De-bonding method and de-bonding device
During the thermal slip debonding process, the bottom chuck and thermal slip structure are used to avoid the oxidation of the metal layer on the back of the wafer, and the metal layer is protected by gas purge, the problem of oxidation of the metal layer during thermal slip debonding is solved, and the understanding is achieved The bonded wafers are directly diced or shipped, and reduce the risk of fragmentation.
Patent Information
- Application Number
- CN202411505467.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-25
- Publication Date
- 2025-02-07
AI Technical Summary
During the thermal slip debonding process, the metal layer on the back of the wafer is prone to oxidation, resulting in the debonded wafer being unable to be directly scribed or shipped, and deposition of the back metal layer after debonding increases the risk of defragment.
By placing the bonding structure in the processing chamber in the direction of the slide towards the bottom chuck, the slide contacts the bottom chuck with the metal layer on the back of the wafer away from the bottom chuck. The separation of the slide from the wafer is then achieved by adsorbing and thermally sliding the wafer, avoiding the use of polycrystalline silicon carbide ceramic disks, thereby preventing the oxidation of the metal layer. Meanwhile, the processing chamber is subjected to gas purging to avoid oxidation of the metal layer.
It realizes the avoidance of oxidation of the metal layer on the back of the wafer after debonding, simplifies understanding of the bonding device structure, reduces costs, and avoids the risk of fragmentation caused by debonding, so that the debonded wafer can Directly cut or ship.
Smart Images
Figure CN119400715A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to a debonding method and a debonding device. Background Art
[0002] As the most commonly used, lowest-cost and relatively simple method in the debonding process, thermal slip has been widely used in the semiconductor backside process. In the field of SiC devices (mainly including power devices and RF devices), different types of devices will result in different materials for the metal layer deposited on the back of the device. For example, the material of the back metal layer of the power device is mainly silver, while the back metal layer of the RF device is mainly electroplated gold.
[0003] In the process of hot-slip debonding, the bonding structure formed by bonding the wafer and the carrier is usually placed on a polycrystalline silicon carbide ceramic disk, and the back side of the wafer is in contact with the polycrystalline silicon carbide ceramic disk. After heating for a period of time, the carrier is adsorbed by a suction cup located above the polycrystalline silicon carbide ceramic disk and the carrier is hot-slipped to achieve debonding of the carrier and the wafer. However, in the current process of hot-slip debonding, due to the oxygen dangling bonds on the surface of the polycrystalline silicon carbide ceramic disk, the metal layer on the back side of the wafer in contact with the polycrystalline silicon carbide ceramic disk will be oxidized. In order to avoid oxidation of the back metal layer, the current method is to deposit the back metal layer after debonding, which not only increases the risk of wafer fragments, but also runs counter to the original intention of forming a bonding structure.
[0004] Therefore, how to solve the problem of the metal layer on the back of the wafer being easily oxidized during the hot slip debonding process so that the debonded wafer can be directly diced or shipped, and avoid the risk of fragmentation caused by depositing the back metal layer after debonding, is a technical problem that needs to be solved urgently. Summary of the invention
[0005] The present invention provides a debonding method and a debonding device, which are used to solve the problem that the metal layer on the back side of the wafer is prone to oxidation during the hot slip debonding process, so that the wafer after debonding can be directly diced or shipped, avoiding the risk of fragmentation caused by depositing the back side metal layer after debonding.
[0006] According to some embodiments, the present invention provides a debonding method, comprising the following steps:
[0007] Forming a bonding structure, the bonding structure comprising a wafer and a carrier, the wafer comprising a bonding surface and a back surface that are relatively distributed, the bonding surface of the wafer being bonded to the carrier, and a metal layer being formed on the back surface of the wafer;
[0008] placing the bonding structure on the bottom chuck in the processing chamber with the carrier facing the bottom chuck;
[0009] The wafer is adsorbed and thermally slid above the bottom chuck to separate the wafer from the carrier.
[0010] In some embodiments, the wafer is a silicon carbide wafer.
[0011] In some embodiments, the specific steps of forming the bonding structure include:
[0012] Providing a wafer, wherein the wafer comprises a bonding surface and a back surface that are relatively distributed;
[0013] Bonding the wafer and the carrier wafer with the bonding surface of the wafer facing the carrier wafer;
[0014] The metal layer is formed on the back side of the wafer.
[0015] In some embodiments, before placing the bonding structure on the bottom chuck in the processing chamber with the carrier facing the bottom chuck, the following steps are also included:
[0016] A gas purge process is performed on the processing chamber.
[0017] In some embodiments, the specific steps of performing a gas purge process on the processing chamber include:
[0018] Perform the following cycle steps multiple times, the cycle steps comprising:
[0019] Filling the processing chamber with nitrogen or an inert gas at a first flow rate;
[0020] The gas in the processing chamber is evacuated.
[0021] In some embodiments, after performing multiple cycles, the method further includes the following steps:
[0022] continuously filling the processing chamber with nitrogen or an inert gas at a second flow rate, wherein the second flow rate is less than the first flow rate;
[0023] The bottom chuck is heated.
[0024] In some embodiments, the processing chamber has a top chuck located above the bottom chuck; the specific steps of adsorbing and thermally sliding the wafer above the bottom chuck and separating the wafer from the carrier include:
[0025] The bottom chuck rises in a vertical direction until the wafer contacts the top chuck;
[0026] The top chuck absorbs the wafer and drives the wafer to slide in a horizontal direction until the wafer is separated from the carrier.
[0027] In some embodiments, after the wafer is adsorbed and thermally slid above the bottom chuck to separate the wafer from the carrier, the following steps are further included:
[0028] The wafer is turned over and cleaned.
[0029] According to some other embodiments, the present invention also provides a debonding device, comprising:
[0030] A processing chamber, for accommodating a bonding structure to be debonded, wherein the bonding structure comprises a wafer and a carrier, the wafer comprises a bonding surface and a back surface which are relatively distributed, the bonding surface of the wafer is bonded to the carrier, and a metal layer is formed on the back surface of the wafer;
[0031] A bottom chuck, located in the processing chamber, for carrying the bonding structure in a direction where the carrier is facing the bottom chuck;
[0032] The heat-slip structure is located in the processing chamber and above the bottom chuck. The heat-slip structure is used for adsorbing and heat-slipping the wafer to separate the wafer from the carrier.
[0033] In some embodiments, it also includes:
[0034] The purge structure is communicated with the processing chamber and is used for performing gas purge on the processing chamber.
[0035] In some embodiments, the purge structure includes:
[0036] a gas filling structure, comprising an input pipe in communication with the processing chamber, the input pipe being used to fill the processing chamber with nitrogen or an inert gas at a first flow rate;
[0037] The exhaust structure comprises an output pipeline connected to the processing chamber and a vacuum pump connected to the output pipeline, wherein the vacuum pump is used to exhaust the gas in the processing chamber through the output pipeline.
[0038] In some embodiments, the bottom chuck can move up and down in the vertical direction;
[0039] The thermal sliding structure further includes a top chuck located above the bottom chuck, and the top chuck can absorb the wafer and drive the wafer to slide in a horizontal direction.
[0040] The debonding method and debonding device provided by the present invention, during the debonding process, a bonding structure is placed on the bottom chuck in the processing chamber in the direction of the carrier toward the bottom chuck, so that the carrier contacts the bottom chuck, and the metal layer on the back of the wafer is away from the bottom chuck, and the carrier and the wafer are separated (i.e., debonding) by adsorbing and thermally sliding the wafer. Since the wafer is adsorbed and thermally slid, there is no need to set a polycrystalline silicon carbide ceramic disk for carrying and transferring the wafer on the bottom chuck, thereby avoiding the oxygen dangling bonds in the polycrystalline silicon carbide ceramic disk from oxidizing the metal layer on the back of the wafer, so that the wafer after debonding can be directly diced or shipped, avoiding the risk of fragments caused by the deposition of the back metal layer after debonding. In addition, during the debonding process, the present invention performs gas purge on the processing chamber, thereby avoiding the oxidation of the metal layer on the back of the wafer by the oxidizing gas in the processing chamber, and further realizing the protection of the metal layer on the back of the wafer. BRIEF DESCRIPTION OF THE DRAWINGS
[0041] Figure 1 is a flow chart of a debonding method in a specific embodiment of the present invention;
[0042] Figure 2 is a schematic diagram of a structure before a bonding structure is placed on a bottom chuck in a specific embodiment of the present invention;
[0043] Figure 3 is a schematic diagram of a structure after the bonding structure is placed on the bottom chuck in a specific embodiment of the present invention;
[0044] Figure 4 is a schematic diagram of the structure after the top chuck contacts the wafer in a specific embodiment of the present invention;
[0045] Figure 5 It is a schematic diagram of the structure after the wafer and the carrier are separated in a specific implementation manner of the present invention. DETAILED DESCRIPTION
[0046] The specific implementation manner of the debonding method and the debonding device provided by the present invention will be described in detail below with reference to the accompanying drawings.
[0047] This specific embodiment provides a debonding method, Figure 1 : is a flow chart of the debonding method in a specific embodiment of the present invention. Figure 1 As shown, the debonding method comprises the following steps:
[0048] Step S11, forming a bonding structure, wherein the bonding structure includes a wafer and a carrier, the wafer includes a bonding surface and a back surface that are relatively distributed, the bonding surface of the wafer is bonded to the carrier, and a metal layer is formed on the back surface of the wafer;
[0049] Step S12, placing the bonding structure on the bottom chuck in the processing chamber with the carrier facing the bottom chuck;
[0050] Step S13, adsorbing and thermally sliding the wafer above the bottom chuck to separate the wafer from the carrier.
[0051] In some embodiments, the wafer is a silicon carbide wafer, because the hardness of the silicon carbide wafer is relatively high, thereby preventing the wafer from being damaged during the process of adsorption and thermal sliding of the wafer.
[0052] In other embodiments, the wafer may also be, but is not limited to, silicon germanium, germanium, gallium arsenide, or indium phosphide.
[0053] Figure 2 is a schematic diagram of a structure before placing the bonding structure on the bottom chuck in a specific embodiment of the present invention. In some embodiments, the specific steps of forming the bonding structure include:
[0054] Providing a wafer 21, wherein the wafer 21 includes a bonding surface and a back surface that are relatively distributed;
[0055] Bonding the wafer 21 and the carrier wafer 22 in a direction where the bonding surface of the wafer 21 faces the carrier wafer 22;
[0056] The metal layer is formed on the back side of the wafer 21 .
[0057] For example, the wafer 21 and the carrier 22 are bonded together by a bonding process, so that the bonding surface of the wafer 21 faces the carrier 22, and the back side of the wafer 21 is located on the side of the wafer 21 away from the carrier 22. Afterwards, the wafer 21 can be subjected to back thinning and metal sputtering processes to form the metal layer on the back side of the wafer 21. Since the wafer 21 is carried by the carrier 22 during the back thinning and metal sputtering process, the risk of the wafer 21 being broken can be effectively reduced. In one example, the material of the metal layer can be metallic silver.
[0058] In some embodiments, before placing the bonding structure on the bottom chuck 23 in the processing chamber 20 with the carrier 22 facing the bottom chuck 23, the following steps are also included:
[0059] The processing chamber 20 is subjected to a gas purge process.
[0060] In some embodiments, the specific steps of performing gas purge treatment on the processing chamber 20 include:
[0061] Perform the following cycle steps multiple times, the cycle steps comprising:
[0062] Filling the processing chamber 20 with nitrogen or an inert gas at a first flow rate;
[0063] The gas in the processing chamber 20 is evacuated.
[0064] In some embodiments, after performing multiple cycles, the method further includes the following steps:
[0065] continuously filling the processing chamber 20 with nitrogen or an inert gas at a second flow rate, wherein the second flow rate is less than the first flow rate;
[0066] The bottom chuck 23 is heated.
[0067] For example, by repeatedly filling and exhausting the processing chamber 20 at a relatively fast first flow rate, the air in the processing chamber 20 can be quickly evacuated to prevent the air in the processing chamber 20 from oxidizing the metal layer on the back of the wafer 21, so as to further protect the metal layer on the back of the wafer 21. The inert gas described in this specific embodiment refers to a gas composed of group 0 elements in the periodic table. After performing the cycle steps multiple times, nitrogen or an inert gas is continuously filled into the processing chamber 20 at a relatively low second flow rate, so that the processing chamber 20 continuously maintains an inert atmosphere to ensure that the metal layer is not oxidized by the gas in the processing chamber 20. The second flow rate is less than the first flow rate to avoid the bonding structure in the processing chamber 20 or the wafer 21 after debonding from shaking due to excessive flow of nitrogen or inert gas. Figure 2 The solid arrow in FIG. 2 schematically indicates the direction in which nitrogen or inert gas is filled into the processing chamber 20 .
[0068] Figure 3 It is a schematic diagram of the structure after the bonding structure is placed on the bottom chuck in a specific embodiment of the present invention. The processing chamber 20 also includes a top chuck 25 located above the bottom chuck 23 in the vertical direction. After nitrogen or an inert gas is continuously filled into the processing chamber 20 at a relatively low second flow rate for a period of time, the bottom chuck 23 is heated to a preset temperature to facilitate subsequent heating of the bonding structure to achieve thermal slip. Afterwards, the top chuck 25 adsorbs the wafer 21 in the bonding structure so that the carrier 22 in the bonding structure faces the bottom chuck 23, that is, in the vertical direction, the wafer 21 is above the carrier 22, as shown in FIG. Figure 2 Afterwards, the top chuck 25 places the adsorbed bonding structure on the bottom chuck 23, and makes the carrier 22 contact with the bottom chuck 23, as shown in FIG. Figure 3 As shown. Among them, Figure 3 The solid arrow in FIG. 2 schematically indicates the direction in which nitrogen or inert gas is filled into the processing chamber 20 .
[0069] Figure 4 is a schematic diagram of the structure after the top chuck contacts the wafer in a specific embodiment of the present invention, Figure 5 is a schematic diagram of the structure after the wafer and the carrier are separated in a specific embodiment of the present invention, wherein: Figure 4 and Figure 5 The solid arrow in the figure schematically indicates the direction of filling nitrogen or inert gas into the processing chamber 20. In some embodiments, the processing chamber 20 has a top chuck 25 located above the bottom chuck 23; the specific steps of adsorbing and thermally sliding the wafer 21 above the bottom chuck 23 and separating the wafer 21 from the carrier 22 include:
[0070] The bottom chuck 23 rises in the vertical direction until the wafer 21 contacts the top chuck 25;
[0071] The top chuck 25 absorbs the wafer 21 and drives the wafer 21 to slide in a horizontal direction until the wafer 21 is separated from the carrier 22 .
[0072] For example, after the bonding structure is placed on the bottom chuck 23, the heated bottom chuck 23 transfers heat to the bonding structure, so that the bonding glue between the wafer 21 and the carrier 22 melts. Then, the bottom chuck 23 rises vertically until the wafer 21 contacts the top chuck 25. Figure 4 The top chuck 25 absorbs the wafer 21 in contact with it and drives the wafer 21 to slide horizontally, thereby separating the wafer 21 from the carrier 22 (ie, debonding). Figure 5As shown. In this specific embodiment, the top chuck 25 is used to adsorb and thermally slide the wafer 21, so there is no need to set a polycrystalline silicon carbide ceramic disk for carrying the wafer 21 on the bottom chuck 23, thereby avoiding the oxygen dangling bonds in the polycrystalline silicon carbide ceramic disk from oxidizing the metal layer on the back of the wafer under heating conditions, avoiding the blackening of the metal layer made of silver or the like, and ensuring the quality of the metal layer on the back of the wafer 21 after bonding, so that the wafer after debonding can be directly diced or shipped, avoiding the risk of fragments caused by the deposition of the back metal layer after debonding. Moreover, since there is no need to set a polycrystalline silicon carbide ceramic disk for carrying the wafer 21 above the bottom chuck 23, it helps to simplify the structure of the debonding device and reduce the debonding cost.
[0073] In some embodiments, after the wafer 21 is adsorbed and thermally slid above the bottom chuck 23 and the wafer 21 and the carrier 22 are separated, the following steps are further included:
[0074] The wafer 21 is turned over and cleaned.
[0075] For example, after the wafer 21 and the carrier 22 are separated, the wafer 21 is cooled in the processing chamber 20, and the wafer 21 is clamped by a robot arm and transferred out of the processing chamber 20, and then the wafer 21 is flipped so that the bonding surface of the flipped wafer 21 faces in the right direction, so that the bonding surface of the wafer 21 can be subsequently cleaned to remove impurities such as residual bonding glue. After the wafer 21 is cleaned, the wafer 21 is transferred to a carrier plate to wait for the next processing step.
[0076] This specific embodiment also provides a debonding device. The structural schematic diagram of the debonding device can be seen in Figure 2-Figure 5 The debonding device may be used as follows: Figure 1-Figure 5 The debonding method described above performs a debonding process on the bonded structure. Figure 1-Figure 5 As shown, the debonding device comprises:
[0077] A processing chamber 20 is used to accommodate a bonding structure to be debonded, wherein the bonding structure includes a wafer 21 and a carrier 22, wherein the wafer 21 includes a bonding surface and a back surface that are relatively distributed, wherein the bonding surface of the wafer 21 is bonded to the carrier 22, and a metal layer is formed on the back surface of the wafer 21;
[0078] A bottom chuck 23 is located in the processing chamber 20 and is used to carry the bonding structure in a direction where the carrier 22 is facing the bottom chuck 23;
[0079] The heat-slip structure is located in the processing chamber 20 and above the bottom chuck 23 . The heat-slip structure is used to absorb and heat-slip the wafer 21 to separate the wafer 21 from the carrier 22 .
[0080] Specifically, the debonding device separates the carrier 22 from the wafer 21 (i.e., debonding) by adsorbing and thermally sliding the wafer 21 through the thermal sliding structure. Since the wafer 21 is adsorbed and thermally slid, there is no need to set a polycrystalline silicon carbide ceramic disk for carrying and transferring the wafer 21 on the bottom chuck 23, thereby avoiding the oxygen dangling bonds in the polycrystalline silicon carbide ceramic disk from oxidizing the metal layer on the back of the wafer 21, so that the wafer 21 after debonding can be directly diced or shipped, avoiding the risk of fragments caused by the deposition of the back metal layer after debonding. Moreover, since there is no polycrystalline silicon carbide ceramic disk for carrying the wafer 21 above the bottom chuck 23, it helps to simplify the structure of the debonding device and reduce the debonding cost.
[0081] In order to prevent the metal layer on the back side of the wafer 21 from being oxidized by the residual oxidizing gas in the processing chamber 20, and further protect the metal layer on the back side of the wafer 21, in some embodiments, the debonding device further includes:
[0082] The purge structure is communicated with the processing chamber 20 and is used for performing gas purge on the processing chamber 20 .
[0083] In some embodiments, the purge structure includes:
[0084] A gas filling structure, comprising an input pipe in communication with the processing chamber 20, wherein the input pipe is used to fill the processing chamber 20 with nitrogen or an inert gas at a first flow rate;
[0085] The exhaust structure includes an output pipe connected to the processing chamber 20 and a vacuum pump connected to the output pipe, wherein the vacuum pump is used to exhaust the gas in the processing chamber 20 through the output pipe.
[0086] In some embodiments, the bottom chuck 23 can move up and down in the vertical direction;
[0087] The thermal sliding structure further includes a top chuck 25 located above the bottom chuck 23 . The top chuck 25 can absorb the wafer 21 and drive the wafer 21 to slide in a horizontal direction.
[0088] The debonding method and debonding device provided in this specific embodiment, during the debonding process, the bonding structure is placed on the bottom chuck in the processing chamber in the direction of the carrier toward the bottom chuck, so that the carrier contacts the bottom chuck, and the metal layer on the back of the wafer is away from the bottom chuck, and the carrier and the wafer are subsequently separated (i.e., debonded) by adsorbing and thermally sliding the wafer. Since the wafer is adsorbed and thermally slid, there is no need to set a polycrystalline silicon carbide ceramic disk for carrying and transferring the wafer on the bottom chuck, thereby avoiding the oxygen dangling bonds in the polycrystalline silicon carbide ceramic disk from oxidizing the metal layer on the back of the wafer, so that the wafer after debonding can be directly diced or shipped, avoiding the risk of fragments caused by the deposition of the back metal layer after debonding. In addition, in the process of debonding, the processing chamber is purged with gas to avoid the oxidation of the metal layer on the back of the wafer by the oxidizing gas in the processing chamber, further realizing the protection of the metal layer on the back of the wafer.
[0089] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.
Claims
1. A debonding method, characterized in that: The steps include: Forming a bonding structure, the bonding structure comprising a wafer and a carrier, the wafer comprising a bonding surface and a back surface that are relatively distributed, the bonding surface of the wafer being bonded to the carrier, and a metal layer being formed on the back surface of the wafer; placing the bonding structure on the bottom chuck in the processing chamber with the carrier facing the bottom chuck; The wafer is adsorbed and thermally slid above the bottom chuck to separate the wafer from the carrier.
2. The debonding method according to claim 1, characterized in that: The wafer is a silicon carbide wafer.
3. The debonding method according to claim 1, characterized in that: The specific steps of forming the bonding structure include: Providing a wafer, wherein the wafer comprises a bonding surface and a back surface that are relatively distributed; Bonding the wafer and the carrier wafer with the bonding surface of the wafer facing the carrier wafer; The metal layer is formed on the back side of the wafer.
4. The debonding method according to claim 1, characterized in that: Before placing the bonding structure on the bottom chuck in the processing chamber with the carrier facing the bottom chuck, the following steps are also included: A gas purge process is performed on the processing chamber.
5. The debonding method according to claim 4, characterized in that: The specific steps of performing gas purging treatment on the processing chamber include: Perform the following cycle steps multiple times, the cycle steps comprising: Filling the processing chamber with nitrogen or an inert gas at a first flow rate; The gas in the processing chamber is evacuated.
6. The debonding method according to claim 5, characterized in that: After executing multiple cycles, the following steps are also included: continuously filling the processing chamber with nitrogen or an inert gas at a second flow rate, wherein the second flow rate is less than the first flow rate; The bottom chuck is heated.
7. The debonding method according to claim 6, characterized in that: The processing chamber has a top chuck located above the bottom chuck; the specific steps of adsorbing and thermally sliding the wafer above the bottom chuck and separating the wafer from the carrier include: The bottom chuck rises in a vertical direction until the wafer contacts the top chuck; The top chuck absorbs the wafer and drives the wafer to slide in a horizontal direction until the wafer is separated from the carrier.
8. The debonding method according to claim 1, characterized in that: After the wafer is adsorbed and thermally slid above the bottom chuck to separate the wafer from the carrier, the following steps are also included: The wafer is turned over and cleaned.
9. A debonding device, characterized in that: include: A processing chamber, for accommodating a bonding structure to be debonded, wherein the bonding structure comprises a wafer and a carrier, the wafer comprises a bonding surface and a back surface which are relatively distributed, the bonding surface of the wafer is bonded to the carrier, and a metal layer is formed on the back surface of the wafer; A bottom chuck, located in the processing chamber, for carrying the bonding structure in a direction where the carrier is facing the bottom chuck; The heat-slip structure is located in the processing chamber and above the bottom chuck. The heat-slip structure is used for adsorbing and heat-slipping the wafer to separate the wafer from the carrier.
10. The debonding device according to claim 9, characterized in that: Also includes: The purge structure is communicated with the processing chamber and is used for performing gas purge on the processing chamber.
11. The debonding device according to claim 10, characterized in that: The purge structure comprises: a gas filling structure, comprising an input pipe in communication with the processing chamber, the input pipe being used to fill the processing chamber with nitrogen or an inert gas at a first flow rate; The exhaust structure comprises an output pipeline connected to the processing chamber and a vacuum pump connected to the output pipeline, wherein the vacuum pump is used to exhaust the gas in the processing chamber through the output pipeline.
12. The debonding device according to claim 9, characterized in that: The bottom chuck can move up and down in the vertical direction; The thermal sliding structure further includes a top chuck located above the bottom chuck, and the top chuck can absorb the wafer and drive the wafer to slide in a horizontal direction.