CN100454144C

CN100454144C - Method for double-sided etching of wafers

Info

Publication number: CN100454144C
Application number: CNB200410055871XA
Authority: CN
Inventors: 杨辰雄
Original assignee: Touch Micro System Technology Inc
Current assignee: Touch Micro System Technology Inc
Priority date: 2004-08-05
Filing date: 2004-08-05
Publication date: 2009-01-21
Anticipated expiration: 2024-08-05
Also published as: CN1731287A

Abstract

A method for etching wafer on both sides includes providing a wafer including at least a rotation axis region and at least two penetration regions on both sides of the rotation axis region. Then, a portion of the wafer in the region of the rotation axis is removed from a bottom surface of the wafer. Then, the bottom surface of the wafer is adhered to a load carrier by an adhesive layer, and the wafer in the two penetrating areas is removed from the upper surface of the wafer until the wafer penetrates through the wafer.

Description

The method of two-sided etched wafer

Technical field

The present invention relates to a kind of method of two-sided etched wafer, particularly relate to and a kind ofly utilize two-sided etching manufacturing process to make the method for little turning axle.

Background technology

Micro electronmechanical (micro electro mechanical system, MEMS) technology is the emerging technology that a kind of height is integrated electronic circuit and machinery etc., and be applied to making various elements, for example little inductor, micro-actuator, micro motor and switching element etc. widely with electronics and mechanical dual nature.Compared to semiconductor element, microcomputer electric component is owing to often have special physical construction, therefore when making if directly utilize standard semiconductor fabrication techniques, formed structure often precision is not good, and can't reach the requirement of microcomputer electric component.Wherein little turning axle is a structure common in the microcomputer electric component, and because the shape of turning axle and surface state are very huge with the stress influence that can bear for the reliability of turning axle rotation, therefore the requirement for shape and surface state is strict especially when making little turning axle.

Please refer to Fig. 1 to Fig. 3, Fig. 1 is the synoptic diagram of a little turning axle 10, and Fig. 2 and Fig. 3 are the existing method synoptic diagram of making little turning axle.As shown in Figure 1, little turning axle 10 has an overhung construction, and can be subjected to the driving in voltage, light or magnetic field etc. and rotate according to the direction shown in the arrow among Fig. 1, therefore the shape of little turning axle 10 must be very accurate, and have level and smooth surface and uniform axis body, can guarantee reliability and reach the requirement that counter stress bears.The method of the little turning axle 10 of existing making is as described below.

As shown in Figure 2, at first provide a wafer 20, and form an etching stopping layer 22 and a photoresist pattern 24 in basal surface and upper surface respectively at wafer 20.As shown in Figure 3, then carry out an etching manufacturing process, utilize photoresist pattern 24, removing not by the wafer 20 of photoresist pattern 24 protections, and stop at etching stopping layer 22 until eating thrown wafer 20 as a shielding firmly.

Yet, existing method is in the process of eating thrown wafer 20, do not consider of the influence of the uniformity coefficient of etching uniformity coefficient and wafer 20 thickness, so the yield rate of etching manufacturing process can't be controlled effectively because each regional etch-rate of wafer 20 is different easily to etch-rate.For instance, when the etching manufacturing process proceeds to final stage and is about to eating thrown wafer 20, the etching total area will produce acute variation and cause the etching manufacturing process to produce the variation that can't expect.In addition, when being etched to etching stopping layer 22, very easily side etching phenomenon taking place and produce as shown in Figure 3 undercutting 26, and then influence the structure of little turning axle.As previously mentioned, in case the precision of the shape of little turning axle is not good, promptly can have a strong impact on the reliability of little turning axle.

In view of this, the applicant concentrates one's attention on to observe and study it, and proposes the present invention of improvement, with reliability and the yield rate that promotes little turning axle according to these shortcomings and foundation correlation experience for many years.

Summary of the invention

Therefore, fundamental purpose of the present invention is providing a kind of method of two-sided etched wafer, to improve the difficult problem that prior art can't overcome.

According to a preferred embodiment of the invention, provide a kind of method of making little turning axle.At first, provide a wafer, this wafer comprises at least one turning axle district and at least two penetrating regions, and this two penetrating region is positioned at two sides in this turning axle district.Then remove this wafer that part is positioned at this turning axle district by a basal surface of this wafer.Basal surface with this wafer utilizes an adhesive coating to be pasted on the load carrier subsequently, and is positioned at this wafer of this two penetrating region until penetrating this wafer by the upper surface removal of this wafer.

The present invention also provides a kind of method of two-sided etched wafer, it comprises: a wafer is provided, this wafer comprises at least one first area and at least one second area, and the area of this first area is less than the area of this second area, and this second area partially overlaps this first area; Carry out one first photoetching corrosion manufacturing process, remove this wafer to one predetermined depth that is positioned at this first area by a first surface of this wafer; This first surface of this wafer is attached on the load carrier; Carry out one second photoetching corrosion manufacturing process, by a second surface of this wafer remove be positioned at this second area but do not comprise be positioned at this first area this wafer until this wafer of eating thrown, wherein said predetermined depth is greater than the summation of the amount of variability of the amount of variability of the second photoetching corrosion manufacturing process and this wafer thickness.

The present invention also provides a kind of method of making little turning axle, and it comprises: a wafer is provided, and this wafer comprises at least one turning axle district and at least two penetrating regions, and this two penetrating region is positioned at two sides in this turning axle district; First surface by this wafer is removed this wafer to one predetermined depth that part is positioned at this turning axle district; And remove this wafer of being positioned at this two penetrating region by a second surface of this wafer until penetrating this wafer, wherein said predetermined depth is greater than the summation of the amount of variability of the amount of variability of the technology of the wafer of being removed two penetrating regions by the second surface of wafer and this wafer thickness.

Because method of the present invention utilizes two-sided etching mode to make little revolute axes configuration, it is wayward effectively to avoid in the etching manufacturing process etching total area to change the excessive etching result that causes, and incident lateral erosion problem when being etched to etching stopping layer, therefore can guarantee that little turning axle has satisfactory texture, and then promote the reliability of little turning axle and the stress that can bear.

In order further to understand feature of the present invention and technology contents, see also following about detailed description of the present invention and accompanying drawing.Yet accompanying drawing only for reference with aid illustration usefulness, be not to be used for to the present invention's limitr in addition.

Description of drawings

Fig. 1 is the synoptic diagram of a little turning axle.

Fig. 2 and Fig. 3 are the existing method synoptic diagram of making little turning axle.

Fig. 4 to Fig. 8 makes the method synoptic diagram of little turning axle for a preferred embodiment of the present invention.

The simple symbol explanation

10 little turning axle 20 wafers

22 etching stopping layers, 24 photoresist patterns

26 undercutting, 50 wafers

52 photoresist patterns, 54 turning axle districts

56 adhesive coatings, 58 load carriers

60 photoresist patterns, 62 penetrating regions

Embodiment

Please refer to Fig. 4 to Fig. 8, Fig. 4 to Fig. 8 makes the method synoptic diagram of little turning axle for a preferred embodiment of the present invention.As shown in Figure 4, at first provide a wafer 50, a silicon wafer for example, and form a photoresist pattern 52 in the basal surface of wafer 50, to define the position in a turning axle district 54.As shown in Figure 5, then carry out an etching manufacturing process, for example (reactive ionetching RIE), utilizes photoresist pattern 52 as a shielding firmly to a reactive ion etching, removes wafer 50 to one predetermined depths that are positioned at turning axle district 54.Wherein above-mentioned predetermined depth must be damaged in the subsequent etch manufacturing process with the structure of avoiding little turning axle greater than the summation of the amount of variability of the amount of variability of follow-up another etching manufacturing process of being undertaken by the upper surface of wafer 50 and wafer 50 thickness.

As shown in Figure 6, then remove photoresist pattern (figure does not show), and utilize an adhesive coating 56 that the basal surface of wafer 50 is engaged on the load carrier 58.Form another photoresist pattern 60 in the upper surface of wafer 50 more subsequently, to define the position of two penetrating regions 62.Wherein adhesive coating 56 optional with photoresists, metal, silicon dioxide, benzocyclobutene (Benzocyclobutene, BCB), pi (polyimide), silicon dioxide, metal, adhesive tape, UV adhesive tape or the material that can utilize wet etching, heating or irradiation mode to remove such as cured.58 of load carriers can be the material that silicon, glass, quartz or pottery etc. are compatible to semiconductor fabrication process.

As Fig. 7, then carry out another etching manufacturing process, for example a reactive ion etching manufacturing process utilizes photoresist pattern 60 as a shielding firmly, removes the wafer 50 that is positioned at penetrating region 62.Wherein when the etching manufacturing process proceeds to the degree of depth shown in Figure 7, the wafer that is positioned at turning axle district 54 can present suspended state, and this moment the etching total area maximum variable quantity only be chip area in the chip areas deduction turning axle district 54 in the penetrating region 62, so etching total area variation that can't produce acute variation and the generation of etching manufacturing process can't be expected.In addition, because this fashion is not etched to adhesive coating 56, the wafer 50 that therefore is positioned at turning axle district 54 also can not produce the phenomenon of lateral erosion.In addition, the size in the turning axle district that the photoresist pattern in present embodiment in the manufacturing process of etching for the first time (figure does not show) is defined is slightly larger than the physical size of little turning axle, can increase the location tolerance of the manufacturing process of etching for the second time by this, the shape of little turning axle of follow-up formation and size can have preferred accuracy by this.

As shown in Figure 8, proceed the etching manufacturing process and be positioned at till the wafer 50 of penetrating region 62, and the photoresist pattern 60 of wafer 50 upper surfaces and the adhesive coating 56 of lower surface are removed the making of promptly finishing little turning axle until eating thrown.It should be noted that adhesive coating 56 is except the function of adhesion wafer 50 and load carrier 58, the function that also has etching stopping layer, when etching proceeds to adhesive coating 56, the etching total area can produce bigger variation, and might produce side etching phenomenon, yet be suspended state owing to be positioned at the wafer 50 in turning

axle district

54, and 54 etched predetermined depths are about to the amount of variability of this etching manufacturing process and the amount of variability of wafer 50 thickness is taken into account in the turning axle district when etching first time manufacturing process, so the wafers 50 in the turning axle district 54 can not be affected.In other words, the structure of little turning axle can not be subjected to the influence of the amount of variability of etching manufacturing process, and has the shape as original expection, therefore has good reliability.

Than prior art, method of the present invention utilizes two-sided etching mode to make little revolute axes configuration, it is wayward effectively to avoid in the etching manufacturing process etching total area to change the excessive etching result that causes, and incident lateral erosion problem when being etched to etching stopping layer, therefore can guarantee that little turning axle has satisfactory texture, and then promote the reliability of little turning axle and the stress that can bear.

The above only is the preferred embodiments of the present invention, and all equalizations of doing according to claim of the present invention change and modify, and all should belong to the covering scope of patent of the present invention.

Claims

1. A method for double-sided etching wafer, comprising:

A wafer is provided, the wafer includes at least one first region and at least one second region, the area of the first region is smaller than the area of the second region, and the second region partially overlaps the first region;

performing a first photolithographic etching process to remove the wafer located in the first region from a first surface of the wafer to a predetermined depth;

attaching the first surface of the wafer to a load carrier;

performing a second photolithographic etching manufacturing process, removing the wafer located in the second area but not including the first area from a second surface of the wafer until the wafer is etched through,

Wherein the predetermined depth is greater than the sum of the variance of the second photolithography etching manufacturing process and the variance of the wafer thickness.

2. The method as claimed in claim 1, wherein the first region and the second region are used to define a micro-axis structure.

3. The method of claim 1, wherein the first photolithography fabrication process comprises:

forming a first photoresist pattern on the first surface of the wafer, and exposing the first region by the first photoresist pattern;

etching the wafer not covered by the first photoresist pattern to the predetermined depth from the first surface; and

The first photoresist pattern is removed.

4. The method of claim 1, wherein the first surface of the wafer is attached to the load carrier with an adhesive layer.

5. The method of claim 4, wherein the second photolithography fabrication process comprises:

forming a second photoresist pattern on the second surface of the wafer, and the second photoresist pattern exposes the second region that does not overlap with the first region;

etching through the wafer not covered by the second photoresist pattern from the second surface, stopping at the adhesion layer; and

The second photoresist pattern is removed.

6. The method of claim 4, further comprising performing a step of removing the adhesive layer after the second photolithography process.

7. A method of making a micro-rotating shaft, comprising:

A wafer is provided, the wafer includes at least one rotation axis area and at least two penetration areas, and the two penetration areas are located on two sides of the rotation axis area;

removing a portion of the wafer in the region of the rotational axis from a first surface of the wafer to a predetermined depth; and

removing the wafer located in the two penetration regions from a second surface of the wafer until the wafer is penetrated,

Wherein the predetermined depth is greater than the sum of the variance of the process of removing the two penetrating regions from the second surface of the wafer and the variance of the thickness of the wafer.

8. The method of claim 7, wherein the wafer located in the rotational axis region is removed by etching.

9. The method of claim 7, wherein the wafer located in the two penetration regions is removed by etching.

10. The method of claim 7, wherein the first surface of the wafer is attached to a load carrier with an adhesive layer when removing the wafer located in the penetration region.

11. The method of claim 10, further comprising performing a step of removing the adhesive layer after removing the wafer located in the penetration region.