TWI470750B - A heat dissipation device for transparent atom trapping chip - Google Patents

Description

Heat sink for transparent atomic wafer

The invention "a heat sink for a transparent atomic wafer" is used for general atomic wafer design, mainly for the atomic physics field, which needs to penetrate a laser beam from the front surface of the atomic wafer to the back of the wafer or needs to pass a high current to Atomic capture experiments on metal wires on the front side of the wafer.

Generally, atomic wafers use silicon wafers or aluminum nitride (ALN) as substrates, and metal wires are laid on the front surface of the substrate to pass current to generate corresponding magnetic fields and match several paths. The laser beam produces a magneto-optical trap (MOT) to capture atoms. However, such non-transparent atomic wafer substrates often limit the flexibility of the magneto-optical trap design, and because of the lack of a laser beam that can penetrate the atomic wafer itself, it is often unable to meet the experimental needs of many atomic physics fields. In addition, general atomic wafers are designed without any heat dissipation or thermal conductivity to increase the ultimate current carrying value of the metal wires on the wafer, thus often limiting the flexibility and functionality of the atomic wafer in the design of the magnetic field, and often cannot satisfy many atoms. The need for physical experiments. Therefore, in combination with the above points, a general atomic wafer cannot effectively dissipate or carry away the heat source generated on the wafer, which is often caused by a user who needs to pass a higher current value on the metal wire of the wafer. Trouble and inconvenience in use. In addition, the general atomic wafer can not make the laser beam penetrate the wafer itself, thus greatly reducing the diversity of the magnetic field design, so it is often impossible to meet the special atomic physics experiment requirements.

The "Cold Atom System with Atom Chip Wall" disclosed in U.S. Patent No. 7,126,112, B2, is a single-layer metal wire structure atomic wafer device which is formed as an upper cover of a glass vacuum chamber, and its magnetic field drive current is transmitted through its atomic wafer. The side wire strips are transferred to adjust the magnetic field gradient. The design is still based on the metal wire structure to trap atoms, and the heat generated cannot be effectively dissipated from the wafer. The "Chip Mounting Method" disclosed in U.S. Patent No. 6,796,481, B2, provides a method for bonding two single-layer atomic wafers into a two-layer atomic wafer. Although the foregoing invention design can eliminate the problem that the upper metal wire is overheated by a large current and cannot be eliminated immediately, this method is equivalent to stacking two single-layer atomic wafers into one double-layered wafer, thereby increasing the overall volume of the atomic wafer. . US Patent No. 20100154570A1 "Atom Chip Device" is a metal wire made of an alloy material to reduce the heat generated when a large current is applied to increase the current that the metal wire can carry and prolong the life of the trapped atoms. However, the design of this atomic wafer will increase the cost of fabrication and will not allow the laser beam to penetrate the wafer, thus limiting the flexibility and functionality of the magnetic field design, often failing to meet the needs of many atomic physics experiments. U.S. Patent No. 20070158541A1 "Atomic Device" is designed to perform fast voltage switching by different pairs of electrodes on an atomic wafer to generate corresponding potential energy to trap atoms, so that there is no other metal wire structure on the wafer, only a large number of electrode plates. . Although this design can achieve the purpose of imprisoning atoms, more additional equipment is needed to drive the atomic wafer instead of just a single power supply. In addition, the atomic wafer of the present invention requires a larger surface space to place a plurality of electrode plates than an atomic wafer of a conventional metal wire structure, thereby making the overall area of the atomic wafer larger.

In summary, whether it is a metal wire structure design or a two-layer stacked atomic wafer or a switching electrode plate type atomic wafer, although it can achieve the purpose of trapping atoms, but can not make the laser The beam penetrates the atomic wafer itself, so the design of the magnetic field is less flexible and the overall system of the atomic wafer is too large, which is less suitable for light, simple and low cost.

Therefore, in order to solve the above disadvantages that the atomic wafer cannot penetrate the laser beam and the heat dissipation or heat conduction design on the wafer, the object of the present invention is to design a simple transparent atomic wafer and utilize the good thermal conductivity of the copper metal, and use it together. The plated copper post and the heat-dissipating copper block act as a heat sink for the atomic wafer to increase the limit current carrying value of the metal wire on the wafer and the margin of the atomic chip magnetic field design.

In order to achieve the above object, the present invention contemplates fabricating an atomic wafer with a transparent glass substrate to replace the substrate of the conventional wafer material as an atomic wafer, and plating an anti-reflection layer on the front and back surfaces of the wafer (Anti -reflection coating) to reduce the partial reflection of the laser beam on both sides of the glass substrate and thus affect the accuracy of atomic physics experiments. In this way, the laser beam that cools the atom can penetrate the atomic wafer with transparent characteristics to complete another form of magneto-optical trap, thus increasing the degree of freedom of laser cooling in atomic physics experiments. Moreover, the metal wire fabricated on the atomic wafer can generate a corresponding magnetic field after passing current, so At the same time, the functionality of the original atomic wafer is preserved. In addition, since the present invention uses a glass substrate instead of a conventional tantalum wafer material in which the thermal conductivity of the glass is inferior to that of the tantalum material, the limit current value that the metal wire on the glass substrate can carry is thus greatly reduced. In response to this problem, the present invention contemplates the use of plated copper blocks to increase the area of heat conduction on the front and back sides of the atomic wafer, and also designs a plurality of electroplated copper columns in the drilled glass through holes to heat the copper blocks on the front side of the wafer. The heat is transferred to the heat-dissipating copper block on the back side of the wafer, and the heat source is transferred to the outside of the vacuum chamber by the metal holder of the device atomic wafer. The special heat sink is characterized in that it can increase the carrying current value of the metal wire on the wafer. And no special processing is required, so that the heat source can be effectively conducted to the back side of the wafer while allowing at least 5 amps of current to pass without burning. Therefore, the current value required to generate a magnetic field on the metal wire of the wafer can be satisfied to meet the requirements of most atomic physics experiments. In addition, the present invention also integrates the heat-dissipating copper block process on the front and back sides of the wafer with the metal wire process on the wafer, thereby not increasing the cost and time of atomic wafer fabrication.

As a heat dissipating device for a transparent atomic wafer as described above, the main object of the present invention is to fabricate an atomic wafer with a transparent glass substrate instead of a conventional substrate using a germanium material as an atomic wafer, thereby allowing a thunder of cooling atoms. The beam of light transmits through the wafer itself and increases the ease of use of the atomic wafer.

Another object of the present invention is to design a plurality of heat dissipating devices on the front and back sides of an atomic wafer, and integrate the process with the metal wire process to improve the current carrying capacity of the metal wires for the user to increase the magnetic field design of the wafer. Flexibility and functionality.

To specifically illustrate the principles and design of the present invention, the following specific embodiments are described. FIG. 10 is a schematic diagram showing the overall architecture of the embodiment. The entire structure of the atomic wafer with the transparent and heat dissipating device is fabricated on the transparent glass substrate (101). The transparent glass substrate (101) of the wafer is provided with a thermally conductive electroplated copper pillar (302), and the wafer is positive. A heat-dissipating copper block (301) on the back side of the wafer and a heat-dissipating copper block (303) on the front side of the wafer are also mounted on the back surface. The copper wire (401) and the wire bonding pad (402) capable of generating a magnetic field are disposed on the front surface of the wafer, and a laser beam penetration window (501) is disposed at the center of the front and back sides of the wafer for cooling atoms. The laser beam passes through.

The process technology of the present invention will be described in detail below. Figure 1 shows a transparent glass substrate (101), FIG. 2 is a schematic cross-sectional view of the transparent glass substrate (101) after the drilling process. Then, an adhesive layer titanium film (201) and a seed layer copper film (202) required for the electroplating process are deposited on the back surface of the transparent glass substrate (101), as shown in FIG. Then, a heat dissipation copper block (301) for heat dissipation on the back side of the transparent glass substrate (101) is plated, as shown in FIG. In addition, the thermally conductive electroplated copper column (302), which is also used for heat dissipation, fills the transparent glass substrate (101) through holes in a bottom-up manner during electroplating, as shown in FIG. The protruding thermally conductive electroplated copper post (302) is then flattened using a chemical mechanical flat polishing process (CMP), as shown in FIG. Then, an adhesive titanium film (201) and a seed layer copper film (202) required for the electroplating process are deposited on the polished transparent glass substrate (101), as shown in FIG. Next, the front surface heat-dissipating copper block (303) and the copper wire (401) of the wafer are plated on the front side of the wafer, as shown in FIG. Finally, the electroplated copper and the bottom adhesive layer titanium film (201) and the seed layer copper film (202) which are connected between the copper wire (401) and the front surface heat-dissipating copper block (303) are etched away by wet etching. , as shown in Figure 9. Finally, the overall architecture diagram of the embodiment shown in FIG. 10 can be obtained.

The present invention is characterized in that a transparent glass substrate (101) is used to fabricate an atomic wafer and a thermally conductive electroplated copper column (302) having a heat transfer function therein. As shown in FIG. 11, the copper wire (401) can be accessed. The heat generated after the high current is diffused to the entire surface of the wafer, and then the heat is transferred to the heat-dissipating copper block (302) to transfer the heat to the heat-dissipating copper block (301) on the back surface of the wafer, so that the atomic wafer is not The limit current carrying capacity of the copper wire (401) is lowered because the transparent glass substrate (101) having poor thermal conductivity is used. In addition, a laser beam penetration window (501) is also designed in the middle of the front and back of the wafer to allow the laser beam of the cooling atom to pass through, as shown in Figure 12, to increase the multifunctionality of the atomic wafer. Sex.

(101) ‧‧‧Transparent glass substrate

(201)‧‧‧Adhesive Titanium Film

(202)‧‧‧Seed layer copper film

(301) ‧‧‧Dissipation copper block on the back of the wafer

(302)‧‧‧ Thermally conductive electroplated copper column

(303) ‧‧‧Front heat sinking copper block

(401)‧‧‧ copper wire

(402)‧‧‧Wire bonding pads

(501)‧‧‧Laser beam penetration window

First Figure Schematic diagram of a transparent glass substrate of an embodiment

Second Figure Schematic diagram of the transparent glass substrate after drilling

Fig. 3 is a schematic cross-sectional view of the vapor-deposited titanium and copper film on the back side of the embodiment

The fourth figure is a cross-sectional view of the heat-dissipating copper block on the back side of the plated wafer

Fig. 5 is a schematic cross-sectional view of a thermally conductive copper pillar plated through a hole in a glass substrate of an embodiment

Figure 6 is a schematic cross-sectional view of the front side of a chemical mechanical flat polished atomic wafer of an embodiment

Fig. 7 is a schematic cross-sectional view showing the vapor deposition of titanium and copper thin films after polishing the front side of the atomic wafer of the embodiment

Figure 8 is a cross-sectional view of the electroplated copper wire and the front side heat-dissipating copper block of the atomic wafer

Figure 9 is a cross-sectional view of the titanium and copper film at the bottom of the etched copper wire and the heat-dissipating copper block of the embodiment

The tenth figure shows the overall structure of the front side of an embodiment

Eleventh Figure 1 Schematic diagram of the overall line architecture of an embodiment

Twelfth Figure Schematic diagram of the overall structure of the back of an embodiment

(101) ‧‧‧Transparent glass substrate

(302)‧‧‧ Thermally conductive electroplated copper column

(303) ‧‧‧Front heat sinking copper block

(401)‧‧‧ copper wire

(402)‧‧‧Wire bonding pads

(501)‧‧‧Laser beam penetration window

Claims (3)

A heat dissipating device for a transparent atomic wafer, the device comprising a transparent glass substrate, a heat dissipating copper block on the front and back sides of the wafer, a metal wire structure on the front side of the wafer, a thermally conductive plated copper post member extending through the wafer, and a laser beam passing through the middle of the wafer The transmissive window constitutes an atomic wafer having transparent and heat-dissipating functional characteristics, characterized in that the laser beam can penetrate the wafer itself, and the wafer has a function of dissipating heat. A heat dissipating device for a transparent atomic wafer according to the first aspect of the invention, wherein the thermally conductive electroplated copper pillar member having a heat conducting function is disposed in a through hole of the transparent glass substrate, that is, between the front and rear heat radiating copper blocks of the wafer, It is characterized in that the heat generated by the current flowing through the metal wire structure on the wafer can be quickly transferred to the heat-dissipating copper block on the back surface of the wafer. A heat dissipating device for a transparent atomic wafer according to claim 1, wherein the positive and negative heat dissipating copper block elements having a heat dissipating function are disposed on the front and back surfaces of the transparent glass substrate, and are characterized by a metal wire structure. The heat generated after the high current is applied can be quickly diffused into the thermally conductive electroplated copper column by the heat dissipating copper block on the front side of the wafer, and the heat is transferred to the outside of the vacuum chamber by the heat dissipating copper block on the back side of the wafer, so that the atomic wafer can be Maintain normal temperature operation.