CN103110414A - Full-bridge chip embedded skull pressure sensor - Google Patents

Abstract

Translated fromChinese

一种全桥芯片植入式颅压传感器，包括敏感芯片，敏感芯片中的方形薄膜位于外壳顶部缺口的正下方，敏感芯片与外壳通过生物胶固粘，敏感芯片的中间布置有四个压阻条，构成惠斯通电桥，当脑颅压作用于传感器芯片时，压力作用于方形薄膜，进而使薄膜发生变形，压阻条在方形薄膜的应力作用下其阻值发生变化，惠斯通电桥失去平衡，输出一个与外界压力相对应的电信号，从而实现传感器芯片对脑颅压的测量，本发明具测量准确，尺寸小，创伤小，可靠性高的优点。

A full bridge chip implantable intracranial pressure sensor, including a sensitive chip, the square film in the sensitive chip is located directly below the top notch of the shell, the sensitive chip and the shell are solidified by biological glue, and four piezoresistors are arranged in the middle of the sensitive chip Strips form a Wheatstone bridge. When the intracranial pressure acts on the sensor chip, the pressure acts on the square film, which causes the film to deform. The resistance of the piezoresistive strip changes under the stress of the square film. The Wheatstone bridge If the balance is lost, an electrical signal corresponding to the external pressure is output to realize the measurement of the intracranial pressure by the sensor chip. The invention has the advantages of accurate measurement, small size, small trauma and high reliability.

Description

Translated fromChinese

一种全桥芯片植入式颅压传感器A full-bridge chip implantable intracranial pressure sensor

技术领域technical field

本发明属于微机械电子技术领域，具体涉及一种全桥芯片植入式颅压传感器。The invention belongs to the technical field of micro-mechanics and electronics, and in particular relates to a full-bridge chip implanted intracranial pressure sensor.

背景技术Background technique

现代临床医疗中，脑水肿、颅脑损伤、帕金森症的治疗过程中都需要掌握病人颅内压力的状况。颅内压（Intracranial Pressure，ICP）是指颅腔内容物对颅腔壁上所产生的压力，又称脑压，是神经外科临床和科研的重要观察指标。颅内压增高是颅内疾病或颅内继发性病变的一种反映，如不能及时发现颅内压增高并采取有效的治疗措施，则可能导致严重后果，甚至危及生命。在临床工作中，单纯依靠观察神经系统症状或CT、MRI影像学资料判断颅内压是否增高，很难说明颅内压的实际水平，故采用持续的颅内压监测作为“早期报警系统”，有利于早期发现和及时处理颅内压增高和颅内疾病，并提高疗效。因此，颅内压作为神经外科临床和科研的重要指标一直受到神经外科临床和科研人员的重视，是神经外科临床和科研的重要观察指标。颅压传感器已有相关的研究和应用，如美国INTEGRA NEUROSCIENCES公司生产的型号为110-4L的CAMINO光纤颅内压力监测系统还有通过手术放置在硬脑膜下的无线电电子式颅内压力检测传感器等，但都存在以下问题：1）价格昂贵，普及应用十分困难；2）无线电充电效率过低；3）测压位置不佳导致的测压不准。In modern clinical medicine, it is necessary to grasp the intracranial pressure of patients in the treatment of cerebral edema, craniocerebral injury and Parkinson's disease. Intracranial Pressure (ICP) refers to the pressure generated by the contents of the cranial cavity on the wall of the cranial cavity, also known as brain pressure, and is an important observation index for neurosurgery clinical and scientific research. Increased intracranial pressure is a reflection of intracranial diseases or secondary intracranial lesions. If the increase in intracranial pressure cannot be detected in time and effective treatment measures are taken, it may lead to serious consequences, even life-threatening. In clinical work, it is difficult to explain the actual level of intracranial pressure by simply relying on the observation of nervous system symptoms or CT and MRI imaging data to determine whether the intracranial pressure is increased. Therefore, continuous intracranial pressure monitoring is used as an "early warning system". It is conducive to early detection and timely treatment of increased intracranial pressure and intracranial diseases, and improves the curative effect. Therefore, intracranial pressure, as an important indicator of neurosurgery clinical and scientific research, has always been valued by neurosurgery clinical and scientific researchers, and is an important observation indicator of neurosurgery clinical and scientific research. There have been relevant researches and applications on intracranial pressure sensors, such as the 110-4L CAMINO optical fiber intracranial pressure monitoring system produced by INTEGRA NEUROSCIENCES in the United States, as well as radio-electronic intracranial pressure detection sensors placed under the dura mater through surgery. , but there are the following problems: 1) the price is expensive, and it is very difficult to popularize and apply; 2) the wireless charging efficiency is too low; 3) the pressure measurement is inaccurate due to the poor location of the pressure measurement.

发明内容Contents of the invention

为了克服上述现有技术的缺点，本发明的目的在于提供一种全桥芯片植入式颅压传感器，主要优势在于测量精准，小尺寸、可靠性好的封装设计带来更小的颅脑创伤，减轻患者病痛，使用方便。In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a full-bridge chip implantable intracranial pressure sensor, the main advantages of which are accurate measurement, small size and good reliability package design to bring less craniocerebral trauma , relieve pain of patients, easy to use.

为了实现上述目的，本发明采用的技术方案为：In order to achieve the above object, the technical scheme adopted in the present invention is:

一种全桥芯片植入式颅压传感器，包括外壳1、敏感芯片2、金丝引线3、生物胶4、电缆线5、后续电路6，外壳1作为基座，其上通过生物胶4粘接有敏感芯片2，敏感芯片2中的方形薄膜位于外壳1顶部缺口的正下方，在敏感芯片2的方形薄膜上配有四个阻值相同的压阻条，四个压阻条构成惠斯通电桥，惠斯通电桥通过金丝引线3和电缆线5连接，通过电缆线5实现给传感器提供桥路电源和输出与压力相关的电压信号，电缆线5将电压信号提供给后续电路6处理。A full bridge chip implantable intracranial pressure sensor, comprising a shell 1, asensitive chip 2, agold wire lead 3, a bio-glue 4, a cable 5, and a follow-up circuit 6, the shell 1 is used as a base, and the bio-glue 4 is glued on it Thesensitive chip 2 is connected, and the square film in thesensitive chip 2 is located directly below the top notch of the casing 1. Four piezoresistive strips with the same resistance value are arranged on the square film of thesensitive chip 2, and the four piezoresistive strips form a whist The energized bridge, the Wheatstone bridge is connected through thegold wire 3 and the cable 5, and the cable 5 is used to provide the bridge power supply to the sensor and output the pressure-related voltage signal, and the cable 5 provides the voltage signal to the subsequent circuit 6 for processing .

所述的敏感芯片2采用了（100）晶面硅。Thesensitive chip 2 is made of (100) crystal silicon.

敏感芯片2上的四个压阻条沿着[110]和晶向布置。The four piezoresistive strips on thesensitive chip 2 are along [110] and crystal orientation arrangement.

所述的敏感芯片2采用250um厚双面抛光N型单晶硅片材料制作。Thesensitive chip 2 is made of 250um thick double-sided polished N-type single crystal silicon material.

由于本发明是将传感器植入硬脑膜下测量，其中敏感芯片2采用MEMS工艺，集感应压力与测量电路于一体，同时为了简化封装去掉了转接电路板，故具有测量准确，尺寸小，创伤小，可靠性高的优点。Because the present invention is to implant the sensor under the dura mater for measurement, wherein thesensitive chip 2 adopts MEMS technology, integrates the induction pressure and the measurement circuit, and removes the transfer circuit board in order to simplify the packaging, so it has accurate measurement, small size, and no trauma. Advantages of small size and high reliability.

附图说明Description of drawings

图1为本发明的结构示意图。Fig. 1 is a structural schematic diagram of the present invention.

图2为压阻条敏感芯片2上的分布示意图。FIG. 2 is a schematic diagram of distribution on the piezoresistive stripsensitive chip 2 .

图3为压阻条构成的惠斯通电桥示意图。Figure 3 is a schematic diagram of a Wheatstone bridge composed of piezoresistive strips.

图4为本发明的应用示意图。Fig. 4 is a schematic diagram of the application of the present invention.

具体实施方式Detailed ways

以下结合附图对本发明的结构与工作原理详细说明。The structure and working principle of the present invention will be described in detail below in conjunction with the accompanying drawings.

参见图1，一种全桥芯片植入式颅压传感器，包括外壳1、敏感芯片2、金丝引线3、生物胶4、电缆线5、后续电路6，外壳1作为基座，其上通过生物胶4粘接有敏感芯片2，敏感芯片2中的方形薄膜位于外壳1顶部缺口的正下方，在敏感芯片2的方形薄膜上配有由MEMS工艺特制的四个阻值相同的压阻条，四个压阻条构成惠斯通电桥，惠斯通电桥通过金丝引线3和电缆线5连接，通过电缆线5实现给传感器提供桥路电源和输出与压力相关的电压信号，就形成了传感器的工作部分，由于极小的封装尺寸限制，在外壳内部不适合设置转接电路板，所以由金丝引线3将惠斯通电桥的信号与传输到电缆线5上，并用生物胶4将焊接点固定在一侧，电缆线5将电压信号提供给后续电路6处理。Referring to Fig. 1, a full-bridge chip-implantable intracranial pressure sensor includes a housing 1, asensitive chip 2, agold wire lead 3, bio-glue 4, a cable 5, and a follow-up circuit 6, and the housing 1 serves as a base on which the Bio-adhesive 4 is bonded withsensitive chip 2. The square film insensitive chip 2 is located directly below the top notch of housing 1. Four piezoresistive strips with the same resistance value are specially made by MEMS technology on the square film ofsensitive chip 2. , four piezoresistive strips form a Wheatstone bridge, and the Wheatstone bridge is connected through thegold wire 3 and the cable 5, and the cable 5 is used to provide the sensor with a bridge power supply and output a pressure-related voltage signal, forming a For the working part of the sensor, due to the limitation of the extremely small package size, it is not suitable to set up an adapter circuit board inside the shell, so the signal of the Wheatstone bridge is transmitted to the cable 5 by thegold wire lead 3, and the bio-glue 4 is used to connect the sensor to the sensor. The welding point is fixed on one side, and the cable 5 provides the voltage signal to the subsequent circuit 6 for processing.

所述的敏感芯片2采用了（100）晶面硅。Thesensitive chip 2 is made of (100) crystal silicon.

所述的四个压阻条沿着[110]和晶向布置。The four piezoresistive strips along [110] and crystal orientation arrangement.

所述的敏感芯片2采用250um厚双面抛光N型单晶硅片材料制作。Thesensitive chip 2 is made of 250um thick double-sided polished N-type single crystal silicon material.

参见图2和3，四个压阻条分别为电阻R1、R2、R3和R4，在敏感芯片2上，电阻R1与电阻R3平行布置，电阻R2与电阻R4平行布置，四个压阻条构成惠斯通电桥。Referring to Figures 2 and 3, the four piezoresistive strips are resistors R1, R2, R3, and R4 respectively. On thesensitive chip 2, resistor R1 is arranged in parallel with resistor R3, and resistor R2 is arranged in parallel with resistor R4. Four piezoresistive strips constitute Wheatstone bridge.

本发明的工作原理是：完成穿刺动作后，将传感器头部置于与斜角边钻孔相对的硬脑膜下的脑组织上，使传感器敏感芯片2朝向脑皮层，被测介质压力直接作用在镀有绝缘保护层的传感器上。分布于敏感芯片2上的四个压阻条构成惠斯通电桥，组成压力测量电路，当颅压作用于传感器芯片时，使得方膜结构发生变形，压阻条在方形薄膜的应力作用下其阻值发生变化，压阻条组成的惠斯通电桥失去平衡，在恒定电源的激励下输出一个与外界压力相对应的电信号，从而实现传感器芯片对脑颅压的测量。The working principle of the present invention is: after the puncture action is completed, the sensor head is placed on the brain tissue under the dura mater opposite to the bevel edge drilling, so that the sensorsensitive chip 2 faces the cerebral cortex, and the pressure of the measured medium directly acts on it. On the sensor coated with insulating protective layer. The four piezoresistive strips distributed on thesensitive chip 2 form a Wheatstone bridge, forming a pressure measurement circuit. When the intracranial pressure acts on the sensor chip, the square membrane structure is deformed, and the piezoresistive strips lose weight under the stress of the square film. When the resistance value changes, the Wheatstone bridge composed of piezoresistive strips loses balance, and under the excitation of a constant power supply, an electrical signal corresponding to the external pressure is output, thereby realizing the measurement of intracranial pressure by the sensor chip.

本发明中敏感芯片2上的压阻条阻值的变化量通过压阻效应的相关公式计算而来，压阻效应是指当半导体材料受到应力作用时，由于载流子迁移率的变化，使其电阻率发生变化的现象。当压阻条处于一定应力作用下时，其阻值变化与其所受应力之间的比例关系式如下：In the present invention, the variation of the resistance value of the piezoresistive strip on thesensitive chip 2 is calculated by the relevant formula of piezoresistive effect. A phenomenon in which the resistivity changes. When the piezoresistive strip is under a certain stress, the proportional relationship between its resistance change and the stress it receives is as follows:

$\frac{\mathrm{<span><span>\&Delta;R</span>\&Delta;R</span>}}{\mathrm{<span><span>R</span>R</span>}}<span><span>=</span>=</span>{\mathrm{<span><span>\&pi;</span>\&pi;</span>}}_{\mathrm{<span><span>l</span>l</span>}}{\mathrm{<span><span>\&sigma;</span>\&sigma;</span>}}_{\mathrm{<span><span>i</span>i</span>}}<span><span>+</span>+</span>{\mathrm{<span><span>\&pi;</span>\&pi;</span>}}_{\mathrm{<span><span>\&tau;</span>\&tau;</span>}}{\mathrm{<span><span>\&tau;</span>\&tau;</span>}}_{\mathrm{<span><span>i</span>i</span>}}$

式中：R——压阻条初始阻值；In the formula: R - the initial resistance of the piezoresistive strip;

π_l——为压阻条横向压阻系数；π_l ——transverse piezoresistive coefficient of piezoresistive strip;

π_τ——压阻条纵向压阻系数；π_τ — longitudinal piezoresistive coefficient of piezoresistive strip;

σ_i——压阻条受到的正应力；σ_i ——the normal stress on the piezoresistive strip;

τ_i——压阻条受到的剪应力。τ_i ——the shear stress on the piezoresistive strip.

因此敏感芯片2在脑颅压作用时产生的应力将会使其上的压阻条的阻值变化，通过惠斯通电桥再将此变化转变为电信号输出，继而实现对脑颅压的感应与测量，压阻效应具有各向异性的特征，沿着不同的方向施加应力或沿不同方向通过电流，材料的电阻率变化均不相同，为了在同样的加速度作用下得到更大的输出电信号，本发明中的敏感芯片2选择（100）晶面硅片，利用（100）晶面硅在[110]和

晶向上具有最大值，在[100]和[010]晶向上几乎为零的特点，压阻条沿着[110]和

晶向分布，提高了传感器芯片对脑颅压的测量精度。Therefore, the stress generated by thesensitive chip 2 under the action of intracranial pressure will change the resistance value of the piezoresistive strip on it, and then convert this change into electrical signal output through the Wheatstone bridge, and then realize the sensing of intracranial pressure And measurement, the piezoresistive effect has the characteristics of anisotropy. When stress is applied in different directions or currents are passed in different directions, the resistivity of the material changes differently. In order to obtain a larger output electrical signal under the same acceleration , thesensitive chip 2 in the present invention selects the (100) crystal plane silicon wafer, and uses the (100) crystal plane silicon in [110] and

The crystal direction has a maximum value, and it is almost zero in the [100] and [010] crystal directions, and the piezoresistive strips are along the [110] and

The crystal orientation distribution improves the measurement accuracy of the sensor chip for intracranial pressure.

Claims (4)

1. full-bridge implanted chip formula cranium pressure sensor, comprise shell (1), sensitive chip (2), spun gold lead-in wire (3), biogum (4), cable (5), subsequent conditioning circuit (6), it is characterized in that: shell (1) is as pedestal, be bonded with sensitive chip () 2 by biogum (4) on it, film square in sensitive chip (2) be positioned at shell (1) top breach under, are furnished with four pressure drag bars that resistance is identical on the film square of sensitive chip (2), four pressure drag bars consist of Wheatstone bridge, Wheatstone bridge by spun gold go between (3) be connected 5 with cable) connect, the voltage signal of bridge mains and output and pressure correlation is provided providing to sensor by cable (5), cable (5) offers subsequent conditioning circuit (6) with voltage signal and processes.

2. a kind of full-bridge implanted chip formula cranium pressure sensor according to claim 1, it is characterized in that: described sensitive chip (2) has adopted (100) crystal face silicon.

3. a kind of full-bridge implanted chip formula cranium pressure sensor according to claim 1 is characterized in that: four pressure drag bars on sensitive chip (2) along [110] and

The crystal orientation is arranged.

4. a kind of full-bridge implanted chip formula cranium pressure sensor according to claim 1, is characterized in that: the making of the thick twin polishing n type single crystal silicon of described sensitive chip (2) employing 250um sheet material.

Images