TW201432860A - Wafer type infrared emitter package - Google Patents

Abstract

A wafer type infrared emitter package comprising an emitter wafer and a casing. The emitter wafer includes: a base having a base body having a top surface and a central cavity extending through the top surface; a thin plate having a one-end end, the peripheral end and the circumference of the central cavity being through a ring Separated by a gap; a resistor formed on the sheet for heating the sheet to generate infrared radiation; at least one elongated beam leg extending from the peripheral end of the sheet and through the annular gap to the base a seat for suspending the sheet within the central cavity to form a thermal bottleneck for heat transfer from the sheet to the elongated beam leg; and a first reflective material overlying the bottom surface of the sheet. Wherein the closed vacuum chamber has a pressure of less than 0.01 torr.

Description

Wafer type infrared emitter package

The present invention relates to a chip-scale infrared emitter package, and more particularly to a method comprising: suspending a substrate by a slim supporting beam. A wafer type infrared emitter package with a membrane and an electric resistor.

Conventionally, a glowing source of illumination can be used to generate infrared radiation and can be used for non-dispersive infrared (NDIR) gas detection. Conventional luminescent sources include filament bulbs and wafer-type infrared emitters, which have disadvantages such as slower thermal response speed and higher power consumption (about 0.6 W), so they are not suitable for battery-operated (battery-operated) ) NDIR gas detection.

U.S. Patent No. 7,989,821 discloses a sealed infrared radiation source made using a semiconductor process technology, the infrared emission source comprising a pedestal having a central cavity, a polysilicon electrical conductor. a sheet, and a housing that encloses the base and the emitter sheet. The emitter sheet has a peripheral end formed on a top surface of the base, whereby the emitter sheet is suspended on the base on. The enclosure defines an enclosed space that can be filled with an inert gas or vacuum to avoid oxidation.

U.S. Patent Publication No. 2012/0267532 discloses an infrared radiation source comprising a susceptor having a central cavity, a thin plate suspended on the susceptor, and a resistive heater. Similar to the aforementioned U.S. patent, the sheet has a peripheral end formed on the top surface of the base.

Although the dimensions of the aforementioned U.S. Published Patent and Published Patent Infrared Emitters can be miniaturized, the patents do not teach that a loop-shaped gap is formed at the peripheral end of the sheet and the crucible substrate. The periphery of the central cavity is used to thermally isolate the sheet and the substrate to reduce heat loss from the sheet. Moreover, these patents do not teach that the pressure within the central cavity has a critical impact on the electro-optical efficiency of the infrared radiation source, representing the efficiency of converting electricity to light energy.

Accordingly, it is an object of the present invention to provide a wafer type infrared emitter package that overcomes the above-discussed shortcomings of the prior art.

Thus, the wafer type infrared emitter package of the present invention comprises an emitter chip and an enclosure. The emitter wafer includes: a susceptor having a silicon base having a top surface and a bottom surface and a central cavity extending through the top surface, the top The surface is opposite to the bottom surface in a vertical direction; a thin plate is aligned in the vertical direction in the central cavity and has a top surface, a bottom surface and a peripheral end, the peripheral end and the middle end The periphery of the central cavity is separated by a loop-shaped gap; a resistor is formed on the top surface of the thin plate for heating the thin plate to generate infrared radiation; at least one elongated beam-shaped leg, Extending from the circumferential end of the sheet and through the annular gap to the base such that the sheet is suspended within the central cavity, thereby creating a thermal bottleneck for heat transfer from the sheet to the elongated beam foot ( Thermal bottleneck; and a first reflective material covering the bottom surface of the sheet. The housing includes a can housing and a transparent window plate, the outer cover defining a window opening that sealingly covers the window and defines a closure together with the outer cover An enclosed vacuum chamber in fluid communication with the central chamber, the emitter wafer being mounted in the enclosed vacuum chamber for emitting the infrared radiation through the window panel. Wherein the closed vacuum chamber has a pressure of less than 0.01 torr.

The effect of the present invention is that the wafer type infrared emitter package of the present invention can significantly reduce the total heat loss of the sheet and can efficiently provide uniform infrared radiation.

100‧‧‧ wafer type infrared emitter package

1‧‧‧transmitter chip

11‧‧‧Base

111‧‧‧ top surface

112‧‧‧ bottom

113‧‧‧Central cavity

114‧‧‧Weekly

115‧‧‧ annular gap

116‧‧‧ cavity definition wall

12‧‧‧Electrical pads

13‧‧‧Sheet

131‧‧‧ top surface

132‧‧‧ bottom

133‧‧‧Wei Duan

14‧‧‧Resistors

141‧‧‧End

15‧‧‧Slim beam feet

16‧‧‧First reflective material

17‧‧‧Second reflective material

18‧‧‧矽 base

19‧‧‧ spacer

2‧‧‧Electrical pins

3‧‧‧Shell

31‧‧‧ Cover

32‧‧‧Transparent window panels

33‧‧‧ window

4‧‧‧vacuum room

5‧‧‧Connected wire

6‧‧‧Infrared filter

Other features and advantages of the present invention will be apparent from the following description of the drawings, wherein: Figure 1 is a cross-sectional view of a first preferred embodiment of a wafer-type infrared emitter package of the present invention; Is a top view of the first preferred embodiment; FIG. 3 is a heat loss diagram illustrating a thin portion of the first preferred embodiment Various heat loss and total heat loss of the plate for the change of pressure in the vacuum chamber in a housing; FIG. 4 is an electro-optical conversion efficiency diagram illustrating the first preferred embodiment (curve a) and two comparative examples (curve Figure 5 is a cross-sectional view showing a second preferred embodiment of the wafer type infrared emitter package of the present invention; Figure 6 is a plan view of the second preferred embodiment; A cross-sectional view of a third preferred embodiment of the wafer type infrared emitter package of the present invention; and Fig. 8 is a cross-sectional view showing a fourth preferred embodiment of the wafer type infrared emitter package of the present invention.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are denoted by the same reference numerals.

1 and 2 illustrate a first preferred embodiment of a wafer-type infrared emitter package 100 of the present invention.

The wafer type infrared emitter package 100 includes an emitter wafer 1, a pair of conductive leads 2, and a casing 3. The transmitter chip 1 includes a pedestal 11 having a top surface 111, a bottom surface 112, and a central cavity 113 extending through the top surface 111. The top surface 111 and the bottom surface 112 are in a a pair of oppositely disposed in a vertical direction; a pair of conductive pads 12 formed on the top surface 111 of the susceptor 11; a thin plate 13 aligned in the vertical direction with the central cavity 113 and having a top surface 131, a bottom surface 132 and a peripheral end 133, the peripheral end 133 The peripheral edge 114 of the central cavity 113 is separated by an annular gap 115; a resistor 14 is formed on the top surface 131 of the thin plate 13 for heating the thin plate 13 to generate infrared radiation; four elongated beam-shaped branches The feet 15 are respectively disposed at four corners of the thin plate 13 and extend from the circumferential end 133 of the thin plate 13 through the annular gap 115 to the base 11 to suspend the thin plate 13 within the central cavity 113. Thereby forming a thermal bottleneck for heat conduction from the thin plate 13 to the elongated beam-shaped leg 15, thereby reducing the heat loss of the thin plate 13 and achieving a uniform temperature distribution of the thin plate 13; and a first reflective material 16 covering On the bottom surface 132 of the thin plate 13. The susceptor 11 is a ruthenium substrate made of a silicon wafer. The housing 3 includes a cover 31 and a transparent window 32. The outer cover 31 defines a window 33 that sealingly covers the window 33 and defines a closed vacuum chamber 4 in conjunction with the outer cover 31. The vacuum chamber 4 is in fluid communication with the central cavity 113. The wafer 1 is mounted in the closed vacuum chamber 4 for emitting the infrared rays through the transparent window 32. The conductive pins 2 are sealingly extended through the bottom wall of the outer cover 31 and penetrate the vacuum chamber 4 to be electrically connected to the conductive pads 12 via a pair of bonding wires 5, respectively. The resistor 14 is formed into a meandering wire-shaped trace and has two end sections 141, the two ends 141 of which are disposed and extend to the elongated beam branch. On the surface of the foot 15.

In the present embodiment, the thin plate 13 and the elongated beam-type leg 15 are made by a micro-electro-mechanical (MEMS) technology.

The first reflective material 16 is made of a metal material having high reflectivity and low emissivity, and is preferably selected from silver, gold, aluminum or platinum. In the present embodiment, the first reflective material 16 is made of gold.

The wafer type infrared emitter package 100 of the embodiment further includes an infrared filter 6 mounted on the transparent window 32 to allow infrared radiation of a predetermined wavelength to penetrate, and not to allow most of the Infrared radiation outside the predetermined wavelength penetrates.

Figure 3 shows the various heat losses and total heat loss of the sheet 13 in the first preferred embodiment for changes in pressure in the vacuum chamber. The sheet 13 has a size of 1 mm x 1 mm and is operated at 750 ° C. Each of the elongated beam legs 15 has a length of 0.2 mm and a cross-sectional area of 0.02 mm × 0.02 mm.

The total heat loss (curve T) of the thin plate 13 is radiant heat loss (curve A, covered with a first reflective material 16 on the bottom surface 132 of the thin plate 13), conduction heat loss (curve B, at the thin plate 13 and the elongate The combination of the hot neck of the beam-type legs 15 and the convective heat loss (curve C, heat loss due to the air in the vacuum chamber 4). In addition, the curve D and the curve E in FIG. 3 respectively represent the conduction heat loss of the peripheral end 133 of a thin plate 13 and the peripheral edge 114 of a central cavity 113 (ie, no thermal bottleneck) and a lack of the first surface on the bottom surface 132. The radiant heat loss of the thin plate 13 covered by the reflective material 16.

Applicant found that when the pressure in the vacuum chamber 4 is higher than 0.5 torr, the convective heat loss (curve C) is greater than the radiant heat loss of curve A and curve E (the convective heat loss is the main influencing factor of the total heat loss), therefore Covering the bottom surface 132 of the thin plate 13 with the first reflective material 16 The thin plate 13 covered by the first reflective material 16 is changed to the thin plate 13 covered with the first reflective material 16 on the bottom surface 132). The reduction in total heat loss is negligible.

Similarly, when the pressure in the vacuum chamber 4 is higher than 0.5 torr, the convective heat loss (curve C) is greater than the conduction heat loss of curve B and curve D (the convective heat loss is the main influencing factor of the total heat loss), Therefore, the thermal bottleneck brought by the elongated beam-shaped legs 15 means that the thin plate 13 covered on the bottom surface 132 with the first reflective material 16 but without the thermal bottleneck is changed to the bottom surface 132 covered with the first reflective material 16 and having The thin plate 13) of the thermal bottleneck is still negligible for the reduction of total heat loss.

In addition, since the radiant heat loss of the curve E (without the first reflective material cover) is much greater than the conduction heat loss of the curve B, the thermal bottleneck caused by the elongated beam-type leg 15 is for the thin plate not covered by the first reflective material 16. The reduction in total heat loss of 13 is negligible.

Accordingly, Applicants have found that it is desirable to reduce the pressure within the vacuum chamber 4 to less than 0.03 torr and to form a first reflective material 16 on the bottom surface 132 of the sheet 13 such that the convective heat loss (curve C) and radiant heat of the sheet 13 The magnitude of the loss (curve A) is approximately the same to significantly affect the reduction in the total heat loss of the thin plate 13 by the thermal necking caused by the elongated beam legs 15 (ie, from curve D to curve B).

Preferably, the enclosed vacuum chamber 4 has a pressure greater than 0.001 torr.

Figure 4 shows a comparison of the electro-optical conversion efficiency of the first preferred embodiment (curve a) and two comparative examples (curve b and curve c). Curve b represents The comparative example differs from the first preferred embodiment in that the first reflective material 16 is lacking. The comparative example represented by the curve c differs from the first preferred embodiment in that the first reflective material 16 is lacking and does not have the thermal neck (ie, the peripheral end 133 of the thin plate 13 and the peripheral edge 114 of the central cavity 113). Complete contact).

As shown in FIG. 4, when the pressure of the vacuum chamber 4 is about 0.1 torr, the electro-optical conversion efficiency of the first preferred embodiment can be increased from about 12% to about 80 as compared with the comparative example represented by the curve c. %; Compared with the comparative example represented by the curve b, the electro-optic conversion efficiency can be increased from about 45% to about 80%. When the pressure in the vacuum chamber is about 0.01 torr, the first preferred embodiment can increase the electro-optic conversion efficiency from about 15% to about 92% compared to the comparative example represented by the curve c; In a representative example, the electro-optic conversion efficiency can be increased from about 48% to about 92%.

Moreover, the power consumption of the first preferred embodiment is only about 0.15 W.

5 and 6 illustrate a second preferred embodiment of the wafer type infrared emitter package 100 of the present invention.

The second preferred embodiment is different from the first preferred embodiment in that the second preferred embodiment includes an elongated beam-shaped leg 15 that interconnects the peripheral end 133 of the thin plate 13 and the central cavity 113. The peripheral edge 114 and the two end portions 141 of the linear line are disposed and extend on the surface of the elongated beam leg 15.

Figure 7 illustrates a third preferred embodiment of the wafer type infrared emitter package 100 of the present invention.

The third preferred embodiment differs from the first preferred embodiment in that the third preferred embodiment further includes a second reflective material 17 formed and overlying the cavity defining wall 116 of the central cavity 113. And on the surface of the outer periphery of the susceptor 11. The second reflective material 17 is made of a metal material having high reflectivity and low emissivity, and is preferably selected from silver, gold, aluminum or platinum. In the present embodiment, the second reflective material 17 is made of gold.

Figure 8 illustrates a fourth preferred embodiment of the wafer type infrared emitter package 100 of the present invention.

The fourth preferred embodiment is different from the first preferred embodiment in that the fourth preferred embodiment includes a base 11 including a base 18 and a top formed on the base 18 The spacer layer 19 on the surface. The thin plate 13, the elongate beam legs 15 and the spacer layer 19 are formed of a ceria material. The conductive pads 12 are formed on the spacer layer 19. The elongate beam legs 15 extend from the peripheral end 133 of the sheet 13 and through the annular gap 115 to the spacer layer 19. The ruthenium substrate 18 is made of a tantalum wafer.

In the present embodiment, the thin plate 13 and the elongated beam leg 15 are formed by forming a ceria layer on the crucible base 18 and then passing through a semiconductor process technology.

In summary, the wafer type infrared emitter package 100 of the present invention comprises a thin plate 13 suspended on a base 11 by at least one elongated beam-shaped leg 15, which can effectively reduce the total heat loss of the thin plate. It is indeed possible to achieve the object of the invention.

However, the above is only the preferred embodiment of the present invention. The scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the present invention in the scope of the invention and the scope of the patent specification are still within the scope of the invention.

100‧‧‧ wafer type infrared emitter package

1‧‧‧transmitter chip

11‧‧‧Base

111‧‧‧ top surface

112‧‧‧ bottom

113‧‧‧Central cavity

114‧‧‧Weekly

12‧‧‧Electrical pads

13‧‧‧Sheet

131‧‧‧ top surface

132‧‧‧ bottom

133‧‧‧Wei Duan

14‧‧‧Resistors

141‧‧‧End

15‧‧‧Slim beam feet

16‧‧‧First reflective material

2‧‧‧Electrical pins

3‧‧‧Shell

31‧‧‧ Cover

32‧‧‧Transparent window panels

33‧‧‧ window

4‧‧‧vacuum room

5‧‧‧Connected wire

6‧‧‧Infrared filter

Claims (7)

A wafer type infrared emitter package comprises: an emitter wafer, comprising: a base having a base, the base having a top surface, a bottom surface and a central cavity extending through the top surface, The top surface and the bottom surface are oppositely disposed in a vertical direction, and a thin plate is aligned in the vertical direction in the central cavity and has a top surface, a bottom surface and a peripheral end, the peripheral end and the periphery of the central cavity being Separated by an annular gap, a resistor is formed on the top surface of the sheet for heating the sheet to generate infrared radiation, at least one elongated beam leg, from the peripheral end of the sheet and through the ring a gap extending to the base to suspend the thin plate within the central cavity, thereby forming a thermal bottleneck for heat conduction from the thin plate to the elongated beam leg, and a first reflective material covering the thin plate And a housing comprising a cover and a transparent window panel, the cover defining a window, the transparent window panel sealingly covering the window and defining a closed vacuum chamber together with the outer cover, the vacuum chamber With Central lumen in fluid communication with the transmitter chip is mounted in the closed vacuum chamber for emission through the window of the infrared radiation plate; wherein the enclosed vacuum chamber having a pressure less than 0.01 torr. The wafer type infrared emitter package of claim 1, wherein the enclosed vacuum chamber has a pressure greater than 0.001 torr. The wafer-type infrared emitter package of claim 1, wherein the central cavity is defined by a cavity defining wall having a bottom and disposed above a bottom surface of the base. The wafer type infrared emitter package of claim 3, further comprising a second reflective material overlying the defined wall of the cavity. The wafer-type infrared emitter package of claim 1, wherein the resistor is a meandering linear line having opposite ends, the two ends of the linear line being disposed and extending to the elongated beam On the surface of the foot. The wafer type infrared emitter package of claim 1, further comprising an infrared filter mounted on the window panel, the infrared filter is capable of penetrating infrared radiation of a predetermined wavelength, and is not allowed Most of the infrared radiation outside the predetermined wavelength penetrates. The wafer type infrared emitter package of claim 1, wherein the first reflective material is made of a metal material selected from the group consisting of silver, gold, aluminum or platinum.