RU216869U1 - Device for connecting semiconductor wafers - Google Patents

Abstract

The utility model relates to the field of connection (splicing, bonding) of semiconductor wafers. As a result of using the proposed device, the reliability of the microassembly will increase. This result is achieved through the use of the following key elements in the design of a multifunctional device for connecting semiconductor wafers of the same or different diameters: heated plates with a rotating base.

Description

The utility model relates to the field of connection (splicing, bonding) of semiconductor wafers.

In the process of manufacturing devices in microelectronics, semiconductor wafers are used, on which structures are formed by lithography, deposition and etching of layers. Improving the reliability of integrated circuits is provided by increasing the heat removal of materials. Heat dissipation requirements increase as the number of metallization levels increases. One solution is vertical integration. To do this, between the two plates have an intermediate semiconductor plate - interposer. TSV grooves (Through-Silicon Vias) are formed in the volume of interposers and filled with metal. As a result of using the bulk of the wafer material, heat dissipation is ensured and thermal degradation of the device is not allowed. In addition, connecting a set of build plates via interposers (or directly) provides the ability to continue achieving next levels of IC integration through vertical integration. This bonding operation is often performed last before the wafer is diced. Before carrying out this operation, a large amount of time and financial resources are spent for the manufacture of halves of the final working device, which proves the extreme importance of a successful connection operation.

An invention is known in which the design of a device for manufacturing a workpiece of a photocathode of a photoelectronic device by thermocompression connection of a semiconductor wafer with a glass workpiece is presented [1].

This technical solution has the following disadvantages and limitations. The proposed device is used only for connecting a semiconductor wafer with a glass blank. That is, you cannot connect two semiconductor wafers. Considering that the glass material does not conduct electricity, the transfer of a useful signal between the samples is impossible. The device allows you to create only the blanks of the photocathode of a photoelectronic device, which significantly limits the scope of the device.

An invention is known, which describes a design for low-temperature direct connection of semiconductor wafers, containing a base, a centrifuge with a carousel with attachment points for semiconductor wafers, a cover for creating a closed space above the connected semiconductor wafers, a heating unit, each attachment point is made with a holder for placement and clamps for separating semiconductor wafers, wherein each semiconductor wafer fastening unit is provided with a split ring with grooves, and the fastening unit holder with cylindrical helical torsion springs located with the possibility of springing the split ring relative to the holder, while the holder and the split ring are placed with the possibility of being connected by a pin made of magnetically soft metal, slots are made in the holder to accommodate clamps for separating semiconductor wafers, and the clamps are spring-loaded with cylindrical helical compression springs relative to the split box the rings, base and carousel of the centrifuge are equipped with a system of magnets located at the same distance from the axis of rotation of the centrifuge with the possibility of their interaction, and the cover for creating a closed space above the semiconductor plates is equipped with magnets spring-loaded in a direction perpendicular to the base, placed with the possibility of their coaxial location with a pin made of magnetically soft metal with the lid closed and the interaction of centrifuge magnets and base magnets [2].

The disadvantages of this invention include the insufficient quality of surface cleaning before joining the plates. Even if the latest surface cleaning systems are used and the minimum time between the operations of the plates between cleaning and joining operations, some defectiveness will be introduced due to dust in the room, due to the contact of the plate with the operator.

A known device, adopted as a prototype, for low-temperature direct connection of semiconductor wafers, containing a base, a centrifuge with a carousel with attachment points for semiconductor wafers, a cover for creating a closed space above the connected semiconductor wafers, a heating unit, characterized in that the base is divided by a gateway into two reaction chambers for connecting and washing the wafers, the gateway is equipped with a mechanism for moving the wafers between the reaction chambers, the reaction chamber for connecting the wafers is equipped with a pump for forming a vacuum atmosphere, the reaction chamber for washing the wafers is equipped with a system for selecting the supply of reagents depending on the type of connected semiconductor wafers [3].

The disadvantages of the prototype include the lack of reliability of the microassembly, the standard limitation on the ability to work with plates of different diameters.

The objective of this utility model is to increase the reliability of the microassembly.

The problem is solved by forming a multifunctional device for connecting semiconductor wafers, containing a base, a centrifuge with a carousel and attachment points for semiconductor wafers, a cover for creating a closed space above the connected semiconductor wafers, a heating unit, heated plates, two reaction chambers for connecting and washing the wafers , a mechanism for moving plates between reaction chambers, a pump for forming a vacuum atmosphere, a system for selecting the supply of reagents depending on the type of connected semiconductor plates, and the heated plates have rotating bases.

In the reaction chamber, heated plates with a rotating base are used to connect the plates (static plates in the prototype). As a result, the top plate can act as a polishing disc to minimize surface roughness, which is especially true for a new type of bonding - hybrid bonding. As the roughness decreases, the shear force required to separate the plates will increase. Thus, the quality of the bonding will improve and the reliability of the micro-assembly in harsh operating conditions will increase.

In FIG. 1 shows a two-dimensional layout for a multifunctional device for connecting semiconductor wafers of the same or different diameters, where: 1 - cover to create a closed space above the connected semiconductor wafers, 2 - reaction chamber for connecting wafers, 3 - base, 4 - gateway, 5 - reaction chamber for washing plates, 6 - mechanism for moving plates between reaction chambers, 7 - system for selecting the supply of reagents, 8 - heating unit, 9 - pump for forming a vacuum atmosphere, 10 - rotating heating plates.

In FIG. 2 shows the manufactured experimental layout of a multifunctional device for connecting semiconductor wafers of the same or different diameters.

In FIG. 3 shows cylindrical (TSV) structures with different aspect ratio of cylinder width to cylinder height: a - aspect ratio 1/10; 6 - aspect ratio 1/5.

In FIG. 4 shows heated plates with a rotating base: a - before contact, b - after, where 11 is the first semiconductor wafer, 12 is the second semiconductor wafer, 13 is the bonding layer (adhesive).

A multifunctional device for connecting semiconductor wafers of the same or different diameters works as follows.

The wafers are cleaned in the reaction rotary chamber for washing the wafers. After that, the plate is moved to the lock by means of a mechanism for moving plates between the reaction chambers. In the reaction chamber for connecting the plates, a vacuum atmosphere is created using a pump and a sealed lid. The next step, through the gateway, the plates enter the reaction chamber to connect the plates. After that, the temperature rises using the heating unit and the pressure plates rotate. Then the plates are connected. After that, the plate goes through a thinning stage, and then TSV structures are formed.

A specific example of implementation.

The surface of semiconductor wafers of various diameters is carried out: 76,100,150 mm, with a thin aluminum film 0.4 µm thick and an adhesive layer with a thickness ranging from 15 µm to 23 µm in a dimethylformamide solution, cleaning is carried out at a maximum rotation speed of 1000 rpm. After that, the plate is moved to the lock by means of a mechanism for moving plates between the reaction chambers. The atmosphere of the reaction chamber is evacuated to a pressure of 10 ^-3 mbar. The plates are transferred to the reaction chamber to connect the plates. Raise the temperature to 300°C at a speed of 10°C/min, the plates rotate at a maximum speed of 950 rpm. Connect the plates. After that, the plate goes through the stage of thinning up to 120 μm, and then TSV structures are formed with an aspect ratio of the width of the cylinder to its height: 1/10 or less.

As a result of using the proposed device, the reliability of the microassembly will increase.

Information sources:

1. RF patent No. 2670498.

2. RF patent No. 2033657.

3. RF patent No. 198545 - prototype.

Claims (1)

A device for connecting semiconductor wafers, containing a base, a centrifuge with a carousel and semiconductor wafer attachment points, a cover for creating a closed space above the connected semiconductor wafers, a heating unit, heated plates, two reaction chambers for connecting and washing the wafers, a mechanism for moving the wafers between the reaction chambers, a pump for forming a vacuum atmosphere, a system for selecting the supply of reagents depending on the type of connected semiconductor plates, characterized in that the heated plates have rotating bases.

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