JP6679666B2 - Wafer permanent bonding method - Google Patents

Description

  The present invention relates to the method of bonding the first contact surface of the first substrate to the second contact surface of the second substrate according to aspect 1.

  The purpose in the permanent or irreversible joining of the substrates is to produce as strong and especially irreversible interconnections as possible between the two contact surfaces of the substrates and thus a high joining force. There are various techniques and manufacturing methods for such joining in the prior art.

  Known manufacturing methods and techniques practiced to date are often not reproducible or not fully reproducible, especially for varying conditions and have little application. Can not. In particular, currently used manufacturing methods often use elevated temperatures, especially above 400 ° C., to ensure reproducible results.

  Technical problems such as high energy consumption and possible destruction of structures present on the substrate have been required for high bond strengths to date, in part far above 300 ° C. It is the result of exceeding high temperatures. The following Patent Document 1 discloses a method of low temperature bonding. Further joining methods are shown in Patent Documents 1 to 8 below.

Other requirements include: front-end-of-line intercompatibility, which is defined as process intercompatibility during the manufacture of electrically active components. To be done. Therefore, the bonding process must be designed such that active components already present on the structure wafer, such as transistors, are not adversely affected or damaged during processing. Criteria for reciprocal compatibility include (mainly in CMOS structures) predominantly chemical element purity and predominantly thermal stress mechanical load bearing capacity.
− Low pollution − No force applied

  The reduced bond strength requires more careful handling of the structure wafer, thus reducing the probability of damage due to direct mechanical loading.

International Publication No. 01/61743 Pamphlet US Patent Application Publication No. 2003/0089950 US Patent Application Publication No. 2002/0048900 US Patent Application Publication No. 2008/0006369 US Pat. No. 5,451,547 European Patent Application Publication No. 0584778 U.S. Pat. No. 5,427,638 JP-A-5-166690

  Therefore, it is an object of the present invention to devise a method of carefully providing a permanent bond with the highest possible bond strength.

  This object is achieved by the features described in aspect 1. Advantageous developments of the invention are described in the subordinate aspects. Any combination of at least two of the features described in at least one of the description, the claims and the drawings is also included within the framework of the invention. Values within a given range of values within a given range of values are also disclosed as boundary values and are claimed in any combination.

  The idea underlying the present invention is to come up with a reservoir for holding the first source on at least one of the substrates, the first source being the second source present in the other substrate. After making contact between the substrates having the raw material of 1 or by making temporary bonding, they are reacted to form irreversible bonding or permanent bonding between the substrates. Before or after forming the reservoir in the one surface layer on the first contact surface, the cleaning of the substrate is generally carried out, especially by a flushing step. This cleaning should generally ensure that there are no particles on the surface, and the presence of such particles will result in unbonded areas. After the temporary bond or the reversible bond is formed by the reservoir and the raw material contained in the reservoir, the reaction that directly strengthens the permanent bond on the contact surface and increases the bonding speed in a controlled manner, especially at the contact surface. At least one, preferably the technical possibility of being triggered by deforming the contact surface facing the reservoir is obtained.

As a temporary bonding step for forming a temporary bond or a reversible bond between substrates, there are various possibilities for the purpose of producing a weak interaction between the contact surfaces of the substrates. The strength of the temporary bond is lower than that of the permanent bond and is at least 1/2 to 1/3, especially 1/5, preferably 1/15, more preferably 1/25. As a guide value, the provisional bonding strength pure deactivation hydrophilic silicon is about 100 mJ / m ^2, the temporary bonding strength of a pure plasma activated hydrophilic silicon is about 200~300mJ / m ^2. Temporary bonding between molecule-wetted substrates, primarily by Van der Waals interactions between molecules with different permanent dipole moments, is suitable to enable temporary bonding between wafers. The following chemical compounds are listed by way of example as interconnecting agents, but are not limited thereto.
-Water-Thiol-AP3000
-Silane, and / or silanol

Suitable substrates according to the present invention are capable of reacting, as a raw material, with a separately supplied raw material to form a product having a higher molar volume, which results in a growth layer on the substrate. Is a substrate on which is formed. The following combinations are particularly advantageous, the left side of the arrow is the name of the feed, the right side of the arrow does not indicate the feed fed, but its product or a by-product that reacts with the named feed. .
_{- Si → SiO 2, Si 3} N 4, SiN x O y
_{- Ge → GeO 2, Ge 3} N 4
-Α-Sn → SnO ₂
− B → B ₂ O ₃ , BN
− Se → SeO ₂
- Te → TeO _2, TeO ₃
-Mg → MgO, Mg ₃ N <sub>2
- Al → Al 2 O 3,</sub> AlN
- Ti → TiO _2, TiN
−V → V ₂ O ₅
-Mn → MnO, MnO ₂ , Mn ₂ O ₃ , Mn ₂ O ₇ , Mn ₃ O <sub>4
- Fe → FeO, Fe 2 O</sub> 3, Fe 3 O 4
− Co → CoO, Co ₃ O <sub>4
- Ni → NiO, Ni 2 O</sub> 3
− Cu → CuO, Cu ₂ O, Cu ₃ N
-Zn → ZnO
_{- Cr → CrN, Cr 23 C} 6, Cr 3 C, Cr 7 C 3, Cr 3 C 2
− Mo → Mo ₃ C ₂
− Ti → TiC
-Nb → Nb ₄ C ₃
− Ta → Ta ₄ C ₃
-Zr → ZrC
-Hf → HfC
-V → V ₄ C ₃ , VC
-W → W ₂ C, WC
− Fe → Fe ₃ C, Fe ₇ C ₃ , Fe ₂ C

As the substrate, the following mixed type of semiconductor is also conceivable.
- III-V: GaP, GaAs , InP, InSb, InAs, GaSb, GaN, AlN, InN, Al x Ga 1-x As, In x Ga 1-x N
-IV-IV: SiC, SiGe
-III-IV: InAlP
- Nonlinear _{optics: LiNbO 3, LiTaO 3, KDP} (KH 2 PO 4)
- solar cell: CdS, CdSe, CdTe, CuInSe 2, CuInGaSe 2, CuInS 2, CuInGaS 2
- conducting _{oxide: In 2-x Sn x O} 3-y

As claimed in the present invention, a reservoir capable of storing a quantity of at least one of the raw materials supplied for the volume expansion reaction directly on at least one of the wafers and on each contact surface. There is. Therefore, the raw material may be, for example, O ₂ , O ₃ , H ₂ O, N ₂ , NH ₃ , H ₂ O ₂ or the like. Based on the tendency of the reaction partners to reduce the energy of the system, especially due to expansion caused by oxide growth, possible gaps, holes, and cavities between the contact surfaces are minimized, and thus between the substrates in these regions. The narrower distance increases the bonding force. In the best case possible, the existing gaps, holes and cavities are completely closed, resulting in an increase in the overall joining surface and correspondingly an increase in joining force as claimed in the invention.

  The contact surface usually exhibits a roughness of secondary roughness (Rq) of 0.2 nm. This corresponds to surface peak-to-peak values in the 1 nm range. These empirical values were determined using atomic force microscopy (AFM).

  The reaction claimed in the present invention is to grow a growth layer from 0.1 to 0.3 nm on a wafer surface of a conventional circular wafer having one monolayer of water (ML) having a diameter of 200 to 300 mm. It is suitable for enabling to do.

  Therefore, as claimed in the present invention, in particular at least 2 ML, preferably at least 5 ML, more preferably 10 ML of fluid, in particular water, is stored in the reservoir.

  It is particularly preferred to form the reservoir by plasma exposure, since plasma exposure further synergistically smoothes and hydrophilizes the contact surfaces. The surface is smoothed by plasma activation mainly by viscous flow of the material of the surface layer. The increase in hydrophilicity is particularly caused by the increase in silicon hydroxyl compound, preferably by the decomposition of the Si—O compound, Si—O—Si, etc. present on the surface, in particular according to the reaction shown in the following chemical formula (1). It is caused by the increase of hydroxyl compounds.

  Another side effect, which is obtained in particular as a result of the above-mentioned effect, is that the temporary bond strength is improved, in particular by a factor of 2 to 3.

The reservoir in the surface layer on the first contact surface of the first substrate is formed, for example, by plasma activation of the first substrate coated with thermal oxide. Plasma activation is carried out in a vacuum chamber so that the conditions required for the plasma can be adjusted. As claimed in the present invention, N ₂ gas, O ₂ gas, or argon gas is used as the plasma discharge with an ion energy in the range of 0 to 2000 eV, so that the reservoir is treated surface, in this case Is formed to a depth of the first contact surface of up to 20 nm, preferably up to 15 nm, more preferably up to 10 nm, most preferably up to 5 nm. As claimed in the present invention, at least one of the respective particle types, atoms and molecules suitable for forming the reservoir can be used. Preferably, atoms or molecules, or both, that can form the reservoir with the required properties are used. Properties of interest mainly include pore size, pore distribution, and pore density. Alternatively, as claimed in the present invention, it is possible to use a gas mixture such as air or a forming gas consisting of 95% Ar and 5% H ₂ . Depending on the gas used, especially N ⁺ in the reservoir portion in the plasma ^{_{treatment, N 2 +, O +,}} O 2 +, Ar + ions are present. The first raw material can be contained in an unoccupied free space.

  The reservoir is formed based on the following considerations. The pore size is less than 10 nm, preferably less than 5 nm, more preferably less than 1 nm, even more preferably less than 0.5 nm, most preferably less than 0.2 nm.

  Pore density is preferably directly proportional to the density of particles that produce pores by collisional action and most preferably varies depending on the partial pressure of the impinging species and depending on the processing time and especially the parameters of the plasma system used. You can also

  The pore distribution preferably has at least one area of highest pore density below the surface, and by varying the parameters of some such areas, such areas are preferably flat-shaped areas (see FIG. 7). Is superimposed on. The pore distribution decreases to zero as the thickness increases. The area near the surface during impact has a pore density that is approximately the same as the pore density near the surface. After completion of the plasma treatment, the pore density on the surface can be reduced as a result of the stress relaxation mechanism. The pore distribution in the thickness direction with respect to the surface has some steep flanks and is rather flat with respect to the bulk, but the flanks decrease continuously (see FIG. 7).

  Similar considerations regarding pore size, pore distribution, and pore density apply to any method not implemented with plasma.

  The reservoir can be designed by controlling and using process parameters and combining them. FIG. 7 shows the concentration of nitrogen atoms implanted by the plasma as a function of penetration depth into the silicon oxide layer. It was possible to obtain two profiles by varying the physical parameters. The first profile 11 is formed by the faster accelerated atoms penetrating deeper into the silicon oxide, whereas the profile 12 is formed after changing the process parameters to a lower density. is there. When the two profiles are superposed, a total curve 13 is obtained, which is the characteristic of the reservoir. The relationship between the concentrations of the implanted atomic species and / or molecular species, or both, is clear. Higher concentrations indicate regions of the structure that are more defective and therefore have more space to accommodate subsequent feedstock. By controlling process parameters in a dedicated manner during plasma activation, it is possible to achieve a reservoir in which the added ions are distributed as evenly as possible over the depth by continuously varying.

  It is conceivable to use a TEOS (tetraethylorthosilicate) oxide layer on at least one of the substrates, at least on the first substrate, as a reservoir or instead of a reservoir formed by plasma. This oxide is generally not as dense as thermal oxides, and for this reason is advantageous to compact as claimed in the present invention. Compaction is carried out by heat treatment in order to set a defined porosity of the reservoir.

  According to an embodiment of the invention, the filling of the reservoir can particularly advantageously be performed simultaneously with the formation of the reservoir, by applying the reservoir as a coating to the first substrate. Already contains the first raw material.

  The reservoir is as a porous layer having a porosity in the nanometer range or less than 10 nm, more preferably less than 5 nm, even more preferably less than 2 nm, most preferably less than 1 nm, most preferably less than 0.5 nm of all. Considered as a layer having channels with a channel density of.

Regarding the step of filling the reservoir with the first raw material or the first raw material group, the following embodiments and combinations thereof are conceivable as claimed in the present invention.
- the step of flushing with a fluid consisting of the raw material, especially fluid containing _{H 2 O, H 2 O 2} , NH 4 OH or their raw materials, - the step exposing the reservoir to the ambient atmosphere - in particular step is flushed with deionized water -Exposing the reservoir to any gas atmosphere, in particular atomic gas, molecular gas, mixed gas-exposing the reservoir to an atmosphere containing water vapor or hydrogen peroxide vapor, and-reservoir already filled with raw material As a surface layer on the first substrate

At least one of the compounds O ₂ , O ₃ , N ₂ , NH ₃ , H ₂ O, H ₂ O ₂ , and NH ₄ OH can be considered as raw material.

  The use of hydrogen peroxide vapor mentioned above is considered a preferred version in addition to the use of water. Hydrogen peroxide has the further advantage of having a higher oxygen to hydrogen ratio. Furthermore, hydrogen peroxide dissociates into hydrogen and oxygen above a certain temperature and / or when using high frequency electromagnetic fields in the MHz range.

  According to an advantageous embodiment of the invention, the growth layer is formed and the irreversible bond is strengthened by diffusion of the first raw material into the reaction layer.

  According to another advantageous embodiment of the invention, the formation of the irreversible bond is typically below 300 ° C., advantageously below 200 ° C., more preferably below 150 ° C., even more preferably below 100 ° C. Most preferably, it is carried out at room temperature, especially for up to 12 days, more preferably for up to 1 day, even more preferably for up to 1 hour, most preferably for up to 15 minutes.

In this specification, irreversible joining 1.5 J / m ^2, greater than especially 2J / m ² greater, preferably particularly advantageous with a bonding strength of 2.5 J / m ² greater.

  The bond strength can be increased particularly advantageously during the reaction, and as claimed in the present invention, a product having a molar volume greater than that of the second raw material is formed in the reaction layer. It In this way, growth is carried out on the second substrate, so that the gaps between the contact surfaces can be closed by a chemical reaction, as claimed in the present invention. As a result, the distance between the contact surfaces, and thus the average distance, is reduced and dead space is minimized.

The formation of the reservoir can be effected by plasma activation, in particular with an activation frequency between 10 and 600 kHz and / or a power density between 0.075 and 0.2 watt / cm ² , and / or between 0.1 and 0. So long as it is carried out by pressurization with a pressure of between 0.6 mbar, additional effects are obtained, such as smoothing of the contact surface, as well as a clear increase in the hydrophilicity of the contact surface.

  Alternatively, the formation of the reservoir claimed in the present invention can also be carried out by using a tetraethoxysilane oxide layer as the surface layer and compressing to a porosity which is in a particularly controlled manner.

  According to another advantageous embodiment of the invention, the surface layer consists mainly, in particular essentially completely, in particular amorphous, in particular silicon dioxide produced by thermal oxidation, and the reaction layer comprises an oxidizable material. , Especially predominantly, preferably essentially completely, of Si, Ge, InP, GaP or GaN. A particularly stable reaction, which closes the existing gaps particularly effectively, is made possible by oxidation.

It is particularly advantageous here, as claimed in the present invention, that there is a growth layer between the second contact surface and the reaction layer, in particular predominantly native silicon dioxide. This growth layer undergoes growth caused by the reactions claimed in this invention. This growth proceeds from the transition Si—SiO ₂ (7) by reforming the amorphous SiO ₂ so that the growth layer, in particular on the interface with the reaction layer, and especially on the first contact surface and the second contact surface. Caused by deformation, especially swelling, in the area of the gap between the contact surface of the. Therefore, the distance between the two contact surfaces is reduced or the dead space is reduced, and as a result, the bonding strength between the two substrates is increased. Temperatures between 200 and 400 ° C, preferably between about 200 ° C and 150 ° C, more preferably between 150 ° C and 100 ° C, most preferably between 100 ° C and room temperature are particularly advantageous.

  It is particularly advantageous here for the growth layer to have an average thickness A between 0.1 nm and 5 nm before forming the irreversible junction. The thinner the growth layer, the faster and easier the reaction between the first source material and the second source material through the growth layer, especially by diffusion of the first source material into the reaction layer through the growth layer. Occurs in

  According to one embodiment of the invention, the formation of the reservoir is advantageously carried out in vacuum. Therefore, it is possible to prevent the reservoir from being contaminated by unwanted materials or compounds.

In another embodiment of the invention, the filling of the reservoir comprises
Exposing the first contact surface to the atmosphere to fill the reservoir with oxygen contained in the atmosphere's moisture and / or air.
Applying the first contact surface to a fluid which is predominantly, preferably almost completely, in particular deionized H ₂ O or H ₂ O ₂ or both.
The first contact surface is at least one of N ₂ gas, O ₂ gas, Ar gas and a forming gas, in particular a forming gas consisting of 95% Ar and 5% H ₂ , in particular ion energy. Is a range of 0 to 2000eV,
-By one or more of the steps of vapor growing any of the above named raw materials to fill the reservoir.

  The reservoir preferably has a thickness R between 0.1 nm and 25 nm, more preferably between 0.1 nm and 15 nm, even more preferably between 0.1 nm and 10 nm, most preferably between 0.1 nm and 5 nm. It is especially effective for the order of steps. Furthermore, according to one embodiment of the present invention, the average distance B between the reservoir and the reaction layer immediately before forming the irreversible junction is between 0.1 nm and 15 nm, in particular between 0.5 nm and 5 nm. Is advantageously between 0.5 nm and 3 nm.

  An apparatus for carrying out the method as claimed in the invention comprises a chamber for forming a reservoir, a chamber specifically provided for filling the reservoir, and a separately provided for forming the temporary bond. Of chambers, all of which are directly connected to each other via a vacuum system.

  In another embodiment, the filling of the reservoir can also be done directly by the atmosphere and thus in a chamber that can be opened to the atmosphere or without a jacket, but semi-automatically and / or It can also simply be done on a structure that can handle the wafer completely automatically.

  Other advantages, features and details of the invention will be apparent from the following description of the exemplary preferred embodiments and the drawings.

FIG. 6 shows the first step of the method claimed in the present invention immediately after contacting the first substrate with the second substrate. FIG. 5 shows another step of the method claimed in the present invention for forming a higher bond strength. FIG. 5 shows another step of the method claimed in the present invention for forming a higher bond strength. FIG. 3 shows another step of the method as claimed in the invention, where the substrate contact surfaces are in contact, following the steps described in FIGS. 1, 2 a and 2 b. FIG. 4 illustrates the claimed steps of the present invention for forming an irreversible / permanent bond between substrates. FIG. 5 is an enlarged view of the chemical / physical process proceeding on two contact surfaces during the steps described in FIGS. 3 and 4. FIG. 5 is another enlarged view of the chemical / physical process proceeding on the interface between two contact surfaces during the steps described in FIGS. 3 and 4. 3 is a graph showing manufacture of a reservoir claimed in the present invention.

  In the drawings, components / mechanisms having the same function and having the same function are identified by the same reference numerals.

In the situation shown in FIG. 1, the chemistry that develops between the first contact surface 3 of the first substrate 1 and the second contact surface 4 of the second substrate 2 during or immediately after the temporary bonding step. Only part of the reaction is shown. This surface is terminated by polar OH groups and is therefore hydrophilic. The first substrate 1 and the second substrate 2 have an attractive force due to a water bridge between OH groups existing on the surface and H ₂ O molecules and an attractive force due to a water bridge between H ₂ O molecules alone. Is held by. The hydrophilicity of at least the first contact surface 3 is increased by the plasma treatment of the first contact surface 3 in the preceding step.

The reservoir 5 in the surface layer 6 made of thermal silicon dioxide is formed by plasma treatment as claimed in the present invention. By performing plasma treatment using O ₂ ions in the range of ion energy between 0 and 2000 eV, the average thickness R of the reservoir 5 becomes about 15 nm, and the ions form channels or holes in the surface layer 6. It

Similarly, before the step shown in FIG. 1 and after the plasma treatment, the storage section 5 is filled with H ₂ O as the first raw material. The reducing species of the ions present during the plasma process, especially O ₂ , N ₂ , H ₂ , Ar can also be located in the reservoir.

Therefore, the contact surfaces 3, 4 still have a relatively wide gap, which is especially occupied by the water present between the contact faces 3, 4. Therefore, existing bond strengths are relatively small, between about 100 mJ / cm ² and 300 mJ / cm ² , especially above 200 mJ / cm ² . In this respect, the conventional plasma activation plays a decisive role because the hydrophilicity of the first contact surface 3 is increased particularly by the plasma activation and the smoothing effect is obtained by the plasma activation.

  The process referred to as temporary bonding, shown in FIG. 1, can proceed preferably at ambient temperature or up to 50 ° C. Figures 2a and 2b show hydrophilic bonds, where the splitting of water by the -OH terminated surface results in Si-O-Si crosslinks. The process of Figures 2a and 2b lasts about 300 hours at room temperature. It lasts about 60 hours at 50 ° C. The situation of Fig. 2b occurs without a reservoir at the indicated temperature.

H ₂ O molecules are formed between the contact surfaces 3 and 4 and are supplied at least in part to further fill the reservoir 5, as long as the free space still exists. Other H ₂ O molecules are removed. In the steps described in FIG. 1, there are about 3 to 5 individual OH-based or H ₂ O layers, and in the steps described in FIG. 1 to FIG. 2a, 1 to 3 layers of H ₂ O. The monolayer is removed or housed in the reservoir 5.

  In the step shown in Figure 2a, hydrogen bridge bonds are formed directly between the siloxane groups, resulting in higher bonding forces. Due to this joining force, the contact surfaces 3, 4 are more strongly attracted to each other and the distance between the contact surfaces 3 and 4 is reduced. Therefore, between the contact surfaces 3 and 4 there are only 1 to 2 individual OH-based layers.

In the step shown in FIG. 2b, the separation of H ₂ O molecules according to the reaction shown in the following chemical formula (2) forms a covalent bond in the form of a silanol group between the contact surfaces 3 and 4, thereby Results in a stronger joining force and requires less space, thus further reducing the distance between the contact surfaces 3 and 4 and finally the contact surfaces 3 and 4 shown in FIG. The minimum distance to reach each other is reached.

  Up to step 3, there is no need to excessively increase the temperature since the storage part 5 is formed, and it is possible to proceed at room temperature. In this way, the process steps described in FIGS. 1 to 3 can be carried out particularly carefully.

  In the method step shown in FIG. 4, preferably up to 500 ° C., more preferably up to 300 ° C., and even up to 300 ° C., in order to form an irreversible or permanent bond between the first contact surface and the second contact surface. Preferably the temperature is raised to a maximum of 200 ° C., most preferably a maximum of 100 ° C., most preferably all above room temperature. These temperatures are relatively low unlike the prior art, and only when the reservoir 5 contains the first raw material for the reaction shown in the following chemical formula (3) shown in FIGS. 5 and 6. It is possible.

Due to the above-mentioned slight temperature rise, H ₂ O molecules diffuse from the storage part 5 to the reaction layer 7 as the first raw material. This diffusion can take place by direct contact between the surface layer 6 formed as an oxide layer and the growth layer, via the gap 9 or from a gap existing between the oxide layers. Therefore, silicon dioxide, a chemical compound having a larger molar volume than pure silicon, is formed from the reaction layer 7 as a reaction product 10 from the above reaction. This silicon dioxide grows at the interface between the reaction layer 7 and the growth layer 8 and thus deforms the layers of the growth layer 8 formed as native oxide towards the gap 9. Again, H ₂ O molecules from the reservoir are needed.

  Due to the presence of gaps in the nanometer range, the native oxide layer 8 may swell, and as a result the stress on the contact surfaces 3, 4 can be reduced. In this way, the distance between the contact surfaces 3 and 4 is reduced, so that the effective contact surface and thus the bond strength are further increased. The weld connection thus made, unlike prior art products which are not partially welded, closes all holes and forms a weld connection over the entire wafer, thus essentially contributing to an increase in bond strength. The type of bond between two amorphous silicon oxide surfaces that are welded together is a mixed form of covalent bonds and ionic moieties.

The above reaction between the first raw material (H ₂ O) and the second raw material (Si) causes the reaction in the reaction layer when the average distance B between the first contact surface 3 and the reaction layer 7 becomes as small as possible. Occurs particularly rapidly or at the lowest possible temperature.

  Therefore, the decisive factors are the pretreatment of the first substrate 1, the selection of the second substrate 2 made of the reaction layer 7 of silicon, and the thinning of the native oxide layer as the growth layer 8. The thinning of the native oxide layer claimed in the present invention is performed for the following two reasons. Due to the newly formed reaction product 10 on the reaction layer 7, the growth layer 8 is directed toward the surface layer 6 which is formed mainly in the region of the nanogap 9 as an oxide layer of the substrate 1 facing the growth layer 8. The growth layer 8 is very thin so that it can be swollen. Furthermore, in order to achieve the desired effect as quickly as possible and at the lowest possible temperature, the shortest possible diffusion path is desirable. Similarly, the first substrate 1 also comprises a silicon layer and an oxide layer formed thereon as a surface layer 6, in which the reservoir 5 is formed at least partially or completely. It

  Therefore, the reservoir 5 claimed in the present invention is filled with at least the amount of the first raw material required to close the nano-gap 9, and therefore the growth layer 8 can be kept in the shortest possible time and / or as long as possible. It can be optimally grown to close the nanogaps 9 at low temperatures.

Embodiments of the present invention will be described below.
・ Mode 1
A method of joining a first contact surface (3) of a first substrate (1) to a second contact surface (4) of a second substrate (2), the method comprising:
Forming a reservoir (5) in the surface layer (6) on the first contact surface (3);
At least partially filling the storage part (5) with a first raw material or a first raw material group;
Contacting the first contact surface (3) with the second contact surface (4) to form a temporary bond connection;
Forming a permanent bond between the first contact surface (3) and the second contact surface (4), the reaction of the first raw material with the second substrate (2). Forming a permanent bond at least partially reinforced by reacting a second source material contained in layer (7);
In particular in the above order.
・ Mode 2
The method according to aspect 1, wherein the formation and / or strengthening of the permanent bond is performed by diffusing the first raw material into the reaction layer (7).
・ Mode 3
Aspect 1 or 2 wherein the formation of the permanent bond is carried out at a temperature between room temperature and 200 ° C., in particular for up to 12 days, more preferably up to 1 day, even more preferably up to 1 hour, most preferably up to 15 minutes. The method described in.
・ Mode 4
Irreversible said junction is greater than 1.5 J / m ^2, greater in particular 2J / m ^2, preferably has a 2.5 J / m ² greater than the bonding strength, according to any of 3 from the embodiment 1 Method.
・ Mode 5
5. The reaction product (10) having a molar volume larger than that of the second raw material is formed in the reaction layer (7) during the reaction, according to any one of the aspects 1 to 4. Method.
・ Mode 6
A method according to any of aspects 1 to 5, wherein the reservoir (5) is formed by plasma activation.
・ Mode 7
7. The method according to any of the preceding aspects 1 to 6, wherein the formation of the reservoir (5) is carried out using in particular a compressed tetraethoxysilane oxide layer as the surface layer (6).
・ Aspect 8
The surface layer (6) is mainly, in particular essentially completely, in particular an amorphous material, in particular silicon dioxide produced by thermal oxidation, and the reaction layer (7) is an oxidizable material, in particular mainly The method according to any of the preceding aspects 1 to 7, which consists essentially, preferably essentially, of Si, Ge, InP, GaP or GaN.
・ Aspect 9
Method according to any of the preceding aspects 1 to 8, wherein there is a grown layer (8) of predominantly native silicon dioxide between the second contact surface (4) and the reaction layer (7).
・ Aspect 10
The method according to aspect 9, wherein the growth layer (8) has an average thickness A between 1 angstrom and 10 nm before forming a permanent bond.
・ Aspect 11
The method according to any one of aspects 1 to 10, wherein the reservoir is formed in a vacuum.
Aspect 12
The reservoir is
Exposing said first contact surface (3) to an atmosphere with a high content of oxygen or water, or both,
Applying said first contact surface (3) to a fluid which is predominantly, preferably almost completely, in particular deionized H ₂ O or H ₂ O ₂ or both;
The first contact surface (3) is applied to at least one of N ₂ gas, O ₂ gas, Ar gas, and forming gas, especially 95% Ar and 5% H ₂ forming gas. Step of applying ion energy in the range of 0 to 2000 eV,
12. A method according to any of aspects 1 to 11 above, which is filled with one or more of:
・ Aspect 13
13. Method according to any of the preceding aspects 1 to 12, wherein the reservoir (5) is formed with an average thickness (R) between 0.1 nm and 25 nm, in particular between 0.1 nm and 20 nm.
Aspect 14
The average distance (B) between the reservoir (5) and the reaction layer (7) immediately before forming the permanent bond is between 0.1 nm and 15 nm, particularly between 0.5 nm and 5 nm, preferably Is between 0.5 nm and 3 nm, a method according to any of aspects 1 to 13 above.
Aspect 15
15. The method according to any of the preceding aspects 1-14, wherein the irreversible bond has a bond strength of 2 times, preferably 4 times, more preferably 10 times and most preferably 25 times the strength of the temporary bond. .

1 1st substrate 2 2nd substrate 3 1st contact surface 4 2nd contact surface 5 Storage part 6 Surface layer 7 Reaction layer 8 Growth layer 9 Nano gap 10 Reaction product 11 1st profile 12 2nd Profile 13 Total curve A Average thickness B Average distance R Average thickness

Claims (10)

A method of joining a first contact surface of a first substrate to a second contact surface of a second substrate, the method comprising:
Forming a reservoir in the surface layer on the first contact surface, the pore distribution of the reservoir decreasing to zero as the thickness increases;
At least partially filling the reservoir with a first raw material or a first raw material group;
Contacting the first contact surface with the second contact surface to form a temporary bond connection;
Only including, the formation of the reservoir is performed using tetraethoxysilane oxide layer as the surface layer, the method.   The method of claim 1, wherein the reservoir is formed by plasma activation.   Further, in the step of forming a permanent bond between the first contact surface and the second contact surface, the first material and the first contact material included in the reaction layer of the second substrate. 3. A method according to claim 1 or 2 including the step of forming an at least partially reinforced permanent bond by reacting with two raw materials. A method of joining a first contact surface of a first substrate to a second contact surface of a second substrate, the method comprising:
Forming a reservoir in the surface layer on the first contact surface, the pore distribution of the reservoir decreasing to zero as the thickness increases;
At least partially filling the reservoir with a first raw material or a first raw material group;
Contacting the first contact surface with the second contact surface to form a temporary bond connection;
A step of forming a permanent bond between the first contact surface and the second contact surface, the step comprising: forming a first bond between the first material and a second layer contained in a reaction layer of the second substrate. Forming an at least partially reinforced permanent bond by reacting with a raw material;
And a mean distance (B) between the reservoir and the reaction layer immediately before forming the permanent bond is between 0.1 nm and 15 nm. The method of claim 4, wherein the reservoir is formed by plasma activation. The method according to claim 4 or 5 , wherein the surface layer comprises an amorphous material and the reaction layer comprises an oxidizable material. The method according to claim 4 or 5 , wherein there is a grown layer of native silicon dioxide between the second contact surface and the reaction layer. The method according to claim 4 or 5 , wherein the reservoir is formed in a vacuum. The reservoir is
Subjecting the first contact surface to a fluid containing deionized H ₂ O or H ₂ O ₂ or both; and the first contact surface with N ₂ gas, O ₂ gas, Ar gas, and Applying at least one forming gas containing 95% Ar and 5% H ₂ ;
6. A method according to claim 4 or 5 filled with one or more of: The method according to claim 4 or 5 , wherein the reservoir is formed with an average thickness (R) of between 0.1 nm and 25 nm .

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