CN110148581A - A metal-semiconductor metallization process and method - Google Patents

Abstract

The invention belongs to the technical field of semiconductor device manufacturing, and in particular relates to a metallization process and a processing method for metal-semiconductor electrodes. The present invention provides a simple process and a corresponding processing method, which sequentially include: providing a semiconductor substrate, the semiconductor includes at least one PN junction, the PN junction structure can be a superimposed structure, and a surface of which has been attached Or mixed oxide thin layer, dielectric film layer; directly apply electrode material on one or both sides of the substrate by sputtering, deposition, electroplating, printing or implantation; for the positive and negative connections that need to be separated The electrodes are separated by corrosion to generate external positive and negative electrodes; the semiconductor material covered with the metal electrodes is heat-treated; finally, the metallization process is completed by implementing an ohmic contact method on the external electrodes.

Description

A metal-semiconductor metallization process and method

technical field

The invention belongs to the technical field of semiconductor device manufacturing, and specifically relates to a metal-semiconductor electrode metallization process and a technical processing method in the field of microelectronics manufacturing, semiconductor light-emitting devices, and photovoltaic solar cell manufacturing.

Background technique

An important process in the fabrication of semiconductor devices is to use metals or alloys to make contact electrodes with low electrical resistance. The metallization process of the electrode structure in the existing metal-semiconductor large-scale integrated circuit manufacturing process is cumbersome and requires an expensive photolithography mask process to selectively chemically corrode the passivation layer, clean it, and then sputter a metal thin film. High-temperature annealing and other processes are implemented, the process is complex, the cost is high, the electrode material formulation is difficult, and the sintering annealing is complicated; in order to improve the battery efficiency of common photovoltaic solar cells, the electrodes need special formulated metal electrode materials. The electrode material metallization process and the new multi-layer passivation film technology have strict requirements on the sintering process, especially the low-doped PN junction problem. . In addition, the natural oxide layer on the semiconductor surface at high temperature and the contamination of the device process will also significantly degrade the contact characteristics. These factors increase the manufacturing difficulty, cost, and defect rate of the conductive electrode material.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is as follows: a metallization process is provided, which can improve the electrode metallization process manufacturing process in the existing metal-semiconductor large-scale integrated circuit manufacturing process at low temperature. Some photolithography mask processes and selective chemical etching of passivation layers are used to reserve lead holes and cleaning processes, but metallization is completed by directly performing selective ohmic contact on the formed metal electrode-semiconductor; for existing light-emitting semiconductors In the manufacturing process of devices and photovoltaic solar cells, by introducing an additional low-temperature ohmic contact process, it is possible to further realize the low-temperature metallization process, reduce the process requirements of sintering temperature, reduce the occurrence of defects, and improve the output efficiency and yield of semiconductor devices.

The technical scheme that the present invention solves the above-mentioned technical problem is:

The first step is to provide a semiconductor substrate, the semiconductor includes at least one PN junction, the PN junction structure can be a series structure in the form of stacking, and one or mixed oxide thin layers, dielectric film layers have been attached to its surface. ;

Further, the thickness of the oxide thin layer and the dielectric film layer is in the range of 1 nm-200 nm, which can be on one side or both sides of the semiconductor material.

In the second step, the electrode material is directly applied to the surface of the substrate by evaporation, sputtering, deposition, electroplating, printing, implantation or filling;

Further, in complex metal oxide semiconductor (MOS) structures in large scale circuits, additional electrodes are deposited on the backside.

In the third step, the electrodes of the P region and the N region to be separated are separated by selective etching, and the electrodes of the semiconductor device that can be connected externally are formed.

The fourth step is to heat treatment the semiconductor material covered with the metal electrode;

Further, the required working temperature is 150 degrees Celsius to 800 degrees Celsius, and the process is to improve the adhesion between the conductive electrode material and the oxide thin layer, the dielectric layer, and the semiconductor material, and to reduce the bulk resistance of the metal electrode. The fifth step is to complete the metallization process by implementing the ohmic contact treatment method on the external positive and negative electrodes;

Further, the required working temperature is room temperature -400 degrees Celsius; the direct current of 1-100kA/cm2 is generated by the power supply or the induced current is injected into the metal electrode PN junction to achieve the purpose of ohmic contact, and its action time ranges from nanoseconds to seconds. ;

A further direct current injection method requires that a forward conduction current within a certain time range is directly applied to the external positive and negative electrodes of the PN junction region of the corresponding semiconductor device through a power supply to form a metal-semiconductor ohmic contact;

In addition, another method of induced current injection is to generate electrical conduction in the semiconductor material for a certain time range through an externally collimated or focused electron beam or light source, and to generate current through an external electrode and a power supply to form a metal-semiconductor in turn. Ohmic contact.

The beneficial effects of the present invention are:

The key point of the present invention is to provide a metal-semiconductor metallization process and a treatment method for different metals, different doping types and different concentrations of semiconductors, optoelectronic materials, and photovoltaic solar cell electrodes. Compared with the prior art, the process and method of the present invention are simple and effective, can be mutually compatible with the existing production process flow, quickly solve the poor contact encountered in metallization, and at the same time simplify the semiconductor lithography production process technology, the electrode sintering process, and simplify the implementation. Semiconductor integrated circuit fabrication, semiconductor light emitting device, photovoltaic solar cell, or integrated photovoltaic module fabrication provides one possible embodiment of metallization.

Description of drawings

Fig. 1 is the process flow diagram of the present invention;

Fig. 2 A simple structure of metal-semiconductor electrode ohmic contact mode;

FIG. 3 is an ohmic contact mode of a metal oxide semiconductor (MOS) structure;

FIG. 4 is an indirect ohmic contact method of a metal oxide semiconductor (MOS) structure;

Detailed ways

A metal-semiconductor metallization process and method: firstly, a substrate containing a semiconductor PN junction is provided, and an oxide or a dielectric film layer can be attached to its surface; the separation is formed by sequentially performing electrodes or corresponding selective etching. The positive and negative electrode structure devices; the subsequent sintering and annealing processes further improve the metallization process so that the electrode materials have good adhesion, low bulk resistance, and semiconductor preliminary devices with external connection capabilities, and finally pass the heater and ohmic contact method. To complete the final metallization process (see Figure 1 for the process flow, and Figure 2, 3, and 4 for the ohmic contact method).

The protection scope of the present invention will be further explained and illustrated by the following examples, but it is not intended to limit the protection scope of the present invention to the scope described in the examples.

Embodiment 1 adopts the process of the present invention for metal-silicon oxide-semiconductor electrode structure

A P-type single crystal silicon substrate, the front surface of which is N-type doped, 80-100nm of silicon nitride is deposited on the surface, the positive and negative electrode materials are implanted on the front and rear surfaces, respectively, after an annealing process at 800 degrees Celsius, and then through a direct current density of 75A/ About cm2, the temperature is 100 degrees Celsius, and the effective string resistance of the metal-silicon oxide-semiconductor is 0.01 ohm.

Example 2 Conducting electricity using the metal-silicon nitride-silicon oxide-semiconductor electrode structure in the process of the present invention

An N-type single crystal silicon substrate, the front surface of which is P-type doped, 80-100nm of silicon nitride is deposited on the surface, the positive and negative electrode materials are implanted on the front and back surfaces, respectively, after an annealing process at 700 degrees Celsius, and then an induced current density of 20kA/ About cm2, at room temperature, its metal-silicon oxide-semiconductor conduction effective series resistance reaches 3 milliohms.

Claims (8)

1. A metallization process for a metal-semiconductor comprising, The first step is to provide a semiconductor substrate, the semiconductor includes at least one PN junction, the PN junction structure can be a series structure in the form of stacking, and one or mixed oxide thin layers, dielectric film layers have been attached to its surface. ; In the second step, the electrode material is directly applied to the surface of the substrate by evaporation, sputtering, deposition, electroplating, printing, implantation or filling; In the third step, the electrodes of the P region and N region to be separated are separated by selective etching to form the electrodes of the semiconductor device that can be connected externally; The fourth step is to heat treatment the semiconductor material covered with the metal electrode; In the fifth step, the metallization process is completed by performing an ohmic contact treatment method on the external positive and negative electrodes. 2. The metallization process of metal-semiconductor according to claim 1, characterized in that the thickness of the oxide thin layer and the dielectric film layer in the first step is in the range of 1nm-200nm, which can be in the range of semiconductor material single-sided or double-sided. 3. The metallization process of metal-semiconductor as claimed in claim 1, characterized in that in the second step, the electrode material is directly applied on the surface of the substrate by sputtering, deposition, electroplating, printing or implantation ; For complex metal-oxide-semiconductor (MOS) structures in large-scale circuits, electrodes need to be deposited on the backside. 4. The metallization process of metal-semiconductor as claimed in claim 1, characterized in that in the third step, for the PN junction electrodes that need to be separated, a photolithography mask technology is used to select electrodes belonging to different PN junction regions. separated by corrosion; forming the external electrode required in step five. 5. The metallization process of metal-semiconductor as claimed in claim 1, characterized in that the required working temperature in the fourth step is 200 degrees Celsius-800 degrees Celsius, and the process is to improve the conductive electrode material and the oxide thin layer, The adhesion of dielectric layers, semiconductor materials, and the bulk resistance of metal electrodes are reduced. 6. The metallization process of metal-semiconductor as claimed in claim 1, wherein the heater (7) required in the fifth step provides a working temperature of room temperature-400 degrees Celsius; The direct current or induced current of 1-100kA/cm2 is injected into the metal electrode PN junction to achieve the purpose of ohmic contact, and its action time ranges from nanoseconds to seconds. 7. A direct current injection method as claimed in claim 6, characterized in that the external positive and negative electrodes (4), (5) of the PN junction region of the corresponding semiconductor device are connected by a power supply (6). A forward conducting current for an adjustable time is directly applied to form a metal-semiconductor ohmic contact. 8. An induced current injection method as claimed in claim 6, wherein the main feature is that through an external collimated or focused radiation source (8), namely an electron beam or a light source, a certain period of time is generated in the semiconductor material. Electricity is conducted, and current is generated through the external electrodes (4), (5) and the power supply (6) at the same time, and metal-semiconductor ohmic contact is formed in turn.