CN103438936A - Capacitive temperature, humidity and air pressure sensor integrated manufacturing method based on SOI chip device layer silicon anodic bonding - Google Patents

Abstract

The invention discloses an integrated manufacturing method of a capacitive temperature, humidity and air pressure sensor based on the silicon anode bonding of the SOI sheet device layer. Combining with combined technology, it can simultaneously prepare the thin film structure required by the integrated sensor, the flat large capacitor structure with a very small electrode gap, and the sealed cavity structure. It is characterized in that it realizes the integrated manufacturing of full capacitance sensitive temperature, humidity and air pressure sensors That is, a low-power integrated multi-sensor structure is realized. The invention can realize the on-chip integration of temperature, humidity and air pressure sensors, greatly reduces the area of the sensor integration structure, reduces the length of interconnection lines, and improves the reliability of the system.

Description

Integrated manufacturing method of capacitive temperature, humidity and air pressure sensors based on silicon anode bonding of SOI chip device layer

technical field

The invention relates to a manufacturing method of a sensor, in particular to an integrated manufacturing method of a capacitive temperature, humidity and air pressure sensor based on silicon anode bonding of an SOI sheet device layer.

Background technique

With the advancement of micromachining technology and the application requirements of miniature intelligent sensor systems, the integration of multiple sensors on a single chip will become a development trend. The on-chip integration methods of multiple sensors can be divided into two categories. The first category is that multiple sensors are manufactured separately and then integrated on the same substrate using multi-chip assembly technology. This type of technology is relatively mature and has been widely used. The advantage of multi-chip assembly technology is that the complexity of a single chip is reduced, so its research and development costs are reduced. The performance of the sensor integration system is difficult to break through. The second type is to directly integrate multiple sensors on a wafer. This method can overcome many shortcomings of multi-chip assembly technology. Its advantages include system size reduction, interconnection length reduction, reliability improvement, and mass production cost reduction. etc., and its disadvantage will be that the difficulty of research and development will increase, so the cost of research and development will increase.

Compared with integrated circuits, the integration of sensors is more difficult, because the working principles and structural solutions of different sensors are very different. From the perspective of working principle, some sensors are based on the principle of resistance sensitivity, and some sensors are based on the principle of capacitance sensitivity; from the perspective of structural scheme, some require special structures such as thin films, and some require special sensitive materials. Therefore, the integrated manufacturing of these sensors with different principles and structures requires the study of a set of specific processing methods.

Contents of the invention

Purpose of the invention: Aiming at the above-mentioned prior art, the present invention provides an integrated manufacturing method for capacitive temperature, humidity and air pressure sensors based on silicon anode bonding of the SOI chip device layer, so as to realize direct integrated manufacturing of various sensors on a wafer.

Technical solution: An integrated manufacturing method for capacitive temperature, humidity and air pressure sensors based on silicon anodic bonding of the SOI device layer. This method is realized based on the SOI device layer silicon and a glass substrate. Substrate silicon, buried oxide layer, and device layer silicon are arranged in sequence; using step-by-step deep silicon etching technology and the combination of SOI device layer silicon and glass anodic bonding technology, the thin film structure, flat large capacitor structure and Sealing the cavity structure to finally form an integrated structure of a humidity sensor, an air pressure sensor and a temperature sensor; the method includes the following steps:

Step 1), dry etching the silicon of the device layer, controlling the etching depth to obtain the silicon film structure of the air pressure sensor and the temperature sensor respectively; using ion implantation technology to reduce the resistivity of the silicon of the device layer, generating a dielectric layer and etching The dielectric strain layer of the humidity sensor, temperature sensor and air pressure sensor is obtained; the device layer silicon is etched through the dry method to obtain the comb tooth capacitance structure of the humidity sensor and the cantilever beam structure of the temperature sensor, and the humidity sensor, air pressure sensor and pressure sensor are obtained at the same time. slots in which the temperature sensors are electrically isolated from each other;

Step 2), depositing and corroding patterns on the surface of the dielectric strain layer of the temperature sensor to obtain a temperature-sensitive metal layer of the temperature sensor;

Step 3), depositing a metal layer on the glass substrate and corroding the pattern to obtain the electrodes of the humidity sensor, air pressure sensor and temperature sensor; coating the humidity sensitive material on the electrode surface of the humidity sensor and corroding the pattern to obtain the humidity sensor Moisture sensing layer; then depositing a metal layer on the surface of the humidity sensing layer of the humidity sensor and corroding the pattern to obtain the upper electrode of the humidity sensor;

Step 4), performing anodic bonding of the SOI device layer silicon and the glass substrate to obtain a sealed bonding surface, and forming a sealed cavity for the air pressure sensor;

Step 5), etching the SOI substrate silicon and the release structure of the buried oxide layer of the SOI sheet to obtain the final humidity sensor, air pressure sensor and temperature sensor.

Beneficial effects: (1) The present invention can realize the on-chip integration of temperature, humidity and air pressure sensors. Compared with the assembly of discrete devices, the area of the integrated system is greatly reduced, the length of the interconnection line is reduced, and the reliability of the system is improved;

(2) The present invention utilizes the step-by-step deep silicon etching technology and the combination of SOI sheet device layer silicon and glass anode bonding technology to simultaneously prepare the thin film structure required by the integrated sensor, the flat plate large capacitance structure with a very small electrode gap, and the sealing Cavity structure;

(3) The present invention realizes the on-chip integration of full capacitance sensitive temperature, humidity and air pressure sensor, the capacitance sensitive sensor has no DC power consumption, and only needs to use AC small signal during capacitance measurement, so temperature, humidity and air pressure sensor integrated structure Very low power consumption.

Description of drawings

Fig. 1 is a schematic diagram of the structure after etching, ion implantation and etching of the silicon of the SOI sheet device layer;

Fig. 2 is a schematic diagram of the structure after the corrosion of the insulating dielectric layer and the metal layer;

Fig. 3 is a schematic diagram of the structure of the metal layer on the glass, the moisture-sensitive material and the metal layer after corrosion;

Fig. 4 is a schematic diagram of the structure after anodic bonding of silicon on the SOI sheet device layer and glass;

Fig. 5 is a schematic diagram of the structure of temperature, humidity and air pressure sensors obtained after the silicon of the SOI sheet substrate and the buried oxide layer are corroded;

Fig. 6 is a top view of three sensor structures obtained by this method.

Detailed ways

The present invention will be further explained below in conjunction with the accompanying drawings.

An integrated manufacturing method for capacitive temperature, humidity and air pressure sensors based on silicon anodic bonding of SOI device layers. The method is realized based on SOI device layer silicon and glass substrate 6. The set substrate silicon 1, the buried oxide layer 2, and the device layer silicon 3 are composed. Using the step-by-step deep silicon etching technology and the combination of SOI device layer silicon and glass anode bonding technology, the thin film structure, the flat large capacitance structure and the sealed cavity structure of the air pressure sensor and temperature sensor are prepared at the same time, and finally the humidity sensor and air pressure sensor are formed. Sensor and temperature sensor integrated structure. The method comprises the steps of:

Step 1), as shown in Figure 1, dry etching the device layer silicon 3, controlling the etching depth to obtain the silicon film structure 31 of the air pressure sensor and the temperature sensor respectively; using ion implantation technology to reduce the resistivity of the device layer silicon 3 , generate a dielectric layer and etch the pattern to obtain the dielectric strain layer 4 of the humidity sensor, temperature sensor and air pressure sensor; then use dry etching to etch through the device layer silicon 3 to obtain the comb-tooth capacitance structure of the humidity sensor and the cantilever beam of the temperature sensor structure, and simultaneously obtain the groove 32 in which the humidity sensor, the air pressure sensor and the temperature sensor are electrically isolated from each other;

Step 2), as shown in Figure 2, deposit and corrode the plate shape pattern of the temperature sensor on the surface of the dielectric strain layer 4 of the temperature sensor, to obtain the temperature-sensitive metal layer 5 of the temperature sensor;

Step 3), as shown in Figure 3, deposit metal layer on glass substrate 6 and corrode pattern and obtain the electrode 7 of humidity sensor, air pressure sensor and temperature sensor; Coat humidity sensitive material on the electrode 7 surface of humidity sensor again and Corrosion pattern obtains the moisture-sensitive layer 8 of humidity sensor; Then deposits metal layer on the surface of the moisture-sensitive layer 8 of humidity sensor and corrodes pattern to obtain the upper electrode 9 of humidity sensor; Wherein, moisture-sensitive material can adopt polyimide, porous silicon.

Step 4), as shown in FIG. 4, anodic bonding of the SOI device layer silicon 3 and the glass substrate 6 to obtain a sealed bonding surface 10, and to form a sealed cavity of the air pressure sensor;

Step 5), as shown in FIG. 5 , etch the release structure of the SOI substrate silicon 1 and the SOI buried oxide layer 2 to obtain the final humidity sensor 11 , air pressure sensor 12 and temperature sensor 13 , as shown in FIG. 6 .

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (1)

1. The capacitive temperature, humidity and air pressure sensor integrated manufacturing method based on SOI sheet device layer silicon anode bonding, it is characterized in that: the method realizes based on SOI sheet device layer silicon and glass substrate (6), and described SOI sheet device The silicon layer is composed of substrate silicon (1), buried oxide layer (2), and device layer silicon (3) arranged in sequence from top to bottom; using step-by-step deep silicon etching technology and SOI sheet device layer silicon and glass anode bond Combined with combined technology, the thin film structure, flat large capacitor structure and sealed cavity structure are prepared at the same time, and finally the integrated structure of humidity sensor, air pressure sensor and temperature sensor is formed; the method includes the following steps: Step 1), dry etching the device layer silicon (3), controlling the etching depth to obtain the silicon film structure (31) of the air pressure sensor and the temperature sensor respectively; using ion implantation technology to reduce the thickness of the device layer silicon (3) Resistivity, generate a dielectric layer and etch the pattern to obtain the dielectric strain layer (4) of the humidity sensor, temperature sensor and air pressure sensor; use dry etching to etch through the device layer silicon (3) to obtain the comb tooth capacitance structure of the humidity sensor and The cantilever beam structure of the temperature sensor simultaneously obtains the groove (32) that the humidity sensor, the air pressure sensor and the temperature sensor are electrically isolated from each other; Step 2), depositing and corroding patterns on the surface of the dielectric strain layer (4) of the temperature sensor to obtain the temperature-sensitive metal layer (5) of the temperature sensor; Step 3), deposit metal layer on described glass substrate (6) and corrode pattern and obtain the electrode (7) of humidity sensor, air pressure sensor and temperature sensor; Coat the electrode (7) surface of described humidity sensor with wet Sensitive material and corroding pattern obtains the moisture-sensitive layer (8) of humidity sensor; Then deposits metal layer on the surface of the moisture-sensitive layer (8) of described humidity sensor and corrodes pattern and obtains the upper electrode (9) of humidity sensor; Step 4), performing anodic bonding of the SOI device layer silicon (3) and the glass substrate (6) to obtain a sealed bonding surface (10), and forming a sealed cavity for an air pressure sensor; Step 5), corroding the SOI sheet substrate silicon (1) and the release structure of the SOI sheet oxide buried layer (2), to obtain the final humidity sensor (11), air pressure sensor (12) and temperature sensor (13).

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