CN100444347C - Washing and drying unit for bonding - Google Patents

Abstract

A cleaning and drying device for bonding, comprising: a circular base, the lower part of which is a disk, on which there is a convex column, the shape of the overall section is inverted T; a sample loading container, including two upper and lower The lower part is a hollow cylinder, and the middle part is cylindrical and can be set on the convex post of the base; the upper part is a square body, and the middle part is a hollow part with two steps; There are two holes on the top; a circular convex edge protrudes from the middle of the outer wall of the sample container; two screw rods with threads at both ends, the lower end is connected to the base, the upper end passes through a beam, and is connected to the screw rod with a nut The upper end; two inserts, inserted into the holes on the side wall of the square body; one cassette is a ring, with many small holes punched on the side wall; when the inserts are inserted into the holes on the sample container, The cassette is sleeved at the insertion piece to fix the insertion piece.

Description

Washing and drying unit for bonding

technical field

The invention belongs to the technical field of semiconductors, in particular to a cleaning and drying device for bonding.

Background technique

For semiconductor devices, optimizing the parameters and structure to achieve the best performance of the device is the goal pursued by people. The optimal design of the device requires the use of a variety of materials, and only by combining their respective good characteristics can the device with the best performance be made. For various lattice-matched materials, a suitable device structure can be grown on a suitable substrate by means of epitaxial growth. However, for lattice-mismatched materials, epitaxial growth is more difficult, and more defects and dislocations may be introduced, which will have a serious adverse effect on the electrical and optical properties of the device. The bonding process can well overcome the difficulties brought by lattice mismatch to device design and material growth

The so-called bonding is to use physical or chemical methods to bond two homogeneous or heterogeneous wafers to each other. It can usually be called direct bonding, fusion bonding, bonding by atomic rearrangement or diffusion bonding. Since bonding does not require any paste, the resistivity and conductivity type of the wafer can be freely selected, and it is not limited by the material lattice and crystal orientation. The bonding structure can withstand various traditional methods such as thinning, polishing, chemical corrosion and high temperature treatment. technology, which has aroused great interest of researchers. Since 1986, IBM's Lasky [Document 1, Lasky J.B., wafer bonding for silicon insulator technologies.Appl.Phys.Lett.48, 78-80 (1986)] and Japan's Toshiba Corporation's Shimbo [Document 2, ShimboM., Furukawa K, Fukuda K.et al.Silicon-to-silicon direct bondingmethod.J.Appl.Phys.60(8), 2987-2989(1986).] Treating Si sheets at high temperature to obtain a bonded Si structure with high bonding strength After that, bonding technology has been greatly developed. So far, hundreds of articles and patents on wafer bonding have been published. Device fabrication and optical integration are widely used, and the bonding technology itself has developed eutectic bonding, adhesive bonding, flip-chip bonding, and non-planar bonding. (nonplanar bonding) and other forms, direct bonding technology is also gradually tending to direct bonding at low temperature.

The general bonding process can be divided into three steps: surface cleaning, spin drying and annealing. The surface cleaning and spin drying steps play a crucial role in the success or failure of bonding, especially for low temperature direct bonding. The bonding process requires a smooth and clean surface at the atomic level. The surface roughness of the wafer needs to be at the nanometer level, and the micron-scale particles adsorbed on the surface will also leave millimeter-scale cavities on the bonding interface. The strict surface requirements give the bonding process posed difficulties. It is necessary to avoid the introduction of dust or particles during cleaning, and the time that the surface is exposed to the air is required to be as short as possible. Minimize clamping or transfer operations with tweezers to avoid possible introduction of metal ions by the tweezers and possible damage to the surface. At the same time, it is also necessary to avoid damage to the wafers caused by collision or contact with each other during cleaning.

Contents of the invention

Therefore the object of the present invention is to provide a cleaning and drying device for bonding, to avoid possible contamination and damage, and to put the dried wafers into an annealing furnace after being bonded conveniently.

A cleaning and drying device for bonding of the present invention is characterized in that it comprises the following parts:

A circular base, the lower part of the circular base is a disk, and there is a convex column in the middle of the upper surface of the disk, and the shape of the overall cross-section is an inverted T shape;

A sample container, including upper and lower parts, the lower part is a hollow cylinder, and the middle vacant part is cylindrical and can be set on the convex post of the base; the upper part is a square body, and the square body is a hollow cylinder with two steps. There are two holes on the opposite side walls of the square body; a circular convex edge protrudes from the middle of the outer wall of the sample container;

Two screw rods with threads at both ends, the lower end is connected to the base, the upper end passes through a beam, and the upper end of the screw rod is connected with a nut;

Two inserts, which can be inserted into the holes on the side wall of the upper square body of the sample loading container;

A cassette, the cassette is an annular body, and a plurality of small holes are punched on the side wall of the cassette;

When the insertion piece is inserted into the hole on the sample loading container, the cassette is sleeved on the insertion piece on the upper square body of the sample loading container to fix the insertion piece.

Among them, the material of the device is made of PTFE material that is not afraid of acid and alkali corrosion, and can withstand the solution and drying temperature within 250 °C.

Wherein the upper part of the sample loading container is a cylinder.

Description of drawings

In order to further illustrate the specific technical content of the present invention, below in conjunction with embodiment and accompanying drawing detailed description as follows, wherein:

Fig. 1 is the three-dimensional structure schematic diagram of the present invention;

Fig. 2 (a) is the structural representation of sample loading container 11 in Fig. 1 of the present invention;

Fig. 2 (b) is the structural representation of the circular base 10 in Fig. 1 of the present invention;

Fig. 2 (c) is the structural representation of cassette 15 among Fig. 1 of the present invention;

Fig. 3 is the structural representation of the placement of the sample after the combination of the present invention;

Fig. 4 is the schematic diagram that the present invention is applied to rotary drying;

Fig. 5 is a schematic diagram of sample bonding after the spin drying of the present invention is completed;

Figure 6 is an infrared perspective image of the bonded InP/Si sample after cleaning.

Detailed ways

Please refer to Fig. 1, Fig. 2 (a), Fig. 2 (b) and shown in Fig. 2 (c), a cleaning and drying device for bonding of the present invention is characterized in that it includes the following parts:

A circular base 10 (Fig. 2(b)), the bottom of the circular base 10 is a disk 101, and there is a convex post 102 in the middle of the top of the disk 101, and the shape of the overall cross-section is an inverted T shape;

A sample loading container 11 (Fig. 2(a)) comprises two parts, the upper and lower parts, the lower part is a hollow cylinder 111, and the vacant part 1110 in the middle is cylindrical and can be sleeved on the boss 102 of the base 10; the part is a square body 112, the middle of the square body 112 is a hollow portion 1122 with two steps; two holes 1121 are opened on the opposite side walls of the square body 112; edge 113;

Wherein the upper part of the sample loading container 11 can also be a cylinder;

Two screw rods 12 with threads at both ends, the lower end is connected to the base 10, the upper end passes through a beam 13, and the upper end of the screw rod 12 is connected to the nut 16;

Two inserts 14 can be inserted into the holes 1121 opened on the side wall of the upper square body 112 of the sample loading container 11;

A cassette 15 (Fig. 2 (c)), the cassette 15 is an annular body, and the sidewall of the cassette 15 is punched with numerous small holes 151;

When the insertion piece 14 is inserted into the hole 1121 on the sample loading container 11 , the cassette 15 is sleeved on the insertion piece 14 on the upper square body 112 of the sample loading container 11 to fix the insertion piece 14 .

Among them, the cleaning and drying device is made of PTFE material that is not afraid of acid and alkali corrosion, and can withstand the solution and drying temperature within 250 °C.

Please refer to Fig. 1, Fig. 2 (a), Fig. 2 (b) and shown in Fig. 2 (c), the present invention is divided into two parts, and Fig. 2 (a) comprises sample loading container 11, two inserting sheets 14 and The circular cassette 15 with several rows of small holes; Fig. 2 (b) includes a circular base 10, two threaded screw rods 12 at both ends, a beam 13 and two nuts 16. The circular cassette 15 is used to block the insert 14, so that it is fixed when cleaning or drying. The upper part of the sample loading container 11 can be square or circular, depending on the shape of the sample to be bonded.

Since the bonding process requires an atomically smooth and clean surface, it has high requirements for the cleaning and drying process. It should be ensured that the tweezers are not in contact with the wafer surface during this process as much as possible, so as not to introduce metal ions or scratch the surface. First, one of the samples to be bonded is placed on the bottom of the sample loading container 11, with the bright surface to be bonded facing upward. Then insert the two inserts 14 into the holes 1121 on the side wall of the sample loading container 11, and then use the circular cassette 15 to cover the inserts 14, so that the inserts 14 are fixed and locked. Then another sample to be bonded is put into the sample loading container 11 , with the bonding surface facing downwards, ensuring that the bonding surfaces of the two samples are opposite, and separated by an insert 14 in the middle. Then the sample loading container 11 is placed on the base 10, and then the screw rod 12, the beam 13 and the nut 16 are installed respectively, and the whole structure is just as shown in FIG. 3 . In this way, the surface cleaning process of the sample can be carried out safely and conveniently. We used Si and InP bonded samples to carry out the performance test of the device with this structure. The cleaning procedure is as follows: first, use acetone and ethanol to perform ultrasonic cleaning (5 minutes for each cleaning, and the temperature is constant at 60 degrees), and then use a mixture of sulfuric acid and hydrogen peroxide. Surface treatment, and then use dilute HF acid (HF: H2O = 1: 10) to remove surface oxides. In this way, the entire cleaning process is completed. Four beakers are used in the cleaning process, which are respectively used to hold acetone, ethanol, sulfuric acid hydrogen peroxide mixture and HF acid solution. The entire cleaning procedure requires no tweezers, and the transfer from one solution to another requires simply transferring the device from one beaker to another. And because the surface of the sample is separated by the insert 14, there is no need to worry about surface scratches caused by mutual friction and collision of the wafer surfaces. The proposal of the present invention makes the bonding cleaning work simple and easy, thus having good operability.

After the cleaning is completed, the sample container 11 can be lifted from the base 10, and then placed on the glue spinner for rotary drying (see Figure 4), so that the conversion from cleaning to rotary drying can be easily realized without clamping by tweezers. And realize the synchronous rotation drying of two samples. The parameters used for spin drying are as follows: the spin speed is 3000 rpm, the spin time is 30 seconds, and the infrared lamp power is 150W.

After the spin drying is completed, the circular cassette 15 is removed, and the insert 14 is pulled out, so that the samples can be attached (see FIG. 5 ). So far the cleaning and drying process has been completed, and then the cleaned and dried samples are taken out from the sample loading container 11 with tweezers, and then put into the annealing furnace for annealing treatment.

The surface of the sample treated in this way is bright and without damage, and can achieve the surface flatness and cleanliness required by bonding, so it is easy to realize Si/InP bonding. Figure 6 is an infrared perspective image of the sample, the bright area is the successfully bonded part, and the dark area is the unbonded part. It can be seen from the figure that the bonding of the sample is basically uniform, except that some boundary effects still exist, and the interface is good, indicating that the cleaning and drying process makes the sample obtain a clean and smooth surface, and the characteristics of the present invention are thus reflected.

The above is only an illustrative description and verification of the present invention. Without departing from the principle and scope of use of the present invention, skilled experimenters can make changes to the experimental methods and some specific design details that meet their own requirements. The design and improvement of the basic idea of the present invention should be included in the claims of the present invention.

Claims (3)

1. A cleaning and drying device for bonding, comprising the following parts: A circular base, the lower part of the circular base is a disk, and there is a convex column in the middle of the upper surface of the disk, and the shape of the overall cross-section is an inverted T shape; A sample container, including upper and lower parts, the lower part is a hollow cylinder, and the middle vacant part is cylindrical and can be set on the convex post of the base; the upper part is a square body, and the square body is a hollow cylinder with two steps. There are two holes on the opposite side walls of the square body; a circular convex edge protrudes from the middle of the outer wall of the sample container; Two screw rods with threads at both ends, the lower end is connected to the base, the upper end passes through a beam, and the upper end of the screw rod is connected with a nut; Two inserts, which can be inserted into the holes on the side wall of the upper square body of the sample loading container; A cassette, the cassette is an annular body, and a plurality of small holes are punched on the side wall of the cassette; When the insertion piece is inserted into the hole on the sample loading container, the cassette is sleeved on the insertion piece on the upper square body of the sample loading container to fix the insertion piece. 2. The cleaning and drying device for bonding according to claim 1, wherein the material of the device is polytetrafluoro material which is not afraid of acid and alkali corrosion, and can withstand the solution and drying temperature within 250°C . 3. The cleaning and drying device for bonding according to claim 1, wherein the upper part of the sample loading container is a cylinder.

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