阅读说明：本技术 一种改善AMR传感器芯片敏感单元offset输出的制备方法 (A kind of preparation method improving AMR sensor chip sensing unit offset output ) 是由 余涛 杨华 张文旭 陈忠志 于 2019-09-20 设计创作，主要内容包括：本发明公开了一种改善AMR传感器芯片敏感单元offset输出的制备方法,本发明采用2次布线的方式将相互独立的磁敏线条单元用Al连接起来,既保证了惠斯通电桥的完整性,又保证了四个电阻桥完全一致性,能够极大的方便IC设计人员设计电路,简化电路的复杂程度,提升传感器芯片的准确性、可靠性和一致性。(The invention discloses a kind of preparation methods of improvement AMR sensor chip sensing unit offset output, the present invention is connected mutually independent magnetosensitive line cell with Al by the way of 2 wirings, both the integrality of Wheatstone bridge had been ensure that, in turn ensure four resistance bridge crash consistency, IC designer can greatly be facilitated to design circuit, the complexity for simplifying circuit, promotes the accuracy, reliability and consistency of sensor chip.)

1. a kind of preparation method for improving AMR sensor chip sensing unit offset output, it is characterised in that: this method uses The modes of at least 2 times wirings carry out the production work of sensing unit, specifically includes the following steps:

Step 1: mutually independent sensing unit lines are grown using lithography stripping technique, it is complete between the lines arranged anyhow It is complete independent, prevent to directly adopt the case where magnetic domain confusion that sensitive material is interconnected and generated leads to resistance variations；

Step 2: growing one layer of silicon nitride film above after having grown sensing unit, the method for then using photoetching is right Silicon nitride layer performs etching processing, and the silicon nitride etch of the position of required interconnection is fallen, and leaks out following sensing unit lines Tip interface；

Step 3: continuing to grow Al layers on surface, using the method for photoetching, the part other than the window that step 2 is outputed is whole It etches away, only retains interconnection portion.

2. a kind of preparation method for improving AMR sensor chip sensing unit offset output according to claim 1, Be characterized in that: the lines both ends of independent lines are class tip design, and angle controls within the scope of 30 ° -50 °, and the both ends of lines are Designed arc-shaped appearance, the purpose done so are to reduce producting process difficulty, guarantee process consistency.

3. a kind of preparation method for improving AMR sensor chip sensing unit offset output according to claim 1, Be characterized in that: the thickness of the silicon nitride film is maintained between 3000 angstroms -5000 angstroms.

4. a kind of preparation method for improving AMR sensor chip sensing unit offset output according to claim 1, Be characterized in that: Al layers of the thickness is maintained between 10000 angstroms -12000 angstroms.

Technical field

The present invention relates to be related to the fabricating technology field of magnetic sensor chips sensing unit, specially a kind of improvement The preparation method of AMR sensor chip sensing unit offset output.

Background technique

The core of magneto-dependent sensor is how to collect the required signal detected and accurately output correlation signal, It under normal circumstances, is all the shape that the sensing unit of sensor is designed to Wheatstone bridge, not by four resistance bridge variations With differential signal is obtained, to obtain the information of measured signal, as shown in Figure 1.This Wheatstone bridge biggest advantage It is that can eliminate single electric bridge variation with temperature and bring negatively affects, since four electric bridges are consistent to the reaction of temperature, Therefore total difference output variation with temperature is zero.The signal value that Wheatstone bridge obtains is the value that measured signal generates, Has higher confidence level.But due to sensing unit be magnetic material, when this sensitive material be single lines be, Domain structure of the inside containing regular arrangement, still, if sensing unit to be directly designed to the electricity using arc structure interconnection When bridge, more chaotic magnetic domain arrangement can be generated in circular arc portion, to influence the resistance value of lines, is caused during the preparation process Keep 4 electric bridges of Wheatstone bridge inconsistent, so as to cause when measured signal is zero, the output (i.e. offset) of electric bridge is not Zero, so as to cause measurement error.

Summary of the invention

The purpose of the present invention is to provide a kind of preparation sides of improvement AMR sensor chip sensing unit offset output Method reduces the offset value of AMR reluctance switch chip sensing unit, it is ensured that the output signal of sensing unit is capable of objective reality The truth with measuring signal is reflected, facilitates IC circuit designer to do processing appropriate to the signal, reduces circuit Complexity, with overcome the deficiencies in the prior art.

To achieve the above object, the invention provides the following technical scheme: a kind of improvement AMR sensor chip sensing unit The preparation method of offset output, this method carry out the production work of sensing unit by the way of at least 2 times wirings, specifically The following steps are included:

Step 1: mutually independent sensing unit lines are grown using lithography stripping technique, it is complete between the lines arranged anyhow It is complete independent, prevent to directly adopt the case where magnetic domain confusion that sensitive material is interconnected and generated leads to resistance variations；

Step 2: growing one layer of silicon nitride film above after having grown sensing unit, the method for then using photoetching is right Silicon nitride layer performs etching processing, and the silicon nitride etch of the position of required interconnection is fallen, and leaks out following sensing unit lines Tip interface；

Step 3: continuing to grow Al layers on surface, using the method for photoetching, the part other than the window that step 2 is outputed is whole It etches away, only retains interconnection portion.

Preferably, the lines both ends of independent lines are class tip design, and angle controls within the scope of 30 ° -50 °, lines Both ends are designed arc-shaped appearance, and the purpose done so is to reduce producting process difficulty, guarantee process consistency.

Preferably, the thickness of the silicon nitride film is maintained between 3000 angstroms -5000 angstroms.

Preferably, Al layers described, thickness is maintained between 10000 angstroms -12000 angstroms.

Compared with prior art, the present invention is connected mutually independent magnetosensitive line cell Al by the way of 2 wirings It picks up and, both ensure that the integrality of Wheatstone bridge, and in turn ensured four resistance bridge crash consistency, can greatly facilitate IC designer designs circuit, simplifies the complexity of circuit, promotes the accuracy, reliability and consistency of sensor chip.

Detailed description of the invention

Fig. 1 is the structural schematic diagram of existing Wheatstone bridge；

Fig. 2 is the schematic layout pattern of independent sensing unit lines in the present invention；

Fig. 3 is the partial enlarged view of independent sensing unit lines in the present invention；

Fig. 4 is the cross-section relation schematic diagram one of sensing unit lines between adjacent in the present invention；

Fig. 5 is the cross-section relation schematic diagram two of sensing unit lines between adjacent in the present invention；

Fig. 6 is the structural schematic diagram in the present invention.

Specific embodiment

Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete Site preparation description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other Embodiment shall fall within the protection scope of the present invention.

Fig. 1-6 is please referred to, the present invention provides a kind of technical solution: a kind of improvement AMR sensor chip sensing unit The preparation method of offset output, this method directly adopt sensitive material and disposably grow complete favour stone electricity before abandoning The sensing unit of bridge shape, then the production work of sensing unit is carried out by the way of being repeatedly routed.Concrete mode are as follows: (1) mutually independent sensing unit lines are grown using lithography stripping technique, as shown in Fig. 2, between the lines arranged anyhow It is completely independent, has prevented to directly adopt the case where magnetic domain confusion that sensitive material is interconnected and generated leads to resistance variations, single line The feature of item are as follows: lines both ends are class tip design, and angle controls within the scope of 30 ° -50 °, and the both ends of lines are designed arc-shaped appearance (as shown in Figure 3), the purpose done so are to reduce producting process difficulty, guarantee process consistency；(2) sensing unit has been grown After, one layer of silicon nitride film is being grown above, thickness is maintained between 3000 angstroms -5000 angstroms, the method for then using photoetching, Processing is performed etching to silicon nitride layer, the silicon nitride etch of the position of required interconnection is fallen, leaks out following sensing unit line The tip interface of item, as shown in Figure 4；(3) continue to grow Al layers on surface, thickness is maintained between 10000 angstroms -12000 angstroms, is adopted With the method for photoetching, the part other than window that (2) step is outputed all is etched away, only retains interconnection portion, such as Fig. 5, Fig. 6 It is shown.After these three steps, due to interconnection portion be Al, be non-magnetic metal, will not be to sensing unit lines inside Magnetic domain has an impact, so will not influence the resistance balance of entire resistance bridge, can effectively eliminate the direct-connected mode of sensitive material Bring resistance difference.

The key point of the present embodiment is mainly that each magnetosensitive unit lines are completely independent, and lines both ends are class tip design, Tip angle controls between 30 ° -50 °；Using silicon nitride as the passivation layer between magnetosensitive unit and interconnecting electrode, thickness exists Between 3000 angstroms to 5000 angstroms, the silicon nitride etch of the position of required interconnection is fallen using photoetching process, exposes the line of underground End portion；Using Al electrode as interconnecting electrode, thickness, will be more using photoetching process between 12000 angstroms to 15000 angstroms Remaining partial etching falls, and only retains interconnection portion

It is formed by a kind of AMR sensor chip sensing unit structure, including Si base 3 according to the above method, in Si base 3 Be laid with vertical and horizontal arrangement and mutually independent sensing unit lines 2, which forms 4 groups, formed four resistance bridges and Wheatstone bridge is constituted, i.e., 2 groups of adjacent sensitive unit lines form 90 degree of angles each other, and the laying of silicon nitride film 1 is covered on quick It leaves a blank on sense unit lines 2 and in the end of sensing unit lines 2, is spread at 2 groups of adjacent sensitive unit lines of the end places of leaving a blank If AL layer 4.

It although an embodiment of the present invention has been shown and described, for the ordinary skill in the art, can be with A variety of variations, modification, replacement can be carried out to these embodiments without departing from the principles and spirit of the present invention by understanding And modification, the scope of the present invention is defined by the appended.