CN217846688U

CN217846688U - Probe optical fiber, wafer and optical fiber and optical waveguide coupling structure

Info

Publication number: CN217846688U
Application number: CN202221475183.9U
Authority: CN
Inventors: 丁晓亮; 田桂霞; 甘飞; 李量; 汪军; 窦佳迪; 包苓暄; 徐菽晗
Original assignee: Suzhou Zhuoyu Photon Technology Co ltd
Current assignee: Suzhou Zhuoyu Photon Technology Co ltd
Priority date: 2022-06-13
Filing date: 2022-06-13
Publication date: 2022-11-18
Anticipated expiration: 2032-06-13

Abstract

The utility model discloses a structure of probe optic fibre, wafer and optic fibre and optical waveguide coupling. The utility model discloses a probe optic fibre has two tangent planes, and first tangent plane is 35 ~ 40 with the optical axis contained angle, and the surface has plated high anti-reflection coating (HR membrane), and the second tangent plane is 10 ~ 20 with the optical axis contained angle, and anti-reflection coating (AR membrane) have been plated to the surface, and the light of transmission takes place the total reflection through first tangent plane in the optic fibre to the angle transmission of being close to the perpendicular to second tangent plane is gone out, and the coupling gets into in the waveguide of silicon optical chip. The utility model discloses a be applied to probe optic fibre of silicon light wafer end-face coupling test has reduced the most advanced size of optic fibre, can be applicable to the width and be 15 mu m, and the degree of depth is 15 mu m's narrow small wafer cutting way, can distribute more chips on the wafer of the same size to reduce the cost of single chip.

Description

Probe optical fiber, wafer and optical fiber and optical waveguide coupling structure

Technical Field

The utility model relates to an optical communication technical field, concretely relates to probe fiber, wafer and optic fibre and optical waveguide coupling's structure.

Background

The silicon optical chip is a photon integrated circuit manufactured by silicon optical materials and devices through special processes, mainly comprises a modulator, a detector, a passive waveguide device and the like, and integrates various optical devices on the same silicon-based substrate. The silicon optical chip has the characteristics of high integration level, low cost, higher transmission bandwidth and the like, and more optical devices can be integrated because the silicon optical chip takes silicon as a substrate of the integrated chip; in the optical module, the cost of the traditional optical chip is very high, and the low cost of the silicon optical chip becomes a huge advantage; the silicon waveguide has a high refractive index contrast ratio between the core layer and the cladding layer, and has a strong binding effect on light, so that the silicon-based optical waveguide device has a small size and high integration level, and the manufacturing and processing technology of the silicon-based optoelectronic device is compatible with CMOS (complementary metal oxide semiconductor), and low-cost large-scale production is easy to realize. Currently, silicon-based optoelectronic chips are applied in the fields of coherent optical communication, optical sensing, laser radar, microwave photonics, and the like, for example, silicon-based optical transceiver chips have been developed in mass production in the fields of optical communication and optical interconnection.

The existing wafer cutting usually adopts mechanical cutting, the width of a reserved cutting channel is generally 100-200 mu m, the utilization rate of a wafer is influenced by the excessively wide cutting channel due to the limited surface area of the wafer, laser hidden cutting is an existing more advanced wafer cutting technology, chips are hardly polluted by fragments, the width of the cutting channel is only about 10 mu m, and more chips can be distributed on the wafer with the same size. And before the silicon optical wafer is cut into the silicon optical chip, the wafer level test is required, because the waveguide coupling interface of the silicon optical chip is usually positioned on the side surface of the chip, the conventional single-mode optical fiber or lens optical fiber cannot extend into a narrow cutting channel due to the overlarge size of the optical fiber, and the coupling test is difficult to perform.

Disclosure of Invention

In order to solve the technical problem, the utility model provides a probe fiber, wafer and optic fibre and optical waveguide coupling's structure.

The probe optical fiber is used for end face coupling test of a silicon optical wafer, and the probe optical fiber is provided with two sections: the optical lens comprises a first section and a second section, wherein a first included angle formed by the first section and an optical axis is 35-40 degrees, and a second included angle formed by the second section and the optical axis is 10-20 degrees;

the included angle formed by the first tangent plane and the second tangent plane ensures that when the end face of the probe optical fiber extends into the wafer, the extending length is limited within 15 mu m by the width of a cutting path on the surface of the wafer and the first tangent plane and the second tangent plane.

As a further improvement of the utility model, the first tangent surface is plated with a high reflection film.

As a further improvement of the utility model, the second section surface is plated with an antireflection film.

As a further improvement of the present invention, the probe optical fiber is a probe optical fiber array.

As a further improvement of the present invention, the probe fiber array further comprises:

the bottom plate is provided with a first V-shaped groove for placing at least two probe optical fibers, and the distance between the end surface of the bottom plate and the tip end of each probe optical fiber is 0.5-2 mm;

and the cover plate is provided with a second V-shaped groove used for being matched with the bottom plate to fix the probe optical fiber, the second V-shaped groove corresponds to the first V-shaped groove, and the distance between the end surface of the cover plate and the tip end of the probe optical fiber is 0.5-2 mm.

The wafer comprises:

a chip manufacturing area;

the waveguide is arranged in the chip manufacturing area;

the cutting channel matched with the probe optical fiber is arranged on the end face of the chip, the width of the cutting channel is 15 micrometers, and the depth of the cutting channel is 15 micrometers.

The optical fiber and the optical waveguide coupling structure is as follows: the structure is composed of the probe optical fiber and the wafer, wherein the probe optical fiber is placed in the cutting channel of the wafer, and the second tangent plane of the probe optical fiber is close to the waveguide.

The utility model has the advantages that: the utility model provides a probe optical fiber, this optic fibre light-emitting end have two tangent planes, have reduced the most advanced size of optic fibre. The included angle between the first section and the optical axis is 35-40 degrees, the surface is plated with a high reflection film, the included angle between the second section and the optical axis is 10-20 degrees, and the surface is plated with an anti-reflection film. Light is reflected from the fiber into the first facet, transmitted out of the fiber through the second facet in a direction approximately normal to the facet, and then into the waveguide end-face coupler of the silicon-on-chip. The distance from the center of the spot transmitted from the second section to the tip of the fiber is less than 10 μm. The utility model provides a probe optic fibre for silicon light wafer end face coupling test can be used to the degree of depth and be 15 mu m, and the width is 15 mu m's cutting street, the area of reducible wafer surface cutting street, consequently, can distribute more chips on the same size's the wafer, has reduced single chip's cost.

Drawings

Fig. 1 shows a probe optical fiber according to the present invention.

Fig. 2 is an optical fiber array of the present invention.

Fig. 3 is a wafer with scribe lines for matching the optical fibers according to the present invention.

Fig. 4 shows a structure of coupling an optical fiber and an optical waveguide according to the present invention.

The reference numbers in the figures illustrate: 11. the wafer manufacturing method comprises a first section, 12, a first included angle, 13, a second section, 14, a second included angle, 31, a wafer, 32, a chip manufacturing area, 33, a cutting channel reserved area, 41, a waveguide, 42 and a cutting channel.

Detailed Description

The present invention is further described with reference to the following drawings and specific embodiments so that those skilled in the art can better understand the present invention and can implement the present invention, but the embodiments are not to be construed as limiting the present invention.

In the present embodiment, the wafer level packaging technology uses a wafer as a processing object, and performs a coupling packaging test on a plurality of chips on the wafer. High-throughput functional testing of silicon photons is a key issue for large-scale chip fabrication, with the most effective coupling scheme being end-face coupling. When a wafer is tested by a traditional optical fiber due to the self volume, a cutting channel needs to be etched on one side of a waveguide before end face coupling, and because a waveguide coupling interface of a silicon optical chip is usually positioned on the side face of the chip, the tip of the traditional optical fiber is oversized, the size of the required cutting channel is usually dozens of micrometers when the end face coupling is carried out, and the utilization rate of the wafer is influenced by the size of the cutting channel. Therefore, the probe optical fiber is designed, the light outlet end of the probe optical fiber is provided with two sections, light can be transmitted out from the side face of the optical fiber and enters the end face coupler of the silicon optical chip, the probe optical fiber is suitable for a cutting channel with the width of 15 micrometers and the depth of 15 micrometers, and the reduction of the size of the cutting channel means that the utilization rate of a wafer is improved.

In this embodiment, a method for manufacturing a probe optical fiber for end-face coupling test of a silicon photonics wafer is provided, including the following steps:

s01: cutting one side of the end face of the optical fiber into a first section 11, wherein a first included angle 12 formed by the first section 11 and an optical axis is 35-40 degrees, and a layer of high-reflection film is plated on the first section 11; when the light transmitted in the optical fiber reaches the first tangent plane 11, the light is reflected on the first tangent plane 11, and the direction of the light path is changed, so that the light is refracted to the end surface at the other side;

s02: cutting the other side end face of the optical fiber into a second section 13, wherein a second included angle 14 formed by the second section 13 and the optical axis is 10-20 degrees, and a layer of antireflection film is plated on the second section 13; light reflected by the first facet 11 is transmitted out of the fiber in a direction approximately perpendicular to the second facet 13.

In this embodiment, a probe fiber for silicon photonics wafer end-face coupling testing is also provided, the probe fiber having a smaller tip size than existing conventional single-mode fibers or lensed fibers. As shown in fig. 1, the probe fiber of the present embodiment has two sections, a first angle 12 formed by the first section 11 and the optical axis is 35 to 40 °, a high reflective film is coated on the surface of the first section 11, a second angle 14 formed by the second section 13 and the optical axis is 10 to 20 °, and an anti-reflection film is coated on the surface of the second section 13. Wherein, the first section 11 cuts the fiber core with an angle of 35-40 degrees, and the top of the second section 13 is connected with the top of the cut fiber core.

To couple light into a silicon photonics chip, light is launched down a cut-out and then deflected into a waveguide. The first included angle 12 of this embodiment is 35 to 40 °, and the angle is selected such that when light is reflected by the first tangent plane 11, the perpendicular distance from the fiber tip to the center of the reflected light spot is less than 10 μm, and the second included angle 14 formed by the second tangent plane 13 and the optical axis is determined according to the angle of the first included angle, so that the light reflected by the first tangent plane 11 is transmitted out of the fiber in a direction approximately perpendicular to the second tangent plane 13. Through the angle selection, when the optical fiber is used for wafer coupling, the section width of the optical fiber flush with the wafer is smaller than 15 micrometers, and therefore, only the area with the width of about 20 micrometers needs to be reserved for manufacturing the cutting path.

To improve testing efficiency, in an alternative embodiment, the optical fiber may be an array of optical fibers, as shown in FIG. 2. The optical fiber array can be fixed in various ways, and in this embodiment, the optical fiber array is fixed by using a bottom plate with a V-shaped groove and a cover plate. The specific fixing mode is as follows: sequentially placing each optical fiber in a V-shaped groove of the bottom plate, and fixing the array optical fibers in the V-shaped groove through an adhesive; reversely buckling the cover plate on the bottom plate on which the optical fiber array is placed; the distance from the tip of the optical fiber to the bottom plate and the lowest end of the cover plate is 0.5 mm-2 mm. When the end face coupling is carried out, the optical fiber array clamped between the bottom plate and the cover plate is inserted into the cutting channel.

In this embodiment, a wafer having scribe lines used with the optical fiber is also provided. Fig. 3 is a schematic view of a wafer according to the present embodiment. In fig. 3, 31 is a wafer; 32 is a chip manufacturing area, namely a position where the waveguide is manufactured; the area 33 between the chips is a scribe lane reservation area.

The manufacturing method of the wafer 31 in this embodiment includes: and manufacturing the required waveguide in a chip manufacturing area, and in order to perform wafer-level test, performing laser recessive cutting on the end face of the chip in the manufacturing process to etch a cutting channel with the width of 15 micrometers and the depth of 15 micrometers.

The scribe lines described in this embodiment are used in combination with the optical fibers or optical fiber arrays manufactured by the above method, the scribe lines of the current wafer are usually cut mechanically, the width of the reserved scribe lines is generally 100-200 μm, the scribe lines of the wafer 31 in this embodiment are cut implicitly with laser, the width of the scribe lines required for laser implicit cutting is generally 10-20 μm, and a narrower scribe line design means that more chips can be distributed on a wafer with the same size, thereby reducing the cost of a single chip.

In this embodiment, a structure for coupling an optical fiber and an optical waveguide is also provided. In the present embodiment, the structure is provided by matching the optical fiber manufactured by the above method with the wafer 31 having the matching scribe line 42. In an alternative embodiment, a structure for coupling an optical fiber and an optical waveguide is shown in fig. 4, where the structure mainly includes a wafer 31 and an optical fiber array, and 31 is the wafer described in the above embodiment; 21 is a light ray array; 41 is a waveguide; 42 is a 15 μm wide and 15 μm deep street. This structure reduces the width and depth of the scribe line 42 on the wafer, improves the wafer utilization when using optical fibers or fiber arrays for wafer coupling, and promotes the coupling efficiency and testing of wafer-level end-face couplers.

In this embodiment, a wafer testing method is also provided. After the above-described optical fiber and optical waveguide coupling structure is formed, the wafer 31 is tested. The light transmitted by the second section 13 of the optical fiber or the optical fiber array enters the waveguide end-face coupler of the silicon optical chip, so that light leakage can be effectively prevented. After the coupling structure is light-transmitting, how much light in the optical fiber is coupled into the waveguide can be detected through the size of the light current of the bonding pad corresponding to the chip.

In the embodiment, based on the advantages of the optical fiber array, the optical parallel coupling of the multichannel input/output of the silicon optical device can be realized, and the test density is increased. The mode can be directly coupled into the silicon optical waveguide, so that compared with an optical fiber array coupled to a grating coupler, the mode has the advantages that light is less prone to loss, the optical bandwidth is larger, and automation of the coupling process can be achieved through a machine vision technology.

The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. Equivalent substitutes or changes made by the technical personnel in the technical field on the basis of the utility model are all within the protection scope of the utility model. The protection scope of the present invention is subject to the claims.

Claims

1. A probe optical fiber is used for end face coupling test of a silicon optical wafer, and is characterized in that: the probe fiber has two cleaved facets: the optical lens comprises a first section and a second section, wherein a first included angle formed by the first section and an optical axis is 35-40 degrees, and a second included angle formed by the second section and the optical axis is 10-20 degrees;

the included angle formed by the first section and the second section ensures that when the end face of the probe optical fiber extends into the wafer, the extending length is limited within 15 mu m by the width of the cutting channel on the surface of the wafer and the first section and the second section.

2. The probe fiber of claim 1, wherein: the first tangent surface is plated with a high-reflectivity film.

3. The probe fiber of claim 1, wherein: and the surface of the second section is plated with an antireflection film.

4. The probe optical fiber according to any one of claims 1 to 3, wherein: the probe optical fiber is a probe optical fiber array.

5. The probe fiber of claim 4, wherein: the probe fiber array further comprises:

6. A wafer, comprising: the method comprises the following steps:

a chip manufacturing area;

the waveguide is arranged in the chip manufacturing area;

the scribe line used in combination with the probe optical fiber according to any one of claims 1 to 3, disposed on the end face of the chip, the scribe line having a width of 15 μm and a depth of 15 μm.

7. A structure for coupling an optical fiber to an optical waveguide, comprising: the structure is composed of the probe optical fiber of any one of claims 1 to 4 and the wafer of claim 6, the probe optical fiber is placed in the scribe line of the wafer, wherein the second section of the probe optical fiber is proximate to the waveguide.