate 12 that are closer to the inside than the cut portion are in a state of being separated from the bonding portion Q. That is, the inner portions thereof are released from the bonding based on the bonding portion Q. In addition, by this cutting, the sealing inside the ring (inside the annular portion) performed by the bonding portion Q is released, and as a result, the adsorption force generated by the pressure difference between the internal pressure and the external pressure disappears. Thereby, the portion of the second substrate 12 that is closer to the inside than the cut portion (hereinafter, referred to as "inner portion 121") is in a state of being separated from both the bonding portion Q and the semiconductor substrate K. In other words, the inner portion 121 of the second substrate 12 is in a state where it is easily peeled off from the semiconductor substrate K.
[0060] <Peeling step S6>
[0061] In the peeling step S6 (refer to Figure 2 ), the inner portion 121 of the second substrate 12 is peeled off from the semiconductor substrate K at the interface between the second substrate 12 and the metal layer 13. Thereby, the metal layer 13 can be exposed inside the annular portion 122 left after peeling in the second substrate 12 (after peeling of the inner portion 121). After that, for the exposed metal layer 13, by using methods such as grinding and etching to remove the metal layer 13, the semiconductor substrate K can be exposed inside the annular portion 122.
[0062] In addition, in the above-described bonding portion forming step S2, when the metal layer 13 is formed on the surface 12a of the second substrate 12 instead of on the surface 11a of the first substrate 11, in the peeling step S6, the inner portion 121 of the second substrate 12 can be peeled off from the semiconductor substrate K at the interface between the metal layer 13 and the semiconductor substrate K. In this case, by peeling off only the inner portion 121 of the second substrate 12, the semiconductor substrate K can be exposed. Also, in the metal layer forming step S21, when the metal layer 13 is formed only in the region on the peripheral portion 112 of the surface 11a of the first substrate 11 or in the region on the surface 12a of the second substrate 12 that is opposite to the peripheral portion 112, there is no metal layer 13 between the semiconductor substrate K and the second substrate 12 inside the peripheral portion 112. Therefore, in this case as well, by peeling off only the inner portion 121 of the second substrate 12, the semiconductor substrate K can be exposed.
[0063] <Singulation step S7>
[0064] In the singulation step S7 (refer to Figure 2)In the case where the semiconductor substrate K is held on the holding wafer 14, dicing is performed on the semiconductor substrate K, whereby a plurality of device regions Rd provided on the semiconductor substrate K are singulated respectively. Specifically, by dicing the semiconductor substrate K along the boundary line Lb (refer to Figure 3 ), the semiconductor substrate K is diced, and the plurality of device regions Rd are singulated respectively. The dicing method at this time can use a blade dicing method, a plasma etching method, a laser ablation method, etc. Thus, a plurality of semiconductor devices having elements Gd such as MOSFETs and Schottky diodes can be manufactured.
[0065] According to the manufacturing method of the present embodiment, as described above, by using the bonding force brought by the annular fixing portion Q and the adsorption force generated by the pressure difference between the air pressure (internal air pressure) inside the ring and the air pressure (external air pressure) outside the ring, the first substrate 11 and the second substrate 12 can be firmly bonded. Therefore, even if the first substrate 11 and the second substrate 12 are not bonded over the entire area of the bonding surface as in the prior art (that is, even if bonding using CMP is not performed), sufficient bonding force for holding the semiconductor substrate K separated from the first substrate 11 on the second substrate 12 in the dividing step S3 can be obtained. In addition, since the semiconductor substrate K and the second substrate 12 are not bonded to each other inside the fixing portion Q, by dicing inside the annular fixing portion Q in the dicing step S5, the inner portion 121 of the second substrate 12 can be easily peeled off from the semiconductor substrate K, and the semiconductor substrate K can be exposed by peeling off the inner portion 121.
[0066] Thus, according to the manufacturing method of the present embodiment, in the manufacturing technology of semiconductor devices having a process of forming the semiconductor substrate K using the dividing layer 111, the processing of the semiconductor substrate K becomes easy after the formation of the semiconductor substrate K (in the present embodiment, after performing the dividing step S3).
[0067] [2] Modification
[0068] [2-1] First modification
[0069] Figure 4It is a conceptual diagram showing a part of the manufacturing method of the first modification example in the processing order. In the above manufacturing method, the reinforcing layer forming step S8 may also be performed after the peeling step S6 and before the singulation step S7. Specifically, in the reinforcing layer forming step S8, on the back surface Kb of the semiconductor substrate K (which is the surface 11a of the first substrate 11) located on the side opposite to the surface Ka of the semiconductor substrate K facing the holding sheet 14, inside the annular portion 122 remaining after peeling (after peeling of the inner portion 121) in the second substrate 12, a reinforcing layer 21 with a specified thickness Te is formed as a reinforcing substrate for the semiconductor substrate K. More specifically, by using a coating method such as a spin coating method or a spraying method, a reinforcing material (for example, a thermoplastic material, etc.) is coated on the back surface Kb of the semiconductor substrate K inside the annular portion 122 of the second substrate 12, and the reinforcing layer 21 with a specified thickness Te can be formed. In addition, the reinforcing material can be an electrically insulating material or a conductive material.
[0070] Then, in the singulation step S7, when cutting the semiconductor substrate K, the reinforcing layer 21 is also cut at the same position as the cutting position of the semiconductor substrate K in a top view, whereby the plurality of device regions Rd provided on the semiconductor substrate K are singulated respectively. Thus, semiconductor devices supported by the reinforcing substrate 21S can be manufactured.
[0071] [2-2] Second modification example
[0072] Figure 5 (A) is a conceptual diagram showing the division layer forming step S1 performed by the manufacturing method of the second modification example. In the above manufacturing method, as the first substrate 11, a substrate with a rounded corner on the outer peripheral surface 11d (in other words, the outer peripheral surface 11d is a convex surface) as shown in Figure 5 (A) may also be used. On the other hand, when using the first substrate 11 with such a shape, if the division step S3 is directly performed after forming the division layer 111, as shown in Figure 5 (B), a sharp edge 11e is formed on the outer peripheral edge of the semiconductor substrate K formed by the division step S3. Moreover, in the manufacturing process of the semiconductor device, such a sharp edge 11e portion may damage other components or form defects to cause defects in the semiconductor substrate K.
[0073] Therefore, as shown in Figure 5As shown in (A) of , after the dividing layer 111 is formed, the peripheral portion 112 of the first substrate 11 (the portion where the outer peripheral surface 11d has a rounded corner) may be cut off. Then, the first substrate 11 from which the peripheral portion 112 has been cut off may be used as the new first substrate 11, and the processing from the bonding portion forming step S2 described above may be performed. By cutting off the peripheral portion 112 of the first substrate 11 (the portion where the outer peripheral surface 11d has a rounded corner) in this way, it is possible to prevent the formation of the sharp edge 11e as described above at the outer peripheral edge of the semiconductor substrate K.
[0074] In addition, from the viewpoint of preventing the formation of the sharp edge 11e as described above, instead of the method of cutting off the peripheral portion 112 of the first substrate 11 (the portion where the outer peripheral surface 11d has a rounded corner) after the dividing layer 111 is formed, the dividing layer 111 may be formed after the peripheral portion 112 of the first substrate 11 (the portion where the outer peripheral surface 11d has a rounded corner) is cut off.
[0075] [2-3] Third modification
[0076] In the above manufacturing method, even when the device forming step S4 is performed at a high temperature, in a case where there is no concern about the problems caused by the expansion of the substrate as described above (the stress generated due to the expansion of the substrate cannot be alleviated, resulting in problems such as defects in the substrate and the element Gd) (for example, when the expansion coefficient of the semiconductor substrate K is the same as that of the second substrate 12, etc.), the following processing may be performed after the dividing step S3.
[0077] Here, according to the annular bonding portion Q formed in the bonding portion forming step S2, the inside of the ring is sealed in a state of a pressure lower than the specified pressure Pt. Therefore, in an atmosphere of the specified pressure Pt or an atmosphere of a pressure higher than the specified pressure Pt, a pressure difference can be generated between the pressure (internal pressure) inside the ring of the bonding portion Q and the pressure (external pressure) outside the ring. As a result, an adsorption force caused by the pressure difference can be generated between the first substrate 11 and the second substrate 12. Thereby, when the first substrate 11 and the second substrate 12 are brought into close contact with each other by using this adsorption force, or when a metal layer 13 is interposed between these substrates, these substrates can be brought into close contact with the metal layer 13.
[0078] Then, after the dividing step S3, the semiconductor substrate K and the second substrate 12 may be heat-treated while maintaining the above-described close contact state (that is, in an atmosphere of the specified pressure Pt or an atmosphere of a pressure higher than the specified pressure Pt). As a result, a compound (such as metal silicide) or an alloy (such as metal-Si alloy) of the main components (such as semiconductor) of the first substrate 11 and the second substrate 12 and the metal that is the main component of the metal layer 13 is generated at their interface. As a result, the semiconductor substrate K and the second substrate 12 are also bonded in the region inside the bonding portion Q.
[0079] In this way, a method of fixing the region inside the fixing portion Q by using the adsorption force caused by the pressure difference can also be achieved even when heat treatment is performed at a low temperature of 1000°C or lower (for example, 400°C) (such as eutectic bonding). In this case, even when the coefficient of thermal expansion of the semiconductor substrate K is different from that of the second substrate 12, the region inside the fixing portion Q can be fixed without causing a large difference in their expansion amounts. In other words, it is possible to fix the region inside the fixing portion Q without generating a large stress caused by the difference in the coefficient of thermal expansion. Therefore, when it is desired to fix the semiconductor substrate K and the second substrate 12 over the entire region of the bonding surface and the fixing of the entire region of the bonding surface will not cause problems in subsequent processing (for example, when the device formation step S4 is not performed at a high temperature), a method that can fix the region inside the fixing portion Q even by heat treatment at a low temperature can be used.
[0080] [2-4] Fourth modification
[0081] Figure 6 FIG. is a conceptual diagram showing a part of the manufacturing method of the fourth modification in the order of processing. In addition, Figure 7 FIG. is a plan view showing the shape of the fixing portion Q formed in this modification. In the above manufacturing method, in the fixing portion formation step S2, for each device region Rd among a plurality of device regions Rd provided in the portion of the first substrate 11 that becomes the semiconductor substrate K, the fixing portion Q may be formed in a ring shape over the entire circumference of the peripheral portion of the device region Rd. At this time, the fixing portion Q is continuously formed in a ring shape in an atmosphere of a pressure lower than the specified pressure Pt, whereby the inside of the ring is sealed in a state of a pressure lower than the specified pressure Pt. In Figure 7 the example of, the shape of each device region Rd is a quadrilateral, and the fixing portion Q is formed in a quadrilateral ring shape along its peripheral portion. In addition, the shape of the fixing portion Q is not limited to a quadrilateral ring shape, and can be appropriately changed to a ring shape of other shapes (circle, polygon, etc.) according to the peripheral shape of each device region Rd.
[0082] According to the formation of such a fixing portion Q, in an atmosphere of a specified air pressure Pt, a pressure difference can be generated between the air pressure (internal air pressure) inside the ring of the fixing portion Q and the air pressure (external air pressure) outside the ring for each device region Rd. As a result, an adsorption force caused by the pressure difference can be generated at multiple positions between the first substrate 11 and the second substrate 12. Thus, in an atmosphere of a specified air pressure Pt, the first substrate 11 and the second substrate 12 can be firmly joined by using the joining force generated by the fixing portion Q and the adsorption force caused by the pressure difference between the internal air pressure and the external air pressure. Thus, even if the first substrate 11 and the second substrate 12 are not joined over the entire region of the joining surface as in the prior art (i.e., even if joining using CMP is not performed), sufficient joining force for holding the semiconductor substrate K separated from the first substrate 11 on the second substrate 12 in the dicing step S3 can be obtained.
[0083] After the dicing step S3 and the device formation step S4, in the cutting step S5, while the semiconductor substrate K and the second substrate 12 are held on the holding sheet 14, cutting is performed at a position between the fixing portions Q formed in two adjacent device regions Rd, respectively, whereby the multiple device regions Rd provided on the semiconductor substrate K can be singulated. As a result, semiconductor devices supported by a support substrate 12S (a substrate formed by cutting the second substrate 12) can be manufactured. At this time, each semiconductor device is supported on the support substrate 12S in a state of being firmly joined to the support substrate 12S by using the joining force brought by the ring-shaped fixing portion Q and the adsorption force caused by the pressure difference between the air pressure (internal air pressure) inside the ring and the air pressure (external air pressure) outside the ring.
[0084] Figure 8 of (A) and Figure 8 of (B) are a conceptual diagram and a top view showing a further modified example of the manufacturing method of the above Figure 6 and Figure 7 . As shown in (A) of Figure 8 and (B) of Figure 8 , in addition to forming the ring-shaped fixing portion Q at the peripheral portion of each device region Rd, a ring-shaped fixing portion Q can also be formed along the peripheral portion 112 (specifically, the peripheral portion of the portion of the first substrate 11 that becomes the semiconductor substrate K) of the first substrate 11.
[0085] According to this structure, peeling and vibration of the substrate end portion during cutting performed in the cutting step S5 can be suppressed by using the ring-shaped fixing portion Q formed along the peripheral portion 112.
[0086] [2-5] Fifth modified example
[0087] In the above manufacturing method, in the fixing portion formation step S2, as the ring-shaped fixing portion Q, it is not limited toFigure 3 (Embodiment), Figure 7 The shape shown in (Fourth Modification) may also form a fixed connection portion having the following shape.
[0088] Figure 9 , Figure 10 (A) of Figure 10 and (B) of
[0089] are top views showing three examples of the shape of the fixed connection portion Q formed in the fifth modification. As shown in these figures, a plurality of device regions Rd may also be divided into several groups, and for each group, the fixed connection portion Q may be formed in a ring shape so as to surround all the device regions Rd within the group. Figure 9 Here, in the example of Figure 10 (A) of Figure 10 and (B) of Figure 10 , the case where the fixed connection portion Q is formed in a ring shape that is independent for each group is shown. On the other hand, in (A) of Figure 10 and (B) of Figure 10 , for the fixed connection portion Q, the case where a circular portion and a straight portion are combined to form the fixed connection portion Q so that a part of the fixed connection portion Q can be shared between groups is shown. Specifically, in (A) of
[0090] [2-6] Sixth Modification
[0091] Figure 11 (A) of Figure 11 is a conceptual diagram showing the fixed connection portion forming step S2 and the cutting step S5 performed by the manufacturing method of the sixth modification. In addition, (B) of
[0092] is a top view showing the shape of the fixed connection portion Q formed in the sixth modification. Figure 10In the example of (B), a case is shown where the fixing portion Q is formed by using a circular portion formed in a ring shape along the peripheral portion 112 and a plurality of straight portions that form a grid by crossing the inside of the circular portion through the boundary line Lb. By forming the grid with the plurality of straight portions in this way, a plurality of annular portions surrounding each device region Rd are formed in the fixing portion Q.
[0093] In the case where the fixing portion Q is formed on the boundary line Lb of the device region Rd like this, in the cutting step S5 (refer to Figure 11 (A)), by cutting the second substrate 12 and the semiconductor substrate K along the boundary line Lb, the fixing portion Q can be removed together with the portions of the second substrate 12 and the semiconductor substrate K that are removed during cutting.
[0094] [2-7] Seventh modification example
[0095] In the above manufacturing method, the method of forming the fixing portion Q in the fixing portion forming step S2 is not limited to the method of forming the fixing portion Q by irradiating the metal layer 13 with a laser, and can be appropriately changed to a method of forming the fixing portion Q by irradiating the interface between them in a state where the first substrate 11 and the second substrate 12 are in direct contact.
[0096] [2-8] Eighth modification example
[0097] Figure 12 It is a conceptual diagram showing the cutting step S5 and the peeling step S6 performed by the manufacturing method of the eighth modification example. In the manufacturing method of the above-described embodiment, in the cutting step S5, only the second substrate 12 among the second substrate 12 and the semiconductor substrate K may be cut annularly along the fixing portion Q at a position inside the annular fixing portion Q. Specifically, only the second substrate 12 is cut in such a way that the cutting line becomes a cutting line surrounding all the device regions Rd provided on the semiconductor substrate K.
[0098] According to this cutting method, the inner portion 121 of the second substrate 12 is in a state of being separated from the fixing portion Q, while the semiconductor substrate K maintains a state where its whole is connected to the fixing portion Q. In other words, it becomes a state where the whole of the semiconductor substrate K is joined by the fixing portion Q to the annular portion 122 remaining after peeling (after peeling of the inner portion 121) in the second substrate 12.
[0099] Thereby, by peeling the inner portion 121 of the second substrate 12 from the semiconductor substrate K in the peeling step S6, the annular portion 122 of the second substrate 12 can be used as an annular support, and the semiconductor substrate K supported by the support can be obtained.
[0100] [2-9] Other modification examples
[0101] In the above manufacturing method, when the air pressure (internal air pressure) inside the ring of the fixing part Q and the air pressure outside the ring (external air pressure) do not require the adsorption force caused by the pressure difference, the shape of the fixing part Q can also be appropriately changed to various shapes not limited to the ring shape. For example, as the fixing part Q, a dot-shaped or open linear (linear shape with ends) fixing part can also be formed.
[0102] It should be considered that the descriptions of the above embodiments and modification examples are illustrative in all aspects and not restrictive. The scope of the present invention is not limited by the above embodiments and modification examples. Furthermore, the scope of the present invention is intended to include all changes within the meaning and scope equivalent to the scope of the claims.
[0103] In addition, as the object of the invention, several steps constituting the manufacturing method of the semiconductor device can be partially extracted from the above embodiments and modification examples, and each step can also be extracted separately.
[0104] Description of reference numerals
[0105] K semiconductor substrate
[0106] Q fixing part
[0107] 11 first substrate
[0108] 11a surface
[0109] 11d outer peripheral surface
[0110] 11e edge
[0111] 11R remaining part
[0112] 12 second substrate
[0113] 12a surface
[0114] 12S supporting substrate
[0115] 13 metal layer
[0116] 14 holding sheet
[0117] 21 reinforcing layer
[0118] 21S reinforcing substrate
[0119] Dt specified depth
[0120] Gd element
[0121] Ka surface
[0122] Kb back surface
[0123] Lb boundary line
[0124] Pt specified air pressure
[0125] Rd device area
[0126] Td thickness
[0127] Te specified thickness
[0128] 111 splitting layer
[0129] 112 peripheral part
[0130] 121 inner part
[0131] 122 annular part
[0132] S1 splitting layer forming step
[0133] S2 fixing part forming step
[0134] S3 splitting step
[0135] S4 device forming step
[0136] S5 cutting step
[0137] S6 peeling step
[0138] S7 singulation step
[0139] S8 reinforcing layer forming step
[0140] S21 metal layer forming step
[0141] S22 laser irradiation step.
Claims
1. A method for manufacturing a semiconductor device, characterized in that, Comprising: A dividing layer forming step of forming a dividing layer at a position at a predetermined depth from the surface of a first substrate mainly composed of a semiconductor, the dividing layer being used to enable a semiconductor substrate having a thickness of the predetermined depth to be separated from the first substrate; An adhering portion forming step of, after the dividing layer forming step, forming an adhering portion for adhering a portion of the first substrate that becomes the semiconductor substrate to a second substrate in a ring shape in an atmosphere at a pressure lower than a predetermined pressure, thereby sealing the inside of the ring; and A dividing step of, after the adhering portion forming step, dividing the first substrate at the dividing layer in an atmosphere of the predetermined pressure.
2. The method for manufacturing a semiconductor device according to claim 1, wherein: In the adhering portion forming step, an adhering portion is formed over the entire circumference of the peripheral portion of the portion of the first substrate that becomes the semiconductor substrate.
3. The method for manufacturing a semiconductor device according to claim 2, wherein: The adhering portion forming step includes: A metal layer forming step of forming a metal layer on at least a region on the surface of the first substrate at least in the peripheral portion, or on at least a region on the surface of the second substrate that faces the peripheral portion; and A laser irradiation step of interposing the metal layer between the first substrate and the second substrate, and in this state, heating a part of the metal layer in the peripheral portion by irradiating the part with a laser to form the adhering portion.
4. The manufacturing method of the semiconductor device according to claim 2 or 3, characterized in that, Further comprising: A device forming step of, after the dividing step, manufacturing at least a part of an element belonging to a semiconductor device in each of a plurality of device regions provided on the semiconductor substrate; And A cutting step of, after the device forming step, holding the semiconductor substrate and the second substrate on a holding sheet in a posture where the semiconductor substrate faces the holding sheet, and in this state, cutting at least the second substrate at a position inside the ring-shaped adhering portion.
5. The manufacturing method of the semiconductor device according to claim 4, characterized in that, Further comprising: A peeling step of, after the cutting step, peeling a part inside the ring-shaped adhering portion of the second substrate from the semiconductor substrate.
6. The manufacturing method of the semiconductor device according to claim 5, characterized in that, Further comprising: A reinforcing layer forming step of, after the peeling step, forming a reinforcing layer with a predetermined thickness as a reinforcing substrate for the semiconductor substrate on the back surface of the semiconductor substrate, which is on the side opposite to the surface of the semiconductor substrate facing the holding sheet, inside the ring-shaped portion remaining after peeling in the second substrate.
7. The method for manufacturing a semiconductor device according to any one of claims 2 to 6, wherein: In the dividing layer forming step, after forming the dividing layer, the peripheral portion of the first substrate is cut off; In the adhering portion forming step, the first substrate from which the peripheral portion has been cut off in the dividing layer forming step is used as a new first substrate, and an adhering portion is formed over the entire circumference of the peripheral portion of the portion of the new first substrate that becomes the semiconductor substrate.
8. The method for manufacturing a semiconductor device according to claim 1, wherein: After the splitting step, heat treatment is performed on the semiconductor substrate and the second substrate in an atmosphere at the specified atmospheric pressure or at an atmospheric pressure higher than the specified atmospheric pressure, so that the semiconductor substrate and the second substrate are bonded in the region inside the bonding portion.
9. The method for manufacturing a semiconductor device according to claim 1, wherein: In the bonding portion forming step, for each device region of a plurality of device regions that are the portions of the semiconductor substrate provided in the first substrate, the bonding portion is formed over the entire circumference of the peripheral portion of the device region.
10. The method for manufacturing a semiconductor device according to claim 9, wherein: The bonding portion forming step includes: a metal layer forming step of forming a metal layer on the surface of the first substrate or the surface of the second substrate; and a laser irradiation step of interposing the metal layer between the first substrate and the second substrate, and in this state, irradiating a part on the peripheral portion of each of the device regions in the metal layer with laser, thereby heating this part to form the bonding portion.
11. The manufacturing method of the semiconductor device according to claim 9 or 10, characterized in that, It further includes: a device forming step of, after the splitting step, manufacturing at least a part of elements belonging to a semiconductor device in the device regions provided in the semiconductor substrate; and a cutting step of, after the device forming step, holding the semiconductor substrate and the second substrate on the holding sheet in a posture where the semiconductor substrate faces the holding sheet, and in this state, cutting the semiconductor substrate and the second substrate at a position between the bonding portions formed in two adjacent device regions respectively.
Citation Information
Patent Citations
Microchip and SOI substrate for manufacturing the same
JP2007250576A