Laser debonding carrier and composite carrier thereof

Abstract

The present disclosure relates to laser debonding carriers and composite carriers thereof. A method includes bonding a package assembly to a composite carrier. The composite carrier includes a base carrier and an absorption layer, and the absorption layer is positioned between the base carrier and the package assembly. A laser beam is projected onto the composite carrier. The laser beam penetrates the base carrier to ablate the absorption layer. The base carrier can then be separated from the package assembly.

Description

Technical Field

[0001] This disclosure relates to laser debonding carriers and their composite carriers. Background Technology

[0002] In integrated circuit packaging, a carrier is often used as a support structure on which the device die is placed and molded. The carrier can be bonded to other package components via temporary or permanent bonding. Temporary bonding is typically performed using a photothermal conversion (LTHC) coating, which adheres the carrier to the package component bonded thereon. LTHC can be degraded using a laser, thereby debonding the carrier from the package component. Permanent bonding can be performed via fusion bonding. After bonding, debonding of the wafer from the corresponding package component requires destroying the carrier, which can be removed using processes such as chemical mechanical polishing, grinding, dry or wet etching. Summary of the Invention

[0003] According to one aspect of this disclosure, a method for debonding via a laser beam is provided, comprising: bonding an encapsulation component to a composite carrier, wherein the composite carrier includes: a substrate carrier; and an absorption layer, wherein the absorption layer is located between the substrate carrier and the encapsulation component; projecting a laser beam onto the composite carrier, wherein the laser beam penetrates the substrate carrier to ablate the absorption layer; and separating the substrate carrier from the encapsulation component.

[0004] According to one aspect of this disclosure, a semiconductor structure is provided, comprising: a composite carrier including: a silicon substrate; a transparent layer; an absorption layer disposed above the transparent layer, wherein the absorption layer comprises titanium; and a bonding layer disposed above the absorption layer, wherein each of the transparent layer, the absorption layer and the bonding layer is a planar layer in whole.

[0005] According to one aspect of this disclosure, a structure configured to debond via a laser beam is provided, the structure comprising: a substrate carrier, wherein the substrate carrier is integrally formed of a homogeneous material and wherein the substrate carrier is transparent to the laser beam; a metal-containing absorbing layer disposed on the substrate carrier, wherein the metal-containing absorbing layer is configured to absorb the laser beam; a metal-containing reflective layer disposed on the metal-containing absorbing layer, wherein the metal-containing reflective layer is configured to reflect the laser beam; and a bonding layer disposed on the metal-containing reflective layer. Attached Figure Description

[0006] The various aspects of this disclosure can be best understood through the following detailed description when read in conjunction with the accompanying drawings. It should be noted that, in accordance with industry standard practice, the various features are not drawn to scale. In fact, the dimensions of the various features can be increased or decreased arbitrarily for ease of discussion.

[0007] Figure 1A , Figure 1B and Figures 2-7 A cross-sectional view is shown of an intermediate stage of the bonding of a carrier to a device substrate and the subsequent debonding process according to some embodiments.

[0008] Figures 8 to 16 A cross-sectional view is shown of the encapsulation process on a composite carrier according to some embodiments, as well as the intermediate stage of debonding between the composite carrier and the resulting encapsulation.

[0009] Figure 17 The reflectivity, absorptivity, and transmittance of titanium nitride films according to some embodiments are shown as functions of their thickness.

[0010] Figure 18 The reflectivity, absorptivity, and transmittance of an aluminum film according to some embodiments are shown as functions of its thickness.

[0011] Figure 19 The reflectivity, absorptivity, and transmittance of titanium nitride films according to some embodiments are shown as functions of wavelength.

[0012] Figure 20 The reflectivity, absorptivity, and transmittance of TiN / Ti / TiN films according to some embodiments are shown as functions of wavelength.

[0013] Figure 21 The reflectivity values ​​of several metals as a function of wavelength are shown according to some embodiments.

[0014] Figure 22 and Figure 23 Some scanning paths of a laser beam on a carrier according to some embodiments are shown.

[0015] Figure 24 The process flow of bonding and debonding of a carrier to a device substrate according to some embodiments is shown. Detailed Implementation

[0016] The following disclosure provides numerous different embodiments or examples for implementing various features of the invention. Specific examples of components and arrangements are described below to simplify this disclosure. Of course, these are merely examples and are not intended to be limiting. For example, the following description of forming a first feature on or over a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features such that the first and second features do not need to be in direct contact. Furthermore, reference numerals and / or letters may be repeated in various examples. Such repetition is for simplicity and clarity and does not in itself indicate a relationship between the various embodiments and / or configurations discussed.

[0017] Furthermore, spatially related terms (e.g., "below," "under," "down," "above," "up," etc.) may be used herein to readily describe the relationship of one element or feature shown in the figure relative to another element(s) or feature(s). These spatially related terms are intended to cover different orientations of the device in use or operation other than those shown in the figure. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially related descriptors used herein will be interpreted accordingly.

[0018] A composite carrier and a method for debonding a permanently bonded composite carrier are provided. According to some embodiments of this disclosure, the composite carrier is bonded to an encapsulation assembly. The composite carrier includes a substrate carrier and an absorbing layer on top of the substrate carrier. A laser ablation process is performed using a laser beam configured to penetrate the substrate carrier without being absorbed by the substrate carrier, but absorbed by the absorbing layer. Therefore, the absorbing layer is ablated, and the substrate carrier can be debonded from the encapsulation assembly. The embodiments discussed herein are intended to provide examples to enable making or using the subject matter of this disclosure, and modifications that can be made while remaining within the intended scope of the different embodiments will be readily understood by those skilled in the art. Similar reference numerals are used to designate similar elements in the various views and illustrative embodiments. Although method embodiments may be discussed as being performed in a particular order, other method embodiments may be performed in any logical order.

[0019] Figure 1A , Figure 1B and Figures 2-7 Cross-sectional views are shown of intermediate stages in the bonding of a device substrate to a composite carrier and the subsequent debonding process according to some embodiments of the present disclosure. The corresponding processes are also schematically illustrated in… Figure 24 The process flow 200 shown.

[0020] refer to Figure 1A This forms a composite carrier 32. The corresponding process is as follows: Figure 24The process flow 200 shown is designated as process 202. First, a substrate 20 is provided. The substrate 20 is formed of a material that is transparent to the laser beam used in the subsequent debonding process. Throughout this specification, when a layer is referred to as "transparent" to laser, this means that the corresponding material does not absorb the energy of the laser beam, for example, the absorption rate (also called absorption rate) is less than about 10%, about 5%, about 2%, or about 1%. According to some embodiments, the substrate 20 may be formed of or contain silicon, while other materials such as glass, silicate glass, etc., may also be used. According to some embodiments, the entire substrate 20 is formed of a homogeneous material in which no other material differs from the homogeneous material is present. For example, the entire substrate 20 may be formed of silicon (doped or undoped), and there are no metal regions, dielectric regions, etc., in the substrate 20.

[0021] Further reference Figure 1A Layer 22 is formed on substrate 20. According to some embodiments, layer 22 is formed of a material transparent to the laser beam used in the subsequent debonding process. According to some embodiments, layer 22 is formed of or contains an oxide-based material, which may be silicon oxide, while other materials such as phosphosilicate glass (PSG), borosilicate glass (BSG), boron-doped phosphosilicate glass (BPSG), and fluorine-doped silicate glass (FSG) may also be used. Layer 22 may be deposited using thermal oxidation of silicon, chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), low-pressure chemical vapor deposition (LPCVD), atomic layer deposition (ALD), etc.

[0022] An absorption layer 24 is deposited on top of layer 22. The absorption layer 24 is formed of a material capable of absorbing laser energy, as will be discussed later. According to some embodiments, the absorption layer 24 is a metal-containing layer, which may be a metal layer, a metal compound layer, or a composite layer comprising multiple layers. According to some embodiments, the absorption layer 24 comprises titanium nitride (TiN). According to an alternative embodiment, the absorption layer 24 comprises titanium (Ti). According to yet another alternative embodiment, the absorption layer 24 comprises TiN / Ti / TiN, which includes a titanium layer sandwiched between two titanium nitride layers. The formation of the absorption layer 24 may include CVD, PVD, ALD, PECVD, etc.

[0023] The absorption layer 24 is used to absorb laser energy during the subsequent debonding process, thereby ablating the absorption layer 24. Therefore, the material of the absorption layer 24 is selected to have a high laser energy absorption rate. Figure 17 The reflectivity (denoted as R), absorptivity (denoted as A), and transmittance (denoted as T) of the TiN layer are shown as functions of the corresponding TiN layer thickness. Reflectivity, absorptivity, and transmittance are percentages. Figure 17This was achieved using infrared (IR) lasers with wavelengths ranging from approximately 1800 nm to approximately 2200 nm. Reflectivity, absorptivity, and transmittance reflect the percentage of laser beam energy reflected, absorbed, and transmitted when the laser beam is projected onto the TiN layer. It should be understood that reflectivity, absorptivity, and transmittance are wavelength-dependent, and different rates will be obtained when laser beams of different wavelengths are used.

[0024] like Figure 17 As shown, the absorption rate of TiN is relatively low when the corresponding TiN layer is thin, but it rises to about 35% as the thickness of the TiN layer increases. The absorption rate of TiN saturates at about 38%, which means that about 38% of the corresponding energy is absorbed. This is a high value for metal-containing absorption layers.

[0025] When the corresponding TiN layer is thinner, the reflectivity of TiN is lower. For example, when the thickness of the TiN layer is about 25 nm, the reflectivity is about 40%, while as the thickness increases, the reflectivity increases to over 60%. This means that a thinner TiN layer is generally better for reducing reflection.

[0026] Furthermore, the transmittance is higher when the corresponding TiN layer is thinner. Transmittance decreases as the thickness increases, and drops to zero when the TiN layer thickness exceeds approximately 140 nm. The sum of absorptivity, reflectivity, and transmittance (“R+A+T”) equals 100%.

[0027] like Figure 17 As shown, the absorptivity affects the percentage of laser energy absorbed by the absorption layer 24; therefore, the absorption layer 24 cannot be too thin, otherwise the absorptivity will be too low. On the other hand, the absorption layer 24 cannot be too thick, otherwise the absorbed energy will diffuse throughout the entire thick absorption layer 24, and the temperature of the absorption layer 24 cannot rise sufficiently to achieve ablation. According to some embodiments, when TiN is used as the absorption layer, the thickness T1 of the absorption layer 24 is... Figure 1A The thickness of the absorber layer 24 can be in the range of approximately 15 nm to approximately 100 nm. Similarly, when the absorber layer 24 comprises a TiN / Ti / TiN composite layer, the thickness of the absorber layer 24 can be in the range of approximately 15 nm to approximately 100 nm.

[0028] When titanium is used to form the absorber layer 24, the surface layer of titanium can be oxidized to form titanium oxide as the primary oxide. Therefore, the titanium layer is typically deposited thicker so that even if oxidation occurs, the remaining unoxidized titanium is still thick enough to serve as the absorber layer 24. Alternatively, the titanium absorber layer 24 has an increased thickness to allow for undesirable oxidation margins. The thickness of the titanium absorber layer 24 can range from about 30 nm to about 100 nm.

[0029] Figure 1AThe formation of a pad layer 26 and a reflective layer 28 according to some embodiments is further illustrated. The pad layer 26 may also be formed of a material transparent to the laser beam subsequently used for debonding, for example, having an absorption rate of less than about 5% or 2%. According to some embodiments, the pad layer 26 is formed of or comprises a silicon-based material, such as silicon oxide, PSG, BSG, BPSG, FSG, etc. The pad layer 26 can be deposited using PECVD, LPCVD, ALD, etc.

[0030] A reflective layer 28 is deposited on top of a backing layer 26. The reflective layer 28 is formed of a material that reflects most of the energy of a laser beam and has a low absorptivity. According to some embodiments, the reflective layer 28 is formed of or comprises a metal layer, a metal alloy layer, or a composite layer comprising one or more metal layers, one or more metal compound layers, and / or one or more metal alloy layers. According to some embodiments, the reflective layer 28 has a reflectivity greater than about 80%, greater than about 90%, or greater than about 95%.

[0031] Figure 18 The reflectivity, absorptivity, and transmittance of aluminum are shown as functions of the thickness of the corresponding aluminum layer. Figure 18 This was achieved using infrared (IR) lasers with wavelengths in the range of approximately 1800 nm to approximately 2200 nm. For example... Figure 18 As shown, when the corresponding aluminum layer is thin, the reflectivity of aluminum is low, while the reflectivity increases as the thickness of the aluminum layer increases. When the thickness of the aluminum layer is greater than about 50 nm, the reflectivity of aluminum saturates at about 93%, which means that about 93% of the corresponding laser energy is reflected. On the other hand, as the thickness of the aluminum layer increases, both transmittance and absorptivity decrease, and when the thickness of the aluminum layer is greater than about 50 nm, both transmittance and absorptivity are very low. Therefore, the thickness T2 of the reflective layer 28 (as shown) Figure 1A The thickness T2 (as shown) can be selected to be greater than about 50 nm to achieve high reflectivity. The thickness T2 can also be in the range of about 50 nm to about 100 nm. While a larger thickness T2 can be used, reflectivity saturation occurs.

[0032] Other metallic materials exhibiting high reflectivity, low transmittance, and low absorptivity can also be used to form reflective layers. For example, copper has a reflectivity of approximately 90% to approximately 98% when the laser wavelength is in the range of approximately 1000 nm to approximately 5000 nm, and silver has a reflectivity of approximately 97% to approximately 99%. Gold also has high reflectivity. Therefore, reflective layer 28 ( Figure 1A The reflective layer 28 may be formed from or comprise of aluminum, copper, silver, gold, or alloys thereof and / or composite layers thereof. According to some embodiments, the reflective layer 28 has a metal percentage greater than about 90% or greater than about 95%, wherein the metal is aluminum, copper, silver, gold, or alloys thereof.

[0033] Other metals, such as steel, nickel, and zinc, can have low reflectivity of about 60% to 70% when the laser wavelength is about 1000 nm, but the reflectivity increases to over 90% when the wavelength is about 5000 nm. Therefore, when the wavelength of the laser beam is higher (e.g., about 1800 nm and about 2200 nm or higher), the reflective layer 28 can also be formed of or contain steel, nickel, zinc, etc.

[0034] Return to reference Figure 1A A bonding layer 30 is deposited on the reflective layer 28. According to some embodiments, the bonding layer 30 is formed of or comprises a silicon-containing dielectric material, which may be formed of or comprise of silicon oxide, silicon oxynitride (SiON), silicon oxycarbide (SiOC), silicon nitride (SiN), silicon carbide (SiC), silicon carbonitride (SiCN), etc. According to some embodiments of this disclosure, the bonding layer 30 is formed using PECVD, CVD, LPCVD, ALD, etc. Throughout the specification, Figure 1A The structure in it is called composite carrier 32.

[0035] Each of layer 22, transparent layer 24, padding layer 26, reflective layer 28, and bonding layer 30 may be a planar layer. The entire top and bottom surfaces of each of layer 22, absorbing layer 24, padding layer 26, reflective layer 28, and bonding layer 30 may be planar and extend to the edge of substrate layer 20.

[0036] Figure 1B A composite carrier 32 according to an alternative embodiment is shown. The composite carrier 32 according to these embodiments is similar to... Figure 1A The embodiment shown differs in that the reflective layer 28 is not formed. The padding layer 26 can also be omitted accordingly. According to these embodiments, the bonding layer 30 is in contact with the absorbent layer 24. (Discussed below) Figures 2 to 7 In the image, the reflective layer 28 and the padding layer 26 are shown using dashed lines to indicate that these layers may or may not be formed.

[0037] Figure 2 The diagram illustrates bonding a device wafer 60 to a composite carrier 32 according to some embodiments. The corresponding process is as follows: Figure 24The process flow 200 shown is illustrated as process 204. Bonding may include fusion bonding, wherein Si-O-Si bonds are formed to connect the bonding layer 30 of the composite carrier 32 to the bonding layer 34 of the device wafer 60. According to some embodiments of the present disclosure, the device wafer 60 may include a plurality of chips / dies 60' therein, one of which is shown. According to some embodiments of the present disclosure, the device die 60' is a logic die, which may be a central processing unit (CPU) die, a graphics processing unit (GPU) die, a microcontroller unit (MCU) die, a baseband (BB) die, an application processor (AP) die, etc. The device wafer 60 may include a semiconductor substrate 36 and an integrated circuit device 40 formed on the substrate 36. The bonding layer 34 is formed beneath the semiconductor substrate 36 and may be formed of a silicon-containing dielectric material (e.g., silicon oxide, silicon oxynitride, silicon carbide, silicon nitride, etc.).

[0038] The semiconductor substrate 36 may be formed of crystalline silicon, crystalline germanium, crystalline silicon-germanium, and / or III-V compound semiconductors (e.g., GaAsP, AlInAs, AlGaAs, GaInAs, GaInP, GaInAsP, etc.). According to some embodiments, vias 38 (sometimes referred to as through-silicon vias (TSVs) or through-semiconductor vias) may be formed to extend into the semiconductor substrate 36, wherein the vias are used to electrically couple features on opposite sides of the semiconductor substrate 36 to each other.

[0039] According to some embodiments, the integrated circuit device 40 is alternatively referred to as front-end process (FEOL). The integrated circuit device 40 may include active devices, such as transistors and diodes, and may or may not include passive devices, such as capacitors, resistors, etc.

[0040] According to an alternative embodiment, a wafer comprising layers 20, 22, 24, 26, 28, 30 and a substrate 36 is first formed, and an integrated circuit device 40 is formed on the surface of the substrate 36, instead of forming a composite carrier 32 and bonding the device wafer 60 to the composite carrier 32.

[0041] On top of the integrated device 40, middle-end process (MEOL) and back-end process (BEOL) structures, also referred to as interconnect structures 42, are formed. Interconnect structures 42 may include interlayer dielectric (ILD) 44 and contact plugs 46 formed in the ILD 44. According to some exemplary embodiments, the ILD 44 is formed of or includes PSG, BSG, BPSG, FSG, silicon oxide, etc. The ILD 44 can be formed using spin coating, flowable chemical vapor deposition (FCVD), CVD, PECVD, etc.

[0042] Contact plug 46 is formed in ILD 44 and is used to electrically connect integrated circuit device 40 to overlying metal lines and vias. According to some embodiments of this disclosure, contact plug 46 is formed of a conductive material selected from tungsten, cobalt, aluminum, copper, titanium, tantalum, titanium nitride, tantalum nitride, alloys thereof, and / or multiple layers thereof.

[0043] According to some embodiments, the interconnect structure 42 further includes metal lines 50 and vias 52, referred to as BEOL. The metal lines 50 and vias 52 are formed in the dielectric layer 48. The dielectric layer 48 is alternatively referred to below as the intermetallic dielectric (IMD) layer 48. According to some embodiments of this disclosure, at least some or all of the dielectric layers 48 are formed of a low-k dielectric material with a dielectric constant (k value) lower than about 3.0. The dielectric layer 48 may be formed of a carbon-containing low-k dielectric material, hydrogen silsesquioxane (HSQ), methyl silsesquioxane (MSQ), etc. According to alternative embodiments of this disclosure, some or all of the dielectric layers 48 are formed of a non-low-k dielectric material. An etch stop layer (not shown), which may be formed of silicon carbide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, or a combination thereof, is formed between the IMD layers 48 and is not shown for simplicity.

[0044] A surface dielectric layer 56 may be formed on the surface of wafer 60. According to some embodiments, the surface dielectric layer 56 may be formed of a non-low-k dielectric material (e.g., silicon oxide) and may be in physical contact with the underlying low-k dielectric layer 48. The surface dielectric layer 56 may have a monolayer structure or a composite structure comprising more than one layer, and may be formed of silicon oxide, silicon nitride, undoped silicate glass (USG), etc. The surface dielectric layer 56 is alternatively referred to as a passivation layer because it functions to isolate the underlying low-k dielectric layer (if present) from the adverse effects of hazardous chemicals and moisture.

[0045] refer to Figure 3 The carrier 62 is bonded to the wafer 60. The corresponding process is as follows: Figure 24 The process flow 200 shown is designated as process 206. According to some embodiments, carrier 62 includes a substrate carrier 64 and a bonding layer 66 on the substrate carrier 64. Carrier 62 may be formed of or contain silicon, glass, etc. According to some embodiments, carrier 62 remains in the final structure and is diced as a portion of a corresponding package. Therefore, carrier 62 can have… Figure 3 The structure shown may have, or may have Figure 1A or Figure 1B The structure shown. According to an alternative embodiment, the carrier 62 is debonded in a subsequent process, thus it can have… Figure 1A or Figure 1B The structure shown.

[0046] The bonding layer 66 may be formed of or contain a silicon-containing dielectric material, such as silicon oxide, silicon oxynitride, silicon carbonitride, etc. Bonding may include fusion bonding, wherein Si-O-Si bonds are formed to interconnect the bonding layer 66 with the dielectric layer 56. Throughout the specification, Figure 4 The structure shown is called composite wafer 67.

[0047] refer to Figure 3 The composite wafer 67 is flipped upside down, and a laser debonding process is performed to debond the substrate carrier 20 from the wafer 60. The corresponding process is described in... Figure 24 The process flow 200 shown is designated as process 208. A laser beam 68 is projected onto the composite wafer 67 to ablate the absorber layer 24, thereby debonding the substrate carrier 20 from the wafer 60. The laser beam 68 has a wavelength that allows it to penetrate the substrate carrier 20, layer 22, and pad layer 26 without being substantially absorbed by these layers. Furthermore, the laser beam 68 has a wavelength that allows it to be absorbed by the absorber layer 24 at a relatively high absorptivity, for example, an absorptivity value greater than about 10%, about 20%, or about 35%, depending on the material, the structure of the absorber layer 24, and the wavelength. The laser beam 68 also has a wavelength that allows it to be reflected by the reflective layer 28 (if formed) at a high reflectivity, for example, a reflectivity greater than about 80% or 90%.

[0048] Figure 19 The reflectivity, absorptivity, and transmittance of the TiN layer as a function of laser wavelength are shown. The thickness of the TiN layer in the corresponding sample is 63 nm. It can be observed that when the wavelength is in the range of approximately 1000 nm to approximately 2000 nm, the absorptivity is in the range of 12% to approximately 23%, which is usable. Furthermore, in this wavelength range, the transmittance is in the range of approximately 70% to approximately 88%, which means that the reflective layer can significantly aid absorption because the reflective layer reflects the laser beam that penetrates the absorption layer 24 to obtain a second absorption opportunity. Therefore, when using TiN as the absorption layer, it is possible to employ... Figure 1A The composite carrier shown.

[0049] Figure 20 The reflectivity R, absorptivity A, and transmittance T of the TiN / Ti / TiN composite layer as a function of laser beam wavelength are shown. It can be observed that when the wavelength is in the range of approximately 1000 nm to approximately 2000 nm, the absorptivity is approximately 30% to 35%, which is higher due to the thinner absorbing layer, resulting in higher power density. Within this wavelength range, the reflectivity is in the range of approximately 58% to approximately 65%. Furthermore, within this wavelength range, the transmittance is in the range of approximately 8% to approximately 10%, meaning that the reflective layer may not significantly contribute to absorption. Therefore, when using the TiN / Ti / TiN composite layer as the absorbing layer, the following can be employed: Figure 1B The composite carrier shown.

[0050] Figure 21 The figure shows the reflectivity values ​​of aluminum, silver, and gold as a function of laser beam wavelength. The graph indicates that when the wavelength is greater than approximately 1000 nm (1 μm), the reflectivity value is greater than approximately 95%, suggesting that aluminum, silver, and gold are good candidates for forming reflective layers.

[0051] According to some embodiments, such as Figure 19 , Figure 20 and Figure 21 The reflected infrared (IR) lasers with wavelengths in the range of approximately 1800 μm to approximately 2200 μm can be used for debonding. Figure 22 The first mode is shown where the laser beam 68 scans the entire composite carrier 32, wherein the composite carrier 32 is scanned line by line by the laser beam 68. Figure 23 A second mode of scanning the composite carrier 32 with the laser beam 68 is shown, wherein the laser beam 68 moves along the radius of the composite carrier 32 while rotating the composite carrier 32 so that the laser beam 68 scans the entire composite carrier 32.

[0052] The laser spot size (diameter or length / width) can be larger than approximately 5 nm to ensure sufficiently high debonding efficiency. Otherwise, the time required to scan the composite carrier 32 would be too long. It is understood that the energy of the laser beam 68 is finite, and the power density decreases as the spot size increases. Therefore, the laser spot size cannot be too large either. According to some embodiments, the laser spot size is selected such that the peak power density of the laser beam is approximately 1E11 W / cm². 2 Up to approximately 1E15 watts / cm 2 Within the specified range. Otherwise, the collision points of the absorbing layer 24 may not be successfully ablated.

[0053] The laser beam 68 is projected in the form of laser pulses. The laser pulses cannot be too long or too short. If the laser pulse is too short, sufficient power density cannot be generated in the laser spot, and the projected spot of the absorption layer 24 cannot be ablated. If the laser pulse is too long, the heat carried by the laser beam 68 will cause the lower wafer 60 ( Figure 4 Excessive temperature rise can degrade or damage the circuitry and / or components. According to some embodiments, the laser pulse duration is approximately 1 x 10⁻⁶. -15 Approximately 1x10 seconds -9 Within a range of seconds. By controlling the power of the laser beam 68, the laser spot size, and the laser pulse duration within an ideal range, the temperature in the wafer 60 can be limited to below approximately 400°C.

[0054] Return to reference Figure 4The energy of the laser beam 68 is absorbed by the absorption layer 24, causing the projected light spot of the absorption layer 24 to be ablated. During ablation, the projected light spot of the absorption layer 24 can be liquefied and evaporated. Furthermore, the laser energy can impact the projected light spot, and the liquefied and evaporated portions of the absorption layer 24 can be pushed up and down to create vacancies. When the laser beam 68 scans the entire absorption layer 24, the entire absorption layer 24 is ablated. Therefore, the substrate 20 and layer 22 can be separated from the underlying pad layer 26 (if a pad layer 26 and reflective layer 28 are formed) or bonding layer 30. The resulting structure is as follows: Figure 5 As shown.

[0055] After debonding, the residual absorbent layer 24 is removed during the cleaning process. For example, the pad layer 26 and reflective layer 28 (if formed) are removed during the etching process. The corresponding processes are as follows: Figure 24 In the process flow 200 shown, it is represented as process 210. The resulting structure is as follows: Figure 6 As shown. Depending on the materials of bonding layers 30 and 34, bonding layer 30 can be removed or retained in the final structure.

[0056] In subsequent processes, conductive features such as redistribution lines (RDLs) and electrical connectors can be formed on the back side of substrate 36 (the top side shown in the figure). The exemplary structure obtained in... Figure 7 As shown below, alternatively, conductive features may be formed on the front side (bottom side shown) of interconnect structure 42. When conductive features are formed on the front side of substrate 36, carrier 62 may be removed first to form conductive features. According to these embodiments, carrier 62 may have the following characteristics: Figure 1A or Figure 1B The structure shown can be used as follows Figure 4 The same laser ablation process shown is used to remove it.

[0057] Figure 7 The formation of an interconnect structure 70 on the back side of a substrate 36 according to some embodiments is shown. The corresponding process is as follows: Figure 24 The process flow 200 shown is designated as process 212. Interconnect structure 70 includes a dielectric layer 72 and an RDL 74 within the dielectric layer 72. An electrical connector 76, which may include solder areas, may be configured to be electrically connected to the RDL 74. The RDL 74 may include a power distribution network (PDN) therein and may also include signal lines.

[0058] Wafer 60 can then be detached to form a package. According to some embodiments, carrier 62 is removed from wafer 60 prior to detachment. According to alternative embodiments, carrier 62 is not removed but retained in the final package. Therefore, carrier 62 is shown as a dashed line to indicate whether it can be removed or retained in the final package.

[0059] Figures 8 to 16 Cross-sectional views are shown of intermediate stages in the formation of an encapsulation on a composite carrier and the debonding of the composite carrier according to some embodiments of the present disclosure. Unless otherwise specified, the materials and formation processes of the components in these embodiments are substantially the same as those of similar components that... Figure 1A , Figure 1B and Figures 2-7 The previous embodiments shown are indicated by similar reference numerals. Therefore, regarding Figures 8 to 16 The details of the formation process and materials of the components shown can be found in the discussion of the preceding embodiments.

[0060] refer to Figure 8 A composite carrier 32 is provided. (Reference has been made.) Figure 1A and Figure 1B The structure, formation process, and materials of composite carrier 32 have been discussed, and therefore will not be repeated here.

[0061] refer to Figure 9 The first layer (one or more) package components 80 are bonded to the composite carrier 32 by fusion bonding. According to some embodiments, there is a single package component 80 bonded to the composite carrier 32. Therefore, the package component 80 can be an uncuttered device wafer, an uncuttered reconstructed wafer (in which discrete device dies are packaged), etc. According to alternative embodiments, multiple package components 80 are bonded to the composite carrier 32. The multiple package components 80 can be physically separated discrete package components. According to some embodiments, the package component 80 is selected from: device dies, packages in which device dies are packaged, system-on-a-chip (SoC) dies comprising multiple integrated circuits (or device dies) integrated as a system, etc., or combinations thereof. The device dies in the package component 80 can be or may include: logic dies, memory dies, input / output dies, integrated passive devices (IPDs), etc., or combinations thereof. For example, the logic device die in package assembly 80 may be a central processing unit (CPU) die, a graphics processing unit (GPU) die, a mobile application die, a microcontroller unit (MCU) die, a baseband (BB) die, an application processor (AP) die, etc. The memory die in package assembly 80 may include a static random access memory (SRAM) die, a dynamic random access memory (DRAM) die, etc. The device die in package assembly 80 may include a semiconductor substrate and an interconnect structure.

[0062] According to some embodiments, package assembly 80 may include a substrate 82, an integrated circuit device 84 on the surface of substrate 82, and a through-substrate via 86 penetrating substrate 82. Substrate 82 may be a semiconductor substrate such as a silicon substrate. Integrated circuit device 84 may include active devices, passive devices, etc. Interconnect structure 88 is located on the front side of package assembly 80 and includes metal lines and vias electrically connected to via 86 and integrated circuit device 84. Top portion of via 86 may extend beyond the rear surface of substrate 82 (top surface shown in the figure) and is located in dielectric layer 90. Bonding pad 92 is electrically connected to via 86 and is located in dielectric layer 94.

[0063] According to some embodiments, the encapsulation component 80 is bonded to the composite carrier 32 by fusion bonding, wherein the bonding layer 30 is bonded to the surface dielectric layer 98 in the encapsulation component 80, for example, wherein Si-O-Si bonds are formed.

[0064] Figure 10 The deposition of gap-filling material (region) 102 (when discrete package assemblies 80 are bonded) to seal package assembly 80 is illustrated. According to some embodiments where package assembly 80 is located in an uncuttered wafer, the gap-filling process may be skipped. According to some embodiments, gap-filling region 102 is formed of or contains inorganic material. For example, forming gap-filling region 102 may include depositing a dielectric liner (e.g., a silicon nitride layer) and a dielectric material (e.g., silicon oxide) over a dielectric liner. According to alternative embodiments, gap-filling region 102 is formed of molding compounds, epoxy resins, resins, and / or the like. A planarization process, such as a CMP process or a mechanical polishing process, is performed to make the rear surface of package assembly 80 (the illustrated top surface) flush with the top surface of gap-filling region 102. Throughout the specification, package assembly 80 and gap-filling region 102 are collectively referred to as reconstructed wafer 104. When viewed in a top view of reconstructed wafer 104, gap-filling region 102 surrounds the corresponding package assembly 80.

[0065] Figure 11 The bonding of the second-layer package assembly 106 to the reconstructed wafer 104 is illustrated. Although a set of package assemblies 106 comprising two package assemblies 106 is shown as an example, multiple sets of package assemblies 106 can be individually bonded to one package assembly 80 in the reconstructed wafer 104. The bonding of the package assembly 106 to the reconstructed wafer 104 can be achieved through hybrid bonding, wherein both metal-to-metal direct bonding and dielectric-to-dielectric bonding (forming Si-O-Si bonds) are formed. According to some embodiments, the package assembly 106 includes a device die, a package, etc.

[0066] Figure 11The diagram further illustrates gap filling of the package assembly 106 in gap filling region 108. The methods and materials for forming gap filling region 108 can be found in candidate methods and materials for gap filling region 102, and therefore will not be repeated. Throughout this specification, package assemblies 80 and 106, as well as gap filling regions 102 and 106, are collectively referred to as reconfigured wafer 110.

[0067] Figure 12 The debonding of the composite carrier 32 to the reconstructed wafer 110 is illustrated. Debonding can be performed by a laser beam 68 projected onto the composite carrier 32. The laser beam 68 penetrates the substrate carrier 20 and layer 22 to reach the absorption layer 24, which is ablated by the laser beam 68. The debonding process is essentially the same as that discussed with reference to the foregoing embodiments and will not be repeated here. Figure 13 The resulting structure after removing the substrate carrier 20 is shown. Figure 14 The structure after removing the dielectric layer 26 and the reflective layer 28 is shown. Figure 15 As shown, bonding layer 30 (together with the surface bonding layer in package assembly 80) can be removed. According to alternative embodiments, bonding layer 30 may remain in the final structure, depending on the material. According to still some alternative embodiments, some surface layers of bonding layer 30 and dielectric layer 98 may be removed during polishing, and the resulting layers are shown as examples. Figure 15 As shown.

[0068] Figure 15 The process of creating a pad opening is illustrated, wherein an opening (occupied by an electrical connector 112) is formed in the dielectric layer 98. According to some embodiments, the opening is formed by a photolithography process, and the dielectric layer 98 is etched to form the opening, wherein the metal pads 97 in the package assembly 80 are exposed to the opening.

[0069] Figure 15 The formation of an electrical connector 112 is also shown. According to some embodiments, the electrical connector 112 includes a solder region that can be formed by placing solder balls in an opening and then reflowing the solder balls to form the solder region. According to an alternative embodiment, the electrical connector 112 includes metal pillars that can be formed by electroplating. Figure 15 The structure shown is referred to as reconstructed wafer 116. A separation process can be performed to cut the reconstructed wafer 116 along scribing 118 and form discrete packages 116' that are identical to each other.

[0070] Figure 16 The diagram illustrates bonding package 116' to package assembly 120 to form package 124. Package assembly 120 may be a package substrate, internal component, package, printed circuit board, etc. Underfill 122 is distributed between package 116' and package assembly 120.

[0071] The embodiments of this disclosure have several advantageous features. By using a laser debonding process, permanently bonded substrates bonded by fusion bonding can be debonded without damage. The substrate can be reused, reducing costs. Since the laser debonding process is faster than using CMP to remove the substrate, throughput is increased. Consistency is also improved because the debonding interface is limited to the absorption layer.

[0072] According to some embodiments of this disclosure, a method includes: bonding an encapsulation assembly to a composite carrier, wherein the composite carrier includes: a substrate carrier; and an absorption layer, wherein the absorption layer is located between the substrate carrier and the encapsulation assembly; projecting a laser beam onto the composite carrier, wherein the laser beam penetrates the substrate carrier to ablate the absorption layer; and separating the substrate carrier from the encapsulation assembly. In one embodiment, the composite carrier further includes a reflective layer located between the absorption layer and the encapsulation assembly, and wherein the reflective layer reflects the laser beam back to the absorption layer. In one embodiment, the absorption layer comprises a metal. In one embodiment, the absorption layer comprises titanium nitride. In one embodiment, the absorption layer comprises a TiN / Ti / TiN composite layer. In one embodiment, the laser beam has a wavelength in the range of about 1800 nm to about 2200 nm. In one embodiment, the substrate carrier includes a first silicon substrate, and the encapsulation assembly includes a second silicon substrate. In one embodiment, the method further includes: sealing the encapsulation assembly in a gap-filling material, wherein the encapsulation assembly includes a first device die; bonding a second device die to the first device die, wherein the laser beam is projected after bonding the second device die; and performing a separation process to form an encapsulation after the substrate carrier is separated from the encapsulation assembly, wherein the first device die and the second device die are located within the encapsulation. In one embodiment, bonding the encapsulation assembly to the composite carrier includes fusion bonding.

[0073] According to some embodiments of this disclosure, a structure includes: a composite carrier comprising: a silicon substrate; a transparent layer; an absorption layer disposed above the transparent layer, wherein the absorption layer comprises titanium; and a bonding layer disposed above the absorption layer, wherein each of the transparent layer, the absorption layer, and the bonding layer is a planar layer. In one embodiment, the transparent layer comprises silicon oxide, and the absorption layer comprises a metal. In one embodiment, the absorption layer comprises titanium. In one embodiment, the absorption layer comprises titanium nitride. In one embodiment, the absorption layer comprises a composite layer comprising: a first titanium nitride layer; a titanium layer disposed above the first titanium nitride layer; and a second titanium nitride layer disposed above the titanium layer. In one embodiment, the structure further comprises: a pad layer disposed above the absorption layer; and a reflective layer disposed above the pad layer, wherein the pad layer and the reflective layer are located between the bonding layer and the absorption layer. In one embodiment, the structure further comprises: a device wafer bonded to the composite carrier, wherein the device wafer includes an additional bonding layer bonded to the bonding layer by fusion bonding.

[0074] According to some embodiments of this disclosure, a structure configured for debonding by a laser beam includes: a substrate carrier, wherein the substrate carrier is integrally formed of a homogeneous material and wherein the substrate carrier is transparent to the laser beam; a metal-containing absorbing layer disposed on the substrate carrier, wherein the metal-containing absorbing layer is configured to absorb the laser beam; a metal-containing reflective layer disposed on the metal-containing absorbing layer, wherein the metal-containing reflective layer is configured to reflect the laser beam; and a bonding layer disposed on the metal-containing reflective layer. In one embodiment, the metal-containing absorbing layer comprises a first titanium nitride layer. In one embodiment, the metal-containing absorbing layer comprises a titanium layer and a second titanium nitride layer, wherein the titanium layer is disposed between and in physical contact with the first titanium nitride layer and the second titanium nitride layer. In one embodiment, the metal-containing reflective layer comprises aluminum, silver, or gold.

[0075] The foregoing has outlined features of several embodiments to enable those skilled in the art to better understand various aspects of this disclosure. Those skilled in the art should understand that they can readily use this disclosure as a basis for designing or modifying other processes and structures to achieve the same purposes and / or the same advantages of the embodiments described herein. Those skilled in the art should also recognize that such equivalent constructions do not depart from the spirit and scope of this disclosure, and that various changes, substitutions, and modifications can be made herein without departing from the spirit and scope of this disclosure.

[0076] Example 1. A method for debonding using a laser beam, comprising:

[0077] The encapsulation component is bonded to a composite carrier, wherein the composite carrier comprises:

[0078] Substrate carrier; and

[0079] An absorbent layer, wherein the absorbent layer is located between the substrate carrier and the encapsulation assembly;

[0080] A laser beam is projected onto the composite carrier, wherein the laser beam penetrates the substrate carrier to ablate the absorption layer; and

[0081] The substrate carrier is separated from the packaging component.

[0082] Example 2. The method according to Example 1, wherein the composite carrier further includes a reflective layer located between the absorption layer and the encapsulation component, and wherein the reflective layer reflects the laser beam back to the absorption layer.

[0083] Example 3. The method according to Example 1, wherein the absorbing layer comprises a metal.

[0084] Example 4. The method according to Example 1, wherein the absorber layer comprises titanium nitride.

[0085] Example 5. The method according to Example 1, wherein the absorption layer comprises a TiN / Ti / TiN composite layer.

[0086] Example 6. The method according to Example 1, wherein the laser beam has a wavelength in the range of about 1800 nm to about 2200 nm.

[0087] Example 7. The method according to Example 1, wherein the substrate carrier includes a first silicon substrate and the packaging assembly includes a second silicon substrate.

[0088] Example 8. The method described in Example 1 further includes:

[0089] The encapsulation assembly is sealed in a gap-filling material, wherein the encapsulation assembly includes a first device die;

[0090] Bonding a second device die to a first device die, wherein the laser beam is projected after the second device die is bonded; and

[0091] After the substrate carrier is separated from the packaging assembly, a separation process is performed to form a package, wherein the first device die and the second device die are located in the package.

[0092] Example 9. The method according to Example 1, wherein bonding the encapsulation component to the composite carrier includes fusion bonding.

[0093] Example 10. A semiconductor structure comprising:

[0094] The composite carrier includes:

[0095] silicon substrate;

[0096] Transparent layer;

[0097] An absorption layer located above the transparent layer, wherein the absorption layer comprises titanium; and a bonding layer located above the absorption layer, wherein each of the transparent layer, the absorption layer and the bonding layer is a planar layer in whole.

[0098] Example 11. The structure according to Example 10, wherein the transparent layer comprises silicon oxide and the absorbent layer comprises metal.

[0099] Example 12. The structure according to Example 11, wherein the absorber layer comprises titanium.

[0100] Example 13. The structure according to Example 11, wherein the absorber layer comprises titanium nitride.

[0101] Example 14. The structure according to Example 11, wherein the absorbent layer includes a composite layer comprising:

[0102] First titanium nitride layer;

[0103] A titanium layer located above the first titanium nitride layer; and

[0104] A second titanium nitride layer is located on top of the titanium layer.

[0105] Example 15. The structure described in Example 10 further includes:

[0106] A padding layer located above the absorbent layer; and

[0107] A reflective layer located above the padding layer, wherein the padding layer and the reflective layer are located between the bonding layer and the absorbing layer.

[0108] Example 16. The structure described in Example 10 further includes:

[0109] A device wafer bonded to the composite carrier, wherein the device wafer includes an additional bonding layer bonded to the bonding layer by fusion bonding.

[0110] Example 17. A structure configured to debond via a laser beam, the structure comprising:

[0111] A substrate carrier, wherein the entire substrate carrier is formed of a homogeneous material, and wherein the substrate carrier is transparent to the laser beam;

[0112] A metal-containing absorbing layer located on the substrate carrier, wherein the metal-containing absorbing layer is configured to absorb the laser beam;

[0113] A metal-containing reflective layer located above the metal-containing absorber layer, wherein the metal-containing reflective layer is configured to reflect the laser beam; and

[0114] A bonding layer located above the metal-containing reflective layer.

[0115] Example 18. The structure according to Example 17, wherein the metal-absorbing layer comprises a first titanium nitride layer.

[0116] Example 19. The structure according to Example 18, wherein the metal-absorbing layer comprises a titanium layer and a second titanium nitride layer, wherein the titanium layer is located between and in physical contact with the first titanium nitride layer and the second titanium nitride layer.

[0117] Example 20. The structure according to Example 18, wherein the metal reflective layer comprises aluminum, silver or gold.

Claims

1. A method for debonding using a laser beam, comprising: The encapsulation component is bonded to a composite carrier, wherein the composite carrier comprises: Substrate carrier; and An absorption layer, wherein the absorption layer is located between the substrate carrier and the encapsulation assembly, and the absorption layer comprises a TiN / Ti / TiN composite layer; A laser beam is projected onto the composite carrier, wherein the laser beam penetrates the substrate carrier to ablate the absorption layer; and The substrate carrier is separated from the packaging component.

2. The method according to claim 1, wherein, The composite carrier further includes a reflective layer located between the absorption layer and the encapsulation component, wherein the reflective layer reflects the laser beam back to the absorption layer.

3. The method according to claim 1, wherein, The laser beam has a wavelength in the range of 1800 nm to 2200 nm.

4. The method according to claim 1, wherein, The substrate carrier includes a first silicon substrate, and the packaging assembly includes a second silicon substrate.

5. The method according to claim 1, further comprising: The encapsulation assembly is sealed in a gap-filling material, wherein the encapsulation assembly includes a first device die; Bonding a second device die to a first device die, wherein the laser beam is projected after the second device die is bonded; and After the substrate carrier is separated from the packaging assembly, a separation process is performed to form a package, wherein the first device die and the second device die are located in the package.

6. The method according to claim 1, wherein, Bonding the encapsulation component to the composite carrier includes fusion bonding.

7. A semiconductor structure comprising: The composite carrier includes: silicon substrate; Transparent layer; An absorption layer located above the transparent layer, wherein the absorption layer comprises titanium; and A bonding layer located above the absorption layer, wherein each of the transparent layer, the absorption layer, and the bonding layer is a planar layer in whole.

8. The structure according to claim 7, wherein, The transparent layer comprises silicon oxide, and the absorbent layer comprises metal.

9. The structure according to claim 8, wherein, The absorber layer comprises titanium.

10. The structure according to claim 8, wherein, The absorber layer comprises titanium nitride.

11. The structure according to claim 8, wherein, The absorbent layer includes a composite layer comprising: First titanium nitride layer; A titanium layer located above the first titanium nitride layer; and A second titanium nitride layer is located on top of the titanium layer.

12. The structure according to claim 7, further comprising: A padding layer located above the absorbent layer; as well as A reflective layer located above the padding layer, wherein the padding layer and the reflective layer are located between the bonding layer and the absorbing layer.

13. The structure according to claim 7, further comprising: A device wafer bonded to the composite carrier, wherein the device wafer includes an additional bonding layer bonded to the bonding layer by fusion bonding.

14. A structure configured to debond via a laser beam, the structure comprising: A substrate carrier, wherein the entire substrate carrier is formed of a homogeneous material, and wherein the substrate carrier is transparent to the laser beam; A metal-containing absorbing layer located on the substrate carrier, wherein the metal-containing absorbing layer is configured to absorb the laser beam, wherein the metal-containing absorbing layer comprises a first titanium nitride layer, a titanium layer and a second titanium nitride layer, and wherein the titanium layer is located between the first titanium nitride layer and the second titanium nitride layer and is in physical contact with the first titanium nitride layer and the second titanium nitride layer; A metal-containing reflective layer located above the metal-containing absorber layer, wherein the metal-containing reflective layer is configured to reflect the laser beam; and A bonding layer located above the metal-containing reflective layer.

15. The structure according to claim 14, wherein, The metal-containing reflective layer includes aluminum, silver, or gold.

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