METHOD FOR MANUFACTURING HIGH-DENSITY THREE-DIMENSIONAL PROGRAMMABLE MEMORY

Abstract

A method for manufacturing a high-density three-dimensional programmable memory, relating to the memory manufacturing technology, comprises the following steps: 1) forming a base structure; 2) grooving the base structure; 3) disposing, storage medium layers required by a preset memory structure layer by layer on an inner wall of the division groove; 4) filling a core medium in the division groove to form a core medium layer; 5) etching, through a mask etching process, to form deep holes along the separation division groove filled with the core where the deep holes truncate the core medium in the division groove; and 6) filling an insulation medium in the deep holes. The method has the beneficial effects of low costs and the highest storage density.

Claims

1. A method for manufacturing a high-density three-dimensional programmable memory, comprising: step 1: forming a base structure, wherein a predetermined number of conductive medium layers and a predetermined number of insulating medium layers are disposed in such a manner that the conductive medium layers and the insulating medium layers are alternately stacked on each other, to form the base structure; step 2: grooving the base structure, wherein the base structure is grooved to form a curved division groove penetrating from a top layer to a bottom layer on the base structure, so that the division groove divides the base structure into two interdigitated structures that are staggered and separated from each other; step 3: disposing storage medium layers required by a preset memory structure layer by layer on an inner wall of the division groove; step 4: filling a core medium in the division groove to form a core medium layer; step 5: etching, through a mask etching process, to form deep holes along the division groove filled with the core medium, wherein the deep holes truncate the core medium in the division groove, to form a predetermined number of core medium blocks that are distributed along a long-side direction of the division groove and that are independent of each other, and each core medium block is still connected to the two interdigitated structures through the storage medium layer; and step 6: filling an insulating medium in the deep holes formed by etching in step 5.

2. The method for manufacturing the high-density three-dimensional programmable memory according to claim 1, wherein in step 3, the preset memory structure is one of the following structures: a PN junction semiconductor memory structure, a Schottky semiconductor memory structure, a resistance change memory structure, a magnetic phase change memory structure, a phase change memory structure, and a ferroelectric memory structure.

3. The method for manufacturing the high-density three-dimensional programmable memory according to claim 1, wherein the preset memory structure is a PN junction semiconductor memory structure, comprising a P-type conductive region, an N-type conductive region, and an insulating medium region disposed therebetween; the conductive medium layer is a P-type semiconductor, and the core medium layer is an N-type semiconductor; or the conductive medium layer is an N-type semiconductor, and the core medium layer is a P-type semiconductor; and step 3 comprises: step 3.1: disposing an insulating layer in the division groove.

4. The method for manufacturing the high-density three-dimensional programmable memory according to claim 1, wherein the preset memory structure is a Schottky diode memory structure, comprising a semiconductor conductive region, a metal conductive region, and an insulating medium region disposed therebetween; the conductive medium layer is a semiconductor required for forming a Schottky diode structure, and the core medium layer is metal required for forming the Schottky diode structure; or the conductive medium layer is metal required for forming the Schottky diode structure, and the core medium layer is a semiconductor required for forming the Schottky diode structure; and step 3 comprises: step 3.1: disposing an insulating layer in the division groove.

5. The method for manufacturing the high-density three-dimensional programmable memory according to claim 1, wherein the preset memory structure is a memory-medium memory structure, and the memory-medium memory is any one of a resistance change memory structure, a magnetic phase change memory structure, a phase change memory structure, and a ferroelectric memory structure; materials of the conductive medium layer and the core medium layer are both metal or polycrystalline silicon; and step 3 comprises: step 3.1: disposing a memory medium layer in the division groove.

6. The method for manufacturing the high-density three-dimensional programmable memory according to claim 1, wherein the preset memory structure is a PN junction semiconductor memory structure, comprising a P-type conductive region, an N-type conductive region, and an insulating medium region disposed therebetween; the conductive medium layer is a P+-type semiconductor, and the core medium layer is an N+-type semiconductor or conductor; and step 3 comprises: step 3.1: disposing an insulating layer in the division groove; step 3.2: disposing a lightly-doped N-type semiconductor layer on an inner wall of the insulating layer; and step 3.3: filling the core medium in a cavity of the division groove provided with the insulating layer and the lightly-doped N-type semiconductor layer.

7. The method for manufacturing the high-density three-dimensional programmable memory according to claim 1, wherein the preset memory structure is a PN junction semiconductor memory structure, comprising a P-type conductive region, an N-type conductive region, and an insulating medium region disposed therebetween; the conductive medium layer is an N+-type semiconductor or conductor, and the core medium layer is a P+-type semiconductor; and step 3 comprises: step 3.1: disposing a lightly-doped N-type semiconductor layer in the division groove; step 3.2: disposing an insulating layer on an inner wall of the lightly-doped N-type semiconductor layer; and step 3.3: filling the core medium in a cavity of the division groove provided with the lightly-doped N-type semiconductor layer and the insulating layer.

8. The method for manufacturing the high-density three-dimensional programmable memory according to claim 1, wherein the preset memory structure is a Schottky semiconductor memory structure, comprising a metal conductive region, a semiconductor conductive region, and an insulating medium region disposed therebetween; step 3 comprises: step 3.1: disposing an insulating layer in the division groove; step 3.2: disposing a semiconductor layer on an inner wall of the insulating layer; and step 3.3: filling the core medium in a cavity of the division groove provided with the insulating layer and the conductor layer; and the conductive medium layer is metal required for a Schottky diode, the semiconductor layer is a semiconductor required for a Schottky diode, and the core medium layer is a conductor.

9. The method for manufacturing the high-density three-dimensional programmable memory according to claim 1, further comprising a step of penetrating through the storage medium layers in a bottom region of the division groove, wherein the step of penetrating through the storage medium layers in the bottom region of the division groove comprises: after performing step 3, etching each storage medium layer in the bottom region of the division groove until the base structure is penetrated through, or the step of penetrating through the storage medium layer in the bottom region of the division groove comprises: after performing step 6, applying power to the filled medium and an underlying circuit, to break down each storage medium layer in the bottom region of the division groove.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0063] FIG. 1 is a schematic perspective view of a base structure disposed on a substrate and an underlying circuit;

[0064] FIG. 2 is a schematic perspective view of a base structure;

[0065] FIG. 3 is a schematic top view of a prototype structure of the present disclosure;

[0066] FIG. 4 is a schematic front view of a prototype structure of the present disclosure;

[0067] FIG. 5 is a schematic top view of a prototype structure obtained after step 2 of the present disclosure;

[0068] FIG. 6 is a schematic cross-sectional view of a prototype structure obtained after step 2 along an A-A′ direction;

[0069] FIG. 7 is a schematic top view of a prototype structure obtained after step 3 of the present disclosure;

[0070] FIG. 8 is a schematic cross-sectional view of a prototype structure obtained after step 3 along an A-A′ direction;

[0071] FIG. 9 is a schematic cross-sectional view of a prototype structure processed through etching penetration along an A-A′ direction;

[0072] FIG. 10 is a schematic top view of a prototype structure obtained after step 4;

[0073] FIG. 11 is a schematic cross-sectional view of a prototype structure obtained after step 4 along an A-A′ direction;

[0074] FIG. 12 is a schematic top view of a prototype structure obtained after step 5;

[0075] FIG. 13 is a schematic top view of a prototype structure obtained after step 6;

[0076] FIG. 14 is a schematic structure diagram of a memory of a first embodiment;

[0077] FIG. 15 is a schematic structure diagram of a memory of a second embodiment; and

[0078] FIG. 16 is FIG. 11 of a disclosure of Chinese Patent No. 201910136928.1.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0079] A method for manufacturing a high-density three-dimensional programmable memory includes steps 1-6:

[0080] Step 1: a base structure is formed. A predetermined number of conductive medium layers and a predetermined number of insulating medium layers are disposed in such a manner that the conductive medium layers and the insulating medium layers are alternately stacked on each other, to form the base structure, as shown in FIG. 1 to FIG. 4. In an actual process, the base structure is disposed on a substrate and an underlying circuit, as shown in FIG. 1 and FIG. 4. In FIG. 4, 41 is a conductive medium layer and 42 is an insulating medium layer; or 42 is the conductive medium layer and 41 is the insulating medium layer, 43 is the underlying circuit, and 44 is the substrate.

[0081] Step 2: the base structure is grooved. The base structure is grooved to form a curved division groove penetrating from a top layer to a bottom layer on the base structure, so that the division groove divides the base structure into two interdigitated structures that are staggered and separated from each other, as shown in FIG. 5 and FIG. 6. FIG. 6 is a schematic cross-sectional view of FIG. 5 along an A-A′ direction.

[0082] Step 3: storage medium layers required for a preset memory structure are disposed layer by layer on an inner wall of the division groove, as shown in FIG. 7 and FIG. 8. In the step, a bottom storage medium region is formed in a bottom region of the division groove after deposition via a deposition process, and the bottom storage medium region insulates a core medium in the subsequent step from the underlying circuit. Therefore, a “penetration” step is required to form conductive connection between a core medium layer and the underlying circuit.

[0083] As a first penetration method, after step 3 and before step 4, a penetration step may etch the storage medium region in the bottom region to form through holes (referring to FIG. 9), so that the core medium filled in step 4 can be in direct contact with the underlying circuit. Alternatively, after step 6, electricity is applied to the core medium and the underlying circuit, to break down the bottom storage medium region, to form a conductive connection, that is, a second penetration method.

[0084] Step 4: the core medium is filled in the division groove to form the core medium layer, as shown in FIG. 10 and FIG. 11.

[0085] Step 5: through a mask etching process, deep holes are etched along the division groove filled with the core medium, where the deep holes truncate the core medium and the storage medium in the division groove, to form multiple core medium blocks that are distributed along the long-side direction of the division groove and that are independent of each other, and each core medium block is still connected to the two interdigitated structures through the storage medium layer, as shown in FIG. 12.

[0086] Step 6: an insulating medium is filled in the deep holes etched in step 5, as shown in FIG. 13.

[0087] In step 3, the preset memory structure is one of the following structures:

[0088] a PN junction semiconductor memory structure, a Schottky semiconductor memory structure, a resistance change memory structure, a magnetic phase change memory structure, a phase change memory structure, and a ferroelectric memory structure.

[0089] A PN junction semiconductor memory structure shown in FIG. 15 is used as an example, and includes a P-type conductive region, an N-type conductive region, and an insulating medium region disposed therebetween. In the present disclosure, storage medium layers are grown layer by layer in the order of “P-type conductive region-insulating medium region-N-type conductive region”. When the conductive medium layer of the base structure is made of a P-type conductive material, there is no need to provide a P-type semiconductor again, and the core medium is an N-type semiconductor. In the manufacturing process of this embodiment, the storage medium layer in step 3 is the insulating medium layer, as shown in FIG. 15.

[0090] Various storage medium layers disposed in the division groove may be a part of structure layers forming the memory, or may be all structure layers forming the memory, which depends on a type of a material of the conductive medium layer in the base structure and that of a material of the core medium layer. For example, if the conductive medium layer of the base structure is made of a P-type material, the inner wall of the division groove can be provided only with an insulating medium layer and an N-type material. If the material of the conductive medium layer and the material of the core medium layer are both conductors, all structure layers of the memory need to be deposited layer by layer on the wall of the groove, and the conductive medium layer and the core medium layer are only used as lead wires.

[0091] First implementation: there are three layers of medium in the division groove.

[0092] This implementation includes steps 1 to 6:

[0093] Step 1: a base structure is formed on the substrate and the underlying circuit. A predetermined number of conductive medium layers (made of a material of a low-resistance semiconductor or conductor) and a predetermined number of insulating medium layers are disposed in such a manner that the conductive medium layers and the insulating medium layers are alternately stacked on each other (for example, a deposition process is used), to form the base.

[0094] Step 2: the base structure is grooved: a division groove is etched on the base structure using a mask definition and a deep well etching process, to divide the base structure into two interdigitated structures that are staggered and separated from each other.

[0095] Step 3: a first medium layer 101 is deposited on an inner wall of the division groove using an atomic layer deposition (ALD) process; and then a second medium layer 102 is deposited on a surface of the first medium layer 101 using the ALD process.

[0096] Step 4: a core medium is filled in the cavity of the division groove provided with the first medium layer and the second medium layer to form a core medium layer.

[0097] Step 5: through a mask etching process, deep holes are etched along the division groove filled with the core medium, where the deep holes truncate the core medium and the storage medium in the division groove, to form multiple core medium blocks that are distributed along the long-side direction of the division groove and that are independent of each other, which are referred to as a core medium block sequence, and each core medium block is still connected to the two interdigitated structures through the storage medium layer.

[0098] Step 6: an insulating medium material is filled in the deep hole.

[0099] In this implementation, the storage medium layer includes a first medium layer and a second medium layer, where involved mediums can be combined as shown in Table 1 below. Each combination indicates an embodiment. FIG. 14 is a schematic structure diagram of this implementation.

TABLE-US-00001 TABLE 1 Base structure First Conductive medium Second Core medium layer medium layer medium layer Embodi- P+-type insulating lightly-doped N+-type ment 1 semiconductor medium N-type semiconductor semiconductor or conductor Embodi- N+-type insulating lightly-doped P+-type ment 2 semiconductor medium P-type semiconductor or conductor semiconductor Embodi- P-type insulating lightly-doped N+-type ment 3 Schottky metal medium N-type semiconductor semiconductor or conductor Embodi- N-type insulating lightly-doped P+-type ment 4 Schottky metal medium p-type semiconductor semiconductor or conductor

[0100] A thickness of the insulating medium in the above table is preferably 0.5 nm to 5 nm. The first medium layer and the second medium layer are both storage medium layers.

[0101] In the present disclosure, interdigitated structures including interdigitated strips and common connecting strips are formed, the two interdigitated structures intersect with each other, a plurality of independent memory units isolated by insulators are present between interdigitated strips, and insulators are the insulating medium filled in the division groove. In each layer of the base structure, each memory unit includes two memory cells. As shown in FIG. 14, the memory cell includes a first medium—a second medium—a core medium, and the material of each layer satisfies the requirement of the PN junction or the Schottky structure.

[0102] Second implementation: there are two layers of mediums in the division groove.

[0103] What this implementation differs from the first implementation lies in that the division groove is provided only with two layers of mediums, that is, a first medium and a core medium.

[0104] FIG. 10 is a schematic diagram of a memory manufactured based on the process of this implementation. FIG. 11 is an enlarged schematic diagram of a single memory unit.

[0105] Mediums involved may be combined as shown in Table 2 below. A first medium layer in the table is a storage medium layer. Each combination indicates an embodiment. The structure is shown in FIG. 15.

TABLE-US-00002 TABLE 2 Base structure First Conductive medium Core medium layer layer medium layer Embodi- P-type insulating N-type ment 5 semiconductor medium semiconductor Embodi- N-type insulating P-type ment 6 semiconductor medium semiconductor Embodi- Schottky metal insulating semiconductor ment 7 medium Embodi- semiconductor insulating Schottky metal ment 8 medium Embodi- conductor memory conductor ment 9 medium

[0106] The memory medium is a resistance change memory, a magnetic phase change memory, a phase change memory, or a ferroelectric memory.

[0107] In the present disclosure, the medium layers other than the core medium layer in the division groove of the base structure are collectively referred to as “storage medium layers”, for example, the first medium layer (insulating layer) in Table 1, the second medium layer in Table 1 (buffer layer), and the first medium layer in Table 2. In the present disclosure, the above layers are all referred to as storage medium layers.

[0108] The process steps of the present disclosure are very concise and can be summarized to include:

[0109] (1) grooving the base structure to form the interdigitated structures;

[0110] (2) disposing the storage medium layer on the inner wall of the groove;

[0111] (3) filling the core medium;

[0112] (4) dividing the core medium; and

[0113] (5) filling the insulating medium.

[0114] FIG. 16 of the present disclosure is FIG. 11 of Chinese patent application No. 201910136928.1. As can be seen from the structure, at least the following steps are required:

[0115] (1) grooving abase structure to form interdigitated structures;

[0116] (2) filling an insulating medium in the groove;

[0117] (3) grooving the filled insulating medium for the second time;

[0118] (4) disposing a data storage layer 150 on an inner wall of the groove formed in step 3;

[0119] (5) filling the insulating medium again;

[0120] (6) deep hole etching; and

[0121] (7) disposing electrodes 162 and 165 in the deep hole.

[0122] Obviously, the process of the present disclosure is greatly simplified.