阅读说明：本技术 开孔晶圆上感光结构层的均匀曝光方法 (Uniform exposure method for photosensitive structure layer on perforated wafer ) 是由 葛凯伦 陈学诣 于 2020-12-30 设计创作，主要内容包括：本发明涉及一种开孔晶圆上感光结构层的均匀曝光方法,根据感光结构层中不同曝光能量需求的区域数量,配合光罩的形状,对感光结构层中的高曝光能量区域进行叠加曝光,使得感光结构层中不同曝光能量需求区域的曝光能量累计达到设定的曝光能量值。该开孔晶圆上感光结构层的均匀曝光方法,满足对不同曝光能量区域的需求能量的曝光操作,有效避免因晶圆局部区域曝光能量需求不同而产生的制程不良,解决一次曝光能量调整的工艺难度。在此基础上,还解决不同曝光能量区域交界处能量过度不平滑的问题,提高生产效率。该开孔晶圆的均匀曝光方法加工的产品良率高,产品品质好。(The invention relates to a uniform exposure method of a photosensitive structure layer on a perforated wafer, which is characterized in that according to the number of areas with different exposure energy requirements in the photosensitive structure layer, the overlapping exposure is carried out on areas with high exposure energy in the photosensitive structure layer by matching with the shape of a photomask, so that the accumulated exposure energy of the areas with different exposure energy requirements in the photosensitive structure layer reaches a set exposure energy value. The uniform exposure method of the photosensitive structure layer on the perforated wafer meets the exposure operation of the required energy of different exposure energy areas, effectively avoids poor manufacturing process caused by different exposure energy requirements of local areas of the wafer, and solves the process difficulty of one-time exposure energy adjustment. On the basis, the problem that the energy at the junction of different exposure energy areas is excessive and unsmooth is solved, and the production efficiency is improved. The uniform exposure method for the perforated wafer has the advantages of high product yield and good product quality.)

1. A uniform exposure method for a photosensitive structure layer on a perforated wafer is characterized in that: according to the number of areas with different exposure energy requirements in the photosensitive structure layer and the shape of the photomask (2), overlapping exposure is carried out on the areas with high exposure energy in the photosensitive structure layer, so that the accumulated exposure energy of the areas with different exposure energy requirements in the photosensitive structure layer reaches a set exposure energy value.

2. The method of claim 1, further comprising the step of uniformly exposing the photosensitive structure layer on the open-hole wafer: aiming at areas with different exposure energy requirements of the photosensitive structure layer, the photosensitive structure layer is divided into A1, A2, … …, Ai and … … An according to the sequence of exposure energy from small to large, and the exposure energy requirement corresponding to the area Ai is Qi; wherein i and n are positive integers, i is more than or equal to 1 and less than or equal to n, and n is more than or equal to 2;

sequentially carrying out n groups of exposure operations; when the ith group of exposure operations are carried out, a mask (2) is used for shielding a region corresponding to energy smaller than Qi, and the exposure energy value Q in the group of exposure operations is Qi-Qz, when i is 1, Qz is 0, and when i is more than 1, Qz is Qi-1.

3. The method as claimed in claim 2, wherein the step of uniformly exposing the photosensitive structure layer on the wafer comprises: when a group of exposure operations are carried out on a slot etching area Qk which needs to carry out slot etching on the photosensitive structure layer, controlling to carry out at least two exposure operations, wherein the sum of the exposure energy of each exposure operation is the exposure energy value corresponding to the group of exposure operations; and in each exposure operation, the area of the photomask (2) covering the groove hole etching area Qk is controlled and changed according to the set offset.

Technical Field

The invention relates to a uniform exposure method of a photosensitive structure layer on a perforated wafer.

Background

In the field of printing equipment, the mainstream of the inkjet printer can be divided into a laser printer and an inkjet printer, and the inkjet printer is subdivided into the mainstream nozzle technical directions of thermal bubble, piezoelectric, continuous and the like according to different adopted nozzle technologies. In the development process of the inkjet printer, the transition from the traditional machining technology to the high-precision micro-electro-mechanical system (MEMS) technology has begun, and the core technology of the current inkjet printer is the micro-electro-mechanical chip of the micro-fluid precise multicolor control technology.

In the production of micro-electromechanical chips by micro-fluid precise multicolor control technology, semiconductor chip process technology and MEMS technology are applied at the same time. When the micro-electro-mechanical chip is applied to a printer, compared with a traditional semiconductor chip, due to the fact that sufficient space needs to be reserved for ink flowing in the chip, etching perforation needs to be conducted in the chip, namely, a wafer is etched and penetrated from the front face to the back face, and an ink flow channel is formed by the etched perforation structure. Therefore, in the process of manufacturing the semiconductor MEMS by ink-jet printing, the structure layer is required to be formed by coating, exposing, and developing the photoresist on the wafer with the through hole and the metal circuit substrate, so as to form the structure shown in fig. 1. In the structure of fig. 1, two photosensitive structure layers are fabricated on a wafer substrate having an ink channel opening, wherein the upper layer of the structure is required to cover the opening portion on the wafer, thereby forming a cavity of the ink channel. In order to ensure the ink-jet effect, the inside and the surface of the upper photosensitive structure layer are required to be smooth and flat, so that the flow of liquid in the cavity is facilitated. Because of the particularity that the MEMS chip needs to manufacture a cavity type three-dimensional structure on a wafer with an opening, the MEMS chip is different from the traditional semiconductor which only needs to carry out photosensitive material coating, exposure and development on a flat wafer substrate to manufacture a plane two-dimensional structure, and the MEMS chip structure can be poor in development caused by insufficient exposure energy or overhigh energy in the manufacturing process. Specifically, when the upper photosensitive structure layer is manufactured, the inner surface of the upper photosensitive structure layer corresponding to the opening portion of the wafer may be etched by the inflow developing solution to form a pit due to insufficient exposure energy, and the surface becomes uneven to affect the liquid flow, as shown in fig. 2. However, if the exposure energy is increased, although the etching pits in the cavity are improved, the exposure energy is too strong, so that the edge of the structure to be etched in the upper photosensitive structure layer is jagged or incompletely developed, which results in losing the original etching shape, as shown in fig. 3.

The above problems are caused by two main reasons: first, the light intensity energy received by the photosensitive layer from top to bottom is gradually attenuated and reduced, because of the through hole on the wafer substrate, the light source directly penetrates the wafer when exposing in the through hole area, and the light source directly irradiates the substrate on the wafer surface to generate reflected light to expose the photosensitive film again in other areas, therefore, under the condition of good energy uniformity of the exposure machine, the exposure energy of the actual area is not uniform when exposing. Secondly, due to the particularity of the MEMS three-dimensional cavity structure, the developing solution can enter the cavity to contact the inner surface of the upper photosensitive structure layer, and the photosensitive film can be etched under the condition of insufficient exposure energy. And in other areas, because the other areas are closely contacted with the upper photosensitive structure layer and the lower photosensitive structure layer, no developing solution enters, and therefore, no etching is generated.

In the prior art, exposure operation with different energies is respectively carried out on areas needing different exposure energies, and when the operation is carried out, the problem of overlapping of the peripheries of the areas with different exposure energies is inevitable, so that the overlapping of the exposure energies of two times occurs at the junctions of the areas with different exposure energies, and then the microstructure is changed, steps are generated, the performance and the strength of the whole structure are influenced, the quality performance of products is reduced, and meanwhile, the yield of the products is improved.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a uniform exposure method for a photosensitive structure layer on a holed wafer, which can meet the requirement of performing exposure operation with corresponding energy on different exposure energy areas, and can avoid the unsmooth transition at the junction of the different exposure energy areas.

The technical scheme adopted by the invention for solving the problems is as follows: a method for uniformly exposing a wafer with holes is characterized in that: according to the number of areas with different exposure energy requirements in the photosensitive structure layer and the shape of the photomask, overlapping exposure is carried out on the high exposure energy areas in the photosensitive structure layer, so that the accumulated exposure energy of the areas with different exposure energy requirements in the photosensitive structure layer reaches a set exposure energy value.

Preferably, for regions of the photosensitive structure layer with different exposure energy requirements, the photosensitive structure layer is divided into a1, a2, … …, Ai and … … An according to the sequence of exposure energy from small to large, and the exposure energy requirement corresponding to the region Ai is Qi; wherein i and n are positive integers, i is more than or equal to 1 and less than or equal to n, and n is more than or equal to 2;

sequentially carrying out n groups of exposure operations; when the ith group of exposure operations are carried out, a region corresponding to the energy less than Qi is shielded by a photomask, and the exposure energy value Q in the group of exposure operations is Qi-Qz, when i is 1, Qz is 0, and when i is more than 1, Qz is Qi-1.

In order to improve the verticality of the etched groove hole side wall, when a group of exposure operations are carried out on a groove hole etching area Qk which needs to carry out groove hole etching on a photosensitive structure layer, at least two times of exposure operations are controlled to be carried out, and the sum of the exposure energy of each time of exposure operation is the exposure energy value corresponding to the group of exposure operations; and in each exposure operation, the area of the mask covering the groove hole etching area Qk is controlled and changed according to the set offset.

Compared with the prior art, the invention has the advantages that: according to the uniform exposure method for the photosensitive structure layer on the perforated wafer, different photomasks are replaced, and then exposure of a high-energy demand area is achieved in an energy superposition mode, so that exposure operation of different exposure energy areas with demand energy is met, poor manufacturing procedures caused by different exposure energy demands of local areas of the wafer are effectively avoided, and the process difficulty of one-time exposure energy adjustment is solved. On the basis, the problem that the energy at the junction of different exposure energy areas is excessive and unsmooth is solved, and the production efficiency is improved. The uniform exposure method for the perforated wafer effectively solves the problem of etching pits generated on the lower surface of the photosensitive structure layer corresponding to the position of the perforated wafer due to insufficient exposure energy, improves the product yield, and meanwhile, can enable the surface of the photosensitive structure layer to be smoother, and improves the product quality.

Drawings

FIG. 1 is a diagram of a wafer product in the prior art.

FIG. 2 is a diagram of a wafer product with etching pits in the prior art.

Fig. 3 is a structural diagram of a wafer product with incomplete development problem in the prior art.

FIG. 4 is a distribution diagram of different exposure energy requirement regions of a photosensitive structure layer according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating an exposure process for an open-pore wafer product according to an embodiment of the present invention.

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.

The uniform exposure method for the photosensitive structure layer on the open-pore wafer in this embodiment can be applied to various semiconductor processes using the open-pore wafer 1 as the substrate.

In the exposure process, a photosensitive structure layer is usually formed by using a photoresist, and a desired structure layer is formed on the wafer 1 through exposure and development operations of the photoresist. When exposure is carried out, a photomask with a required shape is placed above the photosensitive structure layer, ultraviolet light emitted by a light source of the exposure machine irradiates the photosensitive material layer through the notch part on the photomask, and the photosensitive material layer absorbs the energy of the ultraviolet light, so that a designed structure is processed on the wafer 1.

As the uv light propagates through the photoresist, the intensity of the uv light is gradually attenuated, which is related to the light absorption coefficient of the photoresist to the uv light. According to the Lambert empirical law, the light energy is gradually reduced from top to bottom, when the exposure energy is insufficient, the bottom crosslinking reaction of the photosensitive structure layer is insufficient, the photosensitive structure layer is easily etched by the developing solution during development, a pot hole can be formed at the bottom of the photosensitive structure layer, and meanwhile, the bonding part bonded with the material at the bottom of the photosensitive structure layer is easily etched and enters by the developing solution in the lateral direction, so that the adhesive force of the photosensitive structure layer is reduced.

Because the upper surface of the substrate of the wafer 1 is generally a metal layer or an insulating protective layer, during exposure, light rays irradiate the surface of the wafer 1 to generate reflected light, and therefore, in the process of exposure operation, because the pattern of the circuit layer is arranged on the substrate, the light from the exposure area is reflected by different materials of the pattern on the surface of the substrate wafer 1, so that the photosensitive structure layer is subjected to secondary exposure of the reflected light, and the exposure energy required by different areas of the photosensitive structure layer is different. In addition, a light diffraction phenomenon is generated during the exposure operation, and is a representation of the fluctuation of light, when the light passes through an obstacle in the propagation process, such as an edge, a small hole, a thin line, a slit and the like of an opaque object, a part of the light is propagated to a geometric shadow, so that the diffraction phenomenon is generated. The light diffraction in the exposure operation can make the figure edge obtain more energy, causes the expansion of figure on the edge, and when the exposure energy was too strong, the diffraction light intensity was also stronger, leads to originally being sheltered from the regional exposure by the light shield, takes place the cross-linking reaction, can't get rid of cleanly during development, causes the development badly. The Fresnel diffraction causes the edge of the pattern to obtain more energy to cause the expansion of the pattern on the edge, and on the other hand, the expansion of the photoresist serving as the photosensitive structure layer in a developer also causes the expansion of the photoresist pattern. In the case of a fixed photoresist material, thickness, and ultraviolet wavelength, the larger the illumination energy, the larger the offset of the pattern, and the smaller the inclination angle of the sidewall, and the exposure energy needs to be controlled to obtain a pattern that is close to the mask pattern and is perpendicular to the sidewall.

In the uniform exposure method for the photosensitive structure layer on the holed wafer in this embodiment, the high exposure energy regions in the photosensitive structure layer are subjected to the overlay exposure according to the number of the regions with different exposure energy requirements in the photosensitive structure layer and the shape of the photomask 2, so that the exposure energy accumulation of the regions with different exposure energy requirements in the photosensitive structure layer reaches the set exposure energy value.

Specifically, aiming at areas with different exposure energy requirements of the photosensitive structure layer, the photosensitive structure layer is divided into A1, A2, … …, Ai and … … An according to the sequence of exposure energy from small to large, and the exposure energy requirement corresponding to the area Ai is Qi; wherein i and n are positive integers, i is more than or equal to 1 and less than or equal to n, and n is more than or equal to 2.

Sequentially carrying out n groups of exposure operations; when the i-th exposure operation is performed, the mask 2 is used to mask the region corresponding to the energy less than Qi, and the exposure energy value Q in the exposure operation is Qi-Qz, where Qz is 0 when i is 1 and Qz is Qi-1 when i > 1.

At least two exposure operations can be performed in each set of exposure operation process as required to ensure the quality of the final product. Based on the aforementioned diffraction of light during the exposure operation, the diffraction of light is likely to occur during the exposure operation of the slot pattern on the photosensitive structure layer, which further affects the quality of the finally formed slot sidewall. When a group of exposure operations are carried out on the slot etching area Qk which needs to carry out slot etching on the photosensitive structure layer, controlling to carry out at least two exposure operations, wherein the sum of the exposure energy of each exposure operation is the exposure energy value corresponding to the group of exposure operations; and in each exposure operation, the area of the mask 2 covering the groove etching area Qk is controlled and changed according to the set offset.

As shown in fig. 4, in the semiconductor manufacturing using the holed wafer 1 as a substrate, when the holed wafer 1 is used to prepare the microstructure on the uppermost photosensitive structure layer, due to the holed structure in the wafer 1, the photosensitive structure layer has two regions with different exposure energy requirements, which are a region X corresponding to the holed portion of the wafer 1 and a region Y excluding the slot etching region Qk, where the exposure energy required by the region X is greater than the exposure energy of the region Y. Thus, area X is partitioned into a1 and area Y is partitioned into a 2.

As shown in fig. 5, two exposure operations are required to be performed on the uppermost photosensitive structure layer of the holed wafer 1, the active areas in the first exposure operation are a1 and a2, and since the hole etching area Qk required to perform the hole etching is included, in this embodiment, two exposure operations are controlled to ensure the perpendicularity of the etched hole sidewall. In the second set of exposure operations, only one exposure operation is required, and the active area of the exposure operation is a 1.

The exposure energy value of the first group of exposure operations is Q1, the exposure energies corresponding to two exposure operations in the first group of exposure operations in the present embodiment are Q11 and Q12, respectively, and Q11+ Q12 is Q1. In order to improve the preparation quality, the values of Q11 and Q12 are close. As shown in FIG. 4, the mask 2 used in the two exposure operations has different areas, so as to reduce the offset of the processed slot pattern and obtain a more vertical sidewall, and the offset of the processed slot pattern can be smaller than 1 um.

According to the uniform exposure method of the photosensitive structure layer on the perforated wafer, different photomasks 2 are replaced, and then exposure of a high-energy demand area is achieved in an energy superposition mode, so that exposure operation of the demand energy of different exposure energy areas is met, poor manufacturing procedures caused by different exposure energy demands of local areas of the wafer 1 are effectively avoided, and the process difficulty of one-time exposure energy adjustment is solved. On the basis, the problem that the energy at the junction of different exposure energy areas is excessive and unsmooth is solved, and the production efficiency is improved. The uniform exposure method for the perforated wafer 1 effectively solves the problem of etching pits generated due to insufficient exposure energy on the lower surface of the photosensitive structure layer corresponding to the perforated position of the wafer 1, improves the product yield, and meanwhile, can enable the surface of the photosensitive structure layer to be smoother, and improves the product quality.