TW201807805A - Method to fabricate thin film on substrate by forming a thin film layer which is the region of original substrate receiving ion implantation, and a layer of Remnant Substrate without ion implantation, and heating up the bonding structure body, then applying laser irradiation, etc. - Google Patents

Abstract

The present invention provides a method to fabricate a thin film on a substrate. The method comprises the following steps: providing an original substrate; forming an ion separation layer in the original substrate by ion implantation, so that the original substrate, via the ion separation layer, forming a thin film layer which is the region of original substrate receiving ion implantation, and a layer of Remnant Substrate which is the region of original substrate without ion implantation; applying wafer bonding method to bond the target substrate to the original substrate, so that the target substrate bonds to the original substrate into a bonding structure body; heating up the bonding structure body, then apply laser irradiation to process the bonding structure body for separating the thin film layer from the Remnant Substrate, so that the thin film layer can be transferred from the surface of original substrate to the target substrate, wherein the heating temperature is higher than the room temperature and the transition temperature for generating the transition of dielectric constant and the dissipation factor of bonding structure body, and lower than the temperature of activating the Smart cut process.

Description

Method for manufacturing thin film on substrate

The present invention relates to a method for manufacturing a thin film on a substrate, and in particular, to a thin film transfer method for transferring an area equal to the original substrate, a thickness of a nanometer grade, a uniformity of a height film thickness, and a low defect density.

The wafer bonding method can combine two single crystal wafers with very different lattice constants. The intermediate bonding interface does not require any glue and is kept completely clean. However, it can still obtain the same bonding strength as the substrate strength. To meet the strict requirements of interface properties of electronic and optoelectronic materials.

In 1988, Dr. W. Maszara of the United States applied a P ⁺ -type Etch Stop Layer to produce a bonding micron-thick-bond Etch-Back Silicon on Insulator; BESOI), which makes the application of this technology (BESOI) expand to the field of electronic materials, optoelectronic materials and micro-electro-mechanical systems (MEMS). However, the technology still has the disadvantages that the working time of the corrosion stopping layer of the corrosion stopping layer is different at various points, which affects the film thickness uniformity (Total Thickness Variation, TTV), and has become the biggest obstacle for the application of the material to the production of highly integrated circuits. In addition, this process is very time-consuming, not only wasting the original substrate, but also the waste solution produced by it is easy to cause environmental pollution problems, making the manufacturing cost high. During the same period, IBM's method of making SOI materials using the Separation by Implantation Oxygen (SIMOX) method has also developed rapidly. Due to SIMOX's excellent film thickness uniformity, the application of BESOI technology in the field of making highly integrated circuits is almost eliminated.

In 1992, Dr. M. Bruel of France invented a film transfer technology, the "Smart Cut Process". The intelligent cutting method can make the thickness of the bonded SOI material film also have excellent uniformity such as SIMOX. According to Breuer's claimed patent scope in US Patent 5,374,564, the process step is to implant a high dose of ions such as hydrogen, inert gas, etc. into one original substrate, and then bond with another target substrate. Then, heat treatment is applied to polymerize these ions in the implanted layer to generate many microbubbles. Subsequently, these micro-bubbles are connected into a piece, and the upper and lower materials are separated to produce a thin film. The uniformity of the thin film obtained by the smart cut method is very good, the defect density is small, no corrosive liquid is generated, and the hydrogen gas is non-toxic and harmless, there is no environmental pollution problem, and the original substrate material can be recycled.

The intelligent cutting method is accompanied by the lack of thermal stress and low productivity caused by high-temperature heating. Because of the temperature-increasing heat treatment in the thin-film transfer technology of the chi-cut method, various heating sources are used to input heat energy to raise the substrate temperature to excite the kinetic energy of these implanted hydrogen ions, and then aggregate into bubbles, eventually tearing apart. Layer to achieve the purpose of thin film transfer.

However, the above method has the following four major disadvantages:

(1) Before the bonding strength is sufficient to resist the generation of micro-bubbles by the hydrogen ion polymerization in the implanted layer and generate a huge peeling force, the temperature needs to be controlled at a temperature (approximately 450 ° C.) at which hydrogen ions generate bubbles. Therefore, the initially bonded wafers must be controlled to be annealed at a low temperature, which will lengthen the waiting time of the annealing heating, consume a lot of time, and become a bottleneck of the entire thin film transfer process, which affects the production capacity;

(2) The sample needs to be heated at high temperature as a whole, and it needs to be above 500 ° C to ensure the expected film separation results. If there is a difference in the thermal expansion coefficients of the two bonded materials, it is easy to generate great thermal stress at high temperatures and destroy the bonding structure of the two materials. This method often transfers materials of different materials before the film separation occurs, that is, due to heat. Excessive stress causes the bonding structure to break;

(3) The thermal efficiency of converting thermal energy into kinetic energy by annealing is low, which requires a large amount of external energy to be carried out, increasing operating costs;

(4) For some materials, such as alumina or alumina lanthanum substrate, etc., when using the process disclosed by the Zhi-Cut method to perform hydrogen ion implantation and subsequent high-temperature heating treatment, no obvious fineness can be produced. Bubbles to achieve the purpose of separating the membrane.

In 2000, Taiwan's Dr. T.-H. Lee developed a non-thermal process (Nova CutProcess) that uses high-frequency alternating electric or magnetic fields, such as microwaves, to directly excite the internal plant substrates. Into ions or molecular ions (Molecular Ions), generate kinetic energy, increase the collision frequency, cause micro bubbles to rapidly generate and expand, and the implant layer tear effect occurs, and then the film is separated and transferred from the original substrate to the target substrate surface (U.S. Patent 6,486,008 ). This method can effectively increase productivity and reduce time costs. However, the application of this process on large-area wafers, due to (1) sudden high-hot spot unevenness at each point, makes the instantaneous temperature difference at each point inside the sample, resulting in inconsistent separation times at each instant film separation point, Generate internal stress, cause roughening of the transfer surface, and even produce many fine cracks; (2) The uniformity of microwave irradiation is not easy to control, and the accompanying temperature distribution is uneven, which has a certain negative impact on process stability; (3) implantation The ions are widely spaced from each other, and the energy absorption efficiency is low, so the process is limited to small-size wafer fabrication.

In 2003, Dr. T.-H. Lee of Taiwan improved on the above basis, placing the bonded structure in a high-frequency alternating electric or magnetic field device capable of adjusting temperature, raising the Bonding the structure to a constant temperature above room temperature and a positive transition of the dielectric constant and dissipation factor, but this method still has some drawbacks:

(1) Due to the poor uniformity of the energy provided by the microwave, high frequency, and electric induction coupling field in the chip, the surface of the substrate after the chip is prone to a large number of defects;

(2) A large box is needed to process the entire batch of products, otherwise it is difficult to increase production capacity;

(3) Due to the need to use large doses of microwaves and high frequency in the production process, high safety requirements are required, and the cost of processing is increased.

It is an object of the present invention to provide a film transfer method. This method can produce a semiconductor material thin film capable of transferring large area wafers and other area sizes, nano-scale thickness, high uniformity film thickness, and maintaining the original crystal structure.

The invention provides a method for manufacturing a thin film transfer material. The method includes the following steps: providing an original substrate; using an ion implantation method, forming an ion separation layer in the original substrate, so that the original substrate is formed by the ion separation layer : A thin film layer, which is the region in the original substrate that is subjected to ion implantation; and a residual layer, which is the region where the ion is not implanted in the original substrate; using wafer bonding to target A substrate is bonded to the original substrate, the target substrate and the original substrate are bonded to form a bonding structure; and the bonding structure is heated to a temperature higher than room temperature, and a dielectric constant and a dissipation factor of the structure are generated. The transition temperature is changed, and the bonding structure is treated with laser irradiation to separate the thin film layer and the residual layer, so that the thin film layer can be transferred from the surface of the original substrate to the target substrate.

In a preferred embodiment, the ion implantation method is selected from a plasma immersion ion implantation method and a segmented ion implantation method with different implantation temperatures.

In another preferred embodiment, the implanted ion is selected from a hydrogen ion and a hydrogen molecular ion.

In another preferred embodiment, the wafer bonding method is selected from the group consisting of direct bonding method, anode bonding method, low temperature bonding method, vacuum bonding method, and plasma enhanced bonding method.

In another preferred embodiment, the wafer bonding method further includes a surface ionization process, so that the bonding surface between the original substrate and the target substrate can obtain sufficient bonding strength.

In another preferred embodiment, after the ion separation layer is formed and before the bonding, a preheating program is further included to initially polymerize the implanted ions or molecular ions to generate grain boundary cracks, so that the surface of the original substrate is in Critical state of high stress forming bubbles.

In another preferred embodiment, the laser irradiation processing uses a laser-related device to generate lasers, and the laser-related device is selected from the following lasers:

In another preferred embodiment, the transition temperature is higher than room temperature, and lower than 900 ° C. or lower than the temperature required for the completion of Chi Chi in the same period of time.

In another preferred embodiment, when the original substrate is a silicon substrate, the transition temperature is higher than room temperature and lower than 450 ° C.

In another preferred embodiment, the original substrate further includes different dopant atom concentration layers, so as to use different dopant atom concentration layers in the original substrate to form different carrier concentration layers to generate selective sex when laser is irradiated. Response energy.

In another preferred embodiment, different dopant atom concentration layers of the original substrate are formed by ion implantation, molecular beam epitaxial growth, liquid phase epitaxial growth, or gas phase epitaxial growth.

In another preferred embodiment, the laser irradiation time is greater than one minute.

In another preferred embodiment, the material of the original substrate is selected from Group IV semiconductor materials and Group III-V semiconductor materials.

In another preferred embodiment, the group IV semiconductor material and the group III-V semiconductor material are selected from silicon, germanium, silicon carbide, gallium arsenide, and gallium nitride.

In another preferred embodiment, the original substrate is selected from an oxide substrate.

In another preferred embodiment, the oxide is selected from the group consisting of alumina, lanthanum alumina, strontium titanium oxide, and quartz.

In another preferred embodiment, the ion implantation method is a multi-stage implantation method, and the ions are implanted in sections at at least two different implantation temperatures.

In another preferred embodiment, the original substrate is made of silicon, and the multi-stage implantation method includes at least: temperature control between 500 ° C and 800 ° C, and an implantation dose not exceeding 8 × 10 ¹⁶ / cm ² A single-atom hydrogen ion; and a single-atom hydrogen ion at a temperature of not more than 150 ° C. and an implantation dose of more than 2 × 10 ¹⁶ / cm ² or a hydrogen molecule ion of a dose of more than 1 × 10 ¹⁶ / cm ² .

In another preferred embodiment, the original substrate is made of silicon, and the multi-stage implantation method includes at least: temperature control between 500 ° C and 700 ° C, and the implantation dose does not exceed 5 × 10 ¹⁶ / cm ² Hydrogen molecular ions; and monoatomic hydrogen ions with a implantation dose of more than 2 × 10 ¹⁶ / cm ² or a hydrogen molecule ions with a dose of more than 1 × 10 ¹⁶ / cm ² at a temperature not greater than 150 ° C.

In another preferred embodiment, the original substrate is composed of alumina, and the multi-stage implantation method includes at least: temperature control between 550 ° C and 800 ° C, and an implantation dose not exceeding 2 × 10 ¹⁷ / cm ² monoatomic hydrogen ions; and monoatomic hydrogen ions with a implantation dose of more than 2 × 10 ¹⁶ / cm ² or hydrogen molecular ions with a dose of more than 1 × 10 ¹⁶ / cm ² at a temperature not greater than 200 ° C.

In another preferred embodiment, the original substrate is made of alumina, and the multi-stage implantation method includes at least: temperature control between 550 ° C and 800 ° C, and an implantation dose not exceeding 8 × 10 ¹⁶ / cm Hydrogen molecular ions of ² ; and monoatomic hydrogen ions having a implantation dose of more than 4 × 10 ¹⁶ / cm ² at a temperature not greater than 200 ° C. or hydrogen molecular ions of a dose greater than 2 × 10 ¹⁶ / cm ² .

The method of the present invention is as follows: first, an ion implantation (Ion Implantation) method is performed to implant ions or molecular ions on the surface of the original substrate to form a thin film layer separated by the implanted ions; and then, using a wafer bonding method, the original The substrate and the target substrate are bonded to form a bonding structure; the bonding structure is then placed in a laser device capable of adjusting the temperature, the bonding structure is raised to a temperature higher than room temperature, and the dielectric constant and dissipation The constant temperature (the "transition temperature" in the present patent application) caused by the factor to cause a positive transition. During the annealing process (> 150 ° C; silicon crystal material), the dielectric constant of the original substrate can be effectively transformed and increased. And dissipation factors, greatly improving the energy absorption efficiency; however, the temperature is kept lower than the temperature required to perform the smart cut method (approximately 450 ° C according to US Patent 5,374,564; silicon crystal material) to avoid the start of the method and produce the above-mentioned Defects associated with the method. After the temperature has stabilized for a set period of time, the laser is started to perform ionization treatment. The laser generates induction energy. One part is directly absorbed by the implanted ions, and the number of microbubbles nucleation is greatly increased in a short time. The other part is from the substrate. Efficiently absorb, transfer this energy to the implanted ions, increase the kinetic energy, make the implanted ions enter the nucleation point, and a large number of molecules become gas molecules, which are filled in the cracks caused by the gas molecules, and then fused to form a separation membrane and separate The thin film layer above the air film is transferred onto the target substrate.

For thin-film transfer of original substrates such as low dielectric loss oxides, such as SrTiO ₃ , Al ₂ O ₃ , SiO _2, etc., the method of the present invention uses a segmented ion implantation method, which is implanted before high temperature Ions to generate inter-grain boundary cracks, and then implant the ions into the cracks at low temperature to avoid large diffusion loss of the implanted ions, and then effectively replenish the dose to achieve a sufficient ion concentration to generate fine bubbles and polymerize to form a separation membrane. Then the ion implanted original substrate is heated to a temperature above the transition temperature (> 150 ° C), and then the laser is started to perform ionization treatment, which generates induced energy and transfers the implanted ions and the molecules formed by polymerization to increase the kinetic energy. , The implanted ions polymerize into gas molecules and cause cracks, thereby achieving the purpose of film separation. This not only effectively reduces the total dose required for ion implantation, but also saves costs and reduces the density of film defects.

In addition, the method of the present invention can be applied to a film cutting process. For example, firstly, an ion implantation method is used to form one or more ion separation layers in the film, and then the substrate temperature is raised above the transition temperature point. After the temperature equilibrium is stabilized, a laser is irradiated to the film to make the ions The implanted ions in the separation layer are polymerized into gas molecules to form a separation film, and the film is separated to complete the film cutting.

The invention uses a thermal and non-thermal composite process to perform film transfer. The reaction process and production results of this composite process are different from the thermal or non-thermal single process. Taking laser as a means of transmitting energy as an example, the laser absorptivity (ie, proportional to the product of the dissipation factor and the dielectric constant) of general substances, especially hydrogen-silicon complexes and silicon substrates, is often It rises sharply as the ambient temperature rises. In this process, the substrate is preheated to the transition temperature before the laser is applied, the purpose is to increase the effective laser absorption of the original substrate, so that it can absorb a large amount in the subsequent laser irradiation and transfer the energy to the internal plant. Into the ion. The implanted ions inside also directly absorb the laser, which is stimulated to generate a nucleation reaction, which generates many fine nucleus points, efficiently converts and aggregates ions into molecules at a fixed point, and grows and expands into a separation gas film. This thermal and non-thermal composite process is significantly superior to the pure thermal process or pure non-thermal process. Hydrogen ions are used to implant an eight-inch silicon original substrate (the dose of hydrogen ions (H ⁺ ) is 8 × 10 ¹⁶ / cm ² , and the implantation energy is It is 80KeV), and the original substrate is an example in which the bonding structure is completed after bonding with the target substrate through appropriate wafer bonding steps. First, the film is transferred in a pure thermal process (ie, Smart-Cut Process). It takes about 10 minutes to heat the bonding structure at 450 ° C. to transfer the entire film layer to the target substrate 100%. Secondly, the film is transferred by a pure non-thermal process (ie, Nova Cut Process). With 1000W, 2.4GHz microwave irradiation, this combination will be separated automatically in about three to four minutes. However, only about 30% to 65% of the film layer was successfully transferred to the target substrate, and many tear plane boundaries were generated. Finally, the film was transferred by the thermal and non-thermal composite process of the present invention, and the bonded structure was heated to 200 ° C. After 15 minutes, and then applying laser irradiation, it takes about 1 to 2 minutes to completely transfer the entire film layer to the target substrate. At this low temperature (200 ° C), the Smart-Cut Process cannot be performed with a single thermal process; at room temperature, the Nova-Cut Process with a single non-thermal process cannot achieve such results, which proves that The inventive thermal and non-thermal composite process is different from a single thermal or non-thermal process.

In addition, by using laser instead of microwave, it is easy to adjust the energy of the laser to cause the implanted H ⁺ ions to boil on the interface, so as to achieve the effect of the interface fracture. Because the laser generator can precisely control the energy, the energy distribution in the chip is very uniform, and the defects of the interface behind the sliver are reduced. The use of laser generator splits has high efficiency and large production capacity.

Hereinafter, specific exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Please refer to FIG. 1 to FIG. 5, which are schematic flowcharts of the film transfer method of the present invention. The invention provides a method for separating the thin film 02 from the original substrate 01 and transferring the thin film 02 to the target substrate 07.

As shown in FIG. 1, the present invention first uses an ion implantation method to implant ions or molecular ions 06 against the front surface 05 of the original substrate 01 to form an implanted ion separation layer 03. The implanted ion separation layer 03 separates the original substrate 01 up and down into two regions: one is an implanted area containing implanted ions or molecular ions 06, this is a thin film layer 02; one is free of implanted ions or molecular ions 06 Is defined as the Remnant Substrate 04. Since the implantation depth of the thin film layer 02 is determined by the ion implantation energy, the thickness of the thin film layer 02 to be transferred of the original substrate 01 can be accurately controlled. The ion implantation method is selected from plasma immersion ion implantation (Plasma Ion Implantation Immersion) and the segmented implantation ion method with different implantation temperatures, and the ions implanted in the ion implantation method are selected from hydrogen atoms Ions and hydrogen molecular ions.

The purpose of performing this ion implantation method is to implant a large number of ions or molecular ions 06 into the surface layer of the original substrate 01, and by the impact of the ions, the atoms existing in the crystal structure of the original substrate 01 are broken, and the atoms are interrupted in the vicinity thereof. The interatomic bonding even replaces the original atom to form a new weak bond with other neighboring atoms: a hydrogen-silicon composite structure. The implanted ions or molecular ions 06 in the implanted ion separation layer 03 are in an unstable state in the original substrate 01, and the remaining ions with excessive implant dose or some implanted molecular ions 06 that have not been split into single atoms due to impact, It is also embedded in the interstices of the lattice, causing volume strain, which causes the implanted ion separation layer 03 to become a stress concentration region. In addition, the cohesive force between the grain boundaries where the ions are implanted is relatively low, and the mechanical properties of the original substrate 01 near the implanted ion separation layer 03 are also fragile, like a hydrogen embrittlement (Hydrogen Embrittlement).

Then, as shown in FIG. 2, the wafer bonding method is used, and appropriate surface plasma processing is performed, so that the bonding surface of the original substrate 01 and the target substrate 07 can obtain sufficient bonding strength, so that the original substrate 01 and the target substrate can be obtained. 07 is connected to form a bonding structure 10. The wafer bonding method is selected from direct bonding method, anode bonding method, low temperature bonding method, vacuum bonding method, and plasma enhanced bonding method.

As shown in FIG. 3, the membrane separation effect focuses on the energy absorption capacity of the implanted ion separation layer 03. Therefore, when non-heat such as laser is not activated, the temperature of the bonding structure 10 is firstly heated by the heating device 09. Raise the temperature above the transition temperature to increase the laser absorption efficiency (or the product of the dielectric constant and dissipation factor) of the implanted ion separation layer 03, and also increase the laser absorption of the original substrate 01 to transfer energy to the implanted ion separation Layer 03, resulting in a large area and uniform and efficient film transfer. In this step of increasing the dielectric constant and the dissipation factor, the bonding structure 10 of the original substrate 01 and the target substrate 07 is appropriately maintained at a temperature of less than 400 ° C to prevent the execution of the incision method and the side effects of the method. The resulting huge thermal stress further expands the application range of the film transfer process of the present invention.

As shown in FIG. 4, the bonding structure 10 of the original substrate 01 and the target substrate 07 at a stable transition temperature is subsequently subjected to a laser irradiation 08 treatment. Because implanted ions, molecular ions 06, or ions generated after impact, will generate weak atomic bond pairs with the original substrate 01 atoms. Because they have poor anion conductivity, they generate electrical coupling, so they can resist lasers. Irradiation 08 induction, so that the oscillation frequency of atoms implanted near the ion separation layer 03 sharply increased, eventually breaking off the bond, and it can be combined with the same atom split from other places to form gas molecules again. Nuclei filled with gas molecules are formed there. Using these nucleus as a base, the atoms that move between the lattices are captured and aggregated into bubbles.

As shown in Fig. 5, the original substrate 01 increases the dielectric constant and dissipation factor, which effectively induces carriers (electrons or holes) generated by doped atoms in the laser to accompany the current and flow rapidly, resulting in a large amount of thermal energy. In a non-elastic collision method, the heat is directly transferred to the surrounding implanted ion gas molecules, which rapidly increases the kinetic energy of the gas molecules and sharply increases the volumetric strain caused by the original bubbles. The doped heteroatom concentration layer is formed by ion implantation, molecular beam epitaxial growth, liquid phase epitaxial growth, or gas phase epitaxial growth. This effect will cause the cracks in the implanted ion separation layer 03 caused by the aforementioned bubbles to be subjected to tensile stress caused by rapid increase in volumetric strain, rapidly expand and expand along the fracture tip, and swallow adjacent bubbles, A tear effect is generated, and the thin film layer 02 is separated from the residual layer 04 from the original substrate 01 and transferred to the target substrate 07.

Due to the ionization effect formed by the laser device, the coupling between the implanted ions and the atoms of the original substrate bearing the implanted ions can produce an electrically coupled polarization effect, which accelerates the breaking of bonds to form cracks, and sharply aggregates these implanted ions into Gas molecules. The implanted ions or molecular ions, the molecules polymerized in the ion separation layer and the interface of the grain boundary cracks caused by them, act as active species in the substrate, attracting these fast-flowing carriers with energy, and gathering. Skin effect effect, concentrated flow in this layer, so that the inductive energy can be directly transferred to the molecule through the inelastic collision between the carrier and the molecule in the ion separation layer, increasing its kinetic energy. However, because this kind of kinetic energy transmission is often concentrated instantaneously at a certain point, the instantaneous high temperature point is generated, which in turn affects the uniformity of the overall process temperature distribution and brings a negative smart cut effect: the area of a point has been film-transformed at the moment due to the skin effect. Phenomenon, but there is no transfer phenomenon at other points, causing the transfer film to break.

According to the academic report on the laser conduction absorption in the academia, it is learned that the laser absorption of a general substance is proportional to the product of the dielectric constant and the dissipation factor. The dielectric constant and dissipation factor often change with temperature rise during low-temperature heating, especially the gap between the movable state and the immovable state of the substance, which shows a jump mode transition. For example, the dielectric constant ε _r and dissipation factor tanδ of ice and water at 0 ° C jump from ε _r = 4; tan δ = 0.0009 to ε _r = 81; tan δ = 0.15700, showing an increase of 3,532 times. The hydrogen atom has a similar phenomenon in silicon crystals: it is in a non-movable state at about 150 ° C and below, and in a movable state at about 150 ° C and above. According to this principle, before the laser irradiation of hydrogen ions is implanted into the original substrate, the present invention is heated to a transition temperature (about 150 ° C.) or higher, so that the laser absorption efficiency of the implanted hydrogen ions and the original substrate is greatly increased (control temperature). (Above 150 ℃, below 400 ℃), do not start the intelligent cutting method, but can properly control the laser process stability.

Taking an H ⁺ implanted silicon substrate with a dose of 8 × 10 ¹⁶ / cm ² and an implantation energy of 80 KeV as an example, the ratio of the implanted hydrogen atomic bulk density to the silicon atomic bulk density is about 1:50. Therefore, if silicon atoms can effectively absorb laser energy and transfer hydrogen atoms, it will be very helpful for large-scale area transfer. In addition, when the implantation dose is the critical implantation dose, the thin film separation process can be effectively performed, and the implantation cost can be greatly saved. For example, using the Nova Cut Process, the critical implantation dose is about 5.5 × 10 ¹⁶ / cm ² , and under this condition, the film transfer phenomenon cannot be seen no matter how long the laser irradiation time is. In the Smart Cut Process, the critical implant dose is about 4 × 10 ¹⁶ , and the time and temperature required to perform the thin film separation process at this dose are far greater than the time and temperature for normal execution. However, in the present invention, in a sample with a critical implant dose of about 3.5 × 10 ¹⁶ to 5 × 10 ¹⁶ , the thin film separation process can still be performed normally.

This method, which uses lasers to excite the kinetic energy of the molecules at the transition temperature, can significantly improve the significant lack of uneven membrane separation temperature at the instant of heating. Therefore, in the present invention, the method of applying laser to excite the kinetic energy of the molecule at the transition temperature is used in conjunction with the wafer bonding technology and the ion implantation process to cut an equal area, a uniform thickness, and a low defect density from a large-sized substrate. The film is transferred to another substrate and combined to form a novel material, or it is simply used to fabricate a silicon-on-insulator (SOI) wafer with a nanometer thickness.

In addition, for the thin film transfer of the oxide original substrate with low dielectric loss, such as SrTiO ₃ , Al ₂ O ₃ , SiO _2, etc., because its hydrogen ion implantation is performed in a low temperature environment, although there is a subsequent high temperature heat treatment, There is no obvious ionic polymerization to produce fine bubbles, which makes it impossible to separate the film. Although the substrate can be implanted with ions in a high-temperature environment and then annealed at high temperature to generate air bubbles, this method has poor ion polymerization efficiency. It is necessary to increase the dose of implanted ions to supplement the implantation process at high temperatures. Large diffusion loss of ions. In the present invention, a segmented ion implantation method can be used to implant ions at high temperature first to generate intergranular cracks, and then implant ions into the cracks at low temperature to avoid a large amount of diffusion loss and efficiently replenish the dose, so that When it reaches a sufficient concentration, it is irradiated with lasers above the transition temperature to generate fine bubbles and polymerize to form a separation membrane. The total dose of ion implantation required is lower than the existing technology, which has the effect of reducing costs and film defect density. To achieve the purpose of separating membranes.

Based on the above description, the method of the present invention can be summarized into the following operation methods:

1. Ions are implanted at high temperature first, and grain boundary cracks immediately occur during implantation, but the implanted dose cannot yet cause surface bubbles to be generated. Then, the ions are continuously implanted at a lower temperature to supplement the dose, and then the original substrate 01 and the target substrate 07 are bonded to form a bonding structure 10. When the bonding structure 10 is treated above the transition temperature and subjected to laser irradiation 08, the implanted ions or molecular ions 06 in the original substrate 01 have sufficient energy to polymerize and separate the thin film layer 02.

2. After ion implantation in the original substrate 01 forms the implanted ion separation layer 03, the original substrate 01 is pre-heated to make the implanted ions or molecular ions 06, and preliminary polymerization is performed in the implanted layer to increase the internal pressure. A grain boundary crack is generated, so that the surface of the original substrate 01 is in a high stress critical state to be separated. Then, the original substrate 01 and the target substrate 7 are bonded. Finally, the bonding structure is subjected to laser irradiation 08 above the transition temperature to absorb energy and generate expansion pressure. The implanted ion separation layer 03 is broken, and the separation film is broken. Layer 02.

In the present invention, raising the temperature is an auxiliary process of the process of the present invention, which is not the main means of use as in the traditional heating method. And the sudden rise in temperature is not conducive to film transfer. Therefore, the present invention utilizes a heating device to raise the bonding structure 10 to a temperature above the transition temperature, which is lower than the temperature required for the smart cut method, to achieve the purpose of stabilizing and uniformizing the process temperature, and reducing the thermal stress of the overall bonding structure.

Compared with the conventional thin film transfer process, the method of the present invention applies a laser at a transition temperature, such as a laser irradiation treatment generated by a laser device, to directly excite the kinetic energy of these implanted ions or ion molecules, instead of using a traditional heating process The temperature rise can indirectly stimulate the kinetic energy method of implanted ions or ion molecules, which can efficiently input the required energy and reduce energy consumption. In addition, each layer of the transmission layer can be uniformly excited at the same time, so that the heating temperature distribution caused by the temperature rise effect that occurs after the kinetic energy is excited is uniform, thereby achieving the effect of improving production quality. In addition, the laser excitation kinetic energy method of the present invention can also greatly save process time and shorten production cycle. Compared with the traditional heating and heating method, the method has the advantages of reduced time cost, clean process and convenient operation.

The following lasers can be used in the present invention:

In addition, the method of the present invention is more applicable to a cutting process of a thin film. For example, the ion implantation method is used to form one or more ion separation layers in the film, and then the laser is irradiated to the film at the transition temperature to polymerize the implanted ions in the ion separation layer into gas molecules and separate them. This film completes film cutting.

In the following, the present invention provides some preferred specific embodiments to further explain the manufacturing method and features of the present invention.

Examples

First, the molecular kinetic energy in the laser-excited ion separation layer is taken as an example to explain the principle of the present invention that the laser excites the implanted ions or the kinetic energy of the ion molecules to achieve the purpose of thin film transfer.

Example 1

The original substrate is P-type, with a lattice direction (100), a resistance value of 10-50 ohm-cm, a surface covered with 2000Å silicon dioxide (SiO ₂ ), single-sided polishing, 8 ″ silicon wafer, and a dose of 4.0 × 10 ¹⁶ / cm ² , implantation energy is 200KeV, hydrogen molecular ion (H ₂ ⁺ ) implantation. Target substrate is P type, lattice direction (100), resistance value is 10-50ohm-cm, single-side polished silicon crystal Wafers. Two silicon wafers are bonded to form a bonded structure by plasma-enhanced bonding at room temperature. They are placed in a commercially-adjustable laser cavity and annealed at a temperature of 100 ~ 250 ° C. Ten minutes, and then at this temperature, the reciprocal of the wavelength corresponding to the selected laser is used as the center frequency. After 1 to 5 minutes of laser irradiation, a layer of silicon thin film is separated from the original substrate and transferred to the target substrate with a thickness of about 0.6 μm, a SOI wafer material with silicon dioxide as an insulating layer was synthesized.

Example 2

The original substrate is a P-type, with a lattice direction (100), a resistance value of 10-50 ohm-cm, a single-sided polishing, an 8 ″ silicon wafer, and two hydrogen molecular ion (H ₂ ⁺ ) implantation processes. The implantation temperature of the primary hydrogen molecule ion implantation was 550 ° C, the dose was 1.0 × 10 ¹⁶ / cm ² , and the implantation energy was 200KeV. Immediately after the second hydrogen molecule ion implantation, the implantation temperature was room temperature and the dose It is 4 × 10 ¹⁶ / cm ² , and the implantation energy is 200KeV. The target substrate is a single-sided polished glass wafer. The two silicon wafers are bonded to form a bonding structure by plasma enhanced bonding at room temperature. Inside the commercially available adjustable power laser cavity, the temperature inside the cavity is set to 100 ~ 250 ° C for ten minutes, and then the reciprocal of the wavelength corresponding to the selected laser is used as the center frequency at this temperature, 1 ~ After 5 minutes of laser irradiation, a layer of silicon film was separated from the original substrate and transferred to the target substrate with a thickness of about 0.5 μm, and a SOI wafer material mainly composed of a glass substrate was synthesized.

Example 3

The original substrate is a P-type, with a lattice direction (100), a resistance value of 10-50 ohm-cm, a single-sided polished silicon wafer, and two ion implantations. The first implantation dose is 1 × 10 ¹⁴ / cm ² , the implantation energy is 180KeV, boron ion (B ⁺ ); the second implantation dose is 5 × 10 ¹⁶ / cm ² , the implantation energy is 129KeV, and the hydrogen molecular ion (H ₂ ⁺ ). The target substrate is a single-sided polished glass wafer. The two wafers are bonded to form a bonding structure by plasma-strengthened bonding at room temperature. The wafers are placed in a commercially-adjustable laser cavity, and annealed at a temperature of 100 to 250 ° C for ten minutes. Immediately at this temperature, the reciprocal of the wavelength corresponding to the selected laser is used as the center frequency. After 1 to 5 minutes of laser irradiation, a layer of silicon film is separated from the original substrate and transferred to the target substrate with a thickness of about 0.35 μm. A SOI wafer material mainly composed of a glass substrate.

Example 4

The original substrate is a high-concentration epitaxial layer doped with boron and germanium with a thickness of 1.5 μm and a concentration of (B / Ge: 2.0 × 10 ²⁰ /2.0×10 ²¹ / cm ^-3 ). There is an undoped thickness of 0.35 μm thereon. The lattice direction of the hetero-silicon epitaxial layer (100), a single-sided polished silicon wafer, with a dose of 5 × 10 ¹⁶ / cm ² , an implantation energy of 120 KeV, and hydrogen molecular ion (H ₂ ⁺ ) implantation. The target substrate is a single-sided polished glass wafer. The two wafers are bonded to form a bonding structure by plasma-strengthened bonding at room temperature. The wafers are placed in a commercially-adjustable laser cavity, and annealed at a temperature of 100 to 250 ° C for ten minutes. Immediately at this temperature, the reciprocal of the wavelength corresponding to the selected laser is used as the center frequency. After 1 to 5 minutes of laser irradiation, a layer of silicon thin film is separated from the original substrate and transferred to the target substrate with a thickness of about 0.3 μm. A SOI wafer material mainly composed of a glass substrate.

Example 5

The original substrate was in the lattice direction (100), and the alumina wafer was polished on both sides. After the first dose was 3 × 10 ¹⁶ / cm ² , the implantation energy was 200KeV, and the hydrogen molecular ion (H ₂ ⁺ ) was at 650 ° C. Implanted at temperature. Immediately after the second hydrogen ion implantation, the implantation temperature was room temperature, the dose was 3 × 10 ¹⁶ / cm ² , and the implantation energy was 200 KeV. The target substrate is a single-sided polished lattice-oriented (100) silicon wafer. The two wafers are bonded to form a bonding structure by plasma-strengthened bonding at room temperature. The wafers are placed in a commercially-adjustable laser cavity, and annealed at a temperature of 100 to 250 ° C for ten minutes. Immediately at this temperature, the reciprocal of the wavelength corresponding to the selected laser is used as the center frequency. After 1 to 5 minutes of laser irradiation, a layer of silicon film is separated from the original substrate and transferred to the target substrate with a thickness of about 0.6 μm. A silicon wafer substrate material with a single crystal alumina film as its surface.

In the present invention, the bonded structure is heated to the transition temperature, and then irradiated with laser at this temperature. In addition to applying the above-mentioned principle of polar molecule electrical coupling polarization, it also uses excited substrate atoms as laser absorption materials to assist power change. Because the substrate is a semiconductor material and has a high resistance value, absorbing laser will accelerate the carrier movement in the substrate and generate a large amount of accompanying current, which causes the accompanying induced current to generate energy in accordance with the principle of resistance heating. This energy is directly and quickly transferred through inelastic collision. Molecules formed by implanted ions or molecular ions increase their molecular kinetic energy, without the need to undergo a heating process to increase the temperature of the bonded substrate pair, which indirectly excites the molecular kinetic energy.

Operating laser irradiation at the transition temperature effectively enhances the absorption of laser energy by implanted ions or molecular ions, accelerates kinetic energy, escapes the bondage of atoms near the substrate, breaks the bond formed with it, and meets another detached implanted ion. In combination with the formation of gas molecules and their corresponding nucleation mechanisms, in the process of expanding the microbubbles generated by the nucleation mechanism and causing cracks to grow, other microbubbles are combined to form a gas film. The enhancement of the kinetic energy of implanted ions or molecular ions, on the one hand, directly absorbs the energy of the irradiated laser, and on the other hand, through the inelastic collision with the substrate absorbed by the carrier, a large amount of the energy generated by the carrier is quickly transferred and converted into The molecular kinetic energy increases the frequency of gas collision, generates sufficient internal pressure, expands the gas volume, and separates the film from the substrate.

In the present invention, surface polar molecular clusters are obtained through surface treatment. For example, silicon wafers are treated with a standard RCA cleaning method to obtain water molecule aggregates on the wafer surface, or oxygen plasma-treated surfaces are used to obtain oxygen ion aggregates. Stimulate the surface state of the wafer to be bonded, which can increase the reaction rate between the atoms at the contact surfaces of the two wafers in the bonded structure in a short period of time, and form chemical bonds with each other, which can quickly increase the bonding energy and make it In the subsequent irradiation process, before the film is separated from the original substrate, a certain required strength can be achieved, and the separation from the original substrate due to the formation of bubbles during film separation can be avoided.

The invention raises the bonding structure to the transition temperature, changes the material properties, increases the laser absorption coefficient, makes essential changes in related chemical reactions, changes the laser reaction mode, and achieves the purpose of controlling process stability.

With the laser generator split, it is easy to adjust the laser energy to cause the implanted H ⁺ ions to boil on the interface, thereby achieving the effect of the interface split. Because the laser generator can precisely control the energy, the energy distribution in the chip is very uniform, and the defects of the interface behind the sliver are reduced. The use of laser generator splits has high efficiency and large production capacity.

Although the present invention has been shown and described with reference to various embodiments, those skilled in the art will understand that, without departing from the spirit and scope of the invention, which is defined by the scope of the appended patents and their equivalents, Various changes were made in the details.

01‧‧‧ original substrate
02‧‧‧ film
03‧‧‧ ion separation layer
04‧‧‧ Residual layer
05‧‧‧ front surface
06‧‧‧ ion or molecular ion
07‧‧‧Target substrate
08‧‧‧laser exposure
09‧‧‧Heating device
10‧‧‧ Bonded Structure

The above and other aspects will become more apparent by describing specific exemplary embodiments with reference to the accompanying drawings, in which: FIG. 1 shows a film layer formed by ions or molecular ions facing the front surface of an original substrate by an ion implantation method And residual layer steps. FIG. 2 shows a step of joining the original substrate and the target substrate to form a bonded structure. FIG. 3 shows a step of heating the bonded structure formed by a heating device. FIG. 4 shows a procedure of applying a laser irradiation treatment to the bonded structure. FIG. 5 shows a step of transferring a thin film layer onto a target substrate.

02‧‧‧ film

03‧‧‧ ion separation layer

04‧‧‧ Residual layer

07‧‧‧Target substrate

08‧‧‧laser exposure

09‧‧‧Heating device

10‧‧‧ Bonded Structure

Claims (22)

A method for manufacturing a thin film on a substrate, which is characterized in that the method includes the following steps: providing an original substrate; and forming an ion separation layer in the original substrate by an ion implantation method, so that the original substrate is formed by the ion separation layer: A thin film layer, which is the area where the original substrate is subjected to ion implantation, and a residual layer, which is the area where the ion is not implanted in the original substrate; using the wafer bonding method, the target substrate is Bonding to the original substrate, bonding the target substrate and the original substrate to form a bonding structure; and heating the bonding structure, and then applying laser irradiation to the bonding structure to separate the thin film layer from The residual layer enables the thin film layer to be transferred from the surface of the original substrate to the target substrate, wherein the heating temperature is higher than room temperature and a transition temperature that causes a change in the dielectric constant and dissipation factor of the bonding structure, And it is lower than the temperature at which the incision is started. The method according to claim 1, wherein the ion implantation method is selected from a plasma immersion ion implantation method and a segmented ion implantation method with different implantation temperatures. The method according to claim 1, wherein the implantation ion is selected from the group consisting of a monoatomic hydrogen ion H ⁺ and a hydrogen molecular ion H ₂ ⁺ . The method according to claim 1, wherein the wafer bonding method is selected from the group consisting of direct bonding method, anode bonding method, low temperature bonding method, vacuum bonding method, and plasma enhanced bonding method. The method according to claim 4, wherein the wafer bonding method further includes a surface ionization process, so that a sufficient bonding strength can be obtained on a bonding surface between the original substrate and the target substrate. The method according to claim 1, wherein after the ion separation layer is formed and before the bonding, a preheating program is included to initially aggregate the implanted ions to generate grain boundary cracks, so that the surface of the original substrate is in a state where bubbles are to be formed. High stress critical state; wherein the implanted ion is a monoatomic hydrogen ion H ⁺ or a hydrogen molecular ion H ₂ ⁺ . The method according to claim 1, wherein the laser irradiation process generates a laser using a related device capable of generating a laser; wherein the related device for generating a laser is a device for performing ionization. The method of claim 7, wherein the laser-related device is selected from the following lasers: . The method according to claim 1, wherein the heating temperature is higher than a room temperature and lower than a temperature required for completion of the Zhiqian method in the same time period. The method according to claim 9, wherein when the original substrate is a silicon substrate, the heating temperature is higher than room temperature and lower than 450 ° C. The method according to claim 1, wherein the original substrate further includes different dopant atom concentration layers to form different carrier concentration layers by using the different dopant atom concentration layers in the original substrate to generate a selection when the laser is irradiated. Sexy should be energy. The method according to claim 11, wherein different dopant atomic layers of the original substrate are formed by ion implantation, molecular beam epitaxial growth, liquid phase epitaxial growth, or gas phase epitaxial growth. The method according to claim 1, wherein the laser irradiation time is more than one minute. The method according to claim 1, wherein the material of the original substrate is selected from a group IV semiconductor material and a group III-V semiconductor material. The method according to claim 14, wherein the group IV semiconductor material and the group III-V semiconductor material are selected from silicon, germanium, silicon carbide, gallium arsenide, and gallium nitride. The method according to claim 1, wherein the original substrate is selected from an oxide substrate. The method according to claim 16, wherein the oxide is selected from the group consisting of alumina, alumina lanthanum, strontium titanium oxide, and quartz. The method according to claim 1, wherein the ion implantation method is a multi-stage implantation method, and the ions are implanted in sections at at least two different implantation temperatures. The method according to claim 18, wherein the original substrate is made of silicon, and the multi-stage implantation method includes at least: a temperature controlled between 500 ° C and 800 ° C, and an implantation dose not exceeding 8 × 10 ¹⁶ / cm ² Monoatomic hydrogen ions; and monoatomic hydrogen ions at a temperature not greater than 150 ° C. and implanted doses greater than 2 × 10 ¹⁶ / cm ² or hydrogen molecular ions at a dose greater than 1 × 10 ¹⁶ / cm ² . The method according to claim 18, wherein the original substrate is composed of silicon, and the multi-stage implantation method includes at least: a temperature controlled between 500 ° C. and 700 ° C. and an implantation dose not exceeding 5 × 10 ¹⁶ / cm ² Hydrogen molecular ions; and monoatomic hydrogen ions with a implantation dose of more than 2 × 10 ¹⁶ / cm ² or a hydrogen molecule ions with a dose of more than 1 × 10 ¹⁶ / cm ² at a temperature not greater than 150 ° C. The method according to claim 18, wherein the original substrate is composed of alumina, and the multi-stage implantation method includes at least: temperature control between 550 ° C and 800 ° C, and an implantation dose not exceeding 2 × 10 ¹⁷ / cm ² Monoatomic hydrogen ions; and monomolecular hydrogen ions implanted at a temperature of not greater than 200 ° C. and implanted at a dose greater than 2 × 10 ¹⁶ / cm ² or hydrogen molecular ions at a dose greater than 1 × 10 ¹⁶ / cm ² . The method according to claim 18, wherein the original substrate is composed of alumina, and the multi-stage implantation method includes at least: temperature control between 550 ° C and 800 ° C, and an implantation dose not exceeding 8 × 10 ¹⁶ / cm ² Hydrogen molecular ions; and monoatomic hydrogen ions with a implantation dose of more than 4 × 10 ¹⁶ / cm ² or a hydrogen molecule ions with a dose of more than 2 × 10 ¹⁶ / cm ² at a temperature not greater than 200 ° C.